Doppler speed sensing apparatus
First Claim
1. In a speed sensing system wherein a doppler velocity sensor is used to determine the velocity of a vehicle and provides a doppler output signal indicative of movement of the vehicle relative to the ground along the boresight of said doppler velocity sensor, the improvement comprising:
- accelerometer means for sensing accelerations of said vehicle along the boresight of said doppler velocity sensor and insensitive to accelerations perpendicular to said boresight, said means providing an accelerometer output signal indicative of only said accelerations along said boresight,processing means for processing said accelerometer output signal to derive a velocity error signal indicative of vehicle velocity components other than a velocity component of interest, andmeans for combining said velocity error signal with said doppler output signal to derive a corrected output signal indicative of said velocity component of interest.
1 Assignment
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Accused Products
Abstract
A vehicle velocity sensing system is disclosed which includes a doppler velocity sensor (10, 12) and means for reducing spurious signal components in the output of the sensor. An accelerometer (30, 32) is mounted so as to sense vehicle accelerations along the boresight of the doppler velocity sensor. A processor (34, 36) processes the output of the accelerometer to provide a signal which corresponds essentially to the spurious components of the output of the doppler radar velocity sensor. A signal combiner (38, 40) combines the output of the processor with the output of the doppler velocity sensor to derive a corrected output signal which is more closely indicative of the velocity of the vehicle.
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Citations
15 Claims
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1. In a speed sensing system wherein a doppler velocity sensor is used to determine the velocity of a vehicle and provides a doppler output signal indicative of movement of the vehicle relative to the ground along the boresight of said doppler velocity sensor, the improvement comprising:
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accelerometer means for sensing accelerations of said vehicle along the boresight of said doppler velocity sensor and insensitive to accelerations perpendicular to said boresight, said means providing an accelerometer output signal indicative of only said accelerations along said boresight, processing means for processing said accelerometer output signal to derive a velocity error signal indicative of vehicle velocity components other than a velocity component of interest, and means for combining said velocity error signal with said doppler output signal to derive a corrected output signal indicative of said velocity component of interest. - View Dependent Claims (2, 3, 9, 10, 11)
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4. In a speed sensing system wherein first and second doppler velocity sensors are used to determine the velocity of a vehicle by each providing a doppler output signal indicative of movement of the vehicle relative to the ground along its respective boresight, which doppler output signals are combined to form the velocity indication signal, the improvement comprising:
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first and second accelerometer means for sensing accelerations of said vehicle along the boresight of said first and said second doppler velocity sensor respectively, each accelerometer means being insensitive to accelerations perpendicular to its respective boresight and thus providing an accelerometer output signal indicative of only the accelerations along said boresight, processing means for processing said accelerometer output signals to derive at least one velocity error signal indicative of vehicle velocity components other than a velocity component of interest, and first means for combining said doppler output signals and said at least one velocity error signal to derive a corrected velocity indication signal representative of said velocity component of interest. - View Dependent Claims (5, 6, 7, 12, 13, 14)
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8. In a method of sensing the speed of a vehicle wherein a doppler velocity sensor provides an output signal indicative of the velocity of relative movement between the vehicle and the ground along the boresight of the sensor, the improvement comprising the steps of:
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sensing accelerations along the boresight of said doppler velocity sensor and providing an acceleration signal which varies only with said accelerations along the boresight, processing said acceleration signal to provide a processed signal which varies in accordance with velocity components other than a velocity component of interest, and combining said processed signal with said doppler output signal to derive a corrected output signal indicative of said velocity component of interest.
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15. In a speed sensing system wherein a doppler velocity sensor is used to determine the velocity of an automobile or other land vehicle and provides a doppler output signal indicative of movement of the vehicle relative to the ground along the boresight of said doppler velocity sensor, the improvement comprising:
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a linear accelerometer disposed with its line of action parallel to the boresight of said doppler velocity sensor, so as to thus be sensitive to only those accelerations which are parallel to said boresight, said accelerometer providing an accelerometer output signal indicative of only said accelerations, filter means for filtering said accelerometer output signal to eliminate DC and low frequency components therefrom and thereby provide an AC accelerometer output signal indicative of only oscillatory accelerations of said vehicle relative to the ground along said boresight, integrator means for integrating said AC accelerometer output signal to provide an AC velocity output signal, and means for subtracting said AC velocity output signal from said doppler output signal to derive a corrected output signal indicative of the velocity of said automobile or other land vehicle.
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Specification