US Government As Represented by the Secretary of the Army

Michael R Christian

Ralph H Halladay

Walter E Miller, Jr

William C Pittman

Brian J Smith

Donald E Lovelace

James H Mullins

The system and method for radar calibration using antenna leakage is a simplified means of calibrating the channels in amplitude and phase using natural signal leakage between antennas. It utilizes as calibration signal a wideband sinusoidal Frequency Modulated Continuous Wave (FMCW) waveform with a modulation index and modulation frequency chosen to generate spectral components (or discrete signal frequencies) that fall within the receiver Doppler passband of the radar. The calibration signal is radiated out of the transmitting antenna and enters the radar receiver front-end through the transmit-to-receive antenna leakage which occurs naturally. This technique provides a low-complexity (simpler hardware realization) means for achieving a wideband calibration rapidly and is a practical alternative to the conventional calibration approach that relies on generating offset Doppler signals that are coupled into the radar receiver front-end through the use of couplers and cabling within the radar.

System and method for radar calibration using antenna leakage

The Multiple-Antenna Jamming System (MAJS) is useful for missile-borne jamming of active protection system radars that operate in close proximity to the frequency band of the missile's radio frequency seeker. The MAJS utilizes multiple receiving and transmitting antennas to reduce shadowing effects due to the transmissive radome. It also channelizes the jamming signals into in-seeker-band and out-of-seeker band signals to synchronize the transmission of jamming signals with the emit-listen pattern of the missile seeker and to eliminate the problem of de-sensitizing the RF seeker from the jammer energy. The in-seeker-band jamming signals are transmitted only concurrently with the missile seeker emissions and any signals emanating from an enemy radar are received only during the listen mode of the missile seeker.

Multiple-antenna jamming system

In-Seeker Jamming Device, suitable for an RF missile, utilizes the high-gain antenna and amplifier that are already a part of the missile. During the &ldquo;blind range&rdquo; between the termination of the missile's active tracking of the target at a pre-selected distance from the target and its impact on the target, the Jamming Device produces signals that are broadcast via the missile's antenna and are designed to jam and frustrate the active protection system (APS) radars, thereby rendering the APS radars ineffective and the intended targets vulnerable.

In-seeker jamming device

In a phased array radar, simultaneous beam steering and single-sideband mlation is accomplished in the phase shifters in response to phase control signals produced by the beam steering controller and input to the phase shifters. The beam steering controller produces the phase control signals from a pre-selected beam steering angle, a pre-selected radar intermediate frequency and a voltage representing the frequency error from incomplete compensation of the target motion (doppler) of the previous cycle of the radar. Using the phase shifters thusly eliminates the need for an expensive separate component, the single sideband modulator.

Phased array radar with simultaneous beam-steering and single-sideband

Van Atta array is used to receive a millimeter wave beam from a beam transmitter located in a missile in flight and retransmit the beam back to its source along its original optical path after the beam is phase conjugated and modulated at a tracking station by imparting to it missile guidance information. The missile extracts guidance information from the retransmitted beam and guides its trajectory closer to the course leading to the target.

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Owens Cross Roads, AL, United States of America

Michael R Christian