Inter-vehicle distance measuring system
First Claim
1. Apparatus for measuring distance between automotive vehicles, comprising:
- a light emitter mounted on the rear of a first vehicle for emitting temporally modulated pulses of light;
two spaced apart light sensors mounted on the front of a second vehicle behind said first vehicle for receiving said temporally modulated pulses of light;
data processing means on said second vehicle for switching said sensors on and off to synchronize said sensors with said received temporally modulated pulses of light and for processing said temporally modulated pulses of light received by said spaced apart sensors to measure distance between said first and second vehicles.
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Abstract
A system of active emitters and sensors is provided for measuring distance and communicating between vehicles on an automated highway. The preferred system utilizes a pair of spaced apart sensors at the front of each vehicle for stereo depth perception, two temporally modulated emitters on the rear of each vehicle for redundancy and inter-vehicle communication, and temporally modulated emitters positioned at intervals along the highway for communication from the highway to the vehicles. The emitters may transmit radiation at a wavelength, such as 1 μm IR, for example, that can be detected by low cost detectors. The emitters are modulated temporally to transmit a binary code, resulting in signal-to-noise improvement and increased clutter rejection and operational range. Each sensor may include an array of IR detectors and associated readout circuitry, an imaging lens, a lens array for improving detector fill factor, a filter and polarizer to reject clutter and reduce noise, and a cylindrical lens to provide a good vertical field of view. Detector charge integration is controlled by the binary code of the emitters and depends on the code length and local background illumination. The sensors are connected to a computer processor for processing data received from the emitters and computing distance between vehicles.
78 Citations
19 Claims
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1. Apparatus for measuring distance between automotive vehicles, comprising:
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a light emitter mounted on the rear of a first vehicle for emitting temporally modulated pulses of light; two spaced apart light sensors mounted on the front of a second vehicle behind said first vehicle for receiving said temporally modulated pulses of light; data processing means on said second vehicle for switching said sensors on and off to synchronize said sensors with said received temporally modulated pulses of light and for processing said temporally modulated pulses of light received by said spaced apart sensors to measure distance between said first and second vehicles. - View Dependent Claims (2, 3, 4, 5, 6)
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7. Apparatus for measuring distance between automotive vehicles, comprising:
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light emitting means mounted on the rear of a first vehicle for emitting temporally modulated pulses of light; light sensing means mounted on the front of a second vehicle behind said first vehicle for receiving said temporally modulated pulses of light; data processing means on said second vehicle for switching said light sensing means on and off to synchronize said light sensing means with said received temporally modulated pulses of light and for processing said temporally modulated pulses of light received by said light sensing means to measure distance between said first and second vehicles. - View Dependent Claims (8, 9, 10, 11, 12)
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13. A method of measuring distance between automotive vehicles, comprising the steps of:
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emitting temporally modulated pulses of light from light emitting means on the rear of a first vehicle; receiving said temporally modulated pulses of light with light sensing means on the front of a second vehicle behind said first vehicle; switching said light sensing means on and off to synchronize said light sensing means with said received temporally modulated pulses of light; and processing said received temporally modulated pulses of light to compute distance between said first and second vehicles. - View Dependent Claims (14, 15, 16, 17, 18, 19)
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Specification