Phase rate of change techniques for passive geo-location of radio frequency emitters
First Claim
1. A system for determining a location of a radio frequency (RF) emitter transmitting an RF signal, the system comprising:
- a long baseline interferometer (LBI) including a first antenna and a second antenna positioned on a vehicle to receive the RF signal transmitted by the RF emitter;
a short baseline interferometer (SBI) including a third antenna and a fourth antenna positioned on the vehicle to receive the RF signal transmitted by the RF emitter; and
a processor positioned on the vehicle configured to;
a) determine a first phase rate of change (PROC) of the RF signal received by the LBI over a short time interval to produce a short time interval range estimate of the RF emitter,b) determine a second PROC of the RF signal received by the LBI over a long time interval which is greater than the short time interval, to produce a plurality of long time interval range estimates of the RF emitter,c) determine an angle of arrival (AOA) of the RF signal received by the SBI,d) select one of the plurality of long time interval range estimates based on the short time interval range estimate, ande) determine the location of the RF emitter based on the selected long time interval range estimate and the determined AOA in step c.
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Accused Products
Abstract
The present invention relates to a system for resolving phase ambiguities in phase rate of change (PROC) measurements of a long baseline interferometer (LBI). The system includes an LBI having a first antenna and a second antenna positioned on a vehicle to receive the RF signal transmitted by the RF emitter, and a processor positioned on the vehicle. The processor is configured to determine a first phase rate of change (PROC) of the RF signal received by the LBI over a short time interval to produce a short time interval range estimate of the RF emitter, determine a second PROC of the RF signal received by the LBI over a long time interval which is greater than the short time interval, to produce a plurality of ambiguous long time interval range estimates of the RF emitter, and c) select one of the plurality of long time interval range estimates based on the short time interval range estimate.
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Citations
20 Claims
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1. A system for determining a location of a radio frequency (RF) emitter transmitting an RF signal, the system comprising:
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a long baseline interferometer (LBI) including a first antenna and a second antenna positioned on a vehicle to receive the RF signal transmitted by the RF emitter; a short baseline interferometer (SBI) including a third antenna and a fourth antenna positioned on the vehicle to receive the RF signal transmitted by the RF emitter; and a processor positioned on the vehicle configured to; a) determine a first phase rate of change (PROC) of the RF signal received by the LBI over a short time interval to produce a short time interval range estimate of the RF emitter, b) determine a second PROC of the RF signal received by the LBI over a long time interval which is greater than the short time interval, to produce a plurality of long time interval range estimates of the RF emitter, c) determine an angle of arrival (AOA) of the RF signal received by the SBI, d) select one of the plurality of long time interval range estimates based on the short time interval range estimate, and e) determine the location of the RF emitter based on the selected long time interval range estimate and the determined AOA in step c. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A system for determining a location of a radio frequency (RF) emitter transmitting an RF signal, the system comprising:
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a long baseline interferometer (LBI) including a first antenna and a second antenna positioned on a vehicle to receive the RF signal transmitted by the RF emitter; a navigation system positioned on the vehicle; and a processor positioned on the vehicle configured to; a) determine a first phase rate of change (PROC) of the RF signal received by the LBI over a short time interval to produce a short time interval range estimate of the RF emitter, b) determine a second PROC of the RF signal received by the LBI over a long time interval which is greater than the short time interval, to produce a plurality of long time interval range estimates of the RF emitter, c) record a first position of the vehicle during step a, and a second position of the vehicle during step b using the navigation system, d) select one of the plurality of long time interval range estimates based on the short time interval range estimate, e) repeat steps a-d a predetermined number of times to produce a plurality of selected long time interval range estimates, and a plurality of recorded positions of the vehicle, and f) determine the geo-location of the RF emitter based on the plurality of selected long time interval range estimates and a plurality of recorded positions of the vehicle. - View Dependent Claims (9, 10, 11, 12, 13, 14)
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15. A system for resolving phase ambiguities in phase rate of change (PROC) measurements of a long baseline interferometer (LBI), the system comprising:
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an LBI including a first antenna and a second antenna positioned on a vehicle to receive an RF signal transmitted by an RF emitter; and a processor positioned on the vehicle configured to; a) determine a first phase rate of change (PROC) of the RF signal received by the LBI over a short time interval to produce a short time interval range estimate of the RF emitter, b) determine a second PROC of the RF signal received by the LBI over a long time interval which is greater than the short time interval, to produce a plurality of ambiguous long time interval range estimates of the RF emitter, c) select one of the plurality of long time interval range estimates based on the short time interval range estimate. - View Dependent Claims (16, 17, 18, 19, 20)
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Specification