Locating device
First Claim
1. Apparatus for determining the location of a transmitter comprising:
- (a) receiving means including at least two spaced receivers for receiving electromagnetic radiation from the transmitter,(b) means for demodulating said radiation individually from each of said receivers,(c) means for Fourier transforming the demodulated radiation from each of said receivers, and for providing signals representative of the radiation as a function of frequency,(d) means for performing a complex division of each of said signals, to establish a signal representing the phase difference between the demodulated radiation from each of the signals, and(e) means for providing a signal representative of the time difference based on said phase difference for defining a hyperbolic surface of rotation on which the transmitter is located.
0 Assignments
0 Petitions
Accused Products
Abstract
A system for locating a transmitter in an unknown location comprising apparatus and the method of receiving transmitted signals from said transmitter at the separated locations, demodulating the transmitted signals, performing a Fourier transformation of each of the demodulated signals to represent them as complex functions of frequency, while performing a complex division of pairs of the signals represented as complex functions of frequency, to obtain signals represented by the phase differences between pairs of signals as functions of frequency, and determining from the difference in phase between pairs of signals as a function of frequency the time differences existing between the said pairs of functions. From these time differences the position of the origin of the transmitted signals are determined and displayed.
44 Citations
13 Claims
-
1. Apparatus for determining the location of a transmitter comprising:
-
(a) receiving means including at least two spaced receivers for receiving electromagnetic radiation from the transmitter, (b) means for demodulating said radiation individually from each of said receivers, (c) means for Fourier transforming the demodulated radiation from each of said receivers, and for providing signals representative of the radiation as a function of frequency, (d) means for performing a complex division of each of said signals, to establish a signal representing the phase difference between the demodulated radiation from each of the signals, and (e) means for providing a signal representative of the time difference based on said phase difference for defining a hyperbolic surface of rotation on which the transmitter is located. - View Dependent Claims (2, 3, 4, 5, 6, 9, 10, 11)
-
-
7. Apparatus for determining the location of a transmitter comprising:
-
(a) a central station having at least three receivers, one of which is tuneable to the frequency of electromagnetic radiation emitted by said transmitter, each of which is adapted to provide a demodulated output signal, (b) a pair of spaced field stations, each of which is comprised of a field receiver tuneable to said frequency of electromagnetic radiation of said transmitter, and of a field transmitter coupled to the associated field receiver, the field transmitters being tuned to frequencies different from the transmitter to be located, and different from each other, (c) the individual second and third receivers of the central station being tuned respectively to a respective individual frequency of each of the field transmitters, whereby a burst of electromagnetic energy emitted by the transmitter to be located is received by said one central station receiver and by the pair of field receivers at its emitted frequency, the field transmitters being adapted to retransmit signals representative of said energy on separate frequencies to the second and third central station receivers, (d) filter means for receiving the demodulated output signals connected to the central station receivers, for providing narrow band output signals, (e) means for digitizing the narrow band output signals, (f) computer means for Fourier transforming each of the narrow band output signals, for performing a complex division of pairs of the transformed signals to establish a signal representing the phase difference between said pairs of the narrow band output signals, for providing signals representative of the time difference based on said phase difference for defining hyperbolic surfaces of rotation on which the transmitter is located for pairs of said narrow band output signals, and for providing coordinate signals of the intersection of said hyperbolic surfaces resulting from the time differentials, the coordinate signals being determinative of the possible locations of the transmitter to be located. - View Dependent Claims (8, 12)
-
-
13. A method of locating a transmitter comprising:
-
(a) receiving transmitted signals from said transmitter at these separated locations, (b) demodulating said transmitted signals, (c) performing a Fourier transform of each of the demodulated signals to obtain signals representative of their amplitudes as a function of frequency, and their phases as a function of frequency, (d) performing a complex division of pairs of said signals representative of their phases as a function of frequency, to obtain signals representative of the phase differences between pairs of said signals, and (e) determining and displaying the coordinates of the transmitter at a location at the intersection of a pair of curves, each curve being determined based on time and constant velocity of travel of the transmitted signal related to said phase differences.
-
Specification