Patents Assigned to Interferometrics Incorporated
  • Patent number: 5008679
    Abstract: The method of locating an unknown radio-frequency transmitter includes: (a) receipt of signals radiated from the transmitter by a plurality of receivers; (b) retransmission of the received signals to a plurality of antennas; (c) performing a time difference of arrival (TDOA) calculation which compensates for a relative delay value, which is a function of the distances from the transmitter to each of the receivers, the distances from each of the receivers to the antennas, and the speed of light; (d) performing a frequency difference of arrival (FDOA) calculation which compensates for a relative frequency value, which is a function of the relative velocity of each receiver with respect to the velocity of the Earth; (e) repeating these steps a plurality of times; and (f) determining the location of the unknown transmitter based on the plurality of TDOA and FDOA calculations.
    Type: Grant
    Filed: January 31, 1990
    Date of Patent: April 16, 1991
    Assignee: Interferometrics Incorporated
    Inventors: John E. Effland, John M. Gipson, David B. Shaffer, John C. Webber