Vehicle location monitoring system
First Claim
1. A system for monitoring the location of a vehicle, said system comprising on board said vehicle:
- primary system means for providing an estimated location of the vehicle from an initial known location and heading and from measuring subsequent travel of the vehicle; and
secondary system means for correcting the estimated location of the vehicle as given by the primary system including means for comparing the estimated location with stored locations of "forbidden" areas where the vehicle cannot possibly be.
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Accused Products
Abstract
The system comprises two parts: a first part which operates on a dead-reckoning basis from measurements of, say, measured wheel rotations (CD,CG) and a knowledge of an initial starting point and heading; and a second part which applies corrections to the first. The second part operates on the basis of a simplified map of the area travelled by the vehicle, said map storing only representations of "forbidden" areas (DZI) where the vehicle cannot possibly go, e.g. parks, lakes, large blocks of buildings etc. . . . A judicious selection of forbidden areas can be stored in highly stylized (i.e. simplified) form and still provide adequate information to overcome the inaccuracies inherent to any dead-reckoning system. This requires far less accurate storage for the secondary system than would a map of areas where the vehicle can go. A processor (OC) performs the required calculations and a display (PCV) is optionally provided for the driver, since in some systems, e.g. fleets of police cars, the point of the system is not to tell the driver where he is, but to tell a central control station.
23 Citations
13 Claims
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1. A system for monitoring the location of a vehicle, said system comprising on board said vehicle:
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primary system means for providing an estimated location of the vehicle from an initial known location and heading and from measuring subsequent travel of the vehicle; and secondary system means for correcting the estimated location of the vehicle as given by the primary system including means for comparing the estimated location with stored locations of "forbidden" areas where the vehicle cannot possibly be. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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- 11. A dispatching system to enable a central station to dispatch at least one vehicle from a plurality of vehicles connected by radio to the central station, each vehicle being equipped with an on-board location monitoring system including a primary system for providing an estimated location of the vehicle from an initial known location and heading and from the subsequent travel of the vehicle, a secondary system that corrects the estimated location of the vehicle as given by the primary system including means for comparing the estimated location with stored locations of "forbidden" areas where the vehicle cannot possibly be, said dispatching system including an interrogating device at the central station to offer a run to every vehicle and, on board each vehicle, a transceiver to receive the offered run and a processing device that rates each proposed run on the basis of the estimated location of the vehicle as delivered by the location monitoring system, and wherein said dispatching system further includes polling means for causing the transceiver on each vehicle to respond to a run-offering call from the interrogating central station after a period of time the duration of which is based on the rating attributed to the offered run by the processing unit of the vehicle.
Specification