Devices, systems, and methods for cancellation bandwidth-adjustable nulling of interference
Anti-jamming arrays, systems, and methods are disclosed by forming cancellation nulls having an adjustable cancellation bandwidth and/or null depth to assure reception of position, navigation and timing, command and control, or other signals of interest. Signals are matched with respect to time difference of arrival (TDOA) and phase at a combiner to provide enhanced cancellation depth and bandwidth.
1. A jammer cancelling system comprising:
a cancellation bandwidth (CBW)-adjusting controlled radiation pattern antenna (CRPA) type canceller, and
a first antenna connected via a first signal path to a combiner, the first signal path incorporating a first adjustable delay element connected in series with a phase rotator and a transversal filter, and
at least one second antenna connected to the combiner via a second signal path, the second signal path incorporating a second adjustable delay element connected in series with a controllable transversal filter, and
wherein the second signal path further includes a controllable conduction interrupting switch, and
a power detector connected to the output of the combiner, and
a system controller connected to the first signal path, the second signal path, and the power detector, and
the resulting system providing CBW-adjusted jammer cancelling nulls.
2. The system according to claim 1 , wherein the second adjustable delay element includes at least one type of fixed and adjustable.
3. The system in claim 2 , wherein the second signal path incorporates a phase shifter connected in series with the second adjustable delay element.
4. The system according to claim 1 , wherein the phase rotator is of I/Q type that is operable to adjust the amplitude of I and Q channels to provide phase rotation of the resulting signal with a resolution of 0.1 degrees.
5. The system according to claim 1 , wherein the first adjustable delay element and the second adjustable delay element are operable to provide a delay with a resolution as fine as 2 picoseconds.
6. The system according to claim 1 , wherein the system controller is operable to adjust the first adjustable delay element and/or the second adjustable delay element for providing a time difference of arrival (TDOA) providing a preferred cancellation bandwidth.
7. The system according to claim 1 , comprising a staged design wherein the output of the combiner and an output of a second combiner are connected respectively via the power detector and a second power detector to a third combiner, wherein an output of the third combiner is connected to the system controller via a third power detector, wherein the output from the combiner is combined with the output from the second combiner which outputs serve as inputs to a second-stage combiner.
8. The system according to claim 1 wherein the first adjustable delay element and the second adjustable delay element has a resolution between 20 and 200 picoseconds.
9. The system according to claim 1 , in which the first antenna is connected to the combiner by the first signal path, the at least one second antenna is connected to the combiner by the second signal path, and at least one third antenna is connected to the combiner by at least one third signal path, the first signal path, the second signal path and the at least one third signal path each comprising an adjustable delay element connected in series with a transversal filter.
10. The system according to claim 9 , wherein the at least one third signal path further comprises a switch connected to the system controller.
11. The system according to claim 9 , wherein signals conducted by the at least one third antenna are interrupted and signals from the first antenna and the at least one second antenna are used to determine which information is provided to the system controller for use in adjusting time differences of arrival and/or calculating weights to be applied to signals in transversal filtering.
12. The system according to claim 1 , wherein the first signal path or the second signal path further comprises a coarse-adjustable delay element connected to the system controller for coarse adjusting a time difference of arrival (TDOA).
13. The system according to claim 1 , wherein the system has an asymmetric design, wherein the second signal path comprises an intrinsic delay matching element.