Vehicle speed detection system
First Claim
1. A ground speed detection system incorporating a Doppler sensor, the detection system comprising:
- (a) angular velocity detecting means for detecting the angular velocity of a vehicle with respect to the center of gravity of the vehicle while the vehicle is in pitching movement;
(b) center of rotation detecting means for detecting the center of rotation of the vehicle while the vehicle is in pitching movement; and
(c) vehicle speed correcting means for correcting the ground speed of the vehicle sensed by the Doppler sensor based on the center of rotation detected by the center of rotation detecting means in addition to the angular velocity detected by the angular velocity detecting means.
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Accused Products
Abstract
Correction for compensating for errors caused by the pitching movement of a vehicle is executed with high accuracy at low cost. The ground speed of the vehicle sensed by a Doppler sensor is corrected with angular velocities with respect to the center of gravity of the vehicle. In this correction, the center of rotation of the vehicle and the rotation of the Doppler sensor itself during the pitching movement of the vehicle are taken into account. In order to mount the Doppler sensor at a high level in the vehicle without increasing the output power of the sensor, arrangement is made such that the relationship between the difference between the actual installation level of the Doppler sensor and a reference installation level and the amount of correction of beam depression angle is stored in a look-up table; the beam depression angle corresponding to the actual installation level of the Doppler sensor is calculated through correction with the corresponding correction amount of the table; and the sensed ground speed of the vehicle is corrected with the calculated beam depression angle.
31 Citations
15 Claims
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1. A ground speed detection system incorporating a Doppler sensor, the detection system comprising:
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(a) angular velocity detecting means for detecting the angular velocity of a vehicle with respect to the center of gravity of the vehicle while the vehicle is in pitching movement;
(b) center of rotation detecting means for detecting the center of rotation of the vehicle while the vehicle is in pitching movement; and
(c) vehicle speed correcting means for correcting the ground speed of the vehicle sensed by the Doppler sensor based on the center of rotation detected by the center of rotation detecting means in addition to the angular velocity detected by the angular velocity detecting means. - View Dependent Claims (4, 5, 6, 7, 8, 9, 10, 11, 12)
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2. A ground speed detection system incorporating a Doppler sensor, the detection system comprising:
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(a) angular velocity detecting means for detecting the angular velocity of a vehicle with respect to the center of gravity of the vehicle while the vehicle is in pitching movement and for detecting the angular velocity of the Doppler sensor being rotated; and
(b) vehicle speed correcting means for correcting the ground speed of the vehicle sensed by the Doppler sensor based on the angular velocity of the vehicle and the angular velocity of the Doppler sensor which have been detected by the angular velocity detecting means.
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3. A ground speed detection system incorporating a Doppler sensor, the detection system comprising:
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(a) angular velocity detecting means for detecting the angular velocity of a vehicle with respect to the center of gravity of the vehicle while the vehicle is in pitching movement and for detecting the angular velocity of the Doppler sensor being rotated;
(b) center of rotation detecting means for detecting the center of rotation of the vehicle while the vehicle is in pitching movement; and
(c) vehicle speed correcting means for correcting the ground speed of the vehicle sensed by the Doppler sensor based on the center of rotation detected by the center of rotation detecting means in addition to the angular velocity of the vehicle and the angular velocity of the Doppler sensor which have been detected by the angular velocity detecting means.
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13. A ground speed detection system incorporating a Doppler sensor, the detection system comprising:
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(a) memory means for storing a look-up table containing values of the difference between the actual installation level of the Doppler sensor and a reference installation level, each difference value corresponding to each correction amount for the beam depression angle of the Doppler sensor;
(b) beam depression angle calculating means for calculating the beam depression angle corresponding to the actual installation level of the Doppler sensor mounted on a vehicle, through correction with the corresponding correction amount stored in the memory means; and
(c) correcting means for correcting the ground speed of the vehicle sensed by the Doppler sensor based on the beam depression angle which has been calculated by the beam depression angle calculating means. - View Dependent Claims (14, 15)
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Specification