Abstract: Methods, systems, and apparatus for real-time control of radio frequency (RF) reflectivity to enable radar camouflage are disclosed. A spatially diverse collection of elements, consisting of at least two elements, are used to control the direction of reradiated (reflected) energy from an object or person where direction of the reradiated energy is controlled by a circuit and a controller. The controller and circuit changes the reflectivity of each element individually as a function of time. The effect of the spatial distribution and time varying reflectors is a reflected RF signal that can statistically mimic background clutter.

Abstract: A received signal that includes a target signal and an interference signal is sampled in space and time and then filtered into a matched-filtered signal and into a mis-matched-filtered signal, which is orthogonal to, or nearly orthogonal to, the matched-filtered signal The interference signal is present in both the matched-filtered signal and the mis-matched-filtered signal, whereas the target signal is present in only the matched-filtered signal. In the mis-matched-filtered signal, the interference signal is different from the matched-filtered signal in the temporal property, but is the same as the matched-filtered signal in the spatial property. After the matched-filtered signal and the mis-match-filtered signals have been obtained for the signals received by each antenna element of an array of antenna elements, they are processed to obtain a result vector, W, that is a representation of the target signal without the interference.

Abstract: Systems and methods are provided for mitigating natural and man-made interference through the use of one or more orthogonal, or nearly-orthogonal, projections of the received signal, which is assumed to be contaminated with interference, into one or more orthogonal projection spaces based on properties of the signal of interest. Once separated into orthogonal projection space(s), the system and method use information contained in the orthogonal projection space(s) to separate the signal of interest, or target signal, from the interference and to mitigate the interference.

Abstract: A received signal that includes a target signal and an interference signal is sampled in space and time and then filtered into a matched-filtered signal and into a mis-matched-filtered signal, which is orthogonal to, or nearly orthogonal to, the matched-filtered signal. The interference signal is present in both the matched-filtered signal and the mis-matched-filtered signal, whereas the target signal is present in only the matched-filtered signal. In the mis-matched-filtered signal, the interference signal is different from the matched-filtered signal in the temporal property, but is the same as the matched-filtered signal in the spatial property. After the matched-filtered signals and the mis-match-filtered signals have been obtained for the signals received by each antenna element of an array of antenna elements, they are processed to obtain a result vector, W, that is a representation of the target signal without the interference.

Abstract: Systems and methods are provided for mitigating natural and man-made interference through the use of one or more orthogonal, or nearly-orthogonal, projections of the received signal, which is assumed to be contaminated with interference, into one or more orthogonal projection spaces based on properties of the signal of interest. Once separated into orthogonal projection space(s), the system and method use information contained in the orthogonal projection space(s) to separate the signal of interest, or target signal, from the interference and to mitigate the interference.