초록 ▼

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 compen

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.

대표청구항 ▼

A method of locating an unknown radio-frequency transmitter by remote and passive observation, comprising the steps of: (a) receiving a signal radiated from the transmitter into space, a plurality of receivers at different locations receiving the radiated signal; (b) retransmitting, from each of the

A method of locating an unknown radio-frequency transmitter by remote and passive observation, comprising the steps of: (a) receiving a signal radiated from the transmitter into space, a plurality of receivers at different locations receiving the radiated signal; (b) retransmitting, from each of the plurality of receivers, the signal radiated from the transmitter to a plurality of antennas, each at a known location, one of each of the antennas receiving the retransmtited signal from one of the receivers, each of the received retransmitted signals being delayed by a first path length equal to a distance between the transmitter and one of the receivers and by a second path length equal to a distance between one of the receivers and one of the antennas; (c) receiving the retransmitted signals by the antennas; (d) converting the received retransmitted signals to a plurality of digital signals; (e) performing pre-detection cross-correlation on the plurality of digital signals to obtain a set of data from which a time difference of arrival calculation and a frequency difference of arrival calculation can be made; (f) performing the time difference of arrival calculation which compensates for a relative delay value in the received retransmitted signals from the receivers, the relative delay value being a function of the first path lengths, the second path lengths, and a value equal to the speed of light; (g) performing the frequency difference of arrival calculation which compensates for a relative frequency value in the received retransmitted signals from the receivers, the relative frequency value being related to a difference between a first relative velocity of one of the receivers with respect to the velocity of Earth and a second relative velocity of another of the receivers with respect to the velocity of Earth; (h) repeating each of the prior steps a plurality of times; and (i) determining the location of the transmitter by generating isodelay lines of position based on a plurality of the time difference of arrival calculations, by generating isodoppler lines of position based on a plurality of the frequency difference of arrival calculations, and locating the intersections of paired, generated isodelay and isodoppler lines of position, the intersections defining a region in which the transmitter is located.