US 20040243307 A1
A personal GPS navigation device capable of simultaneously displaying a map, an indication of the current position of the device on the map and a GPS signal strength indicator. The device differs from the prior art in displaying a GPS signal strength indicator at the same time as the navigation map and hence does not require a user to leave the navigation mode to call up a separate GPS information screen in order to see the GPS signal strength. The GPS navigation device of this invention is further capable of displaying icons indication Points of Interest, whose display may be prioritised by type or by density of occurrence. The GPS of this invention is further able to calculate a speed of the device and use that speed to change the zoom of the map. The device is also able to change map zoom as the device approaches route situations requiring complex decisions.
1. A personal GPS navigation device programmed to display, at the same time, each of the following:
(a) a map;
(b) an indication of the current position of the device on the map; and
(c) a GPS signal strength indicator.
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20. Computer software for a portable computing device, the software enabling the device to display, at the same time, each of the following:
(a) a map;
(b) an indication of the current position of the device on the map; and
(c) a GPS signal strength indicator.
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 The present invention will be described with reference to the accompanying drawings, in which
FIG. 1A is a photograph of a personal GPS navigation device according to the present invention;
FIG. 1B is a prior art GPS information screen;
FIGS. 2A-2D are screen shots from an implementation showing a GPS signal strength indicator at varying levels;
FIG. 2E is an expanded view of the navigation bar from an implementation, showing the GPS signal strength indicator in more detail;
FIG. 3 is a screen shot from an implementation showing how Point of Interest data can be inserted into a database running on the device;
FIGS. 4A-4B are screen shots from an implementation showing how different kinds of Point of Interest icons can be selectively enabled/disabled for display;
FIGS. 5A-5E are screen shots from an implementation showing how Point of Interest icons can be prioritised to reduce screen clutter;
FIGS. 6A-6B are screen shots from an implementation showing how moving Point of Interest icons can be displayed;
FIGS. 7A-7E are screen shots from an implementation showing how actions can be associated with a Point of Interest icons;
FIGS. 8A-8D are screen shots from an implementation showing how map auto-zooming occurs when approaching a decision point;
FIGS. 9A-9B are screen shots from an implementation showing how the map simplifies at higher speeds;
 FIGS. 10A-C are screen shots from an implementation showing how the next major route change is displayed.
 The present invention will be described with reference to an implementation from Palmtop Software BV of Amsterdam, Netherlands called TomTom Navigator™. Referring to FIG. 1, the TomTom Navigator GPS system runs on a PocketPC powered DPA, such as the Compaq ipaq 1 and comprises a GPS receiver 2 and navigation software running on the Compaq ipaq 1.
 In the TomTom Navigator GPS system, routes/roads are described in a database running on the personal GPS navigation device as lines—i.e. vectors (i.e. start point, end point, direction for a road, with an entire road being made up of many hundreds of such sections, each uniquely defined by start point/end point direction parameters). A map is then a set of such road vectors, plus points of interest (POIs), plus other geographic features like park boundaries, river boundaries etc, all of which are defined in terms of vectors. All map features (e.g. road vectors, POIs etc.) are defined in a co-ordinate system that corresponds or relates to the GPS co-ordinate system, enabling a device's position as determined through a GPS system to be located onto the relevant road shown in a map.
 Route calculation uses complex algorithms applied to score large numbers of potential different routes. Once a route is calculated by the PDA, the PDA in effect has stored in a database a sequence of road names and actions to be done at predetermined distances along each road of the route (e.g. after 100 meters, turn left into street x).
 1. GPS Signal Strength Indicator
 FIGS. 2A-D show a typical navigation screen (aerial view) created by the TomTom Navigator GPS system for a vehicle driving down Central Park West in New York, N.Y., USA. The position of the vehicle is given by the arrow 5. A navigator bar, indicated generally at 6, includes essential navigation information. It also includes a GPS signal strength indicator 4. The GPS signal strength indicator 4 is visible in normal navigation mode and hence there is no need to task away to a separate GPS information screen to see this information; minimising the need to task away from the main navigation mode screen (showing the map and current vehicle location) is very useful as the device is meant to be used as an in-vehicle navigation system and driver distractions need to be at a minimum. Further, its apparent similarity to the familiar network coverage indicator in a mobile telephone screen makes it an easily understood user interface element.
 The GPS signal strength indicator 4 consists of 4 bars with the following functional meanings:
 4 bars 4 a visible: Received GPS signal is strong enough to give 3D fix at high level of accuracy (FIG. 2A)
 3 bars 4 b visible: Received GPS signal is strong enough to give a 3D fix; (FIG. 2B)
 2 bars 4 c visible: Received GPS signal is strong enough to give a 2D fix (FIG. 2C)
 1 bar 4 d visible: Received GPS Signal is present, but not strong enough to obtain a position fix (FIG. 2D)
 0 bars visible: No signal detected.
FIG. 2E shows the navigation bar 6 in more detail. It includes the following:
 GPS signal strength indicator 4. An indication of the number of satellites from which GPS signals are being received is also give—in this case 7.
 Name 8 of the current road or route being travelled along (Madison Aveneue in this case)
 Distance to next turning to be taken 9 (35 yards in this case)
 Nature of next turning to be taken 10 Cm this case, a right turn).
 Further UI Features
 The following features are also present in the TomTom Navigator GPS system. Each may be used independently of any other feature (and independently of displaying the GPS signal strength indicator with the map in navigation mode).
 2. Ability to Download POI
 POIs are points of interest, such as museums, restaurants, petrol stations etc. The TomTom Navigator GPS system comes pre-loaded with several thousand POIs, which can automatically appear on a displayed map. POIs exist as a POI type and a longitude and latitude position in the TomTom Navigator GPS system database resident on the device.
 An enhancement to the conventional use of POIs is to enable them to be downloaded to the device (e.g. over the internet or a wireless connection (using SMS or WAP etc) and inserted into the database. FIG. 3 shows the menu screen listing three new POIs 11, with location data; the user can choose to insert these into his database by selecting the ‘insert’ button 12.
 This approach enables third parties to supply POIs from a remote database over a WAN, with possibilities for promoting different POIs. For example, a national chain of gas stations could allow users to download to their personal GPS navigation devices the location of all of its gas stations, which could then be displayed with the correct logo at the correct map locations. The logos could also animate to draw attention to themselves. Location based advertising is also possible (for example, a department store with a sale on could allow POIs of its stores with a special ‘Sale’ logo to be downloaded). User can also create their own new categories of POIs and exchange them with others: hence, POIs for special interest categories can evolve, driven by the needs of users. An example might be that photographers could generate POIs for locations with outstanding views and store these POIs on not only their own personal GPS navigation devices, but also exchange them with other photographers. Motorists could identify particularly enjoyable roads with a new POI type and exchange these with others. Virtually any kind of location information can be categorised with a POI and hence captured in the TomTom Navigator GPS system database resident on the device for display on a map and also exchange with other users.
 3. POI Selection
 Proliferating the nature of possible POI stored could lead to considerable screen clutter, with much irrelevant information. Printed maps, for example, frequently include too much POI data, making it difficult to find a specific kind of POI of interest. The TomTom Navigator GPS system addresses this by listing all POI types and allowing the user to select which particular types are to be displayed: FIGS. 4A and 4B show a typical selection of POI types; only the checked item(s) will be displayed on a map: in this case, only gas stations, as shown in FIG. 4A since only the gas station POI check box 13 is selected. FIG. 4B shows that check box de-selected: no gas stations will now be displayed on the map in navigation mode.
 4. POI Prioritization
 The TomTom Navigator maps are divided into grid cells (Navigator 1.0, for instance, uses a 4×5 grid). Within each cell, only a single POI is displayed on a map at a time. This reduces screen clutter. FIGS. 5A-E show a map of New York at progressively greater enlargement; enlargement is increased by the user moving the zoom control 14 down. Hence, in FIG. 5A, there is a single gas station indicated as being present in the central Manhattan area 15. (As an aside, it should be noted that GPS signal strength indicator is still apparent at 16). Zoomed in, as shown in FIG. 5B, there are three gas stations 16 in central Manhattan. Zoomed in still further, as shown in FIG. 5C, there are many more now shown, plus POIs of other types, such as hotels (the bed icons, 18). Zooming in further still, FIG. 5D, shows even more POIs. Further still, FIG. 5E, shows restaurants (icon 19), as well as all hotels.
 This logical introduction of different POI types, dependent on the zoom level is based on certain POIs (low-density POIs, like gas stations and amusement parks) being displayed in priority over others (high density POIs like restaurants). Further, certain high-density POIs are not displayed at all any more if you zoom out beyond a certain threshold (e.g. no restaurant POIs if map shows more than a certain number of square miles).
 5. Moving POIs
 Another useful feature of the TomTom Navigator GPS system is that POIs do not need to have a fixed location in the database: their location in the database can be regularly, continuously or occasionally updated to show a new location; when this happens, the associated POI icon's position on the map will automatically move to the newly defined location. This feature is useful for tracking assets (e.g. vehicles; people too) and utilises the feature note earlier of sharing POI data: a vehicle could send regular SMS messages with its current location (using its own GPS system) to a mobile telephone equipped personal GPS navigation system, which could then use the location co-ordinates in the SMS message to update a POI uniquely associated with that vehicle. As the vehicle location alters, its position will change on the map, as shown in FIGS. 6A and 6B, where truck 20 can be seen moving down the route. Hence, a very low cost, yet sophisticated, asset tracking system can be deployed using this approach.
 6. Associating an Action with a POI
 Selecting a POI can trigger a related action, such as opening a window with information about or functions relating to the POI, or a communication application that enables the user to call/text etc. that POI, or a browser window that opens a web page relating to that POI. Triggering may be direct or indirect (i.e. there are intervening steps).
FIGS. 7A and 7B illustrate opening a window with functions relating to the POI—in FIG. 7A, the user has selected the icon for Manhattan Hotel 21: when he does this, the name of the hotel 22 is displayed above the hotel POI icon. When the user selects the name 22, pop up menu list (23 in FIG. 7B appears). Window 23 lists various functions relating to the Manhattan Hotel, such as navigating to it (i.e. making it the destination for a route calculation algorithm; the TomTom Navigator software then calculates a route from the current location to the Manhattan Hotel). Another option is “Nearby points of interest’ 24; if selected, a list of nearby POIs is shown, FIG. 7C, in ascending order of distance from the hotel. The user can see that 12 yards from the Manhattan Hotel is the Golden Eagle restaurant 25. If the user selects this entry 25, then more information on it is shown, including various contact numbers. FIG. 7D shows the information for a different hotel, this time in Berlin; if the user selects the web URL, then the device opens a browser window and opens the requested web page. If the user touches the telephone number, it is automatically called (assuming the device has phone capabilities). If the user selects the ‘Show on map’ item 26, the hotel 27 is shown again on the map, a seen in FIG. 7E.
 7. Auto-Zooming of Map as Car Nears a Decision-Point
 Another feature is that the map will automatically zoom-in when approaching a decision point, such as s turning, roundabout, intersection, merge etc. This ensures that the user can see detail when he needs it, without giving too much detail when it is not needed.
 FIGS. 8A-D show the user 30 turning right. In FIG. 8A, the user 30 can see that there is a right turn ahead from the map at 31 and from the right turn arrow 32 on the navigation bar. The navigation bar shows that the turning is 210 yards ahead 33.
 As the user approaches the turn, the map progressively and automatically zooms in so that, at 100 yards from the turning, FIG. 8B, the scale is considerably greater. 35 yards from the turning, FIG. 8C, and the scale has increased even more. After the turn has been completed, the zoom returns to its default zoom level, FIG. 8D.
 8. Auto-Zooming Depending on the Speed of the Car
FIG. 9A shows the vehicle 40 travelling at 70 mph (see navigation bar at 41) along route 42. If the user were instead traveling at 7 mph, as shown in FIG. 9B, then the map would be automatically zoomed in to show more detail. This ensures that the user can see the map extending far enough ahead to allow timely decisions to be made. In effect, the user sees a certain number of seconds ahead rather than a certain distance.
 9. Screen Simplifies Above User Defined Speed
 A related feature is that the screen simplifies above speed (which may be user defined): this reduces unnecessary screen clutter and fast moving but irrelevant detail. Hence, in FIG. 9B, roundabout 44 is shown as the user is travelling slowly at 7 mph; but in FIG. 9A, the roundabout detail is not shown at al as the vehicle is travelling at 70 mph.
 10. Show Next Major Route Change
 FIGS. 10A-C shows how the TomTom Navigator system can display the next major route change. In FIG. 10A, it is exiting interstate highway 287/87: window 50 summarises 30 this. This shows a user departing from familiar territory (e.g. home) that the main purpose of many coming instructions is to take him to a certain highway exit. Allows driver to relax on long motorway journey since he can see at a glance that his exit is still 275 miles 51 away.
 This feature can also show a user that the main purpose of many coming instructions is to take him to a certain highway—which allows him to follow the road signs rather than the instructions.
 11. Nightview
 The conventional navigation mode view, FIG. 11A, can be replaced with a night view mode, FIG. 11B, which uses a light road against darker surroundings, plus lower brightness and very muted colors. The glare of the normal (daylight) colours, and the total amount of light coming from the whole PDA screen, can be bothersome and maybe even dangerous when the user drives at night).
 Appendix 1
 Navigator 2.0 Features
 The following new features are present in the Navigator 2.0 software; this software runs on a Pocket PC powered PDA, such as the Compaq ipaq and provides a GPS based navigation system when the PDA is coupled with a GPS receiver. The combined PDA and GPS system is designed to be used as an in-car navigation system.
 1. Field of the Invention
 This invention relates to a personal GPS navigation device. A personal GPS navigation device is any electronic device that can process GPS location data and display the location of the device on a map. The device may be a dedicated navigation device, or a general purpose electronic device, such as a personal digital assistant, smart phone, mobile telephone, laptop or palmtop computer. The device may be portable or fixed in a vehicle.
 2. Description of the Prior Art
 Personal navigation devices are becoming increasingly common. A particularly successful approach is to connect a PocketPC™ powered PDA (personal digital assistant) to a GPS receiver: the PDA, when running navigation software, becomes a GPS based personal navigation device. Another successful format is the dedicated GPS device, used by hikers, sailors etc. In some countries, mobile telephones will have to be equipped with a GPS receiver in order to be able to send the location of that telephone in the event of an emergency, greatly increasing the adopting of GPS technology as a mass-market technology. Portable GPS receiver devices have also been used in personal safety devices as described in, for instance, U.S. Pat. No. 6,480,557 to Rog, et al. entitled “Portable GPS-receiver for a personal safety system”, the contents of which are hereby incorporated by reference.
 GPS device have also been incorporated into road vehicles and integrated into road map data bases to provide navigation and vehicle tracking systems as described in, for instance, U.S. Pat. No. 4,837,700 to Ando, et al. entitled “Method and apparatus for processing data in a GPS receiving device in a road vehicle” and U.S. Pat. No. 5,225,842 to Brown, et al. entitled “Vehicle tracking system employing global positioning system (GPS) satellites”, the contents of both of which patents are hereby incorporated by reference.
 One common feature of current personal GPS navigation devices is that they can display a GPS information screen, such as the screen shown in FIG. 1B. The GPS information screen shows: how many GPS satellite signals are being received and their individual strength at 3 a; the location co-ordinates of the device at 3 b; the speed of the device at 3 c; the direction of movement of the device at 3 d; the relative orientation of GPS satellites that a signal is being picked up from at 3 e. The GPS information screen is useful when getting a first GPS fix. Once a fix has been established, most users then switch to the map mode, which causes a map to be displayed on the screen of the personal navigation device, indicating the location of the device with an arrow.
 In a first aspect, a personal GPS navigation device is programmed to display, at the same time, each of the following:
 (a) a map;
 (b) an indication of the current position of the device on the map; and
 (c) a GPS signal strength indicator.
 Hence, the device differs from the prior art in displaying a GPS signal strength indicator at the same time as the navigation map (e.g. when the device is in navigation mode) and hence does not require a user to leave the navigation mode to call up a separate GPS information screen in order to see the GPS signal strength. This is very useful, particularly for ordinary consumers, who can see at a glance if the reason that location tracking has been lost is because the received GPS signals are inadequate. (The approach is similar to how network coverage is shown on both the idle screen of a cellular mobile telephone and when a voice call is being made: it is very useful to have the strength of the network coverage graphically represented on the screen that is seen when actually about to make/receive or actually making a voice call.)
 In one implementation, the GPS signal strength indicator comprises several bars, with all bars being visible if the strength of the received GPS signal exceeds a predefined requirement and none visible if the GPS signal strength is below a second predefined requirement. The term ‘bar’ should be expansively construed to cover any region, icon, graphic of any shape that can visually represent a signal strength level. The GPS signal strength indicator can be part of the main display used to display the map or can be discrete, separate hardware entirely, such as LED indicators on the housing of the device. A bar is ‘visible’ if it is readily visually differentiated from other bars; these other bars may still be visually apparent, but in a less prominent manner than a ‘visible’ bar.