Detection of angular displacement to an object from the moving vehicle
First Claim
1. A method for determining the angular displacement of an object in front of a motor vehicle from the center axis of said vehicle, comprising the steps of:
- transmitting a first sequence of alternately occurring bursts of energy at first and second frequencies from a first antenna and a second sequence of alternately occurring bursts of energy at first and second frequencies from a second antenna at alternate intervals with the bursts of said first sequence, said first and second antennas being mounted equally spaced from said center axis of said vehicle;
receiving the signals reflected from said object;
deriving first and second Doppler signals from the received signals resulting from the reflection of the bursts transmitted from said first antenna and deriving third and fourth Doppler signals from the received signal resulting from the reflection of the bursts transmitted from said second antenna;
generating a first signal representing the phase difference between said first and second Doppler signals and a second signal representing the phase difference between said third and fourth Doppler signals; and
computing said angular displacement using said first and second phase difference representative signals.
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Abstract
A pair of first and second antennas is mounted at the front end of a roadway vehicle. A first sequence of recurring bursts of energy at two different frequencies is transmitted from the first antenna and a second sequence of similar bursts of energy is transmitted from the second antenna at alternate intervals with the bursts of energy transmitted from the first antenna. The signals transmitted from the first and second antennas are reflected from an object and received respectively by the first and second antennas and sampled at appropriate intervals to derive a first set of two Doppler signals from the signal received by the first antenna and a second set of two Doppler signals from the second antenna. The relative phase between the Doppler signals derived from the first antenna and the relative phase between those derived from the second antenna are detected by first and second phase detectors, respectively. The outputs from the phase detectors are subtracted from each other to utilize the difference therebetween as an input data to a microcomputer to determine the angular displacement of the object from the center axis of the vehicle.
31 Citations
14 Claims
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1. A method for determining the angular displacement of an object in front of a motor vehicle from the center axis of said vehicle, comprising the steps of:
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transmitting a first sequence of alternately occurring bursts of energy at first and second frequencies from a first antenna and a second sequence of alternately occurring bursts of energy at first and second frequencies from a second antenna at alternate intervals with the bursts of said first sequence, said first and second antennas being mounted equally spaced from said center axis of said vehicle; receiving the signals reflected from said object; deriving first and second Doppler signals from the received signals resulting from the reflection of the bursts transmitted from said first antenna and deriving third and fourth Doppler signals from the received signal resulting from the reflection of the bursts transmitted from said second antenna; generating a first signal representing the phase difference between said first and second Doppler signals and a second signal representing the phase difference between said third and fourth Doppler signals; and computing said angular displacement using said first and second phase difference representative signals. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. Apparatus for determining the angular displacement of an object in front of a roadway vehicle from the center axis of the vehicle, comprising:
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first and second antennas mounted at the front end of said vehicle equally spaced from said center axis of said vehicle; means for generating a sequence of alternately occurring bursts of oscillation at first and second frequencies; means for alternately feeding said sequence of bursts to said first and second antennas such that a first sequence of alternately occurring bursts of oscillation at said frequencies is transmitted from said first antenna and a second sequence of alternately occurring bursts of oscillation at said frequencies is transmitted from said second antenna at alternate intervals with the bursts of said first sequence; a mixer for providing the interaction between local oscillation from said generating means and return signals received at said first and second antennas as a result of said transmitted bursts being reflected from said object; means for deriving from the output from said mixer first and second Doppler signals respectively representative of Doppler shifts resulting respectively from the reflection of the bursts at said first and second frequencies transmitted from said first antenna, and third and fourth Doppler signals respectively representative of Doppler shifts resulting repsectively from the reflection of the bursts at said first and second frequencies transmitted from said second antenna; means for generating a first signal representative of the difference in phase between said first and second Doppler signals; means for generating a second signal representative of the difference in phase between said third and fourth Doppler signals; and computing means programmed to process said first and second phase difference representative signals to obtain said angular displacement. - View Dependent Claims (9, 10, 11, 12, 13, 14)
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Specification