Apparatus and methods for locating a target utilizing signals generated from a non-cooperative source
First Claim
1. In a receiver aircraft on a predetermined route of flight, apparatus for locating a position of a reflector of electromagnetic signals relative to a receiver of said electromagnetic signals, said apparatus comprising:
- a. first means for processing a plurality of said received electromagnetic signals which are characterized by their generation from a plurality of signal emitters which are both unassociated from and non-cooperative with said receiver, and for generating a first signal output of said processed signals, said signal emitters including (i) known signal emitters having locations and signal characteristics which are known prior to said flight and which are known to be receivable along said route of flight, and (ii) unknown signal emitters having locations and signal characteristics which are not known prior to said flight and which are also receivable along said route of flight;
b. second means for selecting one of said received signals having a first component which is reflected from said reflector, and a second nonreflected component, in a manner that said selected signal is an optimum signal for locating the position of said reflector, said second means including(1) means for determining the geographical locations of said signal emitters relative to the aircraft,(2) computer means including(a) memory means for storing, prior to the flight,(i) known signal characteristics including signal frequencies, of the known signal emitters,(ii) known geographical locations of the known signal emitters, and (iii) selection data for selecting signal characteristics and geographical locations of said unknown signal emitters which are optimum for locating the position of the reflector,(b) means, responsive to said first signal output, for comparing the characteristics and locations of the received signals with the signal characteristics and locations of the known signal emitters, so as to identify the known received signals along the route of flight,(c) means, responsive to said first signal output, for comparing the characteristics and locations of the unknown signal emitters with the selection data so as to select at least one unknown signal emitter for locating the position of the reflector,(d) means for comparing the identified known signals with the selected unknown signal and for selecting the optimum signal therefrom based on their relative signal qualities including signal strength and freedom from clutter;
c. third processing means including(1) means for determining a time interval between receipt of the first reflected signal component and the second nonreflected signal component, and(2) means, responsive to the determined time interval, for defining a length of an electromagnetic signal path of the first signal component.
1 Assignment
0 Petitions
Accused Products
Abstract
The positions of a non-cooperative emitter (illuminator) and reflector (target) relative to a receiver of electromagnetic energy, which neither directly nor indirectly controls the illuminator, is determined utilizing emissions received directly from the illuminator as well as reflected emissions from the target. A range RI between the receiver and the non-cooperative illuminator is determined by measuring the time difference between receiving the reflected signals at a pair of interferometer antennas located at the wing tips of a receiver aircraft. Calculation of the location of the target is accomplished by utilizing range RI, as well as a time differential Δt between the receipt of the reflected signals at the interferometer antennas and the receipt of a corresponding direct signals at a radar antenna located at the aircraft. In the event there is clutter in the reflected signal which hinders the determination of the time differential Δt, clutter processing is performed utilizing the direct signals as a coherent reference and by cross-correlating the direct and reflected signals. The determination of the bearing of the target and the illuminator relative to the receiver is accomplished by an amplitude comparison of the signals received at multiple ports of a multiple beamed phased array radar antenna. The bearing information together with the range and time differential is processed to provide the necessary commands for generating a visual display of the positions of target and illuminator relative to the receiver.
72 Citations
17 Claims
-
1. In a receiver aircraft on a predetermined route of flight, apparatus for locating a position of a reflector of electromagnetic signals relative to a receiver of said electromagnetic signals, said apparatus comprising:
-
a. first means for processing a plurality of said received electromagnetic signals which are characterized by their generation from a plurality of signal emitters which are both unassociated from and non-cooperative with said receiver, and for generating a first signal output of said processed signals, said signal emitters including (i) known signal emitters having locations and signal characteristics which are known prior to said flight and which are known to be receivable along said route of flight, and (ii) unknown signal emitters having locations and signal characteristics which are not known prior to said flight and which are also receivable along said route of flight; b. second means for selecting one of said received signals having a first component which is reflected from said reflector, and a second nonreflected component, in a manner that said selected signal is an optimum signal for locating the position of said reflector, said second means including (1) means for determining the geographical locations of said signal emitters relative to the aircraft, (2) computer means including (a) memory means for storing, prior to the flight, (i) known signal characteristics including signal frequencies, of the known signal emitters, (ii) known geographical locations of the known signal emitters, and (iii) selection data for selecting signal characteristics and geographical locations of said unknown signal emitters which are optimum for locating the position of the reflector, (b) means, responsive to said first signal output, for comparing the characteristics and locations of the received signals with the signal characteristics and locations of the known signal emitters, so as to identify the known received signals along the route of flight, (c) means, responsive to said first signal output, for comparing the characteristics and locations of the unknown signal emitters with the selection data so as to select at least one unknown signal emitter for locating the position of the reflector, (d) means for comparing the identified known signals with the selected unknown signal and for selecting the optimum signal therefrom based on their relative signal qualities including signal strength and freedom from clutter; c. third processing means including (1) means for determining a time interval between receipt of the first reflected signal component and the second nonreflected signal component, and (2) means, responsive to the determined time interval, for defining a length of an electromagnetic signal path of the first signal component. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
-
-
12. In a receiver aircraft on a predetermined route of flight, a method for locating a position of a reflector of electromagnetic signals relative to a receiver of said electromagnetic signals, said method comprising:
-
(a) processing a plurality of said received electromagnetic signals which are characterized by their generation from a plurality of signal emitters which are both unassociated from and non-cooperative with said receiver, and generating a first signal output of said processed signals, where said signal emitters include (i) known signal emitters having locations and signal characteristics which are known prior to said flight and which are known to be receivable along said route of flight, and (ii) unknown signal emitters having locations and signal characteristics which are not known prior to said flight and which are also receivable along said route of flight; (b) selecting one of said received signals having a first component which is reflected from said reflector, and a second nonreflected component, in a manner that said selected signal is an optimum signal for locating the position of said reflector, said selecting being accommplished by; (1) determining geographical locations of said signal emitters relative to the aircarft, (2) utilizing computer means by; a. storing in memory means of said computer means, prior to the flight, (i) known signal characteristics including signal frequencies, of the known signal emitters, (ii) known geographical locations of the known signal emitters, and (iii) selection data for selecting signal characteristics and geographical locations of said unknown signal emitters which are optimum for locating the position of the reflector, b. in response to said first signal output, comparing the characteristics and locations of the received signals with the signal characteristics and locations of the known signal emitters, so as to identify the known received signals along the route of flight, c. in response to said first signal output, comparing the characteristics and locations of the unknown signal emitters with the selection data and selecting at least one unknown signal emitter for locating the position of the reflector, d. comparing the identified known signals with the selected unknown signal and selecting the optimum signal therefrom based on their relative signal qualities including signal strength and freedom from clutter; (c) determining a time interval between receipt of the first reflected signal component and the second nonreflected signal component of said selected signal, and (d) in response to the determined time interval, defining a length of an electromagnetic signal path of the first signal component of said selected signal. - View Dependent Claims (13, 14, 15, 16, 17)
-
Specification