WO2010081564A1

WO2010081564A1 - Electronic apparatus, channel usage data communications system and method of setting a radio data system communications unit

Info

Publication number: WO2010081564A1
Application number: PCT/EP2009/058837
Authority: WO
Inventors: Theo Kamalski; Henny Verweij
Original assignee: Tomtom International B.V.
Priority date: 2009-01-14
Filing date: 2009-07-10
Publication date: 2010-07-22
Also published as: CN102187584A; TW201027037A; WO2010081539A1

Abstract

An electronic apparatus (200) comprises a processing resource (202) operably coupled to a receiver (224) of location-related data and arranged to perform, when in use, location determination. The apparatus also comprises a Radio Data System (RDS) communications unit (254) capable of receiving Radio Frequency (RF) signals within a Frequency Modulation (FM) spectrum range. The processing resource (202) is arranged to access channel availability data associated with location data and to cooperate with the RDS communications unit (254) in order to set the RDS communications unit (254) to be able to use an RF channel identified by the channel availability data in respect of a transmission location that corresponds to the location data, the RDS communications unit (254) being set in response to the processing resource (202) determining that the channel availability data indicates that the RF channel is expected to be available for transmission thereon at the transmission location associated therewith.

Description

ELECTRONIC APPARATUS, CHANNEL USAGE DATA COMMUNICATIONS SYSTEM AND METHOD OF SETTING A RADIO DATA SYSTEM COMMUNICATIONS

UNIT

Field of the Invention

The present invention relates to an electronic apparatus of the type that, for example, is capable of receiving location-related data for subsequent processing. The present invention also relates to a channel usage data communications system of the type that, for example, comprises a server apparatus capable of communicating with a navigation apparatus to service a request for data. The present invention further relates to a method of setting a Radio Data System (RDS) communications unit, the method being of the type that, for example, selects an available Radio Frequency (RF) channel for communicating an RF signal from a navigation apparatus to an external RF tuner, such as a Frequency Modulation (FM) radio in a vehicle.

Background to the Invention

Portable computing devices, for example 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 PND comprises a processor, memory and map data stored within said memory. The processor and memory cooperate to provide an execution environment in which a software operating system is typically 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 can be on a steering wheel if the device is built into a vehicle), and a microphone for detecting user speech. In one particular arrangement, the output interface display may be configured as a touch sensitive display (by means of a touch sensitive overlay or otherwise) additionally to 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 Bluetooth, Wi-Fi, Wi-Max, GSM, UMTS and the like.

PNDs 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 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 PNDs 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).

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 telephone 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 with which the user's computing resource is communicating 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 PN Ds 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 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.

As mentioned above, 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 GO 940 LIVE model manufactured and supplied by TomTom International B.V., provide a reliable means for enabling users to navigate from one position to another. Such devices are of great utility when the user is not familiar with the route to the destination to which they are navigating.

In order to facilitate in-vehicle use of the PND, some PNDs are equipped with a Frequency Modulation (FM) transmitter, for example the GO 940 LIVE model PND mentioned above. Instead of amplified audio signals being reproduced by a loudspeaker of the PND, the FM transmitter frequency modulates and transmits the audio signals on a user-selectable frequency. When in a vehicle, a user of the PND tunes an FM radio located in the vehicle to the user-selected frequency so that the FM radio receives the frequency modulated audio signal, demodulates the frequency modulated audio signal and reproduces the audio signal through loudspeakers coupled to the FM radio. Of course, the FM radio can be part of an in-vehicle entertainment system capable of FM reception and including a Compact Disc (CD) multi-changer and other facilities.

It should be noted that it is desirable to use the loudspeakers of in-vehicle entertainment systems via FM transmission for other types of portable device, for example so-called MP3 players and/or mobile telephones. Indeed, it is known for such other portable devices to possess so-called Short-Range Radio (SRR) FM transmitters to transmit audio information to FM receivers.

However, transmission of audio using the SRR transmitter suffers from a number of disadvantages. One disadvantage is the limited transmission power of the SRR FM transmitter that can sometimes result in poor audio quality being experienced by a user. The poor audio quality is exacerbated by a so-called Faraday cage effect created by metallic vehicle bodywork and metal coatings used in relation to vehicle windows. Indeed, the poor audio quality can, in part, manifest itself as poor stereo reproduction. In this respect, a poor received field intensity of an RF signal leads to low channel separation and hence only monophonic or low-quality stereo sound reproduction by a receiving FM radio.

Additionally, the number of available FM channels that are free at any given time for use by the SRR is limited and location dependent. The FM channel "landscape", i.e. those FM channels in an FM spectrum that are in use and available for use, changes with location as different frequencies are used for broadcasts in different geographic locations. Hence, when the SRR is moving from one geographic area to another geographic area, for example when the SRR is disposed within a vehicle that is travelling between cities, some of the relatively small number of available FM channels cease to remain available and other unavailable FM channels, previously in use, become available. This is a function of FM spectrum usage in different the geographic areas. Consequently, the SRR has to be re-tuned regularly as the frequency landscape changes.

A further problem encountered in relation to the SRR is when one SRR is located in relatively close proximity to another SRR, for example when two PNDs actively employing respective SRRs are waiting in respective vehicles at a set of traffic lights. In such circumstances, the SRRs can serve as sources of interference for one another. In a particularly disadvantageous situation, audio navigation instructions transmitted by an SRR of one PND in a first vehicle is received by an FM tuner in a second, neighbouring, vehicle where another PND is located and transmitting audio information to the FM tuner in the second vehicle. The driver of the neighbouring vehicle can thus receive and consequently follow navigation instructions of the PND of the first vehicle and not the PND located in the second vehicle where the instructions are heard. In this respect, such interference can easily occur when two vehicles are waiting at traffic lights as mentioned above, the incorrect instructions leading to, for example, one vehicle taking a turn at the traffic lights instead of proceeding ahead. This type of problem is partly due to the restricted number of available FM channels as mentioned above, leading to a higher probability of two neighbouring SRRs transmitting on the same FM channel. Furthermore, the problem use of the same FM channel only increases as the number of devices employing SRRs increases.

In order to mitigate such problems, it is known for portable devices, for example a PND, to employ an additional tuner to search for available FM channels. This provides scope to take advantage of Radio Data System (RDS) capabilities possessed by many in-vehicle entertainment systems, for example RDS FM radios. On an available channel, a portable device equipped with an RDS encoder transmits, inter alia, a Programme Identification (Pl) code, a Programme Service (PS) name (for example, "TomTom") and a list of Alternative Frequencies (AFs), the available channel and the list of AFs being selected from free channels detected amongst the FM landscape of channels in which the portable device is operating. The portable device also typically transmits an audio test message on the same available channel. The formation and transmission of the Pl code, the PS name and the list of AFs are in accordance with the RDS technical specification set out by the International Electrotechnical Commission (IEC).

AFs are usually used by broadcasters to identify their respective broadcast networks. A transmitted list of AFs indicates frequencies of adjacent transmitters associated with a same radio programme as a transmitter currently being received. FM radios in vehicles use the list of AFs to select and remain tuned to a transmitter with a best signal strength associated with the same network. The FM radios store the list of AFs received from the transmitter and update the list of AFs each time the FM radios tune to a different transmitter in the network. However, in the context of SRR transmitters, the AF feature can be used by the portable device to enable use of different frequencies so as to avoid interference both with mainstream broadcasters and other SRR transmissions.

In the vehicle, for example, the user sets the FM radio to scan for an FM transmission from the portable device and identified by the RDS information transmitted by the portable device. When the transmission by the portable device has been found by the FM radio, the frequency modulated audio signal transmitted by the portable device, typically the audio test message, is reproduced by the loudspeakers of the FM radio and a display of the FM radio displays the PS name, namely "TomTom" in this example.

Whilst employing RDS functionality in conjunction with the SRR can reduce coincidence of FM channel usage, the basic problem of poor audio quality reproduction is not necessarily solved. Indeed, it can be argued that use of the RDS in relation to S RR transm ission actually red uces system performance, because the RDS implementation described above typically requires the provision of an integrated transmitter and receiver that cannot be simultaneously active. In this regard, when frequency band scans or signal strength measurements are performed as part of a process to decide whether to re-tune to another frequency, the transmitter does not transmit whilst the receiver is active. Hence, a communications link between the SRR and the FM radio is interrupted, which can result in strong audio "noise" being heard by the user of the FM radio and disruption of listening, for example music and/or navigation instructions.

Unfortunately, regular frequency band scans need to be performed in order for the PND or other portable device to operate properly in a continuously changing FM channel landscape without intervention from the user. Furthermore, shortening the frequency band scans and performing multiple shorter band scans that, together, cover the FM spectrum of frequencies so as to avoid the noticeable interruption caused by a single long band scan of the FM spectrum has, in fact, an opposite effect, because switching times of current SRR chipsets are too slow, resulting in the mere act of deactivating the transmitter and activating the receiver being noticeable and this is before any measurements even take place.

Summary of the Invention According to a first aspect of the present invention, there is provided an electronic apparatus comprising: a processing resource operably coupled to a receiver of location-related data and arranged to perform, when in use, location determination; and a Radio Data System (RDS) communications unit capable of receiving Radio Frequency (RF) signals within a Frequency Modulation (FM) spectrum range; wherein the processing resource is arranged to access channel availability data associated with location data and to cooperate with the RDS communications unit in order to set the RDS communications unit to be able to use an RF channel identified by the channel availability data in respect of a transmission location that corresponds to the location data, the RDS communications unit being set in response to the processing resource determining that the channel availability data indicates that the RF channel is expected to be available for transmission thereon at the transmission location associated therewith.

The channel availability data may be arranged to provide in respect of the location data an indication of expected conflict of use with a known source of RF signal transmission also associated with the location data in the event that the RF channel is used by the RDS communications unit.

The location determination may provide a current location and the transmission location is the current location.

A predetermined plurality of RF channels may comprise the RF channel. The predetermined plurality of RF channels may be a subset of all channels in the Frequency Modulation (FM) spectrum range.

The predetermined plurality of RF channels may be substantially equally spaced across the FM spectrum range.

The plurality of RF channels may number 25 or less RF channels.

The processing resource may be arranged to access the channel availability data associated with the location data and to cooperate with the RDS communications unit in order to set the RDS communications unit to use another RF channel identified by the channel availability data in respect of the transmission location that corresponds to the location data; the RDS communications unit may be set in response to the processing resource determining that the channel availability data indicates that the RF channel is expected to be available for transmission thereon at the transmission location associated therewith and the RF channel is found to be unavailable in practice.

The processing resource may be arranged to record that the RF channel is unavailable in respect of the location data.

The channel availability data may comprise channel quality information. The apparatus may further comprise a look-up table comprising the channel availability data. The RF channel may constitute an Alternative Frequency (AF) channel.

The apparatus may further comprise a local data store arranged to store the channel availability data.

The apparatus may further comprise a cellular communications unit arranged to support receipt of a cell broadcast message; the cell broadcast message may comprise update data for updating the channel availability data.

The update data may include an identity of an RF channel to be used. The RF channel may be a best known RF channel for a geographic area associated with a current location of the apparatus. The cellular communications unit may be arranged to support receipt of a cell broadcast message; the cell broadcast message may comprise an instruction to enter a measurement mode. The instruction to enter the measurement mode may be in respect of collection of data associated with performance of an RF channel.

The location data may identify a location and the transmission location corresponds to the location data by being within a predetermined distance of the location.

The location data may identify a geographical area; the transmission location may correspond to the location data by being within the geographical area.

The channel availability data may correspond to availability of the RF channel when wireless receipt by a tuner of at least part of the FM spectrum range is suppressed.

Availability of the RF channel may correspond to signal strength of a wirelessly received signal on the RF channel being less than or equal to a predetermined signal strength threshold. According to a second aspect of the present invention, there is provided a navigation apparatus comprising the electronic apparatus as set forth above in relation to the first aspect of the invention.

The navigation apparatus may be a portable navigation device.

According to a third aspect of the present invention, there is provided a channel usage data communications system comprising: an electronic apparatus as claimed in any one of the preceding claims; and a server apparatus comprising a server data store, the server data store being arranged to store the channel availability data; wherein the server apparatus is capable of communicating with the electronic apparatus in order to service a request for the channel availability data. The server apparatus may be arranged to provide the electronic apparatus with channel availability data associated with a number of RF channels of the predetermined plurality of RF channels and in respect of common location data.

The channel availability data associated with the number of RF channels may constitute respective Alternative Frequencies.

The system may further comprise: an FM tuner coupled to a channel suppression module; wherein a wireless signal received by the tuner may be suppressed by the channel suppression module.

According to a fourth aspect of the present invention, there is provided a method of setting a Radio Data System (RDS) communications unit, the method comprising: accessing channel availability data associated with location data; determining that the channel availability data indicates that a Radio Frequency (RF) channel within a Frequency Modulation (FM) spectrum range is expected to be available for transmission thereon by the RDS communications unit at a transmission location corresponding to the location data; and setting the RDS communications unit in respect of the transmission location to be able to use the RF channel identified by the channel availability data, the RDS communications unit being set in response to the determination that the channel availability data indicates that the RF channel is expected to be available for transmission thereon.

According to a fifth aspect of the present invention, there is provided a computer program element comprising computer program code means to make a computer execute the method as set forth above in relation to the third aspect of the invention.

The computer program element may be embodied on a computer readable medium.

According to a sixth aspect of the present invention, there is provided an electronic apparatus comprising: a processing resource operably coupled to a receiver of location-related data and arranged to perform, when in use, location determination in order to determine a current location; and a Radio Data System (RDS) communications unit capable of receiving Radio Frequency (RF) signals within a Frequency Modulation

(FM) spectrum range; wherein the processing resource is arranged to cooperate with the

RDS communications unit in order to monitor at a current location an RF channel from a predetermined plurality of RF channels and to store performance data in respect of the

RF channel and the current location associated therewith; and the predetermined plurality of RF channels is a subset of all channels in the FM spectrum range.

It is thus possible to provide an electronic apparatus, a channel usage data communications system, and method of setting a radio data system communications unit that enable audio information to be reproduced by a Frequency Modulation (FM) tuner, for example disposed in a vehicle, with improved quality as a result of an ability to find quickly an available RF channel. Audio interruptions and durations thereof caused by the Alternative Frequency functionality of the RDS supported by the FM tuner is thus minimised as the need to re-tune is reduced. User experience in relation to the navigation apparatus is therefore improved as a result of the potentially annoying interruptions to listening being reduced in number and duration and the possibility of missing, for example, audible navigation instructions is thus also minimised. Hence, the user is less likely to deviate from a calculated route being followed. The ability to prevent deviation by a driver from the route being followed not only reduces inconvenience to the user, but also improves safety whilst driving. Conflict between the navigation apparatus and a source of RF transmissions, for example a transmitter of a radio station, both trying to transmit on an RF channel in respect of a same geographic area is obviated or at least mitigated. The need to re-tune to evaluate an RF channel in the FM spectrum is thus minimised. As a result of the improved performance described above, less manual re-tuning of the FM tuner is also required, thereby reducing driver workload and hence also improving safe use of the navigation apparatus and/or the FM tuner.

Other 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

At least one embodiment of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which:

Figure 1 is a schematic illustration of an exemplary part of a Global Positioning System (GPS) usable by a navigation apparatus;

Figure 2 is a schematic diagram of a channel usage data communications system and/or a data collection system supporting communication between a navigation apparatus and a server apparatus;

Figure 3 is a schematic diagram of electronic components of a navigation apparatus constituting an embodiment of the invention;

Figure 4 is a schematic diagram of a part of Figure 3 coupled to a radio data system communications unit;

Figure 5 is a schematic representation of an architectural stack employed by the navigation apparatus of Figure 3; Figure 6 is a schematic diagram of a module supported by the navigation apparatus of Figure 3; Figure 7 is a schematic diagram of the navigation apparatus of Figure 3 when located in a vehicle;

Figure 8 is a schematic diagram of a docking arrangement for optional use in the vehicle of Figure 7; Figure 9 is a schematic diagram of connectivity between an FM tuner, the navigation apparatus and an antenna input adaptor of Figure 7;

Figure 10 is a schematic diagram of the antenna input adaptor of Figures 7 and 9 in greater detail;

Figure 11 is a flow diagram of a method of communicating a radio-frequency signal using the navigation apparatus of Figure 3;

Figures 12 to 17 are screen shots from a display of the navigation apparatus following the method of Figure 1 1 ;

Figure 18 is a graph of FM spectrum usage when employing the antenna input adaptor of Figures 7, 9, and 10; Figure 19 is another graph of FM spectrum usage when employing the antenna input adaptor of Figures 7, 9, and 10;

Figure 20 is a flow diagram of a method of re-tuning a receiver;

Figure 21 is a flow diagram of a response by the receiver to the method of Figure 20; and Figure 22 is a flow diagram of a channel usage data collection method constituting a further embodiment of the invention.

Detailed Description of Preferred Embodiments

Throughout the following description identical reference numerals will be used to identify like parts.

One or more embodiments of the present invention will now be described with particular reference to a PND. It should be remembered, however, that the teachings herein are not limited to PNDs but are instead universally applicable to any type of electronic processing device capable of determining a location thereof, for example but not essentially those configured to execute navigation software in a portable and/or mobile manner so as to provide route planning and navigation functionality. It follows therefore that in the context of the embodiments set forth herein, an electronic apparatus is intended to include (without limitation) any type of route planning and navigation apparatus, irrespective of whether that device is embodied as a PND, a vehicle such as an automobile, or indeed a portable computing resource, for example a portable personal computer (PC), a mobile telephone or a Personal Digital Assistant (PDA) executing, for example, route planning and navigation software. Indeed, a mobile telephone, smartphone, a music player, such as an MP3 player, or the like can simply be employed in respect of some embodiments without the benefit of route planning or navigation software. With the above provisos in mind, the Global Positioning System (GPS) of Figure

1 and the like are used for a variety of purposes. In general, the 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 allows 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 100 comprises a plurality of satellites 102 orbiting about the earth 104. A GPS receiver 106 receives spread spectrum GPS satellite data signals 108 from a number of the plurality of satellites 102. The spread spectrum data signals 108 are continuously transmitted from each satellite 102, the spread spectrum data signals 108 transmitted each comprise a data stream including information identifying a particular satellite 102 from which the data stream originates. As mentioned above, the GPS receiver 106 generally requires spread spectrum data signals 108 from at least three satellites 102 in order to be able to calculate a two- dimensional position. Receipt of a fourth spread spectrum data signal enables the GPS receiver 106 to calculate, using a known technique, a three-dimensional position. In Figure 2, a channel usage data communications system comprises a navigation apparatus 200 capable of communicating, if desired in an embodiment, with a server 150 via a communications channel 152 supported by a communications network that can be implemented by any of a number of different arrangements. The communication channel 152 generically represents the propagating medium or path that connects the navigation apparatus 200 and the server 150. The server 150 and the navigation apparatus 200 can communicate when a connection via the communications channel 152 is established between the server 150 and the navigation apparatus 200 (noting that such a connection can be a data connection via mobile device, a direct connection via personal computer (not shown) via the internet, etc.).

The communication channel 152 is not limited to a particular communication technology. Additionally, the communication channel 152 is not limited to a single communication technology; that is, the channel 152 may include several communication links that use a variety of technology. For example, the communication channel 152 can be adapted to provide a path for electrical , optical , and/or electromagnetic communications signals, etc. As such, the communication channel 152 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, free space, etc. Furthermore, the communication channel 152 can include intermediate devices such as routers, repeaters, buffers, transmitters, and receivers, for example. In one illustrative arrangement, the communication channel 152 is supported by telephone and computer networks. Furthermore, the communication channel 152 may be capable of accommodating wireless communication , for example, infrared communications, radio frequency communications, such as microwave frequency communications, etc. Additionally, the communication channel 152 can accommodate satellite communication if required.

The communication signals transmitted through the communication channel 152 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 152. These signals may be modulated, encrypted and/or compressed signals as may be desirable for the communication technology. In this example, the navigation apparatus 200 comprising or coupled to the GPS receiver device 106, is capable of establishing a data session, if required, with network hardware of a communications network, for example a "mobile" communications network via a wireless communications terminal (not shown), such as a mobile telephone, PDA, and/or any device with mobile telephone technology, in order to establish a digital connection, for exa m p le a digital connection via known Bluetooth technology. Thereafter, through its network service provider, the mobile terminal or user equipment can establish a network connection (through the Internet for example) with the server 150. As such, a "mobile" network connection can be established between the navigation apparatus 200 (which can be, and often times is, mobile as it travels alone and/or in a vehicle) and the server 150 to provide a "real-time" or at least very "up to date" gateway for information.

In this example, the navigation apparatus 200 is a Bluetooth enabled navigation apparatus in order that the navigation apparatus 200 can be agnostic to the settings of the wireless communications terminal, thereby enabling the navigation apparatus 200 to operate correctly with the ever changing spectrum of mobile telephone models, manufacturers, etc. Model/manufacturer specific settings can, for example, be stored on the navigation apparatus 200, if desired. The data stored for this information can be updated.

Although not shown, instead of requiring the wireless communications terminal to provide access to the communications network, the navigation apparatus 200 can, of course, comprise mobile telephone technology, including an antenna, for example, or optionally using an internal antenna of the navigation apparatus 200. The mobile telephone technology within the navigation apparatus 200 can also include an insertable card (e.g. Subscriber Identity Module (SIM) card). As such , mobile telephone technology within the navigation apparatus 200 can similarly establish a network connection between the navigation apparatus 200 and the server 150, via the Internet for example, in a manner similar to that of any wireless communications-enabled terminal.

As explained above, the establishing of the network connection between the mobile device (via a service provider) and another device such as the server 150, using the Internet for example, can be done in any suitable known manner. In this respect, any number of appropriate data communications protocols can be employed, for example the TCP/IP layered protocol. Furthermore, the mobile device can utilize any number of communication standards such as CDMA2000, GSM, IEEE 802.1 1 a/b/c/g/n, etc. Hence, it can be seen that the Internet connection can be utilised, which can be achieved via a data connection using the mobile telephone or mobile telephone technology.

The server 150 includes, in addition to other components which may not be illustrated, a processor 1 54 constituting a processing resource and operatively connected to a memory 156 and further operatively connected, via a wired or wireless connection 158, to a mass data storage device 160. Depending upon the embodiment being implemented, the mass storage device 160 contains a store of, inter alia, location- based channel availability data and/or channel usage data. Further details of such data are set out later below. The mass storage device 160 can be a separate device from the server 150 or can be incorporated into the server 150. The processor 154 is further operatively connected to transmitter 162 and receiver 164, to transmit and receive information to and from the navigation apparatus 200 via the communications channel 152. The signals sent and received may include data, communication, and/or other propagated signals. The transmitter 162 and receiver 164 may be selected or designed according to the communications requirement and communication technology used in the communication design for the channel usage data communications system. Further, it should be noted that the functions of transmitter 162 and receiver 164 may be combined into a single transceiver.

As mentioned above, the navigation apparatus 200 can be arranged to communicate with the server 150 through communications channel 152. In one embodiment, the navigation apparatus 200 employs transmitter 166 and receiver 168, for example as part of internal mobile telephone technology, to send and receive data through the communications channel 152, noting that these devices can further be used to communicate with devices other than the server 150. Further, the transmitter 166 and receiver 168 are selected or designed according to communication requirements and communication technology used in the communication design for the navigation system and the functions of the transmitter 166 and receiver 168 may be combined into a single transceiver in a like manner to that described above in relation to the server apparatus 150. Of course, the navigation apparatus 200 comprises other hardware and/or functional parts, which will be described later herein in further detail. Software stored in server memory 156 provides instructions for the processor

154 and allows the server 150 to provide services to the navigation apparatus 200 and/or perform other data processing tasks. For example, the server apparatus 150 can provide a service involving processing requests for channel availability data from the navigation apparatus 200 and transmitting the channel availability data retrieved from the mass data storage 160 to the navigation apparatus 200. Of course, the server apparatus 150 can, optionally, support other functionality as will be described in further detail later below.

The server 150 can be used as a remote source of data accessible by the navigation apparatus 200 via, for example, a wireless channel. The server 150 may include a network server located on a local area network (LAN), wide area network (WAN), virtual private network (VPN), etc. Indeed, as mentioned above, a Personal Computer (PC) can be connected between the navigation apparatus 200 and the server 150 to establish an Internet connection between the server 150 and the navigation apparatus 200.

The navigation apparatus 200 may be provided with information from the server 150 via information downloads which may be periodically updated automatically or upon a user connecting the navigation apparatus 200 to the server 150 and/or may be more dynamic upon a more constant or frequent connection being made between the server 150 and navigation apparatus 200 via a wireless mobile connection device. An example of a suitable update service is a modified version of the "IQ Routes" service available from TomTom International B.V.

Referring to Figure 3, it should be noted that the block diagram of the navigation apparatus 200 is not inclusive of all components of the navigation apparatus, but is only representative of many example components. The navigation apparatus 200 is located within a housing (not shown). The navigation apparatus 200 includes a processing resource, for example a processor 202, the processor 202 being coupled to an input device 204 and a display device, for example a display screen 206. Although reference is made here to the input device 204 in the singular, the skilled person should appreciate that the input device 204 represents any number of input devices, including a keyboard device, voice input device, touch panel and/or any other known input device utilised to input information. Likewise, the display screen 206 can include any type of display screen such as a Liquid Crystal Display (LCD), for example.

In one arrangement, one aspect of the input device 204, the touch panel, and the display screen 206 are integrated so as to provide an integrated input and display device, including a touchpad or touchscreen input 310 (Figure 8) to enable both input of information (via direct input, menu selection, etc.) and display of information through the touch panel screen so that a user need only touch a portion of the display screen 206 to select one of a plurality of display choices or to activate one of a plurality of virtual or "soft" buttons. In this respect, the processor 202 supports a Graphical User Interface (GUI) that operates in conjunction with the touchscreen. In the navigation apparatus 200, the processor 202 is operatively connected to and capable of receiving input information from input device 204 via a connection 210, and operatively connected to at least one of the display screen 206 and an output device 208, via respective output connections 212, to output information thereto. The output device 208 is, for example, an audible output device (e.g. including a loudspeaker). As the output device 208 can produce audible information for a user of the navigation apparatus 200, it should equally be understood that input device 204 can include a microphone and software for receiving input voice commands as well. Further, the navigation apparatus 200 can also include any additional input device 204 and/or any additional output device, such as audio input/output devices. The processor 202 is operably coupled to a memory resource 214 via connection 216 and is further adapted to receive/send information from/to input/output (I/O) ports 218 via connection 220, wherein the I/O port 218 is connectible to an I/O device 222 external to the navigation apparatus 200. The memory resource 214 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 222 may include, but is not limited to an external listening device, such as an earpiece for example. The connection to I/O device 222 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 earpiece or headphones.

Figure 3 further illustrates an operative connection between the processor 202 and an antenna/receiver 224 via connection 226, wherein the antenna/receiver 224 can be a GPS antenna/receiver for example. It should be understood that the antenna and receiver designated by reference numeral 224 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. In order to support the functionality described herein, the processor 202 is also coupled to a Frequency Modulation (FM) port 228.

It will, of course, be understood by one of ordinary skill in the art that the electronic components shown in Figure 3 are powered by one or more 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 Figure 3 are contemplated. For example, the components shown in Figure 3 may be in communication with one another via wired and/or wireless connections and the like. Thus, the navigation apparatus 200 described herein can be a portable or handheld navigation apparatus.

Turning to Figure 4, the processor 202 is capable of communicating via the FM port 228 with a Radio Data System (RDS) communications unit 254. The RDS communications unit 254 comprises an RDS encoder 256 and communications circuitry to transmit both audio and RDS data in accordance with the RDS technical specification, for example as described in the IEC/CENELEC EN 62106 specification for RDS. As RDS communications units are known in the art, further detailed description of the structure of the RDS communications unit 254 will not be provided herein for the sake of clarity and conciseness of description. However, it should be appreciated that the RDS communications unit 254 includes an FM transmitter (not shown), an FM receiver (not shown) and a Traffic Message Channel (TMC) receiver (not shown) coupled to an RDS output port 258 that supports a wired connection to the RDS communications unit 254.

Turning to Figure 5, the memory resource 214 of the navigation apparatus 200 stores a boot loader program (not shown) that is executed by the processor 202 in order to load an operating system 262 from the memory resource 214 for execution by functional hardware components 260, which provides an environment in which application software 264 can run. The operating system 262 serves to control the functional hardware components 260 and resides between the application software 264 and the functional hardware components 260. The application software 264 provides an operational environment including the GUI that supports core functions of the navigation apparatus 200, for example map viewing, route planning, navigation functions and any other functions associated therewith. In this example, the application software 264 supports a channel availability query module 266. In another embodiment, the application software 264 additionally or alternatively supports a channel usage information acquisition module 268.

Referring to Figure 6, where channel usage data harvesting is required, the channel usage information acquisition module 268 is employed and comprises a channel scan control module 270 capable of communicating with a usage data processing module 272. The channel scan control module 270 is operably coupled, via the WAN mentioned above, to a remote channel usage database 274 supported by the mass storage device 160 of the server 150. Additionally, the usage data processing module 272 is also operably coupled to a temporary data store 276 supported by the memory resource 214. The harvesting of channel usage date will be described later herein. Referring to Figure 7, in the following examples, the navigation apparatus 200 is to be used in a vehicle, for example an automobile 300 having an in-vehicle entertainment system, for example an audio entertainment system, such as an FM radio 302 or tuner having an FM receiver (not shown) therein and a display 303. The FM radio 302 is coupled to a loudspeaker system 304. However, the skilled person should appreciate that the navigation apparatus 200 can be deployed in other environments where an RDS capable FM receiver exists that is coupled to one or more loudspeakers, the use of the loudspeakers being desired for audio output of audio signals originating from another device or apparatus, for example the navigation apparatus 200. The navigation apparatus 200 is, in this example, coupled to an antenna input adaptor device 306, the antenna input adaptor 306 being coupled in-line between the FM tuner 302 and an antenna (not shown). To facilitate use thereof, the portable or handheld navigation apparatus 200 of Figure 3 can be connected or "docked" in a known manner in the automobile 300, or any other suitable vehicle, for example to a bicycle, a motorbike or a boat. The navigation apparatus 200 is then removable from the docked location for portable or handheld navigation use. In this respect (Figure 8), the navigation apparatus 200 may be a unit that includes the integrated input and display device 310 and the other components of Figure 3 (including, but not limited to, the internal GPS receiver 224, the microprocessor 202, a power supply (not shown), memory resource 214, etc.).

The navigation apparatus 200 may sit on an arm 312, which itself may be secured to a vehicle dashboard/window/etc, using a suction cup 314. This arm 312 is one example of a docking station to which the navigation apparatus 200 can be docked. The navigation apparatus 200 can be docked or otherwise connected to the arm 312 of the docking station by snap connecting the navigation apparatus 200 to the arm 312 for example. The navigation apparatus 200 may then be rotatable on the arm 312. To release the connection between the navigation apparatus 200 and the docking station, a button (not shown) on the navigation apparatus 200 may be pressed, for example. Other equally suitable arrangements for coupling and decoupling the navigation apparatus 200 to a docking station are well known to persons of ordinary skill in the art.

Turning to Figure 9, a first input port 316 of the antenna input adaptor 306 is coupled to the antenna 318 by an antenna cable 320. A second input port 322 of the antenna input adaptor 306 is coupled to the RDS output port 258 of the navigation apparatus 200 by a wired connection, for example, a first antenna patch lead 324. An output port 326 of the antenna input adaptor 306 is coupled to an antenna input port 328 of the FM tuner 302 by a second antenna patch lead 330.

Referring to Figure 10, the first input port 316 of the antenna input adaptor 306 is coupled to the output port 326 thereof via a first switching unit 332. The first input port 316 is also coupled to a ground potential 334 via an antenna switching unit 336. The output port 326 of the antenna input adaptor 306 is also coupled to the second input port 322 thereof via a second switching unit 338. The antenna input adaptor 306 also comprises a control unit 340, the control unit 340 being coupled to the second input port 322 of the antenna input adaptor 306. In this example, the control unit 340 is also coupled to the first switching unit 332, the antenna switching unit 336 and the second switching unit 338 in order to be able to operate selectively the first switching unit 332, the antenna switching unit 336 and the second switching unit 338.

In this example, the first switching unit 332, the antenna switching unit 336 and the second switching unit 338 are any suitable switching devices, for example RF attenuators, Field Effect Transistors (FETs) or any other compatible solid state switching device. Indeed, the types of devices employed for the first switching unit 332, the antenna switching unit 336 and the second switching unit 338 can be a combination of different types of switching devices if it is expedient to make such a combination for a given application. Although, in this example, the antenna input adaptor 306 is described as an external device, the skilled person should appreciate that the antenna input adaptor 306 can be provided as an internal module in, for example, the FM tuner 302 or the navigation apparatus 200. In such embodiments, it should be understood that the antenna input adaptor module nevertheless still serves to adapt an antenna input port of an FM tuner that would, otherwise, be directly coupled to the antenna 318 without an ability to selectively decouple the antenna 318 from the FM tuner 302 in an automated manner.

In operation (Figure 11 ), it is assu med , for the sake of conciseness of description, that the antenna input adaptor 306 is already disposed in the automobile 300 and the first input port 316 of the antenna input adaptor 306 is coupled to the antenna 318 and the output port 326 is coupled to the FM tuner 302 in the manner already described above. Furthermore, in a default first state, the control unit 340 sets the first switching unit 332 to permit electrical coupling of the first input port 316 to the output port 326 of the antenna input adaptor 306. In the first state, the control unit 340 also sets the antenna switching unit 336 to decouple the first input port 316 and hence the antenna 318 from the ground potential 334 and sets the second switching unit 338 to decouple the second input port 322 and hence the navigation apparatus 200 (when connected) from the output port 326 of the antenna input adaptor 306.

In this example, a user of the navigation apparatus 200 wishes to drive to an office from home using traffic avoidance functionality of the navigation apparatus 200. After entering the automobile 300, the user couples the RDS output port 258 of the navigation apparatus 200 to the second input port 322 of the antenna input adaptor 306 using the first antenna patch lead 324 to complete the configuration already described above in relation to Figure 9. The user then powers-up (Step 400) the navigation apparatus 200 (Figure 12) and touches the touchscreen display 310 in order to access a menu structure supported by the GUI (Step 402). The user then selects (Step 404) the "Change preferences" menu option 350 (Figure 13) and then negotiates the menu structure (Step 406) to reach a "Speaker preferences" menu option 352 (Figure 14). Upon selecting the speaker preferences menu option 352, the GUI displays a first screen of speaker preference options 354 (Figure 15) in respect of audible instructions provided by the navigation apparatus 200. In this example, the user wishes the audible instructions to be played through the loudspeakers 304 in the automobile 300 and so selects (Step 408) an "FM to your car radio" option 356. The user then presses a "Done" soft button 358 to indicate that a final selection has been made and the GUI then displays a second screen of speaker preference options 360 (Figure 16) in respect of music provided by or via the navigation apparatus 200. In this example, it is possible to couple an electronic music player to the navigation apparatus 200 in order to permit play of music through the navigation apparatus 200, either through an internal speaker of the navigation apparatus 200 or another external output device. For the sake of simplicity, this example assumes that no music player or other source of audio signals is coupled to the navigation apparatus 200. However, the skilled person will appreciate that the principles described herein in relation to reproduction of the navigation instructions through the loudspeakers 304 of the FM radio 302 are applicable to the option of use of the loudspeakers 304 in relation to other sources of audio signals. As a consequence of the above assumption, the user does not modify any options presented on the second screen of speaker preference options 360 in respect of music and simply presses another "Done" soft key 362.

Thereafter, the RDS communications unit 254 can generate (Step 410) a trigger or control signal that is communicated to the antenna input adaptor 306 via the first antenna patch lead 324 and detected by the control unit 340 by virtue of the coupling of the control unit 340 to the second input port 322. However, in this example an RF signal used to communicate the audio information constitutes the control signal. In response to receipt of the trigger signal, circuitry of the control unit 340 transitions the antenna input adaptor 306 into a second state by setting the first switching unit 332 so as to decouple the first input port 316 from the output port 326 of the antenna input adaptor 306. In the second state, the control unit 340 also sets the antenna switching unit 336 to couple the first input port 316, and thus the antenna 318, to the ground potential 334 and sets the second switching unit 338 to couple the second input port 322 to the output port 326 of the antenna input adaptor 306 in place of the first input port 316.

Turning to Figure 18, the coupling of the antenna 318 to the ground potential 334 serves to suppress or attenuate RF signals received by the FM radio 302 via the antenna 318. Indeed, attenuation can be achieved by simply decoupling the antenna 318 from the output port 326 of the antenna input adaptor 306 and hence the FM radio 302 without coupling to the ground potential 334. However, the degree of attenuation is improved when the antenna 318 is coupled to the ground potential 334. As depicted in Figure 18, RF signals usually received on FM channels with associated strong signal strengths are attenuated, thereby providing channel "headroom", i.e. FM channels are "cleared" of RF signals from the receiving perspective of the navigation apparatus 200 and the FM radio 302, thus providing a greater number of available channels for use in the process of communicating audio information from the navigation apparatus 200 to the FM radio 302. In this respect, RF signals usually of strong signal strengths are attenuated to a level whereby they are no longer significant interference sources.

Referring to Figure 19, instead of scanning the entire FM spectrum of frequencies in order to identify available frequencies, the processing resource 202 and the RDS communications unit 254 supports a scheme that uses a predetermined plurality of frequency points or RF channels in the FM spectrum. The predetermined plurality of alternative frequency points serves as a common set of alternative frequencies to which reference can be made consistently, thereby enabling information concerning the FM spectrum to be collected and/or distributed with a common meaning associated therewith. I n this example, the predetermined plurality of alternative frequencies number, for example, 25 frequency points, and are uniformly spaced across the FM spectrum of frequencies. The predetermined plurality of RF channels is a subset of all channels in the FM spectrum range of frequencies.

Use of channel availability data in the context of the predetermined plurality of alternative frequencies will now be described. It will therefore be assumed that a database of channel availability data already exists. Collection of channel availability data will therefore be described later herein. The channel availability data can be stored locally by the navigation apparatus 200 or remotely by the server 150.

Once over-the-air reception of the FM spectrum has been attenuated by the antenna input adaptor 306 and the RDS communications unit 254 has been coupled to the antenna input port 328 of the FM tuner 302, in the example where the channel availability data is stored locally, the channel availability query module 266 retrieves (Step 412) channel availability data stored by the memory resource 214 in order to provide the RDS communications unit 254 with information concerning available channels amongst the predetermined plurality of RF channels, for example identifying RF channels that are not expected to be subject to interference. In relation to querying the database of channel availability data, the channel availability query module 266 is arranged to obtain the channel availability data that is associated with a current location of the navigation apparatus 200.

In this respect, the channel availability data stored in the database of channel availability data is location based. Irrespective of whether the database of channel availability data is locally or remotely stored, the channel availability query module 266 simply obtains a current location from a location determination module (not shown) of the application software 264 (or any other suitable mechanism for determining the current location) and uses the current location information, constituting a location at which transmission of audio information is desired, to query the database of channel availability data. Querying the database of channel availability data can be performed in a number of different ways as will be described later herein. In order to support querying of the database of channel availability data by location, the channel availability data comprises, in this example, location information to which other data of the channel availability data relates. Hence, in this example the channel availability data comprises, in respect of an associated location, data identifying the predetermined plurality of RF channels and data respectively identifying availability of each of the predetermined plurality of RF channels. In this respect, the channel availability data provides an indication of expected conflict of use with a known source of RF signal transmission also associated with the location information in the event that a given RF channel is used by the RDS communications unit 254. Availability of a channel corresponds to availability of the channel when at least part of the FM spectrum range of frequencies is suppressed . For example, availability can be determined with respect to a predetermined threshold value, such as a predetermined signal strength threshold. A channel can be deemed available if a strength of a received signal in respect of the channel is less than or equal to the predetermined signal strength threshold. As a result of the query executed by the channel availability query module 266, the channel availability data retrieved corresponds to the current location as determined above.

In another example, the channel availability data also comprises data identifying quality of each RF channel of the predetermined plurality of RF channels. An example of such enhanced channel availability data is set out in Table I, below:

Table I

Although the channel availability data is shown as a table above, the skilled person should appreciate that the channel availability data need not be organised in tabular form in other embodiments.

The channel availability data stored in the database of channel availability data can be static and based upon available data concerning FM spectrum usage, for example frequency allocation information contained in a so-called "World Radio Handbook" detailing channel usage and associated location information. Alternatively, the database of channel availability data can be dynamic and "built" from information acquired by a population of navigation apparatus in a manner to be described later herein.

In the event that the database of channel availability data is stored remotely from the navigation apparatus 200, the channel availability query module 266 sends a request

(Step 412) for the channel availability data to a remote source, for example the server

150, storing the database of channel availability data using the wireless communications capability of the navigation apparatus 200. The request message comprises data identifying the nature of the request message and the current location of the navigation apparatus 200. The server 150 receives the request message and a channel usage data search module 155 supported by the processor 154 of the server 150 services the request message by querying the database of channel availability data stored by the data store 160 in order to obtain the channel availability data relating to the current location of the navigation apparatus 200. Thereafter, the server 150 sends a reply message comprising the channel availability data to the navigation apparatus 200, the channel availability query module 266 consequently receiving (Step 414) the channel availability data and processing the channel availability data in a manner to be described later herein.

As mentioned above, the channel availability data can be queried in a number of ways. In this respect, the location data stored in the database of channel availability data can be in accordance with the World Geodetic System, revision 84 (WGS84), and identify a coverage area, for example by identifying two corners of a rectangular area. Alternatively, the location data can identify a central location and a predetermined radius, defining a circular coverage area, can be assumed , for example 5km. Consequently, when the channel availability query module 266 performs a query, the channel availability query module 266 identifies channel availability data where the current or transmission location is within the coverage area mentioned above and hence corresponds to the location data. In an alternative query technique, the channel availability data comprises identities of locations, identified for example by coordinates of a point, associated with the predetermined plurality of RF channels and associated availability data. A query by the channel availability query module 266 comprises seeking channel availability data in respect of a closest location associated with data identifying the predetermined plurality of RF channels to the current location of the navigation apparatus 200.

Once the channel availability data has been obtained from the database of channel availability data, the channel availability data retrieved is analysed (Step 415) by the channel availability query module 266 in order to identify a set of RF channels amongst the predetermined plurality of RF channels that are expected to be available. In Table I, the Channel Occupation Indicator (COI) field comprises availability data, a value of T indicating a channel is occupied, and O' indicating the channel is available. The set of available RF channels of the predetermined plurality of RF channels is communicated by the channel availability query module 266 to the RDS communications unit 254 in order to set the RDS communications unit 254 to use the available RF channels as AFs, whereas the remaining unavailable frequencies from the number of alternative frequencies are precluded from use as AFs in respect of future re-tuning.

Hence, instead of having to scan the entire FM spectrum range of frequencies, the RDS communications unit 254 only has to use a set of available RF channels from the predetermined plurality of RF channels provided by the channel availability query module 266. In another embodiment, the channel availability data can comprise information identifying the quality of a given RF channel. In Table I above, the information identifying channel quality is contained in a Best Choice Indicator (BCI) field of the channel availability data. The information identifying channel quality is, in this example, derived from average signal strength measurements over time or average signal-to- noise ratios over time. However, alternative types of information can be employed to indicate quality, for example if data is collected and available in relation to duration of time when a tuner of a navigation apparatus is tuned to a given channel, then average tuned time can be used as the indicator of channel quality. Irrespective of the metric used to quantify the quality of the channels, the quality can be represented on a scale, for example between 0 and 127.

In a further embodiment, the set of RF channels selected from amongst the predetermined plurality of RF channels can be ordered by the processing resource 202, for example in order of quality of the channels, prior to communication to the RDS communications unit 254. Alternatively, the RDS communications unit 254 can be arranged to receive the set of RF channels and perform the ordering of the channels for use as AFs.

The set of available RF channels identified by the channel availability query module 266 to serve as an initial tuned frequency and the AFs are then stored by another memory resource (not shown), of the RDS communications unit 254. In this respect, it is known that a typical memory allocation made in respect of FM receivers is for storage of 25 AFs, which is consistent with the number of Alternative Frequencies that can be transmitted relating to a Pl code using the type OA message set out in the RDS technical specification. Optionally, in order to avoid filling the memories of receivers, for example of the FM radio 302, the channel availability query module 266 caps the number of AFs selected to a predetermined maximum quantity of AFs that is less than the capacity of the typical memory capacity of receivers, for example by a margin of entries. For example, the number of AFs selected can be less than 25, such as about 20. Once the number of AFs has been selected from the plurality of AFs identified, the RDS communications unit 254 of the navigation apparatus 200 selects a first frequency from the set of available frequencies and tunes to the selected frequency and transmits (Step 416) first RDS data, for example type OA groups, comprising a list of the selected AFs. Of course, the RDS communications unit 254 transmits other RDS data, for example a Programme Identification code and the Programme Service name ("TomTom") associated with the tuned frequency. In this example, the Programme Identification code can be generated in accordance with the technique proposed by the RDS Foru m for portable electronic apparatus known to those skilled in the art. Furthermore, the list of AFs is usually communicated over a series of messages or groups.

The GUI then passes to an instruction screen (Figure 17), which instructs the user to tune the FM radio 302, in the present example located in the automobile 300, to a channel identified by the Programme Service name "TomTom". The user therefore sets the FM radio 302 to scan for stations (Step 418), RDS capabilities of the FM radio 302 enabling the name of each station detected to be presented by the display 303 of the FM radio 302. The above procedure therefore eventually results in the FM radio 302 being tuned to the TomTom "channel", the frequency associated with the TomTom channel being the selected tuned frequency. The first RDS data, for example the type OA group comprising the list of selected AFs, is also received in respect of the tuned frequency. As part of the tuning process, the FM radio 302 stores the selected AFs received in a respective space allocated in the memory (not shown) thereof reserved for a channel being received.

Once the FM radio 302 has acquired the "TomTom" broadcast, the user presses a further "Done" soft key 364 (Figure 17) and the GUI responds by returning (Step 420) to a map display screen (Figure 12). Once the FM radio 302 has been tuned to the TomTom channel, audio signals transmitted by the navigation apparatus 200, for example navigation instructions when navigation functionality of the navigation apparatus 200 is used, are reproduced by the loudspeakers 304 once, for example, a route has been set or an instruction provided to avoid traffic by a user of the navigation apparatus 200. In this respect, the RF signal associated with the audio information is communicated from the navigation apparatus 200 to the FM radio 312 via a wired connection formed by the first and second antenna patch leads 324, 330 and the antenna input adaptor 306.

Referring back to Figure 18, due to the wired connection between the navigation apparatus 200 and the FM radio 302, the received signal strength associated with the TomTom channel 372 is high, unattenuated and a substantial margin exists between the received signal strengths of the TomTom channel 372 and the other (attenuated) FM channels 370 received via the antenna 318. Indeed, further attenuation is also achieved where the FM radio 302 employs Automatic Gain Control (AGC) in order to attenuate the RF signal associated with the TomTom channel 372, thereby also further attenuating the usually good, but unwanted, already attenuated received RF signals mentioned above. Of course, even better attenuation can be achieved where the AGC is selective. Turning to Figure 20, the navigation apparatus 200, via the RDS communications unit 254, transmits (Step 422) RDS data including the number of AFs as mentioned above, the AFs being stored in the allocated memory space of the FM radio 302. In the geographic area associated with the current location, the FM spectrum "landscape" from the perspective of the FM radio 312 and/or the RDS communications unit 254 can change as a result of a number of different factors, for example the introduction of a new channel broadcast in the geographic area or as a result of travel of the navigation apparatus 200 because signals originating from some FM signal transmitters become more dominant as the automobile 300 travels towards these FM signal transmitters, and signals originating form some other FM signal transmitters become less dominant as the automobile 300 travels away from these FM signal transmitters. In addition to broadcasts from radio stations, broadcasts can originate from other devices equipped with SRRs within sufficient proximity to the FM radio 302. The RDS communications unit 254 therefore monitors quality of the FM channel currently being used to transmit audio information from the navigation apparatus 200. As mentioned above, the received signal strength measured at the FM tuner 302 in respect of some FM channels increases and the received signal strength decreases in respect of other FM channels. Hence, interference can increase unexpectedly and received signal strength associated with the RF signals sent by the navigation apparatus 200 can fall. The RDS communications unit 254 therefore monitors, via the FM receiver thereof, the interference and once the level of the interference reaches a level that is deemed detrimental (Step 424) to the quality of reproduction by the FM radio 302 of the audio information transmitted by the navigation apparatus 200, it is deemed necessary to re-tune the RDS communication unit 254 to another frequency. In this respect, the another frequency is selected (Step 426) from the set of AFs previously selected. Typically, the another frequency is a first AF in the list of AFs. The RDS communications unit 254 then re-tunes (Step 428) to the another frequency and continues transmitting the audio information mentioned above (Step 430) using an alternative channel corresponding to the first AF.

At the FM radio 302 (Figure 21 ), the receiver thereof monitors (Step 450) receive signal strength. Whilst the receive signal strength associated with the tuned frequency is sufficiently strong, the receiver of the FM radio 302 continues to receive on the tuned frequency in accordance with the RDS technical specification. However, when the receive signal strength falls below a threshold value, the FM radio 302 accesses the memory thereof to identify a first AF from the number of AFs stored in the memory of the FM radio 302 and re-tunes (Step 452) to the first AF selected. The FM radio 302 then monitors (Step 454) the receive signal strength associated with the first AF retrieved from the memory of the FM radio 302. If the signal strength associated with the first AF is inadequate, the FM radio 302 accesses the memory thereof again to identify a second AF from the number of AFs stored in the memory of the FM radio 302 and re-tunes (Step 456) to the second AF selected. The above procedure (Steps 454 and 456) is repeated until another AF has been found that has an adequate signal strength associated therewith. The RDS communications unit 254 mirrors this re-tuning behaviour of the FM radio 302 by using the same AF list and so the RDS communications unit 254 and the FM radio 302 step through the same channels stored in the respective AF lists substantially in tandem until a suitable channel is found. Hence, whilst a channel is expected to be available, another channel is used when the channel is found to be unavailable in practice.

Once the FM receiver 302 has tuned to an AF having adequate signal strength associated therewith and a correct Programme Identification code, the FM radio 302 proceeds to continue receiving (Step 458) the audio information mentioned above. Whilst the navigation apparatus 200 is travelling, and as mentioned above, the

FM spectrum landscape can change. In addition to the reasons already provided above in relation to the geographic area, the navigation apparatus 200 can travel sufficiently far to leave the geographic area in respect of which the channel availability data is currently being used and enter a new geographic area. In such circumstances, it is necessary to ensure that the channel availability data being used by the RDS communications unit 254 is updated with current channel availability data. In this respect, the channel availability query module 266 periodically acquired the current location of the navigation apparatus 200 from the location determination module mentioned above. The current location is used to query the database of channel availability data in order to ensure that the channel availability data currently being used by the RDS communications unit 254 is current and appropriate for the current location of the navigation apparatus 200. In the event that the channel availability query module 266 determines that the channel availability data is no longer current with respect to the current location, the channel availability query module 266 finds new channel availability data for the updated current location of the navigation apparatus 200 in the database of channel availability data. The new channel availability data is acquired and passed to the RDS communications unit 254 and the RDS communications unit 254 transmits type OA groups identifying new AFs derived from the new channel availability data. The new AFs are generated and used in the manner already described above in relation to the initial acquisition of the channel availability data.

Once the user has finished using the navigation apparatus 200 and the navigation apparatus 200 is either powered-down or the first antenna patch lead 324 is disconnected from the navigation apparatus 200 and/or the antenna input adaptor 306, the control unit 340 operates the first switching device 332, the antenna switching device 336 and the third switching device 338 such that antenna input adaptor 306 transitions back to the first state described above. Indeed, the navigation apparatus 200 can be arranged specifically to issue a control signal to the antenna input adaptor 306 to implement the transition back to the first state, although in this example the response by the control unit 340 is automatic by virtue of the control unit 340 monitoring the first antenna patch lead 324. In this respect, in this embodiment the control unit 340 uses the presence or absence of the RF signal received at the second input port 332 as the control signal. Of course, the skilled person should appreciate that, if desired, a separate, dedicated, control line can be provided between the navigation apparatus 200 and the antenna input adaptor 306 to provide the control signal to influence the control logic of the control unit 340. In the above embodiment where the database of channel availability data is stored locally by the navigation apparatus 200 or in an alternative embodiment, it can be necessary to update part or all of the channel availability data. This is achieved by an update communication, for example an update message or messages received, from the server 150. In this respect, it is assumed that the server 150 is capable of storing channel availability data in order to provide the update communication. However, the skilled person will appreciate that another suitable server can be employed and not necessarily the same server as is used to service any requests for channel availability data based upon a current location of the navigation apparatus 200.

The update communication can be communicated from the server 150 to the navigation apparatus 200 via a wireless data communication using the GPRS of a GSM network, a UMTS data session or one or more cell broadcast messages, for example a GSM cell broadcast message. Additionally or alternatively, the update of the part or all of the channel availability data can be performed when the navigation apparatus 200 is capable of communicating with the server 150 via a wired Internet connection, for example via a device management application, such as the TomTom HOME device management application. It should be appreciated that updates need not be in respect of all of the predetermined plurality of channels for a given location, but can be in respect of one or more channels.

In any of the above embodiments, where an RF channel is expected to be available, but is found in practice to be unavailable, the unavailability of the RF channel at the current location can be, in another embodiment, recorded and, optionally, communicated to the server 150 as an update in accordance with any communication technique described herein.

As mentioned above, the database of channel availability data can be generated and/or maintained by a population of navigation apparatus. In this respect, the database of channel availability data can be initiated from a core of frequency allocation information data obtained from the World Radio Handbook as a starting point, i.e. the frequency allocation data constitutes seed data, or the database can be built from an empty status. In the present example, the database of channel availability data, whether initially empty or populated by the seed data acquired from the World Radio Handbook or any other suitable source of information concerning geographic distributions of FM spectrum usage, is stored by the data store 160 of the server 150.

In this example, the server 150 is dedicated to generation of the database of channel availability data. However, the skilled person should appreciate that the server 150 can, in other embodiments, be shared for other purposes, for example as described in the embodiments above.

Operation of the above server apparatus 150 will now be described in the context of channel availability data being generated by a population or community of navigation apparatus and communicated to the server apparatus 150 or another computing resource in order to create and/or supplement the database of channel availability data. However, the skilled person should appreciate that channel availability data harvesting can additionally or alternatively be performed for maintenance of the database of channel availability data when stored locally by each navigation apparatus 200 individually.

In the present example, each of the navigation apparatus in the population, for example the navigation apparatus 200, is configured with an ability to collect RF channel usage information relating to a current location of the navigation apparatus 200. Collection of channel availability data can be triggered, if desired, upon a certain criterion being met, for example a current location calculated being a predetermined distance from a last known location. Turning to Figure 22, the navigation apparatus 200 is powered-up (Step 460) and participates in a journey of a user thereof. The user can optionally require navigation assistance or any other service supported by the navigation apparatus 200, but the navigation apparatus 200 can equally be powered-up and used for free-driving.

During a period of time when the navigation apparatus 200 is powered-up, the location determination module of the application software 264 mentioned above is used by the channel scan control module 270 of the channel usage information acquisition module 268 in order to determine (Step 462) a current location of the navigation apparatus 200. Thereafter, the channel scan control module 270 determines (Step 464) whether the distance travelled with respect to a previous recorded current location is equal to or exceeds a distance threshold value, for example 2km. Alternatively, the channel scan control module 270 can measure elapse of time in order to determine whether channel usage data needs to be collected. In the present example, the criterion is distance and so the channel scan control module 270 makes the above assessment (Step 464) in order to determine whether channel usage data needs to be collected. In the event that the channel scan control module 270 determines that insufficient distance has been travelled, the channel scan control module 270 waits (Step 466) a predetermined amount of time and then repeats the above steps of determining the current location and determining whether the navigation apparatus 200 has travelled sufficient distance to necessitate collection of channel usage data (Steps 462, 464). In this respect, the determination of distance travelled is not assessed with respect to the previous current location that resulted in a decision that insufficient distance had been travelled by the navigation apparatus 200, but with respect to the last recorded current location resulting in a determination that channel usage data needed to be collected.

When channel usage or performance data collection is triggered, the channel scan control module 270 instructs the RDS communications unit 254 to perform a scan (Step 468) in respect of each RF channel of the predetermined plurality of channels mentioned above in relation to previous embodiments, for example by sweeping a respective range of frequencies about, and including, each of the frequencies associated with the predetermined plurality of RF channels instead of the entire FM spectrum range of frequencies. The size of the range of frequencies swept corresponds to, for example, the bandwidth of an FM "channel". The predetermined plurality of channels is pre-stored in the navigation apparatus 200 for use by the channel scan control module 270.

If desired, instead of using the FM receiver as described above, a TMC receiver of the RDS communications unit 254 can be used to perform the scans in respect of the number of candidate alternative frequencies. Typically, a TMC broadcast provides a sufficient number of small time slots containing no TMC data to permit performance of each scan, for example respectively during an empty time slot, without loss of receipt of TMC messages during measurement in respect of the predetermined plurality of channels. An empty time slot can be a time slot that does not comprise TMC content. Consequently, should the RDS communications unit 254 be involved in communicating audio information from the navigation apparatus 200 to the FM radio 302 for reproduction thereby, the reproduction of the audio information is not interrupted by measurements made by the TMC receiver of the RDS communications unit 254.

For each channel in respect of which the RDS communications unit 254 has performed a scan, the channel scan control module 270 communicates the results of each scan to the usage processing module 272 for further processing. In this respect, the usage processing module 272 obtains a signal strength value in respect of the FM spectrum as attenuated by the antenna input adaptor 306. The signal strength value is provided by the RDS communications unit 254 via the channel scan control module 270. The usage processing module 272 stores the signal strength value obtained and the location information associated therewith in the temporary data store 276.

In another embodiment, the channel usage data comprises multiple measurements in respect of a geographic area. The geographic area can be identified in a number of ways, for example by a pair of coordinates identifying a rectangular area. For each channel of the predetermined plurality of RF channels, the channel scan control module 270 acquires multiple signal strength measurements in respect of and within the geographical area. The usage processing module 272 then creates a record or log entry in accordance with a suitable data structure and comprising multiple measurements for each channel of the predetermined plurality of channels in respect of the geographic area. An example of a record, shown in tabular form by way of example, is set out below in Table II:

value value value value value

value

Table Il

In yet another embodiment, the channel usage data can be collected and expressed in another manner. Instead of collecting multiple measurements, the channel scan control module 270 acquires multiple measurements between two locations, for example points on boundaries of the geographic area mentioned above. In this respect, the measurements of signal strength acquired by the channel scan control module 270 are communicated to the usage processing module 272 and used to maintain a record of a maximum field strength value and an average field strength value calculated in respect of each channel of the predetermined plurality of channels. The interval between measurements is, in this example, in accordance with the distance criterion described previously above. The usage processing module 272 creates a record or log entry in accordance with a suitable data structure and comprising the maximum signal strength measured and the average signal strength for each channel of the predetermined plurality of channels in respect of the geographic area. An example of a record, shown in tabular form, is set out below in Table III:

Table

I n a further embodiment, the above-described techniques for collection of channel usage data can be combined if desired.

As mentioned above, the channel usage data is recorded in a log, for example a log file, which is stored by the digital memory of the navigation apparatus 200. The log is communicated to the server apparatus 150 when a communications session is next established between the navigation apparatus 200 and the server apparatus 150, for example using the TomTom HOME system whereby the navigation apparatus 200 is docked with the Personal Computer (PC) (mentioned above) or other computing device and the communications session is established via an Internet connection to which the PC is coupled. Data transfers can thus take place between the navigation apparatus 200 and the server 150. Of course, if the navigation apparatus 200 is suitably equipped to support wireless communications over a WAN, for example where the navigation apparatus 200 is equipped with a cellular telephone module or operably coupled to a mobile telephone, the navigation apparatus 200 can send periodic updates to the server apparatus 150 without having to wait to be docked with the PC.

At the server apparatus 150, the channel usage data is aggregated and processed in order to generate channel availability data for predetermined geographical areas. In this respect, the aggregated data can be binned by dividing the geographical area into cells of a predetermined shape, for example circular, hexagonal or square, and averaging the signal strength values collected for each cell. Thereafter, the processed channel usage data can be used to determine channel availability data for geographic areas, for example channel availability values determined with respect to a signal strength threshold value and, if desired, channel quality data determined in relation to a predetermined scale as described above.

In another embodiment, it can be desirable to provide a measurement mode and a non-measurement mode in respect of the above-described measurements. In this regard, the navigation apparatus 200 can be controlled, for example, remotely to enter or leave the measurement mode. One way of selectively controlling entry into or exit from the measurement mode in a given geographic area is by arranging the application software 264 of the navigation apparatus 200 to detect a GSM cell broadcast bearing an instruction message to enter or leave the measurement mode. In response to the instruction message to enter the measurement mode, the navigation apparatus 200 performs the collection of channel usage data in accordance with any of the above- described embodiments until another instruction message is received to leave the measurement mode or the navigation apparatus 200 is powered down, or optionally when the navigation apparatus 200 leaves the current cell.

In a further embodiment, the GSM cell broadcast facility can be used to provide the navigation apparatus 200 with an identity of an RF channel. The RF channel identified can be a best known RF channel to use in a geographic area associated with the current location of the navigation apparatus 200. In this respect, the RF channel can be identified for transmission to one or more navigation apparatus in a given geographic area in response to, for example, a number of reports of poor channel conditions. Such reports can be automatically generated by the one or more navigation apparatus.

In the above example, although a GSM cell broadcast has been employed, the cell broadcast facility need not be a GSM cell broadcast and other cell broadcast facilities supported by other communications systems can be employed, for example the UMTS. Indeed, the instruction message need not be communicated by a point-to- multipoint communication and point-to-point communications, for example Short Message Service (SMS) communications, can be employed. In yet a further embodiment, the channel availability data stored locally can be maintained for private use by the navigation apparatus 200 and only shared with the server 150 if permitted by the user. In such an embodiment, the channel usage data collected by the navigation apparatus 200 is processed locally in the manner described above as opposed to being processed by the server 150. Hence, it can be seen that the channel availability data stored by the navigation apparatus 200 is specific to the exposure of the navigation apparatus 200 to the FM spectrum of frequencies in locations where the navigation apparatus 200 has been present. It should therefore be understood where channel availability data has been generated and is not, for example, available from a central repository or sharing arrangement, the channel availability data stored locally is transferable, for example by storage by portable storage media, or through a facility supported by a device management application for transfer of the channel availability data between devices, for example when the user purchases a replacement navigation apparatus. The data transfer facility supported by the device management application can cooperate with a remote server to provide the facility, for example to enable central storage of data. Whilst the above examples have been predominantly described in the context the

RDS, the skilled person will appreciate the above embodiments can be employed in relation to the different technical specification implemented in North America, for example in the United States of America, known as the Radio Broadcast Data System (RBDS). Hence, for the avoidance of doubt, references herein to the RDS should be construed to embrace the RBDS as well.

It should 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, it should be noted that although the RDS communications unit 254 described herein is internal to the navigation apparatus 200, the FM port 228 can be provided for coupling an external RDS communications unit to the navigation apparatus 200 or any other suitable portable electronic apparatus. As another example, whilst embodiments described in the foregoing detailed description refer to GPS, it should be noted that the navigation apparatus may utilise any kind of position sensing technology as an alternative to (or indeed in addition to) the GPS. For example the navigation apparatus may utilise other global navigation satellite systems (GNSS) such as the proposed European Galileo system when available. 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, for example the long range navigation (LORAN)-C system.

By way of further example, it should be appreciated that although the above embodiments have been described in the context of a navigation apparatus, the techniques described herein are not only applicable to navigation apparatus, but also to any other electronic apparatus capable of location self-determination and in respect of which it is desirable to transmit RDS or RDBS data on an FM channel for receipt by an FM receiver, for example mobile telephones or media players, such as music players, in particular but not exclusively MP3 players or accessories therefor. Alternative embodiments of the invention can be implemented as a computer program product for use with a computer system, the computer program product being, for example, a series of computer instructions stored on a tangible data recording medium, such as a diskette, CD-ROM, ROM, or fixed disk, or embodied in a computer data signal, the signal being transmitted over a tangible medium or a wireless medium, for example, microwave or infrared. The series of computer instructions can constitute all or part of the functionality described above, and can also be stored in any memory device, volatile or non-volatile, such as semiconductor, magnetic, optical or other memory device.

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. An electronic apparatus comprising: a processing resource operably coupled to a receiver of location-related data and arranged to perform, when in use, location determination; and a Radio Data System (RDS) communications unit capable of receiving Radio Frequency (RF) signals within a Frequency Modulation (FM) spectrum range; wherein the processing resource is arranged to access channel availability data associated with location data and to cooperate with the RDS communications unit in order to set the RDS communications unit to be able to use an RF channel identified by the channel availability data in respect of a transmission location that corresponds to the location data, the RDS communications unit being set in response to the processing resource determining that the channel availability data indicates that the RF channel is expected to be available for transmission thereon at the transmission location associated therewith.

2. An apparatus as claimed in Claim 1 , wherein the channel availability data is arranged to provide in respect of the location data an indication of expected conflict of use with a known source of RF signal transmission also associated with the location data in the event that the RF channel is used by the RDS communications unit.

3. An apparatus as clai med i n Cla im 1 or Clai m 2 , wherein the location determination provides a current location and the transmission location is the current location.

4. An apparatus as claimed in Claim 1 or Claim 2 or Claim 3, wherein a predetermined plurality of RF channels comprises the RF channel.

5. An apparatus as claimed in Claim 4, wherein the predetermined plurality of RF channels is a subset of all channels in the Frequency Modulation (FM) spectrum range.

6. An apparatus as claimed in Claim 4 or Claim 5, wherein the predetermined plurality of RF channels are substantially equally spaced across the FM spectrum range.

7. An apparatus as claimed in Claim 4 or Claim 5 or Claim 6, wherein the plurality of RF channels numbers 25 or less RF channels.

8. An apparatus as claimed in any one of the preceding claims, wherein the processing resource is arranged to access the channel availability data associated with the location data and to cooperate with the RDS communications unit in order to set the RDS communications unit to use another RF channel identified by the channel availability data in respect of the transmission location that corresponds to the location data, the RDS communications unit being set in response to the processing resource determining that the channel availability data indicates that the RF channel is expected to be available for transmission thereon at the transmission location associated therewith and the RF channel is found to be unavailable in practice.

9. An apparatus as claimed in Claim 8, wherein the processing resource is arranged to record that the RF channel is unavailable in respect of the location data.

10. An apparatus as claimed in any one of the preceding claims, wherein the channel availability data comprises channel quality information.

1 1. An apparatus as claimed in any one of the preceding claims, further comprising a look-up table comprising the channel availability data.

12. An apparatus as claimed in any one of the preceding claims, wherein the RF channel constitutes an Alternative Frequency (AF) channel.

13. An apparatus as claimed in any one of the preceding claims, further comprising a local data store arranged to store the channel availability data.

14. An apparatus as claimed in any one of the preceding claims, further comprising a cellular communications unit arranged to support receipt of a cell broadcast message, the cell broadcast message comprising update data for updating the channel availability data.

15. An apparatus as claimed in any one of the preceding claims, wherein the location data identifies a location and the transmission location corresponds to the location data by being within a predetermined distance of the location.

16. An apparatus as claimed in any one of claims 1 to 14, wherein the location data identifies a geographical area, the transmission location corresponding to the location data by being within the geographical area.

17. An apparatus as claimed in any one of the preceding claims, wherein the channel availability data corresponds to availability of the RF channel when wireless receipt by a tuner of at least part of the FM spectrum range is suppressed.

18. An apparatus as claimed in Claim 17, wherein availability of the RF channel corresponds to signal strength of a wirelessly received signal on the RF channel being less than or equal to a predetermined signal strength threshold.

19. A navigation apparatus comprising the electronic apparatus as claimed in any one of the preceding claims.

20. A channel usage data communications system comprising: an electronic apparatus as claimed in any one of the preceding claims; and a server apparatus comprising a server data store, the server data store being arranged to store the channel availability data; wherein the server apparatus is capable of communicating with the electronic apparatus in order to service a request for the channel availability data.

21. A system as claimed in Claim 20, when dependent upon Claim 4, wherein the server apparatus is arranged to provide the electronic apparatus with channel availability data associated with a number of RF channels of the predetermined plurality of RF channels and in respect of common location data.

22. A system as claimed in Claim 20 or Claim 21 , further comprising: an FM tuner coupled to a channel suppression module; wherein a wireless signal received by the tuner is suppressed by the channel suppression module.

23. A method of setting a Radio Data System (RDS) communications unit, the method comprising: accessing channel availability data associated with location data; determining that the channel availability data indicates that a Radio Frequency (RF) channel within a Frequency Modulation (FM) spectrum range is expected to be available for transmission thereon by the RDS communications unit at a transmission location corresponding to the location data; and setting the RDS communications unit in respect of the transmission location to be able to use the RF channel identified by the channel availability data, the RDS communications unit being set in response to the determination that the channel availability data indicates that the RF channel is expected to be available for transmission thereon.

24. A computer program element comprising computer program code means to make a computer execute the method as claimed in Claim 23.

25. A computer program element as claimed in Claim 24, embodied on a computer readable medium.

26. An electronic apparatus comprising: a processing resource operably coupled to a receiver of location-related data and arranged to perform, when in use, location determination in order to determine a current location; and a Radio Data System (RDS) communications unit capable of receiving Radio Frequency (RF) signals within a Frequency Modulation (FM) spectrum range; wherein the processing resource is arranged to cooperate with the RDS communications unit in order to monitor at a current location an RF channel from a predetermined plurality of RF channels and to store performance data in respect of the RF channel and the current location associated therewith; and the predetermined plurality of RF channels is a subset of all channels in the FM spectrum range.