Guided munition with passive homing to a GPS jammer
A modular radio frequency (RF) seeker may be modularly connected with a projectile having a diameter of about four inches or less. The modular RF seeker may have a plurality of RF antennas, wherein at least two RF antennas are spaced apart from each other at a distance that is less than one wavelength of a signal band of interest that is to be detected by the modular RF seeker. A modular connector that modularly connects with another portion of the projectile, wherein when modularly connected, the plurality of RF antennas are in operative communication with a guidance kit on the projectile that guides the projectile toward at least one signal jammer emitting a jamming signal at the signal band of interest.
1 . A guided munition comprising:
a modular first portion located at a front end of a guided munition;
a modular second portion located rearward of the modular first portion, wherein the modular second portion selectively connects with the modular first portion;
a radio frequency (RF) seeker that receives a signal from a signal jammer, wherein the RF seeker has at least two antennas that are spaced apart from each other at a distance that is less than one wavelength of the signal that is to be detected by the RF seeker; and
command and control logic that receives data from the RF seeker based on the signal received at the RF seeker, and the command and control logic guides the guided munition to the signal jammer, wherein the guided munition is configured to detonate near the signal jammer and thereby disable the signal jammer.
2 . The guided munition of claim 1 , wherein the RF seeker is located on one of the modular first portion and the modular second portion.
3 . The guided munition of claim 1 , wherein the RF seeker comprises:
a plurality of dual polarization antennas located on one of the modular first portion and the modular second portion.
4 . The guided munition of claim 1 , wherein the RF seeker comprises:
a plurality of linear patch antennas located on one of the modular first portion and the modular second portion.
5 . The guided munition of claim 1 , wherein the command and control logic performs at least one of (1) cross correlation and (2) multiple signal classification (MUSIC) of the data from the seeker to obtain relative phase and amplitude of the signal.
6 . The guided munition of claim 5 , wherein the command and control logic direction finds a location of the signal jammer based on the relative phase and amplitude of the signal.
7 . The guided munition of claim 6 , further comprising:
a lookup table, wherein the command and control logic direction finds a location of the signal jammer based on relative phase and amplitudes contained in the lookup table.
8 . The guided munition of claim 1 , wherein the command and control logic is provided with a roll, pitch, and yaw of the guided munition, and the command and control logic instructs the guided munition to move and position the roll at an orientation such that all antennas that compose the seeker receive at least some of the signal and none of the antennas are in an exact cross polarization relative to each other.
9 . The guided munition of claim 1 , wherein the signal has a bandwidth that is in a range from about 11 MHz to about 15.5 MHz.
10 . The guided munition of claim 1 , wherein the signal has a wavelength that is in a range from about 4 inches to about 12 inches.
11 . A modular radio frequency (RF) seeker for selective connection with a projectile, the modular RF seeker comprising:
a plurality of RF antennas, wherein at least two RF antennas are spaced apart from each other at a distance that is less than one wavelength of a signal band of interest that is to be detected by the modular RF seeker; and
a modular connector that modularly connects with another portion of the projectile, wherein when modularly connected, the plurality of RF antennas are in operative communication with a guidance kit on the projectile that guides the projectile toward at least one signal jammer emitting a signal at the signal band of interest.
12 . The modular RF seeker of claim 11 , wherein the guidance kit includes command and control logic to cross correlate data received from the RF seeker to obtain relative phase and amplitude of the signal and direction finding a location of the at least one signal jammer based on a relative phase and amplitude of the signal.
13 . A method comprising:
installing a radio frequency (RF) seeker on a guided munition, wherein the RF seeker receives a signal from a signal jammer, wherein the RF seeker has at least two antennas that are spaced apart from each other at a distance that is less than one wavelength of the signal that is to be detected by the RF seeker; and
installing command and control logic on the seeker, wherein the command and control logic receives data from the RF seeker based on the signal received at the RF seeker, wherein the command and control logic guides the guided munition to the signal jammer, wherein the guided munition is configured to detonate near the signal jammer and thereby disable the signal jammer.
14 . The method of claim 13 , wherein after the RF seeker has been installed on the guided munition, the RF seeker receives the signal emanating from the signal jammer located at or near a point of interest (POI); and
wherein after the command and control logic has been installed on the guided munition, the command and control logic alters a trajectory of the guided munition in response to receiving the jamming signal and directs the trajectory of the guided munition toward the signal jammer.
15 . The method of claim 14 , wherein after the command and control logic has been installed on the guided munition, the command and control logic correlates data from the RF seeker to obtain relative phase and amplitude of the signal.
16 . The method of claim 15 , f wherein after the command and control logic has been installed on the guided munition, the command and control logic direction finds a location of the signal jammer based on the relative phase and amplitude of the signal.
17 . The method of claim 16 , wherein after the command and control logic has been installed on the guided munition, the command and control logic compares the relative phase and amplitude of the signal to values in a look up table, wherein the command and control logic direction finds a location of the signal jammer based on relative phase and amplitudes contained in the lookup table.
18 . The method of claim 13 , wherein after the RF seeker has been installed on the guided munition, the guided munition positions at least one of roll, pitch and yaw at an orientation such that all antennas that compose the seeker receive at least some of the signal and none of the antennas are in an exact cross polarization relative to each other.
19 . The method of claim 13 , wherein the signal has a bandwidth that is in a range from about 11 MHz to about 15.5 MHz.
20 . The method of claim 13 , wherein the signal has a wavelength that is in a range from about 4 inches to about 12 inches.