Radar trilateralization position locators

• US 3,918,056 A
• Filed: 11/30/1973
• Issued: 11/04/1975
• Est. Priority Date: 11/04/1971
• Status: Expired due to Term

• Current Assignee: James W. Merrick
• Original Assignee: James W. Merrick
• Inventors: Merrick, James W.
• Primary Examiner(s): Wilbur, Maynard R.
• Assistant Examiner(s): Montone, G. E.
• Application Number:
  US05/420,448
• Time in Patent Office: 704 Days
• Field of Search: 343/6.5LC,6.5R,6.5SS,5DP,17.1R,17.1PF,7.3,112R,112TC,18B
• US Class Current: 342/46
• CPC Class Codes: G01S 13/46 Indirect determination of position data
• CPC Class Codes: G01S 13/876 Combination of several spaced transponders or reflectors of known location for determining the position of a receiver G01S13/874 takes precedence
• CPC Class Codes: G01S 2013/466 by Trilateration, i.e. two antennas or two sensors determine separately the distance to a target, whereby with the knowledge of the baseline length, i.e. the distance between the antennas or sensors, the position data of the target is determined

Abstract

A radar position locator system uses a mobile and at least two stationary transceivers. The stationary transceivers function somewhat as a surveyor'"'"''"'"'s bench mark system where a transceiver at each end serves to locate the ends of a previously surveyed line; this line then becomes a survey baseline. Each transceiver is individually identified by a coded stream of radar pulses, as, for example, a stream of pulses transmitted at a predetermined transceiver identifying pulse repetition rate. A selected number of validated radar signals are transmitted between the mobile and stationary transceivers. The round trip transmission times of several of these signals are averaged, and a digital read out indicates the distance represented by such averaging.

Claims

1. A radar trilateralization position locator system including a first unit and at least two other monitoring units, each of said monitoring units being uniquely identified by its own pulse repetition rate, said first unit comprising digital gate means for generating and transmitting cyclically recurring digitally repetitive interrogation radar signals to said other monitoring units at a fixed monitoring unit identifying pulse repetition rate, digital gate means in each of said other units for monitoring said interrogation radar signals to digitally detect the particular and unique cyclic digital signals having the pulse repetition rate identifying the monitoring unit, digital means in the particular one of the other monitoring units which is identified by a detected pulse repetition rate for digitally retransmitting a radar signal at said cyclically recurring repetition rate as a reply signal to said first unit, and means in said first unit operated responsive to the receipt of said reply signal for indicating the time required for said signal to make a round trip from said first unit to the other monitoring unit identified by said detected cyclically recurring pulse repetition rate and return to said first unit.

2. The system of claim 1 and means for transmitting said radar signals over at least two separate radio frequency link channels between said first and other units.

3. The system of claim 1 and means for repeatedly re-transmitting said interrogation pulses until a selected number of apparently valid reply signals have been received.

4. The system of claim 1 and means responsive to the time indicating means for validating timed radar signals comprising means for repeatedly storing data responsive to transmitting radar signals, data accumulation means, means of transferring said stored data to said data acccumulator means, means in said accumulator for accepting the transferred data which is consistent with previously accumulated data and rejecting data which is non-consistent therewith, and means responsive to the accumulation of a predetermined amount of said accepted data for giving a read out of the average of said accumulated data.

5. A radar trilateralization position locator system including a first unit having means for giving mobile support to said first unit and at least two other monitoring units having means for giving stationary support to each of said other units, said first unit comprising means including an antenna and circuit means controlled by digital circuitry for transmitting to said other monitor units a digital interrogation radar signal having cyclically recurring digital pulses at a selected pulse repetition rate corresponding to a fixed digitally encoded address which identifies only one monitoring unit, means including an antenna and circuit means controlled by digital circuitry in each of said other units for monitoring said interrogation radar signals to detect the pArticular one of said encoded digital signals having a fixed rate which identifies the monitoring unit, each of said units having its own independent power supply, means in the other monitoring unit identified by a detection of the fixed pulse repetition rate for re-transmitting a radar signal at the same fixed rate as a reply to said first unit which is transmitting that fixed rate, digital gate means in said first unit operated responsive to the receipt of said reply signal at the same transmitted fixed repetition rate for indicating the time required for said signal to make a round trip from said first unit to said identified other monitor unit and return to said first unit, and display means for displaying a read out of said indicated time.