Abstract: A system and method for generating a counter-measure signal in response to an incoming radar signal from a remote linear frequency modulated (LFM) pulse compression radar system. One method comprises the steps of receiving an incoming radar signal having a time period T; storing at least a portion of the radar signal in a memory; extracting predetermined segments of the radar signal from the memory; replicating the predetermined segments to create a predetermined plurality of each of the predetermined segments; concatenating the plurality of predetermined segments into a further signal, like ones of the plurality of predetermined segments adjacent one another; and transmitting the further signal to the remote radar system.

Abstract: A digital polarimeteric system employs a signal time stretching technique and digital signal processing of the time-stretched signal to accurately measure the polarization of a received RF signal with commercially available digital hardware. A superheterodyne receiver down converts received RF signal components to IF, and analog-to-digital converters sample the signal components at much lower sampling rates than would normally be required to accurately measure the signal polarization. Each signal sample is “time stretched” by storing each sample in M locations in a memory, such that N samples occupy M×N memory locations. A digital signal processor applies incremental phase shifts to the digital samples until a phase-shifted combination of the digital samples yields a minimum null output. The phase shifts producing the minimum null identify the polarization of the received signal.

Abstract: An electronic warfare (EW) cross-eye system comprises two antennas separated a distance, d, a part, where d is much greater than the wavelength, ?, of a tracking signal emitted by a fire control radar (i.e., d>>?). The EW cross-eye system further comprises a receive polarimeter for measuring the tracking signal and a second polarimeter for synthesizing the measured tracking signal to produce, for transmission, a jamming signal comprising a pair of inverted amplitude signals that are 180 degrees out of phase with each other.

Abstract: An electronic warfare (EW) cross-eye system comprises two antennas separated a distance, d, a part, where d is much greater than the wavelength, ?, of a tracking signal emitted by a fire control radar (i.e., d >>?). The EW cross-eye system further comprises a receive polarimeter for measuring the tracking signal and a second polarimeter for synthesizing the measured tracking signal to produce, for transmission, a jamming signal comprising a pair of inverted amplitude signals that are 180 degrees out of phase with each other.

Abstract: A method determines range from a moving platform to an emitter. The method receives a RF signal from the emitter; counts a number of phase reversals of the received RF signal during a period of time; measures a Doppler frequency during the period of time; and determines the range to the emitter based on both the number of counted phase reversals and the measured Doppler frequency.

Abstract: A polarization measurement system and method that determines the polarization of a received signal within one received pulse. The polarimeter accepts series of samples representing horizontal and vertical signal components representing the polarization of a received signal. The samples are discrete time measurements, with each sample representing a magnitude separated in time by a predetermined angular resolution. The samples are combined with other samples in numerous sets of calculations operating in parallel, the various sets of calculations employing different transfer functions, so as to produce numerous series of output values. Characteristics of these series are examined to select a particular series, and thus select the transfer function which provided the series having a desired characteristic such as a best null. The parameters of the transfer function which provides the desired characteristic provide information representative of the signal polarization.

Abstract: A solid state active aperture high power polarization agile transmitter, either single or dual polarization, employing nonreciprocal antenna elements, designed such that it can be used in an Electronic Warfare (EW) system that is more efficient and less expensive. Antenna beam steering is accomplished with variable phase shifters that are used to set the RF signal phase of each element. The beam steering function is implemented with a hardware architecture where the phase shifters are built-in ahead of the power amplifiers such that these low power phase shifters impart phase delays to low power signals without wasting RF signal power and hence improving efficiency. These power transmitter devices are also more reliable, lighter in weight and smaller in size.

Abstract: A digital polarimeter employs a signal time stretching technique to apply polarization phase shift characteristics to digitally generated polarization agile signal components. An RF signal to be transmitted is down-converted to an intermediate frequency and digitally sampled at a rate feasible with currently-available analog-to-digital converters. Horizontal and vertical signal components of the sampled IF signal are generated by processing the digital signal samples. Each digital signal sample is “time stretched” by storing each sample in M memory locations, such that N samples occupy M×N memory locations. Because each sample is stored in M memory locations, each incremental phase shift from one memory location to the next corresponds to 1/Mth of the actual sampling interval. The stretching process effectively increases the digital sampling frequency, yielding sufficient phase resolution.

Abstract: A solid state active aperture high power polarization agile transmitter, either single or dual polarization, employing nonreciprocal antenna elements, designed such that it can be used in an Electronic Warfare system that is more efficient and less expensive. Antenna beam steering is accomplished with variable phase shifters that are used to set the RF signal phase of each element. The beam steering function is implemented with a hardware architecture where the phase shifters are built-in ahead of the power amplifiers such that these low power phase shifters impart phase delays to low power signals without wasting RF signal power and hence improving efficiency. These power transmitter devices are also more reliable, lighter in weight and smaller in size.

Abstract: Electronic Warfare (EW) systems aboard aircrafts are used to protect them from guided missile by denying threat radar systems the ability to track the aircrafts. In a typical operation, a threat radar system transmits RF signals aimed at the target aircraft. The surface of the target reflects a portion of the incident signal back towards the threat radar antenna where the reflected signal is detected, allowing the threat radar system to determine the target's range, angle and velocity. The present invention relates to EW systems that are dependent on measuring the RF phase of a signal transmitted by a target tracking threat radar. The use of the invented technique will make it possible to implement a robust Electronic Counter-Measures (ECM) technique, known as Cross-Eye, using two airborne platforms. The technique is very effective in preventing a threat radar from tracking a target aircraft and guiding a launched missile to the target aircraft.