Doppler-effect vehicle ground speed detecting apparatus with means for adjusting frequency of generated wave
First Claim
1. A Doppler-effect speed detecting apparatus for detecting a ground speed of a motor vehicle, including (a) a transmitter for transmitting a wave towards a ground surface, (b) a receiver for receiving a portion of the transmitted wave which is reflected by the ground surface, (c) output means for producing an output indicative of the ground speed of the vehicle, according to a Doppler effect on the basis of a frequency of said transmitted wave as transmitted from said transmitter and a frequency of the reflected wave as received by said receiver, and (d) frequency changing means for changing the frequency of said transmitted wave so that a sensitivity of said receiver is held within a predetermined optimum range, wherein the improvement comprises:
- said frequency changing means including restricting means for restricting a change in the frequency of said transmitted wave due to deterioration of a condition of said ground surface which causes said sensitivity to be lowered.
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Accused Products
Abstract
An apparatus for detecting a vehicle ground speed, including a transmitter for transmitting a wave towards a ground surface, and a receiver for receiving a portion of the transmitted wave reflected by the ground surface. The apparatus produces an output indicative of the vehicle ground speed, according to a Doppler effect on the basis of the frequencies of the transmitted wave and the reflected wave, and further includes a device for changing the frequency of the transmitted wave so that the sensitivity of the receiver is held within a predetermined optimum range. The device is adapted to restrict or inhibit a change in the frequency of the transmitted wave due to deterioration of the condition of the ground surface which causes the receiver sensitivity to be lowered.
12 Citations
10 Claims
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1. A Doppler-effect speed detecting apparatus for detecting a ground speed of a motor vehicle, including (a) a transmitter for transmitting a wave towards a ground surface, (b) a receiver for receiving a portion of the transmitted wave which is reflected by the ground surface, (c) output means for producing an output indicative of the ground speed of the vehicle, according to a Doppler effect on the basis of a frequency of said transmitted wave as transmitted from said transmitter and a frequency of the reflected wave as received by said receiver, and (d) frequency changing means for changing the frequency of said transmitted wave so that a sensitivity of said receiver is held within a predetermined optimum range, wherein the improvement comprises:
said frequency changing means including restricting means for restricting a change in the frequency of said transmitted wave due to deterioration of a condition of said ground surface which causes said sensitivity to be lowered. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
Specification