Patent Application
20080242315
1. Field of the Invention
The present invention pertains generally to traffic management and information systems, and more particularly to a method of targeting and tracking a mobile telematics unit.
2. Discussion of Prior Art
Conventional traffic management and navigational systems have been developed to improve vehicular travel on mapped thoroughfares (i.e., roads, streets, boulevards, highways, etc.) by providing vehicular units with real-time traffic information. Typically these systems utilize one or more probe vehicles equipped with particularized data collection modules, including a global positioning system (GPS) receiver, and a communication sub-system for transmitting intra-vehicular and/or exterior traffic data to and receiving instructions from a traffic management center (TMC).
However, periodically and sometimes continuously transmitting location data from millions of vehicles can result in large wireless communication costs and potentially burden the cellular network. Various methods have been proposed whereby the vehicle would determine if and when it should transmit its data, so that less interesting data need not be transmitted. These approaches all require additional onboard capabilities, generally including additional hardware and software, with concomitantly increased costs (and significant delays in implementation). Another approach requires that the central sever maintain records of the past driving history and likely routes of each vehicle, so that it can call those vehicles that are likely to be on the roads of interest. But this approach has serious privacy concerns and probably can only be used for captive fleets. Further, substantial operating costs often result, because probe vehicles are not initially eliminated when outside of the relevant geographic scope of the inquiry.
Thus, although effective, conventional systems present cost concerns associated with implementation and operation, resulting in a continued need in the art for an easier to implement and more efficient method of providing real-time traffic information to vehicles.
Responsive to these concerns, the present invention provides methods of collecting data from a target unit, wherein the unit includes a cellular communication device that at least periodically sends registration request signal data to a carrier. The carrier determines a current cellular communication cell serving the unit based on the registration request signal data, and compiles a cell history log for the unit that includes a list of cells within which the unit transmitted within a preceding period. A third-party facility such as a TMC communicates with the carrier and unit, and is configured to primarily perform the method.
Generally, the method includes determining a desired inquiry path at the facility. Registration request signal data is monitored and a cell history log for at least one unit is compiled at the carrier. The registration request signal data and history log are received at the facility. A transmission location, transmission time and unit phone number are determined based on the registration request signal data. A recently traveled path based on the list of cells is estimated. The desired inquiry and recently traveled paths are compared, so as to determine a target unit. Finally, an estimated travel time for traversing the estimated recently traveled path is determined based in part on the registration request signal data or history log and a map database at the facility.
In other aspects of the invention, probe vehicle determination and use are included in the method so as to refine the estimated travel time and provide additional probe data collection. In one example, the method further includes calling the probe unit at the facility to establish a communication link, determining probe data at the unit, and uploading the data to the facility. The probe data may include the current vehicular location, speed, heading, temperature, windshield wiper actuation status, and fog light actuation status.
The present invention provides advantages over and benefits inconsistent with prior art traffic management systems. Among other things, the invention is useful for providing a system wherein software or hardware additions are not required when the unit includes a cellular communication device. In other words, the invention takes advantage of existing cellular network communication systems to provide a more cost effective traffic information and management system. Further, the invention is further useful for significantly reducing wireless communications and associated costs typically experienced with prior art systems, by selectively targeting probe units prior to generating a direct communication link therewith. As such, the inventive system is useful for providing less burden on cellular networks compared to conventional probe systems, and more accurate traffic information compared to non-GPS probe systems. The system works at any probe penetration level, whereas performance increases with penetration, but no minimum level is required. Finally, the system provides flexibility to dynamically self-tune and/or focus areas of interest, and provides critical information for refining hand-off algorithms.
Other aspects, embodiments, and advantages of the present invention will be apparent from the following detailed description of the preferred embodiment(s) and the accompanying drawing figures.
A preferred embodiment(s) of the invention is described in detail below with reference to the attached drawing figures, wherein:
a is a schematic plan view of the target unit shown in
a is a schematic plan view of a probe vehicular unit equipped to participate in the preferred embodiments shown in
b is a schematic view of the facility in accordance with a preferred embodiment of the present invention, particularly illustrating a map database, identification database, electronic control unit (ECU), and communication links in relation thereto;
As shown in the illustrated embodiments (
The carrier 18 records and utilizes the signal data to determine the servicing geographic cell 20 (as defined by the location of the tower 16 in conjunction with the location of neighboring towers), so as to economically and efficiently complete a page or call directed towards the unit 12. As the unit 12 travels geographically, the unit 12 traverses or crosses into a plurality of adjacent cells 20 (
The system 10 includes a third-party facility 22, such as a TMC or “call center,” that is communicatively coupled to the carrier 18, and inventively configured to estimate a recently traveled path (RTP) for the unit 12 based on the cell log and a map database 24 of interconnecting cellular thoroughfares (
The preferred facility 22 is configured to receive the request 22a, determine the desired inquiry path based on the request 22a and map database 24, determine the cells circumscribing the desired inquiry path, and send a query to the carrier 18 for only those electronic serial numbers having cell logs containing hand-offs between at least a portion of the circumscribing cells. Having satisfied the query, these units 12 are deemed target units 12t.
The preferred facility 22 is further configured to determine whether a target unit 12t is also an equipped probe unit 12p (
Thus, the system 10 is generally configured to function as a TMC or information service that takes advantage of pre-existing and increasingly omnipresent cellular communications networks to derive the traffic information of interest. The system 12 is described and illustrated herein with respect to a vehicular unit 12 (i.e., where the unit 12 is housed within a vehicle), such as a motorcycle, car, SUV, or truck. However, it is appreciated by those of ordinary skill in the art that the advantages and benefits of the present invention may be utilized in other applications featuring mobile units having cellular communication and positioning capabilities, such as implantation devices, cellular telephones, PDA's, and/or smart devices containing GPS technology. It is also appreciated that the present invention offers further non-obvious and distinguishable functionality, configuration, and capabilities, in comparison to a system or method of identifying and/or simply tracking the location of units using registration request signal data, which is known in the art. For example, U.S. Pat. No. 6,853,910 to Oesterling et al., the teachings of which are incorporated herein by reference in their entirety, discloses various embodiments of a system and method of tracking the general location of a vehicle.
More particularly, each registration request signal includes, among other things, an electronic serial number singularly associated with the transmitting unit 12, and the transmission time of the signal, which includes the date and time. At the tower 16, the request signal is appended with the tower location or a tower identifier, wherein the later configuration the identifier can be matched at the carrier 18 to a previously inputted or determined tower location, so as to determine a transmission location. As previously mentioned, the carrier 18 functions to determine a current cellular communication cell serving the unit 12 based on the transmission location of the signal data, and then adds the cell to the cell history log for the unit 12. The cell log comprises a list of the cells within which the unit transmitted within a preceding period.
After the period the log begins to circulate by replacing the last entry with the current. For the intents and purposes of the present invention, the period is configured to provide meaningful data. In other words, the period of recordation is such that the unit 12 is able under regularly anticipated speeds to traverse a minimum number of cells. For example, where cells average approximately ten square miles and present hexagonal configurations (
The facility 22 includes a preferred algorithm for determining the ETT of a given thoroughfare (or link) based on the transmission times, cell information, and information obtained from the map database 24. As an example, one such method of calculating the ETT for an intra-cell link or segment is represented in
To calculate the ETT for traversing an interior adjacent cell 20i (i.e., when at least three adjacent cells are provided), the preferred algorithm takes the difference between the last transmission time in the preceding adjacent cell 20p and the first transmission time in the succeeding adjacent cell 20s (
More preferably, and as shown in
The preferred units 12p are programmed to automatically read probe data including the GPS location data (longitude, latitude, heading, and time) every minute and store the data onboard in a circular buffer that maintains the past 10 minutes of information. More preferably, however, both the frequency and retention periods are adjustable so as to accommodate proper system performance (depending upon local, speed of travel, criticality, etc.) and/or user preference.
Thus, where properly equipped, the unit 12 is configuration to upload the probe data from the memory 30 to the facility 22 through the cellular communication device 14, DSP 26, and modem 28, so as to present a participating probe unit 12p. In this configuration, the facility 22 first matches the electronic serial number of the unit 12, as taken from the registration request signal data, with an identification number preferably obtained from a database 36. The database 36 is preferably stored at the facility 22, but may also be retrievable from a remote location. In the illustrated embodiment the identification number of the vehicle unit 12 is more commonly referred to as the VIN number. The identification number is then utilized to obtain the phone number of the unit 12. More particularly, the preferred database 36 further includes the phone number, so that both the identification and phone numbers are retrieved concurrently within the same record.
The preferred facility 22 is further configured to autonomously call the probe unit 12p using the phone number, so as to establish a communication link 22b with the probe unit 12p. As such, the facility is similarly equipped with a cellular communication device, modem, and DSP (not shown). Finally, so as to enable voice communications between the unit 12, facility 22, and a human operator 38 at the probe unit 12p, the probe unit 12p is preferably also equipped with a microphone 40, and at least one speaker 42 that are communicatively coupled to the DSP 26.
Alternatively, as shown in
The features and functionality of the preferred methods of operation of the present invention are designed to be executed from a computer usable medium storing a computer program, such as a compact disc, digital video disc, magnetic media, semiconductor memory, nonvolatile or permanent memory and autonomously by at least one electronic control unit 46 at the facility 22 and/or unit 12. As such, the facility 22 as well as the unit 12 contains the necessary software and hardware to perform accordingly.
At a step 106, the facility 22 receives a request from a requesting unit 12r, determines a desired inquiry path (DIP) based on the request, and determines if the RTP for each equipped unit 12 in its database matches the DIP. If none, the method returns to step 100; otherwise, the method proceeds to step 108 where a target probe unit 12p is found and called to establish a communication link 22b. The link 22b is used to upload probe data, including position data, stored for a predetermined period (e.g., not less than 10 minutes) to the facility 22.
At a step 110, positioning data is matched to a map database comprising links, and more algorithms are ran to determine an actual link speed and travel time for each probe vehicle 12p. Next, at step 112 the actual speeds and travel times for each unit 12p on a given link are combined to more accurately estimate an overall average link speed or travel time. Finally, at a step 114, the overall average link speed or travel time is downloaded to the requesting unit 12r. More preferably, the overall link data for all links are further combined to maintain an estimate of current traffic conditions at step 116, so as to be queriable, and maintain/update maps, dynamic routing, prediction of future traffic conditions, etc.
At step 208, the database is further scanned to determine if the target units are participating probe units 12p. If none, then the method returns to step 200; otherwise the method proceeds to step 210, wherein each probe unit 12p is called, so as to obtain probe data, including position data. At a step 212, positioning data is matched to a map database comprising links, and more algorithms are run to determine an actual link speed and travel time for each probe vehicle 12p. Next, at step 214 the actual speeds and travel times for each unit 12p on a given link are combined to more accurately estimate an overall average link speed or travel time. Finally, at a step 216, the overall average link speed or travel time is downloaded to the requesting unit 12r. More preferably, the overall link data for all links are further combined to maintain an estimate of current traffic conditions at step 218, so as to be queriable, and maintain/update maps, dynamic routing, prediction of future traffic conditions, etc.
At step 306, the electronic serial numbers of the target units 12t are compared to an identification database to determine which if any are also probe units 12p. If the unit 12t is not also a probe unit 12p, then at an intermediate step 306a an ETT is determined based on transmission times and locations, a lower level of confidence is assigned to it, and the method then skips to step 312. If a probe unit 12p is found at step 306, then the method proceeds to step 308 where the target probe unit 12p is called to obtain probe data, including position data.
Next, at a step 310, positioning data is matched to a map database comprising links, and more algorithms are run to determine an actual link speed and travel time for each probe vehicle 12p. At a step 312 the actual speed and travel time for each of the probe units 12p of a given link are combined with other data including the ETT's for the target units 12t to more accurately estimate an overall average link speed or travel time. Finally, at a step 314, the overall average link speed or travel time is downloaded to the requesting unit 12r. More preferably, the overall link data for all links are further combined to maintain an estimate of current traffic conditions at step 316, so as to be queriable, and maintain/update maps, dynamic routing, prediction of future traffic conditions, etc. It is appreciated that this method is useful with any number of participating probe vehicles 12p: with 0% penetration, the system reverts to the conventional hand-off-based system; as penetration increases, so do the accuracy and reliability of the estimates.
The preferred forms of the invention described above are to be used as illustration only, and should not be utilized in a limiting sense in interpreting the scope of the general inventive concept. Obvious modifications to the exemplary embodiments and methods of operation, as set forth herein, could be readily made by those skilled in the art without departing from the spirit of the present invention. The inventors hereby state their intent to rely on the Doctrine of Equivalents to determine and assess the reasonably fair scope of the present invention as pertains to any system or method not materially departing from but outside the scope of the invention as set forth in the following claims.
