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US 10,705,177 B2Granted
Method and system for determining an unambiguous angle of arrival using interferometry
AssigneeRaytheon Company
InventorsIan S. Robinson, Bradley A. Flanders
Life of this patent
Estimating the term…
Abstract
A direction finding interferometer shares receivers among antennas and aperiodically switches between those antennas. The phase differences for a subset of the antenna pairs are measured for each pulse and the results are combined with the results from subsequent pulses to resolve ambiguities. An angle of arrival common to two subsets of angles of arrival is the unambiguous angle of arrival.
Claims23
A method of determining an unambiguous angle of arrival (AoA) of a signal from an emitter, the method comprising:
- (a) coupling a first receiver to an antenna in a first sub-set of antennas of an array of antennas, wherein the first receiver is only coupled to one antenna at a time;
- (b) coupling a second receiver to an antenna in a second sub-set of antennas of the array, wherein no antenna in the second sub-set is in the first sub-set of antennas and wherein the second receiver is only coupled to one antenna at a time;
- (c) receiving, respectively, at the first and second receivers, first and second components of a first signal from the emitter detected at the corresponding antenna;
- (d) measuring a frequency and phase difference between the received first and second components;
- (e) calculating a set of ambiguous angles of arrival (AAoA) of the first signal as a function of the measured phase difference;
- (f) collecting the calculated AAoA into a set of AAoAs associated with a combination defined by:
- (i) the first signal, (ii) the antenna to which the first receiver is connected and (iii) the antenna to which the second receiver is connected;
- (h) coupling the second receiver to another antenna of the second sub-set of antennas and repeating steps (c)-(f) a predetermined number of times;
- (i) repeating step (h) a predetermined number of times;
- and
- (j) identifying an AAoA common to each set of AAoAs as the unambiguous AoA of the first signal.
8 more elements
A method of determining an unambiguous angle of arrival (AoA) of a signal from an emitter, the method comprising:
- (a) switchably coupling a first receiver to only one antenna at a time, the one antenna in a first sub-set of antennas of an array of antennas;
- (b) switchably coupling a second receiver to only one antenna at a time, the one antenna in a second sub-set of antennas of the antenna array, wherein no antenna in the first sub-set is in the second sub-set of antennas;
- (c) receiving, respectively, at the first and second receivers, first and second components of a first signal from the emitter detected at the corresponding antenna;
- (d) measuring a phase difference between the received first and second components;
- (e) calculating an ambiguous angle of arrival (AAoA) of the first signal as a function of the measured phase difference;
- (f) collecting the calculated AAoA into a set of AAoAs associated with a combination defined by:
- (i) the first signal, (ii) the antenna to which the first receiver is connected and (iii) the antenna to which the second receiver is connected;
- (h) switchably coupling one or both of the first and second receivers to any one other antenna of the respective sub-set of antennas and repeating steps (c)-(f) a predetermined number of times;
- (i) repeating step (h) a predetermined number of times;
- and
- (j) identifying an AAoA common to each set of AAoAs as the unambiguous AoA of the first signal.
8 more elements
A system for determining an unambiguous angle of arrival (AoA) of a signal from an emitter, the system comprising:
- an array of linearly arranged antennas comprising first and second sub-sets of antennas, wherein no antenna in the second sub-set is in the first sub-set;
- a switching device coupled to the antenna array and configured to:
- switchably couple one first sub-set antenna at a time to a first output and switchably couple one second sub-set antenna at a time to a second output;
- a first receiver coupled to the first output of the switching device;
- a second receiver coupled to the second output of the switching device;
- and
- a processor, coupled to the switching device and the first and second receivers, configured to implement a method of:
- (a) coupling, via the switching device, the first receiver to an antenna in the first sub-set of antennas;
- (b) coupling, via the switching device, the second receiver to an antenna in the second sub-set of antennas;
- (c) receiving, respectively, from the first and second receivers, first and second components of a first signal from the emitter detected at the corresponding antenna;
- (d) measuring a phase difference between the received first and second components;
- (e) calculating an ambiguous angle of arrival (AAoA) of the first signal as a function of the measured phase difference;
- (f) collecting the calculated AAoA into a set of AAoAs associated with a combination defined by:
- (i) the first signal, (ii) the antenna to which the first receiver is connected and (iii) the antenna to which the second receiver is connected;
- (h) coupling, via the switching device, the second receiver to another antenna of the second sub-set of antennas and repeating steps (c)-(f) a predetermined number of times;
- (i) repeating step (h) a predetermined number of times;
- and
- (j) identifying an AAoA common to each set of AAoAs as the unambiguous AoA of the first signal.
15 more elements
Dependencies are inferred from the claim text.