Accession Number : ADD015738

Title :   Fix-Tracking System.

Descriptive Note : Patent, Filed 6 Aug 81, patented 2 Mar 93,

Corporate Author : DEPARTMENT OF THE NAVY WASHINGTON DC

Personal Author(s) : Alsup, James M ; Jelks, Edward C

Report Date : 02 Mar 1993

Pagination or Media Count : 8

Abstract : An apparatus determines the location of a signal source having coordinates (x, y). The source may be located as far away as two thousand km and does not require knowledge of ionospheric height or layer structure. The apparatus comprises at least three receivers adapted to receive the signals from the signal source. The coordinates, (x1, Y1), (x2, y2) and (x3, Y3), of each of the receivers are very precisely known. One receiver is capable of receiving signal from the other two receivers through different means (e.g. a wide-band telephone link). A plurality of at least three timers, one connected to each receiver, measures precisely the time difference of arrival (TDOA) of the signals from the signal source. A plurality of at least three means, connected one to each of the receiving means, determine the vertical angles at which the signal from the signal source is received by each of the receivers. More precisely, each receiver is in reality a phased array of individual antenna elements whose joint output can be used to measure both vertical angle and azimuth. Means are provided for calculating the coordinates (x, y) of the signal source from the measured vertical angles and the time differences of arrival.

Descriptors :   *TRACKING, *RADIO SIGNALS, *LOCATORS, HIGH FREQUENCY, RADIO RECEIVERS, EMITTERS, SOURCES, RADIO COUNTERMEASURES, PATIENTS

Subject Categories : Radio Countermeasures

Distribution Statement : APPROVED FOR PUBLIC RELEASE