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Title: Time-of-flight radio location system

A bi-static radar configuration measures the direct time-of-flight of a transmitted RF pulse and is capable of measuring this time-of-flight with a jitter on the order of about one pico-second, or about 0.01 inch of free space distance for an electromagnetic pulse over a range of about one to ten feet. A transmitter transmits a sequence of electromagnetic pulses in response to a transmit timing signal, and a receiver samples the sequence of electromagnetic pulses with controlled timing in response to a receive timing signal, and generates a sample signal in response to the samples. A timing circuit supplies the transmit timing signal to the transmitter and supplies the receive timing signal to the receiver. The receive timing signal causes the receiver to sample the sequence of electromagnetic pulses such that the time between transmission of pulses in the sequence and sampling by the receiver sweeps over a range of delays. The receive timing signal sweeps over the range of delays in a sweep cycle such that pulses in the sequence are sampled at the pulse repetition rate, and with different delays in the range of delays to produce a sample signal representing magnitude of a received pulse in equivalentmore » time. Automatic gain control circuitry in the receiver controls the magnitude of the equivalent time sample signal. A signal processor analyzes the sample signal to indicate the time-of-flight of the electromagnetic pulses in the sequence. The sample signal in equivalent time is passed through an envelope detection circuit, formed of an absolute value circuit followed by a low pass filter, to convert the sample signal to a unipolar signal to eliminate effects of antenna misorientation.« less
Inventors:
 [1]
  1. (Livermore, CA)
Issue Date:
OSTI Identifier:
871122
Assignee:
Regents of University of California (Oakland, CA) LLNL
Patent Number(s):
US 5661490
Contract Number:
W-7405-ENG-48
Research Org:
Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
Country of Publication:
United States
Language:
English
Subject:
time-of-flight; radio; location; bi-static; radar; configuration; measures; direct; transmitted; rf; pulse; capable; measuring; jitter; pico-second; 01; inch; free; space; distance; electromagnetic; range; feet; transmitter; transmits; sequence; pulses; response; transmit; timing; signal; receiver; samples; controlled; receive; generates; sample; circuit; supplies; causes; time; transmission; sampling; sweeps; delays; sweep; cycle; sampled; repetition; rate; produce; representing; magnitude; received; equivalent; automatic; control; circuitry; controls; processor; analyzes; indicate; passed; envelope; detection; formed; absolute; value; followed; pass; filter; convert; unipolar; eliminate; effects; antenna; misorientation; signal causes; control circuitry; receive timing; sample signal; signal representing; pulse repetition; electromagnetic pulses; equivalent time; signal processor; control circuit; repetition rate; timing signal; timing circuit; absolute value; transmit timing; pass filter; free space; radio location; receiver sweeps; signal sweeps; sweep cycle; transmitter transmits; processor analyzes; received pulse; receiver samples; rf pulse; detection circuit; controlled timing; circuit supplies; magnetic pulse; signal process; radar configuration; transmitted rf; time-of-flight radio; envelope detection; electromagnetic pulse; bi-static radar; configuration measures; direct time-of-flight; /342/