WO2010081549A1

WO2010081549A1 - Navigation device & method

Info

Publication number: WO2010081549A1
Application number: PCT/EP2009/050380
Authority: WO
Inventors: Markus Winkler
Original assignee: TomTom International BV
Current assignee: TomTom International BV
Priority date: 2009-01-14
Filing date: 2009-01-14
Publication date: 2010-07-22
Anticipated expiration: 2011-07-14

Abstract

This invention relates to a navigation device (200) comprising: a processor (210) that is configured to access digital map data and calculate a route (404) to a destination, said route (404) comprising one or more manoeuvres; characterised in that the navigation device (200) further comprises: a store (230) for landmark data (402), which data indicates the position of landmarks in said digital map, a landmark data interrogator (414) that is configured to access said landmark data store (230) to determine whether there is a landmark located in the vicinity of a said manoeuvre, and a navigation instruction generator (416) operable in the event that said landmark data interrogator determines that a said landmark is located in the vicinity of said manoeuvre to generate for that manoeuvre an enhanced navigation instruction that refers to said landmark for provision to a user of said navigation device (200).

Description

NAVIGATION DEVICE & METHOD

Field of the Invention

This invention relates to navigation devices and to methods for generating navigation instructions. Illustrative embodiments of the invention relate to portable navigation devices (so-called PNDs), in particular PNDs that include Global Positioning System (GPS) signal reception and processing functionality. Other embodiments relate, more generally, to any type of processing device that is configured to execute navigation software so as to provide route planning, and preferably also navigation, functionality.

Background to the Invention

Portable navigation devices (PNDs) that include GPS (Global Positioning System) signal reception and processing functionality are well known and are widely employed as in-car or other vehicle navigation systems. In general terms, a modern PNDs comprises a processor, memory (at least one of volatile and non-volatile, and commonly both), and map data stored within said memory. The processor and memory cooperate to provide an execution environment in which a software operating system may be established, and additionally it is commonplace for one or more additional software programs to be provided to enable the functionality of the PND to be controlled, and to provide various other functions.

Typically these devices further comprise one or more input interfaces that allow a user to interact with and control the device, and one or more output interfaces by means of which information may be relayed to the user. Illustrative examples of output interfaces include a visual display and a speaker for audible output. Illustrative examples of input interfaces include one or more physical buttons to control on/off operation or other features of the device (which buttons need not necessarily be on the device itself but could be on a steering wheel if the device is built into a vehicle), and a microphone for detecting user speech. In a particularly preferred arrangement the output interface display may be configured as a touch sensitive display (by means of a touch sensitive overlay or otherwise) to additionally provide an input interface by means of which a user can operate the device by touch.

Devices of this type will also often include one or more physical connector interfaces by means of which power and optionally data signals can be transmitted to and received from the device, and optionally one or more wireless transmitters/receivers to allow communication over cellular telecommunications and other signal and data networks, for example Wi-Fi, Wi-Max GSM and the like. PND devices of this type also include a GPS antenna by means of which satellite-broadcast signals, including location data, can be received and subsequently processed to determine a current location of the device.

The PND device may also include electronic gyroscopes and accelerometers which produce signals that can be processed to determine the current angular and linear acceleration, and in turn, and in conjunction with location information derived from the GPS signal, velocity and relative displacement of the device and thus the vehicle in which it is mounted. Typically such features are most commonly provided in in-vehicle navigation systems, but may also be provided in PND devices if it is expedient to do so. The utility of such PNDs is manifested primarily in their ability to determine a route between a first location (typically a start or current location) and a second location (typically a destination). These locations can be input by a user of the device, by any of a wide variety of different methods, for example by postcode, street name and house number, previously stored "well known" destinations (such as famous locations, municipal locations (such as sports grounds or swimming baths) or other points of interest), and favourite or recently visited destinations.

Typically, the PND is enabled by software for computing a "best" or "optimum" route between the start and destination address locations from the map data. A "best" or "optimum" route is determined on the basis of predetermined criteria and need not necessarily be the fastest or shortest route. The selection of the route along which to guide the driver can be very sophisticated, and the selected route may take into account existing, predicted and dynamically and/or wirelessly received traffic and road information, historical information about road speeds, and the driver's own preferences for the factors determining road choice (for example the driver may specify that the route should not include motorways or toll roads).

In addition, the device may continually monitor road and traffic conditions, and offer to or choose to change the route over which the remainder of the journey is to be made due to changed conditions. Real time traffic monitoring systems, based on various technologies (e.g. mobile phone data exchanges, fixed cameras, GPS fleet tracking) are being used to identify traffic delays and to feed the information into notification systems.

PNDs of this type may typically be mounted on the dashboard or windscreen of a vehicle, but may also be formed as part of an on-board computer of the vehicle radio or indeed as part of the control system of the vehicle itself. The navigation device may also be part of a hand-held system, such as a PDA (Portable Digital Assistant) a media player, a mobile phone or the like, and in these cases, the normal functionality of the hand-held system is extended by means of the installation of software on the device to perform both route calculation and navigation along a calculated route.

Route planning and navigation functionality may also be provided by a desktop or mobile computing resource running appropriate software. For example, the Royal Automobile Club (RAC) provides an on-line route planning and navigation facility at http://www.rac.co.uk, which facility allows a user to enter a start point and a destination whereupon the server to which the user's PC is connected calculates a route (aspects of which may be user specified), generates a map, and generates a set of exhaustive navigation instructions for guiding the user from the selected start point to the selected destination. The facility also provides for pseudo three-dimensional rendering of a calculated route, and route preview functionality which simulates a user travelling along the route and thereby provides the user with a preview of the calculated route.

In the context of a PND, once a route has been calculated, the user interacts with the navigation device to select the desired calculated route, optionally from a list of proposed routes. Optionally, the user may intervene in, or guide the route selection process, for example by specifying that certain routes, roads, locations or criteria are to be avoided or are mandatory for a particular journey. The route calculation aspect of the PND forms one primary function, and navigation along such a route is another primary function.

During navigation along a calculated route, it is usual for such PNDs to provide navigation instructions, for example visual and/or audible instructions, to guide the user along a chosen route to the end of that route, i.e. to the desired destination. It is also usual for PNDs to display map information on-screen during the navigation, such information regularly being updated on-screen so that the map information displayed is representative of the current location of the device, and thus of the user or user's vehicle if the device is being used for in-vehicle navigation.

An icon displayed on-screen typically denotes the current device location, and is centred with the map information of current and surrounding roads in the vicinity of the current device location and other map features also being displayed. Additionally, navigation information may be displayed, optionally in a status bar above, below or to one side of the displayed map information, examples of navigation information include a distance to the next deviation from the current road required to be taken by the user, the nature of that deviation possibly being represented by a further icon suggestive of the particular type of deviation, for example a left or right turn. The navigation function also determines the content, duration and timing of audible instructions by means of which the user can be guided along the route. As can be appreciated a simple instruction such as "turn left in 100 m" requires significant processing and analysis. As previously mentioned, user interaction with the device may be by a touch screen, or additionally or alternately by steering column mounted remote control, by voice activation or by any other suitable method.

A further important function provided by the device is automatic route re- calculation in the event that: a user deviates from the previously calculated route during navigation (either by accident or intentionally); real-time traffic conditions dictate that an alternative route would be more expedient and the device is suitably enabled to recognize such conditions automatically, or if a user actively causes the device to perform route re-calculation for any reason. It is also known to allow a route to be calculated with user defined criteria; for example, the user may prefer a scenic route to be calculated by the device, or may wish to avoid any roads on which traffic congestion is likely, expected or currently prevailing. The device software would then calculate various routes and weigh more favourably those that include along their route the highest number of points of interest (commonly known as POI) tagged as being for example of scenic beauty, or, using stored information indicative of prevailing traffic conditions on particular roads, order the calculated routes in terms of a level of likely congestion or delay on account thereof.

Other POI-based and traffic information-based route calculation and navigation criteria are also possible. For example, it has previously been proposed to provide location information regarding many other types of POI (such as airports, petrol stations, vehicle dealerships, railway stations, places of worship (e.g. Church's) automatic teller machines and such like) and to provide the user with the option to selectively display some or all of these POI on the digital map, and optionally to notify the user when they pass close to a given POI or indeed to direct the user, for example from a current location, to a selected POI.

Although the route calculation and navigation functions are fundamental to the overall utility of PNDs, it is possible to use the device purely for information display, or "free-driving", in which only map information relevant to the current device location is displayed, and in which no route has been calculated and no navigation is currently being performed by the device. Such a mode of operation is often applicable when the user already knows the route along which it is desired to travel and does not require navigation assistance.

Devices of the type described above, for example the 720T model manufactured and supplied by TomTom International B. V., provide a reliable means for enabling users to navigate from one position to another.

As will be appreciated, such devices are of particular utility when the user is not familiar with the route to the destination that they are navigating to. However, whilst such devices are typically very useful in such circumstances, the user's unfamiliarity with the destination and calculated route to that destination can complicate the navigation process. In particular, the user's unfamiliarity with the route can cause uncertainties which inconvenience and stress the user of the device.

For example, as aforementioned it has previously been proposed to provide users with audible navigation instructions of the type "turn left in 200 metres", and in circumstances where there are a number of left turns ahead of the user it can be difficult for a user to judge whether it is the first, second or third left turning that is 200 metres ahead of their current position, and which they should take to continue along the calculated route. This problem is further exacerbated by the fact that there is typically a margin of error associated with navigation systems, and as such even those users who are good at judging distances can find it difficult to immediately appreciate which of the various turns available they should take to remain on the calculated route. In an attempt to address this problem it has previously been proposed to generate more detailed navigation instructions for provision to the user. For example, it has previously been proposed to indicate the name of the street into which the user should turn to remain on the calculated route, e.g. "turn left in 200 metres into Station Road". Whilst this is indeed an improvement on a simple turn instruction, it is often the case that street names are missing or not readily visible. As such a user may not be able to determine whether the street they are approaching is indeed the street that they should be turning into, or at best are only able to confirm that it is indeed the street that they should be turning into when they are very close to the street in question and about to make a manoeuvre.

As will be appreciated, in such circumstances the user is left feeling confused about which street they should take to continue on the route, and this confusion can cause the user to be distracted from the task at hand. When the user concerned is driving a vehicle, such distractions can be dangerous and it would clearly be advantageous if such distractions could be avoided by providing the user with navigation instructions that can more readily be followed.

One aim of the present invention is to address such problems, in particular by providing a user of a navigation device with navigation instructions that can more readily be followed. Summary of the Invention

In pursuit of this aim, a presently preferred embodiment of the present invention provides a navigation device comprising: a processor that is configured to access digital map data and calculate a route to a destination, said route comprising one or more manoeuvres; characterised in that the navigation device further comprises: a store for landmark data, which data indicates the position of landmarks in said digital map, a landmark data interrogator that is configured to access said landmark data store to determine whether there is a landmark located in the vicinity of a said manoeuvre, and a navigation instruction generator operable in the event that said landmark data interrogator determines that a said landmark is located in the vicinity of said manoeuvre to generate for that manoeuvre an enhanced navigation instruction that refers to said landmark for provision to a user of said navigation device.

Another embodiment of the present invention relates to a method of navigation, comprising the steps of: accessing digital map data and calculating a route to a destination, said route comprising one or more manoeuvres; accessing a store for landmark data, which data indicates the position of landmarks in said digital map, to determine whether there is a landmark located in the vicinity of a said manoeuvre, and in the event that a said landmark is determined to be located in the vicinity of said manoeuvre, generating for that manoeuvre an enhanced navigation instruction that refers to said landmark for provision to a user of a navigation device.

Yet another embodiment of the invention relates to computer software comprising one or more software modules operable, when executed in an execution environment, to cause a processor to: access digital map data and calculate a route to a destination, said route comprising one or more manoeuvres; access a store for landmark data, which data indicates the position of landmarks in said digital map, and to determine whether there is a landmark located in the vicinity of a said manoeuvre, and in the event that a said landmark is determined to be located in the vicinity of said manoeuvre, to generate for that manoeuvre an enhanced navigation instruction that refers to said landmark for provision to a user of a navigation device.

A further embodiment of the present invention relates to a format for representing a digital map, the digital map including: (a) a road information component representing at least a position of a road in the map; and (b) a landmark information component representing, for the map, a position of a landmark in the map; wherein said landmark information component is interpretable by a processor of a navigation device to generate an enhanced navigation instruction that refers to said landmark for association with a computed manoeuvre. Advantages of these embodiments are set out hereafter, and further details and features of each of these embodiments are defined in the accompanying dependent claims and elsewhere in the following detailed description.

Brief Description of the Drawings

Various aspects of the teachings of the present invention, and arrangements embodying those teachings, will hereafter be described by way of illustrative example with reference to the accompanying drawings, in which:

Fig. 1 is a schematic illustration of a Global Positioning System (GPS); Fig. 2 is a schematic illustration of electronic components arranged to provide a navigation device; Fig. 3 is a schematic illustration of the manner in which a navigation device may receive information over a wireless communication channel;

Figs. 4A and 4B are illustrative perspective views of a navigation device; Fig. 5 is an illustrative representation of a navigation device memory module; Figs. 6a to 6d are Venn diagrams illustrating possible relationships between landmark data and POI data;

Fig. 7 is a diagrammatic representation of part of a calculated route; Fig. 8 is a schematic representation of the software employed by the navigation device;

Fig. 9 is an illustrative flow diagram depicting the steps of one method by which the teachings of the present invention may be implemented;

Fig. 10 is an illustrative flow diagram depicting the steps of another method by which the teachings of the present invention may be implemented; and

Fig. 1 1 is an illustrative flow diagram depicting the steps of yet another method by which the teachings of the present invention may be implemented.

Detailed Description of Preferred Embodiments

Preferred embodiments of the present invention will now be described with particular reference to a PND. It should be remembered, however, that the teachings of the present invention are not limited to PNDs but are instead universally applicable to any type of processing device that is configured to execute navigation software so as to provide route planning and navigation functionality. It follows therefore that in the context of the present application, a navigation device is intended to include (without limitation) any type of route planning and navigation device, irrespective of whether that device is embodied as a PND, a navigation device built into a vehicle, or indeed a computing resource (such as a desktop or portable personal computer (PC), mobile telephone or portable digital assistant (PDA)) executing route planning and navigation software.

With the above proviso in mind, Fig. 1 illustrates an example view of Global Positioning System (GPS), usable by navigation devices. Such systems are known and are used for a variety of purposes. In general, GPS is a satellite-radio based navigation system capable of determining continuous position, velocity, time, and in some instances direction information for an unlimited number of users. Formerly known as NAVSTAR, the GPS incorporates a plurality of satellites which orbit the earth in extremely precise orbits. Based on these precise orbits, GPS satellites can relay their location to any number of receiving units. The GPS system is implemented when a device, specially equipped to receive

GPS data, begins scanning radio frequencies for GPS satellite signals. Upon receiving a radio signal from a GPS satellite, the device determines the precise location of that satellite via one of a plurality of different conventional methods. The device will continue scanning, in most instances, for signals until it has acquired at least three different satellite signals (noting that position is not normally, but can be determined, with only two signals using other triangulation techniques). Implementing geometric triangulation, the receiver utilizes the three known positions to determine its own two-dimensional position relative to the satellites. This can be done in a known manner. Additionally, acquiring a fourth satellite signal will allow the receiving device to calculate its three dimensional position by the same geometrical calculation in a known manner. The position and velocity data can be updated in real time on a continuous basis by an unlimited number of users.

As shown in Figure 1 , the GPS system is denoted generally by reference numeral 100. A plurality of satellites 120 are in orbit about the earth 124. The orbit of each satellite 120 is not necessarily synchronous with the orbits of other satellites 120 and, in fact, is likely asynchronous. A GPS receiver 140 is shown receiving spread spectrum GPS satellite signals 160 from the various satellites 120.

The spread spectrum signals 160, continuously transmitted from each satellite 120, utilize a highly accurate frequency standard accomplished with an extremely accurate atomic clock. Each satellite 120, as part of its data signal transmission 160, transmits a data stream indicative of that particular satellite 120. It is appreciated by those skilled in the relevant art that the GPS receiver device 140 generally acquires spread spectrum GPS satellite signals 160 from at least three satellites 120 for the GPS receiver device 140 to calculate its two-dimensional position by triangulation. Acquisition of an additional signal, resulting in signals 160 from a total of four satellites 120, permits the GPS receiver device 140 to calculate its three-dimensional position in a known manner.

Figure 2 is an illustrative representation of electronic components of a navigation device 200 according to a preferred embodiment of the present invention, in block component format. It should be noted that the block diagram of the navigation device 200 is not inclusive of all components of the navigation device, but is only representative of many example components.

The navigation device 200 is located within a housing (not shown). The housing includes a processor 210 connected to an input device 220 and a display screen 240. The input device 220 can include a keyboard device, voice input device, touch panel and/or any other known input device utilised to input information; and the display screen 240 can include any type of display screen such as an LCD display, for example. In a particularly preferred arrangement the input device 220 and display screen 240 are integrated into an integrated input and display device, including a touchpad or touchscreen input so that a user need only touch a portion of the display screen 240 to select one of a plurality of display choices or to activate one of a plurality of virtual buttons.

The navigation device may include an output device 260, for example an audible output device (e.g. a loudspeaker). As output device 260 can produce audible information for a user of the navigation device 200, it is should equally be understood that input device 240 can include a microphone and software for receiving input voice commands as well.

In the navigation device 200, processor 210 is operatively connected to and set to receive input information from input device 220 via a connection 225, and operatively connected to at least one of display screen 240 and output device 260, via output connections 245, to output information thereto. Further, the processor 210 is operably coupled to a memory resource 230 via connection 235 and is further adapted to receive/send information from/to input/output (I/O) ports 270 via connection 275, wherein the I/O port 270 is connectible to an I/O device 280 external to the navigation device 200. The memory resource 230 comprises, for example, a volatile memory, such as a Random Access Memory (RAM) and a non-volatile memory, for example a digital memory, such as a flash memory. The external I/O device 280 may include, but is not limited to an external listening device such as an earpiece for example. The connection to I/O device 280 can further be a wired or wireless connection to any other external device such as a car stereo unit for hands-free operation and/or for voice activated operation for example, for connection to an ear piece or head phones, and/or for connection to a mobile phone for example, wherein the mobile phone connection may be used to establish a data connection between the navigation device 200 and the internet or any other network for example, and/or to establish a connection to a server via the internet or some other network for example.

Fig. 2 further illustrates an operative connection between the processor 210 and an antenna/receiver 250 via connection 255, wherein the antenna/receiver 250 can be a GPS antenna/receiver for example. It will be understood that the antenna and receiver designated by reference numeral 250 are combined schematically for illustration, but that the antenna and receiver may be separately located components, and that the antenna may be a GPS patch antenna or helical antenna for example. Further, it will be understood by one of ordinary skill in the art that the electronic components shown in Fig. 2 are powered by power sources (not shown) in a conventional manner. As will be understood by one of ordinary skill in the art, different configurations of the components shown in Fig. 2 are considered to be within the scope of the present application. For example, the components shown in Fig. 2 may be in communication with one another via wired and/or wireless connections and the like. Thus, the scope of the navigation device 200 of the present application includes a portable or handheld navigation device 200.

In addition, the portable or handheld navigation device 200 of Fig. 2 can be connected or "docked" in a known manner to a vehicle such as a bicycle, a motorbike, a car or a boat for example. Such a navigation device 200 is then removable from the docked location for portable or handheld navigation use.

Referring now to Fig. 3, the navigation device 200 may establish a "mobile" or telecommunications network connection with a server 302 via a mobile device (not shown) (such as a mobile phone, PDA, and/or any device with mobile phone technology) establishing a digital connection (such as a digital connection via known Bluetooth technology for example). Thereafter, through its network service provider, the mobile device can establish a network connection (through the internet for example) with a server 302. As such, a "mobile" network connection is established between the navigation device 200 (which can be, and often times is mobile as it travels alone and/or in a vehicle) and the server 302 to provide a "real-time" or at least very "up to date" gateway for information.

The establishing of the network connection between the mobile device (via a service provider) and another device such as the server 302, using an internet (such as the World Wide Web) for example, can be done in a known manner. This can include use of TCP/IP layered protocol for example. The mobile device can utilize any number of communication standards such as CDMA, GSM, WAN, etc. As such, an internet connection may be utilised which is achieved via data connection, via a mobile phone or mobile phone technology within the navigation device 200 for example. For this connection, an internet connection between the server 302 and the navigation device 200 is established. This can be done, for example, through a mobile phone or other mobile device and a GPRS (General Packet Radio Service)- connection (GPRS connection is a high-speed data connection for mobile devices provided by telecom operators; GPRS is a method to connect to the internet).

The navigation device 200 can further complete a data connection with the mobile device, and eventually with the internet and server 302, via existing Bluetooth technology for example, in a known manner, wherein the data protocol can utilize any number of standards, such as the GSRM, the Data Protocol Standard for the GSM standard, for example.

The navigation device 200 may include its own mobile phone technology within the navigation device 200 itself (including an antenna for example, or optionally using the internal antenna of the navigation device 200). The mobile phone technology within the navigation device 200 can include internal components as specified above, and/or can include an insertable card (e.g. Subscriber Identity Module or SIM card), complete with necessary mobile phone technology and/or an antenna for example. As such, mobile phone technology within the navigation device 200 can similarly establish a network connection between the navigation device 200 and the server 302, via the internet for example, in a manner similar to that of any mobile device.

For GRPS phone settings, a Bluetooth enabled navigation device may be used to correctly work with the ever changing spectrum of mobile phone models, manufacturers, etc., model/manufacturer specific settings may be stored on the navigation device 200 for example. The data stored for this information can be updated.

In Fig. 3 the navigation device 200 is depicted as being in communication with the server 302 via a generic communications channel 318 that can be implemented by any of a number of different arrangements. The server 302 and a navigation device 200 can communicate when a connection via communications channel 318 is established between the server 302 and the navigation device 200 (noting that such a connection can be a data connection via mobile device, a direct connection via personal computer via the internet, etc.).

The server 302 includes, in addition to other components which may not be illustrated, a processor 304 operatively connected to a memory 306 and further operatively connected, via a wired or wireless connection 314, to a mass data storage device 312. The processor 304 is further operatively connected to transmitter 308 and receiver 310, to transmit and send information to and from navigation device 200 via communications channel 318. The signals sent and received may include data, communication, and/or other propagated signals. The transmitter 308 and receiver 310 may be selected or designed according to the communications requirement and communication technology used in the communication design for the navigation system 200. Further, it should be noted that the functions of transmitter 308 and receiver 310 may be combined into a signal transceiver.

Server 302 is further connected to (or includes) a mass storage device 312, noting that the mass storage device 312 may be coupled to the server 302 via communication link 314. The mass storage device 312 contains a store of navigation data and map information, and can again be a separate device from the server 302 or can be incorporated into the server 302.

The navigation device 200 is adapted to communicate with the server 302 through communications channel 318, and includes processor, memory, etc. as previously described with regard to Fig. 2, as well as transmitter 320 and receiver 322 to send and receive signals and/or data through the communications channel 318, noting that these devices can further be used to communicate with devices other than server 302. Further, the transmitter 320 and receiver 322 are selected or designed according to communication requirements and communication technology used in the communication design for the navigation device 200 and the functions of the transmitter 320 and receiver 322 may be combined into a single transceiver.

Software stored in server memory 306 provides instructions for the processor 304 and allows the server 302 to provide services to the navigation device 200. One service provided by the server 302 involves processing requests from the navigation device 200 and transmitting navigation data from the mass data storage 312 to the navigation device 200. Another service provided by the server 302 includes processing the navigation data using various algorithms for a desired application and sending the results of these calculations to the navigation device 200.

The communication channel 318 generically represents the propagating medium or path that connects the navigation device 200 and the server 302. Both the server 302 and navigation device 200 include a transmitter for transmitting data through the communication channel and a receiver for receiving data that has been transmitted through the communication channel.

The communication channel 318 is not limited to a particular communication technology. Additionally, the communication channel 318 is not limited to a single communication technology; that is, the channel 318 may include several communication links that use a variety of technology. For example, the communication channel 318 can be adapted to provide a path for electrical, optical, and/or electromagnetic communications, etc. As such, the communication channel 318 includes, but is not limited to, one or a combination of the following: electric circuits, electrical conductors such as wires and coaxial cables, fibre optic cables, converters, radio-frequency (RF) waves, the atmosphere, empty space, etc. Furthermore, the communication channel 318 can include intermediate devices such as routers, repeaters, buffers, transmitters, and receivers, for example.

In one illustrative arrangement, the communication channel 318 includes telephone and computer networks. Furthermore, the communication channel 318 may be capable of accommodating wireless communication such as radio frequency, microwave frequency, infrared communication, etc. Additionally, the communication channel 318 can accommodate satellite communication.

The communication signals transmitted through the communication channel 318 include, but are not limited to, signals as may be required or desired for given communication technology. For example, the signals may be adapted to be used in cellular communication technology such as Time Division Multiple Access (TDMA), Frequency Division Multiple Access (FDMA), Code Division Multiple Access (CDMA), Global System for Mobile Communications (GSM), etc. Both digital and analogue signals can be transmitted through the communication channel 318. These signals may be modulated, encrypted and/or compressed signals as may be desirable for the communication technology.

The server 302 includes a remote server accessible by the navigation device 200 via a wireless channel. The server 302 may include a network server located on a local area network (LAN), wide area network (WAN), virtual private network (VPN), etc.

The server 302 may include a personal computer such as a desktop or laptop computer, and the communication channel 318 may be a cable connected between the personal computer and the navigation device 200. Alternatively, a personal computer may be connected between the navigation device 200 and the server 302 to establish an internet connection between the server 302 and the navigation device 200. Alternatively, a mobile telephone or other handheld device may establish a wireless connection to the internet, for connecting the navigation device 200 to the server 302 via the internet.

The navigation device 200 may be provided with information from the server 302 via information downloads which may be periodically updated automatically or upon a user connecting navigation device 200 to the server 302 and/or may be more dynamic upon a more constant or frequent connection being made between the server 302 and navigation device 200 via a wireless mobile connection device and TCP/IP connection for example. For many dynamic calculations, the processor 304 in the server 302 may be used to handle the bulk of the processing needs, however, processor 210 of navigation device 200 can also handle much processing and calculation, oftentimes independent of a connection to a server 302.

As indicated above in Fig. 2, a navigation device 200 includes a processor 210, an input device 220, and a display screen 240. The input device 220 and display screen 240 are integrated into an integrated input and display device to enable both input of information (via direct input, menu selection, etc.) and display of information through a touch panel screen, for example. Such a screen may be a touch input LCD screen, for example, as is well known to those of ordinary skill in the art. Further, the navigation device 200 can also include any additional input device 220 and/or any additional output device 241 , such as audio input/output devices for example. Figs 4A and 4B are perspective views of a navigation device 200. As shown in

Fig. 4A, the navigation device 200 may be a unit that includes an integrated input and display device 290 (a touch panel screen for example) and the other components of fig. 2 (including but not limited to internal GPS receiver 250, microprocessor 210, a power supply, memory systems 230, etc.). The navigation device 200 may sit on an arm 292, which itself may be secured to a vehicle dashboard/window/etc, using a suction cup 294. This arm 292 is one example of a docking station to which the navigation device 200 can be docked.

As shown in Fig. 4B, the navigation device 200 can be docked or otherwise connected to an arm 292 of the docking station by snap connecting the navigation device 292 to the arm 292 for example. The navigation device 200 may then be rotatable on the arm 292, as shown by the arrow of Fig. 4B. To release the connection between the navigation device 200 and the docking station, a button on the navigation device 200 may be pressed, for example. Other equally suitable arrangements for coupling and decoupling the navigation device to a docking station are well known to persons of ordinary skill in the art.

Referring now to Fig. 5, as aforementioned the memory resource 230 of the navigation device is configured to store map data 400 that defines a digital map of a region, and the processor 210 is capable of referring to that stored map data to calculate routes and to generate views of, for example, the local environment in which the navigation device is currently located for display on the display screen 240.

In accordance with a preferred embodiment of the present invention the memory resource 230 also includes landmark data 402, that is to say information concerning features that may more easily be noticed by a user of a navigation device than a street sign bearing the name of a road. Such landmarks may comprise, for example, prominent buildings (for example, churches, railway stations or branded restaurants), geographical features (e.g. bridges, rivers, viaducts, railway crossings etc), prominent trees, monuments or more generally any prominent or conspicuous feature that can more easily be noticed by a user of a navigation device than a street sign.

The landmark data may, as shown in Fig. 5, be held separately from the digital map data, for example in a dedicated data store. In another envisaged implementation, the landmark data may comprise part of the digital map data. In either case the landmark information stored for a given landmark includes the geographical location (for example the latitude and longitude) of that landmark as well as an indication of the identity of that landmark (for example, the particular type of a building (e.g. whether it is a church or a railway station), a branded restaurant (e.g. a McDonalds™ restaurant), a river, or a bridge). In a particularly preferred arrangement, landmarks may be categorised (in a similar way in which POI are currently categorised) to facilitate the determination of the identity of a given landmark.

As aforementioned, it has previously been proposed to provide navigation devices with information concerning points of interest (POI) which comprise notable locations that may be of interest to a user of the device. Such POI are typically grouped into categories and a user is typically provided with the ability to select which POI categories are to be displayed in representations of the digital map displayed on the display device 240 of the navigation device 200.

If POI data is provided it is typical for there to be a number of predefined POI categories that each include a number of discrete POI. A user may also be provided with the ability to create POI categories, and to add POI to any created category, and optionally to a predefined POI category.

The POI information maintained in the memory resource 230 may comprise part of the digital map data, or in another arrangement the POI information may be held separately from the digital map data, for example in a dedicated POI data store. In either case the POI information stored for a given POI includes the geographical location (for example the latitude and longitude) of that POI as well as an indication of the POI category that that POI belongs to. Other information associated with POI (such as address information, a telephone number, an image or opening times) may also be stored.

Referring now to Figs. 6a to 6d, there are shown a number of Venn diagrams which schematically illustrate the relationship (if any) between the POI and landmark data sets.

In one embodiment of the present invention shown schematically in Fig. 6a the navigation device may include discrete data sets of POI data and landmark data. In this embodiment the landmark data set does not include any features which are POI.

In another embodiment shown in Fig. 6b, the landmark and POI data sets include data relating to some features that are common to both data sets (i.e. features, for example a building such as a church, that is both a POI and a landmark (for example because it has a conspicuous steeple)). In another embodiment shown in Fig. 6c the landmark data set includes all of the POI data set, and in another embodiment shown schematically in Fig. 6d the POI data set includes all of the landmark data set.

As will be apparent from the following, it is not essential for the navigation device of the present invention to include any POI data. However, if such data is provided then it is likely that the POI and landmark data will have a relationship such as that depicted in Figs. 6b or 6d of the accompanying drawings. Furthermore, as it is typical to provide a relatively large number of POI categories it is likely that the number of features in the POI data set will be much larger than the number of features in the landmark data set.

Data in the POI and/or landmark data sets may be arranged in any of a number of suitable ways, but in one preferred implementation POI data relating to a feature that is also a landmark may include a data category that, if populated, indicates to the processor of the navigation device 200 that that POI is also a landmark.

In another envisaged implementation, the navigation device 200 may include a pre-defined list of POI that are usually relatively easily noticed in an urban environment. In one illustrative example, the list may comprise a subset of the POI categories included in the device, and could include - for example - petrol stations, supermarkets, branded restaurants, branded hotels, vehicle dealerships, vehicle rental facilities, cinemas, concert halls, convention centres, hospitals, pharmacies, churches, police/fire/ambulance stations, post offices, and railway stations.

In another envisaged arrangement, a user wishing to store a POI in their device may be provided with the ability to indicate whether that POI is also a landmark, and to enter an identifier for that landmark (for example by selecting a category to which that landmark belongs).

Other functionally equivalent arrangements will be immediately apparent to persons of ordinary skill in the art. Referring now to Fig. 7 of the accompanying drawings, in very general terms one aspect of the present invention embodies the appreciation that navigation instructions for provision to a user of a navigation device may be significantly enhanced by determining, for any given manoeuvre, whether there is a landmark in the vicinity of that manoeuvre and if that determination is positive, enhancing the navigation instruction by making reference to the landmark concerned. The principal reason for this is that the user of the device should hopefully be more easily able to identify the landmark than a street name, for example.

Referring to Fig. 7, a user of a prior art navigation device following a calculated route 404 that includes a right turn from "Main Street" into "Church Street" would typically be provided at some point (say 100m) in advance of the manoeuvre location with the navigation instruction "turn right in 100m" or "turn right in 100m into Church Street", and in either case it would be left to the user to determine when their vehicle has travelled 100m and make the necessary turn, perhaps whilst trying to determine whether the street they are turning into is in fact "Church Street" (it being remembered of course that the street sign displaying the name "Church Street" will most probably not be visible until the user is at or very near to the junction of Main Street and Church Street).

In accordance with a preferred embodiment of the present invention, the processor 210 of the navigation device 200 is configured at some point before the manoeuvre to interrogate the landmark data 402 to determine whether there are any landmarks in the vicinity of the manoeuvre. If that determination is positive the processor 210 then constructs or retrieves an enhanced navigation instruction which refers to the landmark type for the landmark that is determined to be in the vicinity of the manoeuvre. In this particular example, as a church is adjacent the right hand turn into Church Street, the processor 210 constructs a navigation instruction that comprises an audible (and/or textual message) message which instructs the user to "turn right after the Church into Church Street".

In this way, the user is instructed to look for a landmark that can more readily be seen than, for example, a road sign bearing the street name "Church Street". As such the user can more confidently, and at an earlier point in time, identify the turn that they need to take to keep travelling along the computed route. In a particularly preferred embodiment of the invention the display is configured to provide the user with an icon (in this instance a church shaped icon) that indicates that a landmark is in the vicinity of the manoeuvre and, in this instance, also indicates the landmark type.

In the event that the processor 210 should determine that there are multiple landmarks between the current location of the vehicle and the manoeuvre, then the processor may - in a particularly preferred embodiment - be configured to select the landmark closest to the manoeuvre in question.

Enhanced navigation instructions of the type aforementioned may be generated using any of a number of previously proposed techniques. For example, in the context of an audible instruction the enhanced navigation instruction may be constructed by assembling a number of pre-recorded audible instruction components to provide the desired navigation instruction for relay to the user. For example, the aforementioned navigation instruction "turn right after the Church into Church Street" could be constructed by conjoining a pre-recorded manoeuvre instruction "turn right", a prerecorded landmark position indicator "after" that refers to the position of the manoeuvre with respect to the landmark, a pre-recorded landmark identity indicator "the Church" (which may comprise a landmark category in which this particular landmark has been grouped), a pre-recorded preposition "into" selected with reference to the type of manoeuvre, and a pre-recorded street name component "Church Street". In another arrangement, the enhanced navigation instruction could be generated, again in a known manner, using synthesised speech.

Referring now to Fig. 8 of the accompanying drawings, the memory resource 230 (as well as storing the digital map, landmark data, and optionally POI data) stores a boot loader program (not shown) that is executed by the processor 210 in order to load an operating system 418 from the memory resource 230 for execution by functional hardware components 420, and which provides an environment in which application software 422 can run. The operating system 418 serves to control the functional hardware components 420 and resides between the application software 422 and the functional hardware components 420. The operating system 418 may provide universal services for the application software, for example, including maintaining current time and date information. The application software 422 provides an operational environment implementing core functions of the navigation device 200, for example map viewing, route planning, navigation functions and any other functions associated therewith.

The application software 422 may include one or more software modules as described below. Although the modules are represented separately, it will be appreciated that this is merely for the sake of explanation. Functionality may overlap between modules, and/or one module may comprise another, and/or more modules may be provided. The modules may include one or more of: a graphical user interface (GUI) module 406 that supports other modules by providing a unified input/output interface, and provides an image renderer for map views; a positioning system (e.g. GPS) module 408 for implementing real-time position determination to generate current position information, optionally interfacing with external positioning system hardware as hereinbefore described; a route planning module 410, responsive to information contained in a digital map 400 and to information input by a user of the navigation device 200, for calculating a navigation route from a start location to a destination location. As aforementioned, the digital map 400 is stored by the memory resource 230. a navigation module 412, responsive to (i) the current position information from the positioning system module 408, (ii) the digital map 400, and (iii) the calculated route from the route planning module 410; for implementing real-time navigation guidance for guiding a vehicle driver to navigate along the calculated route. a landmark data interrogator module 414 responsive to (i) the current position information from the positioning system module 408, and (ii) the calculated route from the route planning module 410; to interrogate the landmark data 402 for landmarks proximate manoeuvres that the user is required to make to continue along the calculated route; and a navigation instruction generation module 416 responsive to (i) the calculated from the route planning module 410, and (ii) the landmark data interrogator module 414 to generate - in the event that a landmark is determined to be proximate a given manoeuvre - an enhanced navigation instruction of the type hereinbefore described that refers to the landmark and - in the event that no landmark is determined to be proximate a given manoeuvre - to generate a standard navigation instruction, for example of the type previously proposed.

Referring now to Fig. 9, there is depicted an illustrative flow diagram indicating the steps of one method by which the teachings of the present invention may be implemented.

In a first step 424 of the method, a user interacts (in a conventional manner) with the navigation device 200 to input a destination location, and optionally a start location.

In the absence of an inputted start location the navigation device is configured to assume that any navigation route to be calculated starts at the position in which the device is currently located.

Once the user has specified the location of the destination that they wish to be guided to, the device computes in step 426 a route from the start point to the inputted destination. The device then commences the guidance process in step 428 and provides the user with a graphical representation of their local environment together with navigation instructions to enable the use to follow the route computed in step 426.

In the course of this process, the device (in particular the processor 210) determines its current position in step 430 (for example via GPS) and subsequently determines in step 432 whether its current position matches that of the destination input in step 424, and if this determination is positive the guidance process ceases in step

434.

If the destination has yet to be reached, the device determines in step 436 whether its current position (determined in step 430) indicates that the device is still travelling along the route computed in step 426. If the device determines that it (and by inference the vehicle in which it is travelling) has strayed from the computed route, the route to the destination is recalculated in step 438 and processing reverts to step 430.

If the device is determined in step 436 to be on route, it is then determined in step 440 whether the device is approaching a manoeuvre that must be taken for the device to remain on the route. In a particularly preferred arrangement this determination may be accomplished as a function of the speed at which the device is moving so that at higher speeds a manoeuvre that is relatively far away from the device's current position (as determined in step 430) will still be deemed to be an approaching manoeuvre, whereas at a lower speed that manoeuvre would not yet be deemed to be an approaching manoeuvre. In a simpler implementation the device may be configured to determine whether the calculated route includes any manoeuvres within X metres, for example 500 metres, of the device's current position. If the device should determine that several manoeuvres are present, then it may be configured to select the manoeuvre that is closest to the device's current position. If the device determines that no manoeuvres are approaching, processing reverts to step 430 aforementioned. If, on the other hand, the device determines that a manoeuvre is approaching it interrogates, in step 442, the landmark data 402 held in memory 230 to determine in step 444 whether a landmark is located in close proximity to the approaching manoeuvre. In one envisaged implementation a landmark may be deemed to be in close proximity to an approaching manoeuvre if it is within a predetermined distance, for example up to 50 metres (preferably up to 30 metres), of the manoeuvre in question. In another envisaged implementation, a landmark is deemed to be in close proximity to an approaching manoeuvre if it is located between the manoeuvre in question and the next closest similar manoeuvre to the vehicle, or if there is no similar manoeuvre closer to the vehicle if it is between the vehicle's current position and the manoeuvre in question. In another envisaged implementation of particular utility in the event that multiple landmarks are detected, the landmark data may include an indicator of the prominence of each landmark and the processor may, in the event that several landmarks are present in the vicinity of the manoeuvre, be configured to select the most prominent landmark of that group of landmarks for generation of an enhanced navigation instruction.

If the landmark data 402 indicates that no landmarks are in the vicinity of the approaching manoeuvre, processing continues to step 446 and a conventional navigation instruction (for example of the type "turn right in 100 metres" or "turn right in 100 metres into Church Street") is generated. The navigation instruction is issued to the user of the navigation device in step 448 for example by means of an audible or textual instruction, and processing reverts to step 430 aforementioned.

If the landmark data 402 indicates that a landmark is in the vicinity of the approaching manoeuvre, processing continues to step 450 and an enhanced navigation instruction is generated for issue to the user in step 448, before processing reverts to step 430.

In a preferred embodiment, landmarks in the vicinity of the upcoming manoeuvre are located by comparing stored position information (e.g. stored latitude/longitude data) for a given landmark with position information (e.g. latitude/longitude) for the upcoming manoeuvre. In a preferred implementation once the presence of a suitable landmark has been confirmed, the type of the landmark (e.g. the landmark category) is retrieved from the landmark data and an appropriate navigation instruction is generated which advises the user of the presence and type of the approaching landmark.

In another envisaged implementation of particular utility in the event that multiple landmarks are detected, the landmark data may include an indicator of the prominence of each landmark and the processor may, in the event that several landmarks are present in the vicinity of the manoeuvre, be configured to select the most prominent landmark of that group of landmarks for generation of an enhanced navigation instruction. Fig. 10 is an illustrative flow diagram depicting the steps of a modification of the method described above in connection with Fig. 9. The method depicted in Fig. 10 is similar to that depicted in Fig. 9, and in fact the only difference between these methods is that in the arrangement shown in Fig. 10 the processor is configured, once it has determined in step 444 that there is a landmark in the vicinity of the manoeuvre, to enquire of the user in step 452 whether the landmark in question is actually visible.

For example, in the navigation scenario described above the processor may be configured, once it has determined that there is - in this instance - a Church in the vicinity of the manoeuvre, to relay a message of the type "Can you see the Church on the right?" to the user of the device. For example, the message may be displayed on the display screen of the navigation device, and/or relayed to the user audibly. The user is provided with the opportunity to respond "yes" or "no", either by touching an appropriate virtual button on the touch sensitive screen or by vocalising the appropriate response, and the processor is configured to generate an enhanced navigation instruction in step 450 only if the user can in fact see the landmark in question. If the user cannot see the landmark in question (for example because the landmark is obscured (for example because a large vehicle is parked outside, or because seasonal growth of foliage has temporarily obscured the landmark)) or if no response is forthcoming within a predetermined period of time, processing continues to step 446 and a conventional navigation instruction is generated.

This arrangement has been devised to address the fact that issuing instructions which refer to a landmark that cannot be seen could cause confusion, and hence hinder the navigation process. By checking whether the landmark in question can in fact be seen by the user, these problems can be mitigated.

In one envisaged implementation the processor may be configured to log in an appropriate data store when a user indicates that a given landmark is not visible for a later determination as to whether this particular landmark should continue to be used for navigation purposes. In one arrangement PND users could invoke functionality similar to that of TomTom's known MapShare™ software to upload data concerning landmarks to an operator of the navigation system. This data could then be verified by the navigation system operator and if appropriate a decision could be taken to permanently or temporarily (for example if the landmark is obscured because of seasonal vegetation growth) remove the landmark in question from the landmark data. In another envisaged arrangement, data could be passed unverified to other navigation device users.

Referring now to Fig. 1 1 there is depicted another modification of the methods herein disclosed, in particular to the method described above in connection with Fig. 9. As will be appreciate, in that method navigation instructions are generated "on the fly" as a user travels along a generated route, and whilst this is the preferred arrangement it is not the only way that the teachings of the present invention might be implemented.

In another envisaged arrangement of particular utility in circumstances where the computing power of the device operating the navigation software is more limited (for example if the navigation device comprises a mobile telephone executing navigation software) it is possible to pre-generate at a server of the navigation system navigation instructions for all or part of a route and then download those instructions to the navigation device before the user embarks on the route (typically for routes with a lower number of navigation instructions), or piecemeal as the user progresses along the calculated route (for routes with a larger number of navigation instructions). Transmission of navigation instructions may be accomplished via a wired connection to the server or wirelessly, for example via the mobile telephone air interface.

Referring to Fig. 1 1 , in step 454 a user accesses a navigation website, for example, and inputs details of the journey they wish to undertake. In circumstances where the user has pre-stored their home location, they may only need to input details of the destination to which they wish to travel. In other circumstances, for example where the user is not travelling from their home location, the user may input both the start location and the destination location.

Once the user has inputted details of the journey they wish to undertake, the server maintaining the website with which the user is interacting calculates an appropriate route for the trip to be undertaken by the user in step 456. The server then interrogates stored landmark data in step 458 and generates in step 460 a series of navigation instructions that include, where appropriate, enhanced navigation instructions and/or conventional navigation instructions. The server then transfers in step 462 details of the calculated route and some of all of the generated navigation instructions to the navigation device, for example via a wired link over the internet between the server and a computer to which the navigation device is connected or alternatively over a wireless interface - for example a mobile telephone air interface. As will be appreciated, the amount of memory available in the navigation device will govern how many navigation instructions may be transferred to the device at this point. In circumstances where the route has many instructions associated with it, and the device has a relatively small memory, the server may be configured to transfer a first batch of instructions to the device - subsequent batches being downloaded as the device progresses through the calculated route. In circumstances where the route has a smaller number of instructions and/or the device has a larger memory, all of the navigation instructions for the route may at this stage be downloaded.

In step 464 the user commences guidance, whereupon the device determines its current position in step 466. The device then determines in step 468 if the destination has been reached, and if that determination is positive the navigation process terminates at step 470. If a determination is made that the device is not yet at the destination, a check is made in step 472 to determine whether the device is still on the calculated route.

If the device is determined to have deviated from the calculated route a message is sent in step 474 to the server, for example via the mobile telephone air interface, and the server recalculates the route, generates a revised set of instructions, and transfers at least some of those instructions to the device.

If the navigation device is determined to be on the calculated route, a check is made in step 476 to determine whether the device's current position is associated with a downloaded navigation instruction, and if a navigation instruction is associated with the device position that instruction is relayed to the user of the device.

Next, in step 478, a check is made to determine whether the device has stored therein sufficient instructions to enable the user to be guided to the destination, and if that check should indicate that more instructions are required a request for the next batch of instructions is sent to the server in step 480 (for example via the mobile telephone air interface), and the next batch of instructions is transferred to the navigation device in step 482 (again for example via the mobile telephone air interface). In either case, processing then reverts to step 466 aforementioned.

It will be apparent from the foregoing that the teachings of the present invention provide an arrangement whereby a user can be provided with navigation instructions that enable the user to more easily identify particular manoeuvres that they are required to take to remain on the calculated route and as a consequence of this the potential for user confusion is reduced.

It will also be appreciated that whilst various aspects and embodiments of the present invention have heretofore been described, the scope of the present invention is not limited to the particular arrangements set out herein and instead extends to encompass all arrangements, and modifications and alterations thereto, which fall within the scope of the appended claims.

For example, whilst embodiments described in the foregoing detailed description refer to GPS, it should be noted that the navigation device may utilise any kind of position sensing technology as an alternative to (or indeed in addition to) GPS. For example the navigation device may utilise using other global navigation satellite systems such as the European Galileo system. Equally, it is not limited to satellite based but could readily function using ground based beacons or any other kind of system that enables the device to determine its geographic location. It will also be well understood by persons of ordinary skill in the art that whilst the preferred embodiment implements certain functionality by means of software, that functionality could equally be implemented solely in hardware (for example by means of one or more ASICs (application specific integrated circuit)) or indeed by a mix of hardware and software. As such, the scope of the present invention should not be interpreted as being limited only to being implemented in software. Lastly, it should also be noted that whilst the accompanying claims set out particular combinations of features described herein, the scope of the present invention is not limited to the particular combinations hereafter claimed, but instead extends to encompass any combination of features or embodiments herein disclosed irrespective of whether or not that particular combination has been specifically enumerated in the accompanying claims at this time.

Claims

1. A navigation device (200) comprising: a processor (210) that is configured to access digital map data and calculate a route (404) to a destination, said route (404) comprising one or more manoeuvres; characterised in that the navigation device (200) further comprises: a store (230) for landmark data (402), which data indicates the position of landmarks in said digital map, a landmark data interrogator (414) that is configured to access said landmark data store (230) to determine whether there is a landmark located in the vicinity of a said manoeuvre, and a navigation instruction generator (416) operable in the event that said landmark data interrogator determines that a said landmark is located in the vicinity of said manoeuvre to generate for that manoeuvre an enhanced navigation instruction that refers to said landmark for provision to a user of said navigation device (200).

2. A navigation device according to Claim 2, wherein said navigation instruction generator is configured in the event that no landmarks are determined to be in the vicinity of said manoeuvre to generate a navigation instruction that does not refer to a landmark for provision to a user of said navigation device.

3. A device according to any preceding claim, wherein a said landmark is determined to be in the vicinity of said manoeuvre if the location of said landmark is within a predetermined distance of said manoeuvre.

4. A device according to Claim 3, wherein said landmark is determined to be in the vicinity of said manoeuvre if the location of said landmark is within 50 metres, preferably within 30 metres, of said manoeuvre.

5. A device according to any preceding claim, wherein said navigation instruction generator is configured - in the event that a plurality of landmarks are determined by said landmark data interrogator to be in the vicinity of a said manoeuvre - to select a landmark of said plurality of landmarks that is closest to said manoeuvre.

6. A device according to any of Claims 1 to 5, wherein said landmark data includes an indication of the prominence of each said landmark.

7. A device according to Claim 6, wherein said navigation instruction generator is configured - in the event that a plurality of landmarks are determined by said landmark data interrogator to be in the vicinity of a said manoeuvre - to determine the prominence of each of said plurality of landmarks and to select a most prominent of said plurality of landmarks as the landmark to which said enhanced navigation instruction will refer.

8. A device according to any preceding claim, wherein said navigation instruction generator (416) is configured - in the event that a landmark is determined to be in the vicinity of a manoeuvre - to enquire of the user whether the landmark is visible, and to generate said enhanced navigation instruction only if said user indicates that the landmark can be seen.

9. A device according to any preceding claim, wherein said landmark data store includes information about one or more points of interest.

10. A device according to Claim 9, wherein said landmark data comprises data concerning predetermined points of interest categories.

1 1 . A device according to any preceding claim, wherein said landmark data comprises for each said landmark an indication of the position of said landmark in the digital map and an indication of the identity of said landmark.

12. A device according to Claim 1 1 , wherein said navigation instruction generator is configured to generate an enhanced navigation instruction that refers to said identity indication.

13. A navigation device according to any preceding claim, wherein said destination is user selectable and said navigation device comprises a user interface operable by a user to select said destination.

14. A navigation device according to any preceding claim, comprising an antenna (250) and a receiver (250) for receiving data signals via said antenna, wherein said processor (210) is configured to determine from said received data signals a current location of said navigation device (200), and to set said determined current position as a start position for calculation of said route.

15. A navigation device according to Claim 25, wherein said processor (210) is configured to generate a navigation map depicting a local environment surrounding said current position, and to update said navigation map as the current position changes with movement of the navigation device (200).

16. A method of navigation, comprising the steps of: accessing digital map data and calculating a route (404) to a destination, said route (404) comprising one or more manoeuvres; accessing a store (230) for landmark data (402), which data indicates the position of landmarks in said digital map, to determine whether there is a landmark located in the vicinity of a said manoeuvre, and in the event that a said landmark is determined to be located in the vicinity of said manoeuvre, generating for that manoeuvre an enhanced navigation instruction that refers to said landmark for provision to a user of a navigation device (200).

17. Computer software comprising one or more software modules operable, when executed in an execution environment, to cause a processor (210) to: access digital map data and calculate a route (404) to a destination, said route (404) comprising one or more manoeuvres; access a store (230) for landmark data (402), which data indicates the position of landmarks in said digital map, and to determine whether there is a landmark located in the vicinity of a said manoeuvre, and in the event that a said landmark is determined to be located in the vicinity of said manoeuvre, to generate for that manoeuvre an enhanced navigation instruction that refers to said landmark for provision to a user of a navigation device (200).

18. A format for representing a digital map, the digital map including:

(a) a road information component (400) representing at least a position of a road in the map; and (b) a landmark information component (402) representing, for the map, a position of a landmark in the map; wherein said landmark information component is interpretable by a processor

(210) of a navigation device (200) to generate an enhanced navigation instruction that refers to said landmark for association with a computed manoeuvre.