WO2012089260A1

WO2012089260A1 - Method for improved output of address location and application to navigation devices

Info

Publication number: WO2012089260A1
Application number: PCT/EP2010/070894
Authority: WO
Inventors: Dieter VERHOFSTADT
Original assignee: Tomtom Belgium Nv
Priority date: 2010-12-29
Filing date: 2010-12-29
Publication date: 2012-07-05

Abstract

This invention concerns a navigation device comprising memory (230),an output device (240, 261), an input device (220) and a processor (210). The memory has stored therein map data, the map data comprising a map of navigable paths and, for each navigable path, a navigable path identifier, a section locater identifying a location of end points of one or more sections along the navigable path relative to a total length of the navigable path, each section representing a plurality of address locations, and an address range identifying a series of address identifiers for the one or more sections. The processor (210) is arranged to receive an input of an address identifier and a navigable path identifier from the input device (220), identify a navigable path from the input navigable path identifier, distribute address identifiers within the address range across the one or more sections of the navigable path, identify from the distributed address identifiers a location of the address identifier that corresponds to the input address identifier and cause the output device (240, 261) to generate an output relating to the identified location.

Description

METHOD FOR IMPROVED OUTPUT OF ADDRESS LOCATION AND APPLICATION TO NAVIGATION DEVICES

Field of the Invention This invention relates to improvements in or relating to navigation devices. Illustrative embodiments of the invention relate to portable navigation devices (so- called PNDs), in particular PNDs that include Global Navigation Satellite System (GNSS) 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 path planning and/or navigation, functionality. The invention also concerns the generation of map data for use in navigation devices and systems for generating such map data.

Background to the Invention

Portable navigation devices (PNDs) that include GNSS 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, CDMA and the like.

PND devices of this type also include a GNSS antenna by means of which satellite- broadcast signals, including location positioning data, can be received and subsequently processed to determine a current position 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 position information derived from the GNSS 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 visual and/or audible instructions to guide the user along a chosen route to the end of that route, i.e. 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, determined by the PND using a GNSS receiver. 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 recalculation 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 (known as POIs) 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.

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.

To provide the above-described functionality, it is common for map data stored in the navigation device to comprise address information, such as house numbers. Such address information can require a large amount of storage space and typically, portable navigation devices have limited storage capacity. It is therefore desirable to reduce the storage space required for address information without losing the functionality of identifying a location (such as a starting location or destination) through an address.

WO2007/092817 describes one system for storing and locating address locations that may reduce storage space relative to storing every address location. In this system, the map data comprises a plurality of street segments, each street segment representing one side of one block of a street. For each street segment, the house number and location (longitude and latitude) of the house at each end of the segment is identified. Known address locations between these end points may also be identified. To identify a location of a desired address that is not one of the addresses identified in the data, a navigation device identifies the two closest house numbers that bracket the desired house number and for which the location is known and interpolates the desired address to be between these two closest house numbers.

US2004/0138817 Al describes a similar system. Summary of Invention According to a first aspect of the invention there is provided a navigation device comprising memory, an output device, an input device and a processor, the memory having stored therein map data, the map data comprising a map of navigable paths and, for each navigable path, a navigable path identifier, a section locater identifying a location of end points of one or more sections along the navigable path relative to a total length of the navigable path, each section representing a plurality of address locations, and an address range identifying a series of address identifiers for the one or more sections, wherein the processor is arranged to receive an input of an address identifier and a navigable path identifier from the input device, identify a navigable path from the input navigable path identifier, distribute address identifiers identified by the address range across the one or more sections of the navigable path, identify from the distributed address identifiers a location of the address identifier that corresponds to the input address identifier and cause the output device to generate an output relating to the identified location.

In this way, the storage size of the map data may be reduced because the sections of the navigable paths, where address locations occur, are coded as relative lengths of the navigable path whilst the sectioning of the navigable path insures a degree of accuracy for the determined location. In particular, in one embodiment, the section locater may be a reference to one of a set of section profiles, the set consisting of fewer section profiles than the total number of navigable paths of the map data. In one embodiment, the section locater identifier may comprise a pointer to a section profile. The storage space required for a pointer associated with each navigable path and a set of section profiles may be less than that required for a house number and latitude and longitude at each end of each segment as described in WO2007/092817. Furthermore, to take account of unequal distribution of the addresses along a segment in the system described in WO2007/092817 it is necessary to add additional address locations in the map data between the end points. However, in the invention, such unequal distribution of address locations along a navigable path can be taken into account by sectioning the navigable path into two or more sections. The navigable path may represent a segment of a road, path, channel or the like navigable by vehicle and/or by walking. For example, the navigable path may represent a segment of a path, river, canal, cycle path, tow path, railway line or the like.

An aspect of the invention is the realisation that a distribution of address locations along a navigable path can be defined relative to the length of the navigable path because the absolute location (eg location on the Earth, such as GPS location) of the navigable path is known and the absolute location of the address locations can be derived therefrom. Once a distribution of address locations is separated from absolute locations then it is possible to categorize the distributions into a set of standard section profiles. The categorization of the distributions compresses the data to reduce the storage space required for this information.

A section may be defined as a ratio of the length of the path, such as from 1/5 to 3/5 of the length of the path, or as a percentage of the length of the path, such as 20% to 60% of the length of the path, or the location of end points may be identified by a point and a length of the section that extends one or both sides of that point, for example a midpoint of a section may be defined at 2/5 of the length of the navigable path, the section extending in either direction of this midpoint by 1/5 of the length of the navigable path.

In one embodiment, the address range comprises a first house number and a last house number for the navigable path. It will be understood the term "house number" is used herein to refer to a street number of any type of building not just houses and may also include letters, such as when buildings are identified through a known sequence of letters, such as a sequence of buildings identified by successive letters of the alphabet, or a sequence of a combination of letters and number, such as 20a to 20g. The address range may comprise one or more intermediate house numbers. The processor may be arranged to associate any intermediate house numbers with an end point of a section. In this way, if the density of address locations is higher in one section of the navigable path than another section, the processor is able to determine that the address identifiers should be spread unequally across the two or more sections through the presence of an intermediate house number. For example, a navigable path may be divided into two sections of equal length but the range of address identifiers may comprise house numbers 1 , 10 and 50. In such a scenario, the processor may distribute house numbers 1 to 10 equally across the first section and house numbers 11 to 50 equally across the second section. In an alternative embodiment, the intermediate house number may indicate a change in the numbering from successive numbers to successive letters, for example, 1, 20a, 20g, 50. The processor may be arranged to identify such intermediate address identifiers as indicating such a change and distribute address identifiers having the required type of succession between these intermediate address identifiers, eg, based on the example given above, to follow house number 19 by 20a, 20b, 20c, 20d, 20e, 20f and 20g before moving on to 21. The intermediate house number may also indicate a house number missing from the series, eg an address range, 1, 20, 22, 50 may indicate that there is no house number 21 on the navigable path.

The map data may further comprise a type identifier indicating a characteristic of the buildings to which a section relates. For example, the type identifier may be an indicator that a section relates to apartments, houses, residential buildings, commercial buildings, public buildings or the like. The processor may be arranged to distribute the address identifiers across the one or more sections in a particular manner dependent upon the type identifiers. For example, a type identifier may indicate that a particular weight should be applied to distributing address identifiers across a section having one type identifier over a section having a different type identifier. The processor may be arranged to distribute address identifiers across a section having one type identifier, such as a type identifier indicating that the section relates to apartments, with a higher density than a section having a different type identifier, such as a type identifier indicating that the section relates to houses. The processor may be arranged to generate a set of routing instructions based on the determined location. For example, the determined location may be a starting location or destination of a route. According to a second aspect of the invention there is provided a method of identifying a location using map data, the map data comprising a map of navigable paths and, for each navigable path, a navigable path identifier, a section locater identifying a location of end points of one or more sections along the navigable path relative to a total length of the navigable path, each section representing a plurality of address locations, and an address range identifying a series of address identifiers for the one or more sections, the method comprising receiving an input of an address identifier and a navigable path identifier from the input device, identifying a navigable path from the input navigable path identifier, distributing address identifiers within the address range across the one or more sections of the navigable path and identifying from the distributed address identifiers a location of the address identifier that corresponds to the input address identifier.

According to a third aspect of the invention there is provided a data carrier having stored thereon map data, the map data comprising a map of navigable paths and, for each navigable path, a navigable path identifier, a section locater identifying a location of end points of one or more sections along the navigable path relative to a total length of the navigable path, each section representing a plurality of address locations, and an address range identifying a series of address identifiers for the one or more sections.

The map data may comprise a plurality of section profiles and each section locater may point to one of the section profiles.

The data carrier may be any suitable permanent or semi-permanent storage medium, such as a floppy disk, a CD ROM, a DVD, ROM, RAM, hard-disc, memory stick, SD card, compact flashcard or the like or a transient data carrier such as an electromagnetic or electric signal transmitted wirelessly or via electric or optical cables.

According to a fourth aspect of the invention there is provided a method of creating map data comprising a map of navigable paths, the method comprising identifying for each navigable path one or more sections of the navigable path that comprise address locations, determining locations of each end point of the sections in terms of a relative length of the navigable path to the end point to a total length of the navigable path, comparing the location of the end points to end points of each of a plurality of section profiles and associating the navigable path with one of the plurality of section profiles based on the comparison.

In one embodiment, the method comprises associating the navigable path with the closest matching section profile. For example, the method may comprise associating each navigable path with the section profile that comprises the highest proportion of similar parts (eg parts designated as comprising address locations and/or parts designated as not comprising address locations).

In this way, map data is created that uses less storage space to store the address locations than known techniques.

According to a fifth aspect of the invention there is provided a method of creating map data comprising creating a plurality of section profiles representing possible distributions of address locations on a navigable path.

Creating the plurality of section profiles may comprise a statistical analysis of a distribution of address locations on a plurality of navigable paths (a number of section profiles being less, preferably much less than a number of navigable paths). In one embodiment, creating the plurality of section profiles comprises identifying for each navigable path one or more sections of the navigable path that comprise address locations, determining a location of each end point of the sections in terms of a relative length of the navigable path to the end point to a total length of the navigable path, and determining a plurality of section profiles from a statistical analysis of the determined location of each end point. The section profiles may be chosen such that a comparison between the sections of each navigable path and sections of a section profile meets a predetermined threshold. The predetermined threshold may be that each one of a predetermined percentage of the navigable paths matches a predetermined percentage of at least one of the section profiles. The statistical analysis may be a clustering algorithm and, in one arrangement a k- means clustering algorithm. The clustering algorithm may comprise clustering of the navigable paths based on a distance (in terms of the relative position along the navigable path, eg 0.25L, etc) of end points of sections of the navigable paths from each other. In other embodiments, other clustering methods may be used and this may include hierarchical clustering and fuzzy clustering.

It will be understood that the fifth aspect of the invention may be used in conjunction with the fourth aspect of the invention to create map data. In particular, first a plurality of section profiles may be determined and then each navigable path may be associated with a section profile.

According to a sixth aspect of the invention there is provided a data carrier having stored thereon instructions, which, when executed by a processor, cause the processor to carry out the method according to the second, fourth or fifth aspects of the invention.

According to a seventh aspect of the invention there is provided a system comprising memory and a processor, the memory having stored therein map data comprising a plurality of navigable paths and address data identifying address locations on each of the navigable paths, the processor arranged to carry out the fourth or fifth aspect of the invention using the map data and address data stored in memory.

According to an eighth aspect of the invention there is provided a navigation device comprising memory, an output device, an input device and a processor, the memory having stored therein map data, the map data comprising a map of navigable paths, a plurality of section profiles identifying possible distributions of address locations along a navigable path and, for each navigable path, a navigable path identifier, an address range identifying a series of address identifiers and a pointer associating the navigable path with one of the plurality of section profiles, wherein the processor is arranged to receive an input of an address identifier and a navigable path identifier from the input device, identify a navigable path from the input navigable path identifier, determine, for the identified navigable path, individual address locations by distributing address identifiers of the address range across one or more sections as determined in accordance with the section profile associated with the navigable path, identify from the individual address locations a location of the address identifier that corresponds to the input address identifier and cause the output device to generate an output relating to the identified location. According to a ninth aspect of the invention there is provided a navigation device comprising memory, an output device, an input device and a processor, the memory having stored therein map data, the map data comprising a map of navigable paths, and, for each navigable path, a navigable path identifier, an address range identifying a series of address identifiers and a modifier identifying a modification to be made to the series of address identifiers, wherein the processor is arranged to receive an input of an address identifier and a navigable path identifier from the input device, identify a navigable path from the input navigable path identifier, determine, for the identified navigable path, individual address locations by distributing address identifiers of the address range across the navigable path taking into account the modifier, identify from the individual address locations a location of the address identifier that corresponds to the input address identifier and cause the output device to generate an output relating to the identified location. According to a tenth aspect of the invention there is provided a data carrier having stored thereon map data, the map data comprising a map of navigable paths and, for each navigable path, a navigable path identifier, an address range identifying a series of address identifiers for the navigable path and a modifier identifying a modification to be made to the series of address identifiers.

It will be understood that the modifier is a data element and, for at least, some of the navigable paths may indicate that no modification needs to be made to the series.

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:

Figure 1 is a schematic illustration of a navigation device communicating with a Global Navigation Satellite System (GNSS);

Figure 2 is a schematic illustration of electronic components arranged to provide a navigation device in accordance with an embodiment of the invention;

Figure 3 is a schematic illustration of the manner in which a navigation device may receive information from a server over a wireless communication channel; Figures 4A and 4B are illustrative perspective views of a navigation device;

Figure 5 shows a sectioning of a road segment in an urban area based on the distribution of buildings along the road segment;

Figure 6 shows a sectioning of a road segment in a mixed use area based on the distribution of buildings along the road segment; Figure 7 shows a sectioning of a road segment in a rural area based on the distribution of buildings along the road segment; Figure 8 shows schematically the identification of sections along a road segment for different distributions in relation to a total length of the road segment;

Figure 9 is a flowchart of a method of determining an address location according to one embodiment of the invention;

Figure 10 is a flowchart of a method of creating map data according to one embodiment of the invention; and Figure 11 is a flowchart of a method for generating section profiles for use in the creation of map data according to one embodiment of the invention.

Detailed Description of Preferred Embodiments Preferred embodiments of the present invention will now be described with particular reference to a PND. It should be noted, however, that the teachings of the present invention are not limited to PNDs but are universally applicable to other types of navigation devices that locates a current position on a map. It follows therefore that in the context of the present application, a navigation device is intended to include (without limitation) navigation devices, 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 provisos in mind, Fig. 1 illustrates an example view of Global Navigation Satellite System (GNSS) 100, usable by navigation devices 140. In general, GNSS is a satellite-radio based navigation system capable of determining position, velocity, time, and in some instances direction information. A GNSS comprise a plurality of satellites 120 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. The GNSS satellites relay their location to receiving units 140 via signals 160. The GNSS receiver 140 receives the spread spectrum GNSS satellite signals 160 and determines its position from the position information relayed by the satellites. The navigation device of the invention may use GPS, formerly known as NAVSTAR, Galileo, GLOSNASS, or any other suitable GNSS . The GNSS incorporates a plurality of satellites 120 which orbit the earth in extremely precise orbits. The spread spectrum signals 160, 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 GNSS receiver device 140 generally acquires spread spectrum GNSS satellite signals 160 from at least three satellites 120 for the GNSS 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 GNSS receiver device 140 to calculate its three-dimensional position in a known manner.

The GNSS system is implemented when a device, specially equipped to receive GNSS data, begins scanning radio frequencies for GNSS satellite signals. Upon receiving a radio signal from a GNSS 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.

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 electronic components of the navigation device 200 are located within a housing such as that shown in Figures 4 A and 4B. The navigation device includes a processing device 210 connected to an input device 220 and a display screen, in this embodiment an LCD 240, comprising a backlight driver 241 connected with the processing device 210 . 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 this arrangement the input device 220 and display screen 240 are integrated into an integrated input and display device, including a touchpad or touch screen 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 to 262, for example a loudspeaker 261, an audio amplifier 262 and audio codec 260. The audio device 260 to 262 can produce audio commands for directing the user in accordance with a determined navigable path. In the navigation device 200, processing device 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 and 246, to output information, including a current location, thereto. Further, the processing device 210 is operably coupled to a memory resource 230 via connection 235. 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 memory resource has stored therein map data which comprises a map of navigable paths in an area, for example, a map of navigable paths in a country. In this embodiment, each path of the map data is segmented with each segment having data associated therewith that defined attributes of that segment, for example speed limits, traffic profiles, other road regulations, etc. Figure 2 further illustrates an operative connection between the processing device 210 and a positioning device, in this embodiment a GNSS antenna 250 and receiver 251 via connection 255. The antenna may be a GNSS patch antenna or helical antenna for example. The navigation device 200 further comprises a connection (a further, second receiver) 270 for detachably connecting to a cellular modem 280, such as a mobile telephone, for receiving broadcast signals, such as BCCH, from base stations of cellular networks. The connection 270 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. In another embodiment, device 280 may be a portable television receiver or a radio receiver that can receive TMS/RDS information.

Further, it will be understood by one of ordinary skill in the art that the electronic components shown in Figure 2 are powered by power source 290, in this case a power management integrated circuit 290, in a conventional manner. A wired connection 276, in this embodiment a USB connection, is also provided for connecting the processing device 210 to a computer or the like. Such a connection can be used for software/firmware updates and/or map updates. The navigation device 200 comprises a receiver 295, in this embodiment a connector for connecting to position sensors, in this embodiment a gyroscope 296 and accelerometer 297, such that the CPU 210 can receive signals from the gyroscope 296 and accelerometer 297. As will be understood by one of ordinary skill in the art, different configurations of the components shown in Figure 2 are considered to be within the scope of the present application. For example, the components shown in Figure 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 Figure 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 by using the mounting device 292/294 shown in Figures 5a and 5b. Such a navigation device 200 is then removable from the docked location for portable or handheld navigation use.

Referring now to Figure 3, the navigation device 200 may establish a "mobile" or telecommunications network connection with a server 302 via the cellular modem 280 establishing a digital connection (such as a digital connection via known Bluetooth technology for example). Thereafter, through its network service provider, the cellular 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 "realtime" 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 the 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 DVB-H, DVB-T, CDMA, GSM, Wi-Max, TMC/RDS, 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.

For GPRS 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 Figure 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 processing device 304 operatively connected to a memory 306 and further operatively connected, via a wired or wireless connection 314, to a mass data storage device 3 12. The processing device 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 3 12 may be coupled to the server 302 via communication link 3 14. The mass storage device 3 12 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 processing device, memory, etc. as previously described with regard to Figures 2 and 3, 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 processing device 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 3 1 8 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 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 processing device 304 in the server 302 may be used to handle the bulk of the processing needs; however, processing device 210 of navigation device 200 can also handle much processing and calculation, oftentimes independent of a connection to a server 302.

Figs 4 A 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 Figures 2 and 3 (including but not limited to internal GPS receiver 250, processing device 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 Figure 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 Figure 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.

Stored in memory 230 is map data and, in this embodiment, the map data comprises a map of navigable paths. In this embodiment, the navigable paths are road segments, although, for short roads, a single road segment may comprise the whole road. For each road segment, the map data includes a road identifier, such as a street name, a section locater identifying end points of one or more sections along the road segment, each section representing a plurality of address locations. In this embodiment, the section locater is a pointer to one section profile of a plurality of section profiles of the map data. The section profiles are a set of standard profiles that define different sectional distributions of address locations, which, within a particular statistical threshold, encompass the distributions of sections that exist on the road segments (as described in more detail below). The map data further comprises, for each road segment, an address range identifying a series of address identifiers, such as house numbers, that are located on that road segment.

Figures 5 to 7 illustrate how buildings, and therefore, address locations, may be blocked into sections along a road segment.

As can be seen from the example shown in the Figure 5, which is an image of Kartuizerlaan in Gent, Belgium, in an urban area the sections 350 are likely to be substantially continuous, with the ends of the sections defined by the roads separating the buildings. However, in less congested areas, such as Volaardestraat in Dendermonde, Belgium, as shown in Figure 6, which connects two villages in a densely populated area with a mix of houses and agriculture, the ends of the sections 350 may be defined by other structures, such as fields and the gaps between sections 350 may be much larger. The final example in Figure 7, is Vlassenbroek in Belgium which leads to a small village in a protected rural area. Here the separation between the built up areas along the road is much greater, wherein, on the right side of the road (as viewed in the Figure), only 15% of the road segment at a top end and 20% of the road segment at a bottom end comprise address locations.

Referring to Figure 8, the section profiles identify the sections with reference to the location of end points of the sections. In this embodiment, each end point is identified by identifying a length from one end of the navigable path to the end point of the section relative to the total length of the navigable path. In the example shown in Figure 8, the section locaters are a percentage of the total path length. Figure 8 shows two possible section profiles. The first section profile comprises a single section with end points at 0%> and 55%. The second section profile comprises two sections, the first of which has end points at 30% and 70% and the second of which has end points at 92% and 100%.

Now referring to Figure 9, in use, the processor 210 receives, in step 401 , an input of an address identifier, such as a house number, and a navigable path identifier, such as a street name, from the input device 210. For example, the user may input the house number and street name of the address using a "soft" keyboard displayed on the touch-screen. The user may also be able to identify the address in other ways, for example by inputting a house number and a postal code/zip code. In step 402, the processor 210 identifies a road segment from the received street name/postal code and house number. For example, the processor 210 may first identify a subset of navigable paths that include the road identified by the street name. The processor 201 may then search the address ranges associated with each navigable path of the subset to determine which one includes the house number input by the user. In step 403, the processor 210 identifies from section locaters, a section profile associated with the identified navigable path. From the section profile, the processor 210 determines a position along the navigable path at which end points of sections occur. For example, the section profile may identify a percentage of a total length of the navigable path at which the end points occur. House numbers that fall within the address range associated with the navigable path are then distributed at locations along the sections of the navigable path identified from the section profile. In this embodiment, the house numbers are distributed at equally spaced locations, however as discussed below, the house numbers may be distributed in a non-equal manner as dictated by indicators in the address range /map data.

In step 405, the processor 210 identifies, from the distributed house number locations, a location of the house number input by the user. This location may then be displayed as part of a map on the screen 240 or may be used in a routing algorithm, the routing instructions generated by the routing algorithm being displayed on screen 240 or output via audio output 261.

Figure 10 illustrates a method of creating the map data comprising section profiles. Such a method may be carried out at server 302. The processor 304 of server 302 retrieves map data comprising a plurality of navigable paths, such as a plurality of road segments, and a plurality of section profiles, the road segments as yet unlinked to the section profiles from memory, such as mass storage device 312. In step 501, the processor 304 selects a first road segment from the plurality of road segments of the map data and, in step 502, identifies for the selected road segment one or more sections of the road segment that comprise address locations. For example, the sections may be identified manually or through image recognition, such as computer recognition of the edges of buildings, etc. Such automatic image recognition may be carried out using known techniques. For example, the road segment may be processed by a computer to identify building edges, the computer generating sections along the road segment based on the identified edges. For example, buildings may be blocked together in a section if any gap between building edges is below a threshold distance, such as less than lOmetres. The identification of the sections may be carried out through a combination of automatic building recognition and manual checking. For example, a user may check the computer generated sections to determine if a feature has been mistakenly identified as a building edge.

Once one or more sections Bj, ...,B_n has been determined for the road segment (P), the processor 304 determines the locations, xi, yi of each end point of each section Bi in terms of a relative length of the road segment to the end point to a total length of the road segment. From this it is also possible to define Ej, ...,E_m empty sections that do not have any buildings. M is either n+1 or n-1.

Similarly, each section profile (F) also comprises sections, Bi, ...,B_q, where each section is identified by locations Λ¾ J¾ of each end point of the section Bt in terms of a relative length of the road segment to the end point to a total length of the road segment. It is also possible to define Ei, ...,E_s sections that do not have any buildings. S is either q+1 or q-1.

In step 504, the road segment is matched to a section profile by identifying a section profile that has the highest matching score, in this embodiment, the highest matching score for the equation:

Score(F,P) =∑E_; (P) n E_j (F) +∑B_k (P) n B, (F) , (1)

i.j k,l where (P) denotes the road segment and (F) denotes the section profile. The function n is evaluated to return the number of matching values of the defined sets. The sets defined by x,y may be considered to be sets of integers. However, it will be understood that the score may be assessed at a greater or lesser level of granularity. In essence, the calculation counts a number of empty parts, ie quantized blocks, of a section profile that overlap with empty parts of a road segment and the built-up parts of the section profile that overlap with built-up parts of the road segment. The higher the number of common parts, the higher the score.

In step 505, a section locater associated with the road segment is updated to point to the section profile identified as having the highest score. If an empty street profile is the best match for a road segment this is only associated with the road segment if there are no buildings on the road segment. Otherwise, the next best section profile is chosen.

In section 506, the processor 304 determines if the there are any further road segments of the map data to be assessed. If there are the processor 304 selects in step 507 the next road segment and carries out steps 502 through 505 for the next road segment. Once all road segments have been assigned a section profile the process ends.

The resulting map data may be sent/downloaded to navigation devices 200 for use in locating addresses and routing.

Now referring to Figure 1 1 , a method of creating the section profiles will be described. In the above described method of creating a map it is assumed that the section profiles already exist. Section profiles may be created as part of the map creation process or separate from the map creation process. Furthermore, the section profiles may be created from the same road segments that are then associated with the road segments or another set of road segments. For example, section profiles may be created from roads in Belgium but then used to create map data for Netherlands on the assumption that the section profiles that are appropriate for Belgium will also be appropriate for Netherlands as the distribution of housing along roads in both countries may be similar. The section profiles may be created at server 302. In this embodiment, in step 601, the processor 304 generates a predetermined number of initial section profiles, such as sections comprising 2, 3, 4 or 5 sections, and attributes each section a 1 or 0 depending on whether the section is an empty section or a built-up section. The section profiles will also include two un-sectioned profiles, one for fully empty and the other for fully built-up. The processor 304 receives a sample of navigable paths, such as a plurality of road segments, wherein the built-up and empty sections of the road segments has been identified. At 602, the processor 304 calculates scores using equation (1) for the road segments based on the initial set of section profiles. At step 603, it is determined if a predetermined number of the road segments, in this embodiment 95%, have a maximum score above a predetermined threshold, in this embodiment 75%. If, this threshold requirement is met, the current set of section profiles is kept and the set of section profiles is passed to step 605. However, if the threshold is not met then, at step 604, further section profiles are added and the new set of section profiles is tested to determine if the threshold condition is met. In one embodiment, a new set of section profiles is created by adding new section profiles to the initial set of section profiles, possibly with a higher order of sectioning, such as 6 and/or 7 pieces. However, in another embodiment, only a predetermined number, for example, five, of the most used section profiles of the initial set (the ones that generate the most number of maximum scores for the sample of road segments) are retained and new profiles are added to the retained profiles to build the new set of section profiles.

In step 605, a predetermined number of least used section profiles are removed from the set that met the condition as tested in 603, and, in 606, it is determined whether the set with these profiles removed meets a threshold condition. This threshold condition may be the same as the threshold condition tested in 603. If the threshold condition is still met then a further predetermined number of the least used profiles are removed. If removal of the section profiles causes the set of section profiles not to met the threshold condition, then the last removed profiles are reintroduced and the resultant set of section profiles are stored in memory to be used for creating map data (as described with reference to Figure 10). It will be understood that modifications and alterations can be made to the above described embodiment without departing from the scope of the invention as defined herein. For example, the address range may comprise one or more intermediate house numbers. The intermediate house number(s) may indicate a change in the numbering from successive numbers to successive letters, for example, 1 , 20a, 20g, 50. The address range may further comprise a "type identifier" indicating a characteristic of the building to which the address identifiers relate. For example, the type identifier may be an indicator that the address identifiers relate to apartments, houses, residential buildings, commercial buildings, public buildings or the like. The processor 210 may be arranged to distribute the address identifier across the one or more sections in a particular manner dependent upon the type identifier. For example, house numbers identified as relating to apartments may be distributed with a higher density than house numbers identified as relating to houses.

Claims

1. A navigation device comprising memory, an output device, an input device and a processor, the memory having stored therein map data, the map data comprising a map of navigable paths and, for each navigable path, a navigable path identifier, a section locater identifying a location of end points of one or more sections along the navigable path relative to a total length of the navigable path, each section representing a plurality of address locations, and an address range identifying a series of address identifiers for the one or more sections, wherein the processor is arranged to receive an input of an address identifier and a navigable path identifier from the input device, identify a navigable path from the input navigable path identifier, distribute address identifiers within the address range across the one or more sections of the navigable path, identify from the distributed address identifiers a location of the address identifier that corresponds to the input address identifier and cause the output device to generate an output relating to the identified location.

2. A navigation device according to claim 1, wherein the section locater is a reference to one of a set of section profiles, the set consisting of fewer section profiles than the total number of navigable paths of the map data.

3. A navigation device according to claim 1 or claim 2, wherein the address range comprises a first house number, a last house number and one or more intermediate house numbers and the processor is arranged to associate the first house number, the last house number and each intermediate house number with an end point of a section.

4. A navigation device according to any one of the preceding claims, wherein the map data further comprises type identifiers indicating characteristics of the buildings to which sections relate and the processor is arranged to distribute the address identifier across the one or more sections in a particular manner dependent upon the type identifiers.

5. A navigation device according to any one of the preceding claims, wherein the processor is arranged to generate a set of routing instructions based on the determined location.

6. A method of identifying a location using map data, the map data comprising a map of navigable paths and, for each navigable path, a navigable path identifier, a section locater identifying a location of end points of one or more sections along the navigable path relative to a total length of the navigable path, each section representing a plurality of address locations, and an address range identifying a series of address identifiers for the one or more sections, the method comprising receiving an input of an address identifier and a navigable path identifier from the input device, identifying a navigable path from the input navigable path identifier, distributing address identifiers within the address range across the one or more sections of the navigable path and identifying from the distributed address identifiers a location of the address identifier that corresponds to the input address identifier.

7. A data carrier having stored thereon map data, the map data comprising a map of navigable paths and, for each navigable path, a navigable path identifier, a section locater identifying a location of end points of one or more sections along the navigable path relative to a total length of the navigable path, each section representing a plurality of address locations, and an address range identifying a series of address identifiers for the one or more sections.

8. A data carrier according to claim 7, wherein the map data comprises a plurality of section profiles and each section locater points to one of the section profiles.

9. A method of creating map data a map of navigable paths, the method comprising identifying for each navigable path one or more sections of the navigable path that comprise address locations, determining locations of each end point of the sections in terms of a relative length of the navigable path to the end point to a total length of the navigable path, comparing the location of the end points to end points of each of a plurality of section profiles and associating the navigable path with the one of the plurality of section profiles.

10. A method of creating map data comprising creating a plurality of section profiles representing possible distributions of address locations on a navigable path.

11. A method according to claim 10, wherein creating the plurality of section profiles comprises a statistical analysis of a distribution of address locations on a plurality of navigable paths.

12. A method according to claim 10 or claim 11, wherein creating the plurality of section profiles comprises identifying for each navigable path one or more sections of the navigable path that comprise address locations, determining a location of each end point of the sections in terms of a relative length of the navigable path to the end point to a total length of the navigable path, and determining a plurality of section profiles from a statistical analysis of the determined location of each end point.

13. A data carrier having stored thereon instructions, which, when executed by a processor, cause the processor to carry out the method according to the method of one of claims 6 and 9 to 12.

14. A system comprising memory and a processor, the memory having stored therein map data comprising a plurality of navigable paths and address data identifying address locations on each of the navigable paths, the processor arranged to carry out the method of any one of claims 9 to 12 using the map data and address data stored in memory.

15. A navigation device comprising memory, an output device, an input device and a processor, the memory having stored therein map data, the map data comprising a map of navigable paths, a plurality of section profiles identifying possible distributions of address locations along a navigable path and, for each navigable path, a navigable path identifier, an address range identifying a series of address identifiers and a pointer associating the navigable path with one of the plurality of section profiles, wherein the processor is arranged to receive an input of an address identifier and a navigable path identifier from the input device, identify a navigable path from the input navigable path identifier, determine, for the identified navigable path, individual address locations by distributing address identifiers of the address range across one or more sections as determined in accordance with the section profile associated with the navigable path, identify from the individual address locations a location of the address identifier that corresponds to the input address identifier and cause the output device to generate an output relating to the identified location.