US-12619255-B1 - Self-protecting radio frequency (RF) seekers

US12619255B1US 12619255 B1US12619255 B1US 12619255B1US-12619255-B1

Abstract

Seeker devices and methods of navigation are disclosed. Devices comprise a self-protecting direction finder that can determine direction to a source of RF interference, cancel the interference, and provide direction signals and desirably received signals to the flight controller, which guides navigation with respect to the jammer.

Inventors

Frederick Vosburgh
Kristopher McGuire
Lee B. Baker

Assignees

ARCHAIUS INC.

Dates

Publication Date: 20260505
Application Date: 20240209

Claims (19)

1 . A seeking device for navigating a vehicle comprising a direction finder connected to a flight controller, the direction finder comprising a combiner connected to at least a first antenna via a first signal path and to a second antenna via a second signal path, the combiner being further connected to a direction finder controller, the flight controller and/or an RF receiver, and the flight controller being any type that can control navigation of the vehicle in response to direction finding signals and/or signals from the RF receiver, wherein an output of the combiner includes a power detector; wherein the direction finder is operable to adjust at least one parameter of the first signal path and/or the second signal path based on an output of the power detector; wherein the direction finder controller is operable to determine a direction to a jammer and provide the direction finding signals by processing signals from the combiner; and wherein the flight controller is operable to control navigation of the vehicle in response to the direction finding signals when the signals from the RF receiver are degraded or disrupted.
2 . The seeking device of claim 1 , wherein the direction finder is a jammer mitigation type.
3 . The seeking device of claim 1 , wherein the direction finder is any type that is operable to adjust a phase, an amplitude, and/or a delay of at least a first signal from the first antenna relative to a second signal from the second antenna to reduce an output signal power of the combiner.
4 . The seeking device of claim 1 , wherein the first signal path and/or the second signal path comprise a relative time of arrival adjuster, an amplitude adjuster, and/or a phase adjuster connected to the direction finder controller.
5 . The seeking device of claim 4 , wherein the relative time of arrival adjuster is operable to change an instantaneous bandwidth (IBW) of cancellation to a bandwidth of an RF signal.
6 . The seeking device of claim 4 , wherein the phase adjuster operates by in-phase and quadrature (I/Q) rotation.
7 . The seeking device of claim 1 , wherein the RF receiver is any type that can receive navigation aiding signals.
8 . The seeking device of claim 7 , wherein the flight controller is operable to navigate the vehicle relative to the navigation aiding signals.
9 . The seeking device of claim 1 , wherein the direction finder controller is operable to determine a location of the jammer by determining a plurality of directions to the jammer.
10 . The seeking device of claim 1 , wherein the direction controller is operable to provide the direction finding signals to the flight controller.
11 . A method for navigating a vehicle comprising the steps of providing a direction finder connected to a flight controller; the direction finder comprising a combiner connected to a first antenna via a first signal path and to a second antenna via a second signal path, the combiner being further connected to a direction finder controller and/or an RF receiver; determining a direction to a jammer and providing direction finding signals using the direction finder controller by processing signals from the combiner; controlling navigation of the vehicle using the flight controller in response to the direction finding signals and/or signals from the RF receiver; controlling navigation of the vehicle using the flight controller in response to the direction finding signals when the signals from the RF receiver are disrupted; and controlling navigation of the vehicle using the flight controller in response to the direction finding signals when a signal-to-noise ratio (SNR) of the signals from the RF receiver fall below a threshold.
12 . The method of claim 11 , further comprising adjusting a phase, an amplitude, and/or a delay of a first signal from the first antenna relative to a second signal from the second antenna to reduce an output signal power of the combiner.
13 . The method of claim 12 , wherein adjusting the phase comprises in-phase and quadrature (I/Q) rotation of the first signal from the first antenna.
14 . The method of claim 11 , further comprising determining a location of the jammer by determining a plurality of directions to the jammer.
15 . A vehicle, comprising: a seeking device comprising a direction finder comprising a combiner connected to a first antenna via a first signal path and to a second antenna via a second signal path, the combiner being further connected to a direction finder controller and/or an RF receiver, and a flight controller being any type that can control navigation of the vehicle in response to direction finding signals and/or signals from the RF receiver; wherein the direction finder controller is operable to determine a direction to a jammer and provide the direction finding signals by processing signals from the combiner; wherein the direction finder controller is operable to determine a location of the jammer by determining a plurality of directions to the jammer; and wherein the flight controller is operable to control navigation of the vehicle in response to the direction finding signals when the signals from the RF receiver are disrupted.
16 . The vehicle of claim 15 , wherein an output of the combiner includes a power detector.
17 . The vehicle of claim 16 , wherein the direction finder is operable to adjust at least one parameter of the first signal path and/or the second signal path based on an output of the power detector.
18 . The vehicle of claim 15 , wherein controlling navigation of the vehicle in response to the direction finding signals comprises navigating away from the jammer, navigating towards the jammer, and/or navigating at an angle relative to the direction to the jammer.
19 . A vehicle, comprising: a seeking device comprising a direction finder comprising a combiner connected to a first antenna via a first signal path and to a second antenna via a second signal path, the combiner being further connected to a direction finder controller and/or an RF receiver, and a flight controller being any type that can control navigation of the vehicle in response to direction finding signals and/or signals from the RF receiver; wherein the direction finder is operable to adjust a relative time of arrival of a first signal of the first signal path relative to a second signal of the second signal path to change an instantaneous bandwidth (IBW) of cancellation to a bandwidth of an RF signal; wherein the direction finder controller is operable to determine a direction to a jammer and provide the direction finding signals by processing signals from the combiner; and wherein the flight controller is operable to control navigation of the vehicle in response to the direction finding signals when the signals from the RF receiver are disrupted.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS This application is related to and claims priority from the following US patents and patent applications: this application is a continuation-in-part of U.S. patent application Ser. No. 18/244,942, filed Sep. 12, 2023, which is a continuation-in-part of U.S. patent application Ser. No. 18/238,152, filed Aug. 25, 2023, which is a continuation-in-part of U.S. patent application Ser. No. 18/222,184, filed Jul. 14, 2023, which claims priority from and the benefit of U.S. Provisional Patent Application No. 63/447,771, filed Feb. 23, 2023. Each of the above applications is incorporated herein reference in its entirety. BACKGROUND OF THE INVENTION 1. Field of the Invention This disclosure relates to seeker devices and methods of navigation. More specifically, it relates to devices comprising a self-protecting direction finder that can determine direction to a source of radio frequency (RF) signals. 2. Description of the Prior Art U.S. Pat. No. 8,125,398 by Paulsen discloses GPS-guided artillery shells having a nose-mounted forward-looking antenna and a circumferentially exposed slot antenna aft of the nose. The nose mounted antenna is omni-directional and therefore immune to amplitude variation caused by rotation of the shell in flight. The slot antenna has a gain pattern that does not overlap that of the nose-mounted antenna, and has an on-axis phase center for receiving signals without rotation-induced modulation of amplitude or phase of the received signal induced by spinning of the shell, but neither antenna defends against jamming. Paulsen also teaches aft-looking reception of remote-control signals. In any case, neither antenna provides protection against jamming. U.S. Pat. No. 6,861,983 disclosed by Casabona et al describes methods and apparatus for improving reception of GPS signals by vehicles subject to pitch or roll while traveling on uneven ground by combining signals from two orthogonally oriented antennas to maintain received signal strength to compensate for the effect of rolling. U.S. Pat. No. 7,733,288 by Williams discloses the use of antennas arranged between a receive antenna and source of interference, such as a co-site transmitting antenna, to selectively absorb the transmission, thereby improving the relative strength of desirably received signals. U.S. Pat. No. 10,735,037 for tunable filters, cancellers, and duplexers by Floyd, et al., teaches use of passive mixers to cancel self-interference of wireless transmit signals that couple into a receive antenna, thereby interfering with reception of SOI such as mobile phone signals. The disclosed method uses a copy of the transmit signal, including distortion generated by the power amplifier, which is compensated and combined with the received signal to selectively cancel the transmit signals including its distortion. U.S. Pat. No. 8,965,319 by Wilkerson at al. (2015) discloses methods and devices for reducing radio frequency interference by deterministic, feed-forward cancellation of even saturating jamming signals to selectively isolate radio frequency (RF) signals of interest (SOI). The disclosed method also includes the finding of the direction to a source of jamming superior to other anti-jamming antennas. U.S. Pat. No. 9,519,062 by Vosburgh et al discloses devices and methods for cancelling in-band interference of global positioning system (GPS) signals using evanescent fields to cancel jamming before it enters the receive antenna vs. canceling it after the fact. While this invention provides deep nulls, time delay due to the system design and component limitations result in a narrow cancellation bandwidth, limiting its effectiveness against wideband interference. Given the importance of drones and the ubiquity of drone guns on the battlefield, we propose drones having a navigation system that allows them to navigate by GPS or under remote-control, to defeat jamming of such signals, and to navigate with respect to such jamming, e.g. by homing, even in the face of disruptive jamming to interdict a drone gun or other sources of jamming, providing a low cost/high value vehicle that addresses emerging requirements of modern warfare. The current disclosure of cancellation provides anti-jamming nulls that are wide in the spectral domain and narrow in the spatial domain, provided by devices having a SWAP low enough even for drones, addressing multiple shortcomings of prior anti-jamming systems. SUMMARY OF THE INVENTION The present invention relates to autonomous or remote-controlled vehicles having anti-jamming systems for isolation of radio frequency (RF) signals of interest (SOI) from interference (hereinafter “jamming”) by selective cancellation, and, more specifically adjusting Time Difference of Arrival (TDOA) of antenna signals at a signal combiner for adjusting cancellation, or instantaneous, bandwidth. In one embodiment, the anti-jamming antenna system is of symmetric design in which a first antenna is