Radar system detecting plural obstacles and measuring distance based on full gain and automatic gain control
First Claim
1. A radar system comprising:
- electromagnetic wave transmission means for intermittently emitting an electromagnetic wave of a pulse waveform;
electromagnetic wave reception means for receiving said electromagnetic wave reflected from an obstacle;
distance calculating means for calculating a distance of said obstacle from said radar system based on a time interval between said transmission of said electromagnetic wave from said electromagnetic wave transmission means and said reception said electromagnetic wave by said electromagnetic wave reception means;
first reception control means for controlling a gain of said electromagnetic wave reception means to have a standard sensitivity corresponding to a maximum value of said electromagnetic wave received by said electromagnetic wave reception means; and
second reception control means for controlling said gain of said electromagnetic wave reception means to have its maximum sensitivity,wherein said time interval is calculated based on said electromagnetic wave detected by said electromagnetic wave reception means having said standard sensitivity and said electromagnetic wave detected by said electromagnetic wave reception means having said maximum sensitivity.
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Accused Products
Abstract
First, a variable gain amplifier amplifies an output of a light-receiving element with the gain fixed at the maximum value and a laser diode is repeatedly actuated. Distance data obtained in each measurement is stored in a RAM. Second, the measurement is executed by varying the gain of the variable gain amplifier based on automatic gain control AGC technology. Meanwhile, a full gain distance calculation and a full gain relative speed calculation are carried out based on the distance data stored during the first step. Furthermore, in a third step, an AGC distance calculation and an AGC relative speed calculation are carried out based on the distance data stored during the second step. The full-gain based detection and the AGC based detection are alternately repeated, thereby accurately and reliably detecting a plurality of obstacles in a radar detection area.
115 Citations
20 Claims
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1. A radar system comprising:
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electromagnetic wave transmission means for intermittently emitting an electromagnetic wave of a pulse waveform; electromagnetic wave reception means for receiving said electromagnetic wave reflected from an obstacle; distance calculating means for calculating a distance of said obstacle from said radar system based on a time interval between said transmission of said electromagnetic wave from said electromagnetic wave transmission means and said reception said electromagnetic wave by said electromagnetic wave reception means; first reception control means for controlling a gain of said electromagnetic wave reception means to have a standard sensitivity corresponding to a maximum value of said electromagnetic wave received by said electromagnetic wave reception means; and second reception control means for controlling said gain of said electromagnetic wave reception means to have its maximum sensitivity, wherein said time interval is calculated based on said electromagnetic wave detected by said electromagnetic wave reception means having said standard sensitivity and said electromagnetic wave detected by said electromagnetic wave reception means having said maximum sensitivity. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A radar system for measuring a distance of an obstacle, comprising:
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a semiconductor laser diode emitting a semiconductor laser beam of pulse waveform; a light receiving element receiving said semiconductor laser beam reflected from said obstacle and generating a voltage signal corresponding to an intensity of said semiconductor laser beam received; a drive circuit actuating said semiconductor laser diode; a control circuit connected to said drive circuit for supplying said drive circuit with a drive signal to emit said semiconductor laser beam from said semiconductor laser diode; a variable gain amplifier receiving said voltage signal generated from said light receiving element and amplifying said voltage signal in response to a gain given by said control circuit; a comparator comparing an output of said variable gain amplifier with a reference value and generating a light receiving signal when an output of said variable gain amplifier exceeds said reference value; and a time interval measuring circuit receiving both said drive signal and said light receiving signal to measure a time interval between transmission of said drive signal and reception of said light receiving signal and sending said time interval as distance data to said control circuit, said control circuit calculating distance of the obstacle from said radar system based on said distance data, and wherein said control circuit controls a gain of said variable gain amplifier to have a standard sensitivity corresponding to a maximum value of said semiconductor laser beam receiving by said light receiving element during a first measuring period, and controls said gain of said variable gain amplifier to have its maximum sensitivity during a second measuring period. - View Dependent Claims (10, 11, 12)
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13. An obstacle detecting method for a radar system having beamed energy transmission means for emitting a beam and beamed energy reception means for receiving said beam reflected from an obstacle, said radar system operating in measuring cycles, each measuring cycle comprising:
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a first controlling step of controlling a gain of said beamed energy reception means to have its maximum sensitivity; a first calculating step of calculating a first distance of said obstacle from said radar system based on a time interval between transmission of said beam from said beamed energy transmission means and reception of a reflected beam by said beamed energy reception means having said maximum sensitivity; a second controlling step of controlling said gain of said beamed energy reception means to have a standard sensitivity corresponding to a maximum value of said beam received by said beamed energy reception means; and a second calculating step of calculating a second distance of said obstacle from the radar system based on a time interval between transmission of said beam from said beamed energy transmission means and reception of a reflected beam by said beamed energy reception means having said stand sensitivity. - View Dependent Claims (14, 15, 16, 17, 18, 19, 20)
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Specification