Patent Application
20070005239
This invention relates to distributed navigation systems and in particular to navigation data.
In distributed navigation systems, a global positioning system (GPS) is installed onboard an automobile. The client's onboard distributed navigation device includes a transmitter, receiver and processor that may be in communication with a central unit and may be mounted on the dash of the automobile or may be handheld, depending on the model. Routing information may be provided to the client (user) on a display device, and/or via oral instructions.
The central unit or remote server receives navigation route requests from the client and computes and transmits routing information to the client. The central unit includes a client location module that receives a client's position in longitude, latitude and possibly altitude from a client's onboard GPS receiver. The accuracy of GPS is approximately ten to twenty feet.
The maps processed in a distributed navigator system include large amounts of data. The updating of the voluminous map and location information is performed centrally. The map information includes average travel speed classifications, one way streets, names and road numbers of all streets, expressway ramp details, and other travel information elements. Furthermore, maps may contain points of interest including restaurants, hotels, gas stations, garages, parks, hospitals including their telephone numbers, hours of operation and possibly advertisements. Also, traffic reports and advice may be incorporated into the information sent to the client. Map data is constantly updated regarding road closures and new road construction.
In a distributed navigation system, the heavy computation such as route finding is performed by the central unit based on a route request by the client, freeing up the client device for processing in real time routines such as tracking. A route is computed and downloaded upon a route request transmitted to the remote server by the client.
A distributed navigation system architecture provides two advantages over autonomous navigation systems. In a distributed navigation system the centralized map database requires no maintenance by the client and since the cost of maintenance is spread over all clients, there is low cost to an individual client. However, there may be limited data availability on the client side. That is, when the client requests a route, the server's response is limited to the map data along the main route that has been computed in order to have acceptable response times. If the GPS data is inaccurate, the requested guidance cannot start if only a single route is provided. If the vehicle happens to move away from the planned single route between the time the route request has been initiated and the time the response has been received, the requested guidance cannot start. Accordingly, the client may need to make repeated route requests. Since, as mentioned above, extended amounts of information may be transmitted in a single transmission to the client, the data downloading time in each instance may be substantial.
A distributed navigation system, method and apparatus are described including a junction sieve generator for generating a junction sieve based on a navigation route request, the user's first position, and the configuration area. The junction sieve includes significant crossings within the configuration area, and has guidance information. The route request and the user's first position are provided to a central unit by the client.
The instant disclosure is provided to further explain in an enabling fashion the best modes of making and using various embodiments in accordance with the present invention. The disclosure is further offered to enhance an understanding and appreciation for the invention principles and advantages thereof, rather than to limit in any manner the invention. The invention is defined solely by the appended claims including any amendments of this application and all equivalents of those claims as issued.
It is further understood that the use of relational terms, if any, such as first and second, top and bottom, and the like are used solely to distinguish one from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Much of the inventive functionality and many of the inventive principles are best implemented with or in software programs or instructions and integrated circuits (ICs) such as application specific ICs. It is expected that one of ordinary skill, notwithstanding possibly significant effort and many design choices motivated by, for example, available time, current technology, and economic considerations, when guided by the concepts and principles disclosed herein will be readily capable of generating such software instructions and programs and ICs with minimal experimentation. Therefore, in the interest of brevity and minimization of any risk of obscuring the principles and concepts according to the present invention, further discussion of such software and ICs, if any, will be limited to the essentials with respect to the principles and concepts within the preferred embodiments.
The user's first position is also received 104. The GPS data on the user's first position may be separate or part of the route request. While GPS is a common manner in which to provide a client's position, such information may be manually or otherwise entered as well. Based on the navigation route request and the user's first position, the central unit generates a junction sieve 106 within the configuration area, the junction sieve including significant crossings and guidance information at the crossings.
The central unit generates the junction sieve from tables, calculations and real-time data. The content of the junction sieve is described with reference to
In the configuration area depicted in
The information displayed to the user in a navigation system, whether it is autonomous, distributed, is an arrow that represents the maneuver and eventually with the distance to the maneuver. Advance systems may add certain features such as a three-dimensional arrow in perspective and a progress bar. In general, in a distributed system, the server sends to the client device the data required to display the appropriate arrow at the appropriate time.
As described herein, the client device receives minimal strategic data which includes guidance information at a plurality of significant crossings surrounding the client's first position. This provides sufficient information to guide the client onto an appropriate route for the client's final destination. The data may be as small as 64 bytes per junction but this number may vary greatly depending upon the bandwidth of the data download.
The central unit determines a configuration area 201, depicted in
Accordingly, the junction sieve provides a plurality of routes to the same destination. In
The junction sieve delivered to the client device 106 includes of numeric and textural information that can be used for tracking and guidance. This information is not meant to be presented to the final user. Instead, the client device will use this information to generate appropriate audio and graphic output according to the device capabilities.
The data contained in the junction sieve corresponding to
In this way, the junction sieve contains high level data, such as maneuvers to follow the route from any junction in the sieve. As an illustration of maneuvers, two additional arrows are positioned in the graphic representation. Small arrow 222 with the incoming heading into the junction 212 and a large arrow 224 providing direction out of the crossing 212. Arrows 222 and 224 correspond to instruction 10 in Table 1.
Limited the data to the nodes minimizes the size of data sent over the wireless network. Accordingly, the information of the junction sieve of Table 1 is substantially less than that of a generic map. The high level information provided by the junction sieve is a meta-map not including line segments. In this way, the data feed from the central unit is substantially less than that of a generic map, and the speed at which the data feed may occur is substantially greater.
The junction sieve data can allow the client device to perform basic tracking and provide simple guidance, that is while approaching junctions, until the vehicle is on-route. In an operation performed by the client device 308, the client device confirms the on-route status by providing signals to the central unit indicating the node and incoming segment pair that was matched 303. The tracking and confirmation steps are transparent to the user. Since the data is organized per node rather than per segment, the matching algorithm (discussed with reference to
In a later step, the central unit sends the fully detailed route (enhanced route) starting from the matched pair to the final destination. Upon reception, the client device identifies its current position along the final route and switches to accurate tracking mode. Since the complete geometry is now available thru the segment data, the tracking becomes continuous and the guidance can be provided at any point along the route rather than at the proximity of junctions.
Now referring to
As described with reference to
The meaning of the configuration area is also flexible. Circumstances may dictate the size or dimensions of the configuration area, e.g. depending upon the speed of the client, the distance from the beginning point to the end point, the traffic conditions and the weather conditions.
As the client moves, GPS information may be provided to the central unit. The GPS may monitor the client's position at various intervals or continuously. The tracking and matching algorithm 330 processes GPS information in conjunction with the junction sieve. Initialization according to rudimentary guidance is accordingly provided 332. As the client moves, two different conditions may occur. The client may stay within the configuration area or the client may move outside the configuration area.
If the client stays within the configuration area then the client device 302 or the central unit 304 resolves whether there is a matched junction-maneuver pair. It may be established at that point, or at a later matched junction-maneuver pair that the client has achieved the route. Automatically or manually, a new route request 334 for an enhance route is processed by the client and transmitted to the central unit 304. In that event, an enhance route is generated and transmitted to the client device 336. The enhanced guidance route 338 is annunciated to the user via the client device 314. The enhanced guidance route may be in the form of a generic map as described above.
Turning to
It is understood that while the described process and system avoids some of the complex problems in initializing a distributed navigation client it may also be practical in other situations, e.g. whenever an off-route correction is required, such as in a parking lot or when the client vehicle detours off a planned route.
This disclosure is intended to explain how to fashion and use various embodiments in accordance with the technology rather than to limit the true, intended, and fair scope and spirit thereof. The foregoing description is not intended to be exhaustive or to be limited to the precise forms disclosed. Modifications or variations are possible in light of the above teachings. The embodiment(s) was chosen and described to provide the best illustration of the principle of the described technology and its practical application, and to enable one of ordinary skill in the art to utilize the technology in various embodiments and with various modifications as are suited to the particular use contemplated. All such modifications and variations are within the scope of the invention as determined by the appended claims, as may be amended during the pendency of this application for patent, and all equivalents thereof, when interpreted in accordance with the breadth to which they are fairly, legally and equitable entitled.
