Method and apparatus for generating an indication of loss of positioning integrity in emergency call systems
First Claim
1. A method for determining a loss of accuracy of a positioning system within an Emergency Call System (ECS) installed in a movable vehicle, said method comprising the steps of:
- determining an accuracy of a position solution of said positioning system;
comparing said determined accuracy against a threshold value; and
generating a warning to indicate that said ECS is not operational when said determined accuracy exceeds said threshold value based upon said step of comparing.
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Accused Products
Abstract
The present invention provides an assessment, in real-time, of the integrity of the positioning solution and navigation sensors used to support an Emergency Calling System (ECS) that integrates positioning and cellular phone technology. This integrity information is used, via a warning light displayed to the driver, to indicate when the system will not support Emergency Calling to the accuracies required. The present invention discusses that at least two types of warnings may be generated and provided to the user. The first being an indication that the positioning accuracy will no longer support Emergency Calling. The second being an indication that a sensor or subsystem of the Emergency Call positioning system is malfunctioning and should be serviced as soon as possible whereby such a malfunction may lead to eventual failure of the system.
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Citations
14 Claims
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1. A method for determining a loss of accuracy of a positioning system within an Emergency Call System (ECS) installed in a movable vehicle, said method comprising the steps of:
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determining an accuracy of a position solution of said positioning system; comparing said determined accuracy against a threshold value; and generating a warning to indicate that said ECS is not operational when said determined accuracy exceeds said threshold value based upon said step of comparing. - View Dependent Claims (2, 3, 4, 5)
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6. A method for determining the failure of a subsystem of a positioning system within an Emergency Call System (ECS) installed in a movable vehicle, said positioning system including a global positioning satellite (GPS) subsystem integrated with a dead reckoning (DR) subsystem, said method comprising the steps of:
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determining an inconsistency between position solutions of said DR and GPS positioning subsystems; isolating said inconsistency to either said GPS subsystem or said DR positioning subsystem; and providing an indication that said ECS is not operational when one of said positioning subsystems has failed when compared to a predetermined threshold. - View Dependent Claims (7, 8, 9, 10)
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11. An Emergency Call System (ECS) for installation on a movable vehicle, comprising:
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a cellular telephone system; a positioning system for determining a location of said movable vehicle; at least one sensor for activating said ECS; means for determining an integrity of said positioning system and for providing a warning to a user when said positioning system has failed according to a threshold. - View Dependent Claims (12, 13, 14)
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Specification