Patent ID: 6194850
Filing Date: 2001-02-27
Classification: B60T

Abstract:
A processor system for accurately determining true ground speed in a vehicle having wheel-axles propelled by traction motors, the vehicle equipped with a radar unit for providing a radar signal indicative of vehicle speed relative to the ground, the radar signal being substantially accurate when averaged over a sufficiently long period of time but being generally susceptible to undesirable short term variations, the vehicle further equipped with speed sensors coupled to the wheel-axles to respectively supply respective wheel-axle speed signals, the respective wheel-axle speed signals being substantially accurate over a sufficiently short period of time but being generally susceptible to undesirable long term variations, the processor system comprising:a first subprocessor coupled to process the respective wheel-axle speed signals to supply a wheel-axle speed signal limited to a rate within a range that varies based on predetermined operational parameters of the vehicle; anda second subprocessor coupled to process the radar signal and the rate-limited wheel-axle speed signal from the first subprocessor to supply the true ground speed of the vehicle, the second subprocessor having a filter coupled to supply an estimated creep signal being substantially free of any undesirable short-term variation due to the radar signal, the second subprocessor including a first processor module coupled to process the estimated creep signal from the filter to substantially reduce any undesirable long term variations in the wheel-axle speed signals.