Gm Global Technolgoy Operations, Inc.

Abhijit Patil

Sethu K Madhavan

Eray Yasan

Craig R Markyvech

Daniel N Aloi

Chaminda Basanyake

A software compass used during a GPS outage calculates vehicle heading and presents it upon request. The software compass gathers information from a yaw rate sensor, wheel steering angle sensor, wheel speed sensor, and PRNDL gear position sensor to calculate vehicle heading using a weighting algorithm. Because the yaw rate sensor data is a central factor in calculating vehicle heading, the quality of calibration of the yaw rate sensor is of importance. The disclosed calibration algorithm calculates the yaw rate bias and scale factors to calibrate the yaw rate sensor.

Vehicle compass using telematics unit and vehicle sensor information

A method of improving a vehicle emergency call network used during an enhanced 911 call, which is especially useful in environments having degraded GPS signals. The present method utilizes an independent position enhancement algorithm, such as a dead reckoning algorithm, and converts the output of that algorithm into a compatible format compatible with a position determining entity (PDE). Some independent position enhancement algorithms return output in the form of position information (typically, two- or three-dimensional coordinates), however, most PDEs only accept information in the form of pseudo-ranges. Thus, the present method provides a technique in which the advantages of an independent position enhancement algorithm are enjoyed, yet a compatible output is sent to the PDE.

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Westland, MI, United States of America

Abhijit Patil