A Comprehensive Approach to Adaptive Processing Both on Transmit and Receive Including Presence of Waveform Diversity

Abstract : In this final report, the quality of the adaptive processing is investigated as a function of random position errors in the locations of the sensors. Use of waveform diversity and a comprehensive approach to adaptive processing may not be useful if the sensors deviate from their true positions, due to environmental effects or due to mechanical errors in their positioning. Here, we provide an upper bound for the spatial variations in the locations of the sensors, implying that if the errors are within this bound then acceptable performance can be expected. The equivalent isotropically radiated power (EIRP) degradation due to random position errors for Space-Time Adaptive Processing (STAP) is presented based on the relationship between the EIRP degradation and the standard deviation or the uniform bound of the probability distribution of location of the antenna elements. We simulate a direct data domain least squares (D3LS) approach for STAP under two different conditions. In the first case, the antenna elements at every time instance are assumed to have different spatial positions from the previous time instance. For the other case, the antennas are assumed to be randomly located, but are assumed to be fixed in a coherent processing interval (CPI). It is demonstrated that whether the locations of the antenna are fixed or they vary within a CPI with identical random errors, the output signal to interference and noise ratio (SINR) are almost the same. When the antenna elements are moved randomly, the output SINR is less than the unperturbed case. We can develop a bound on the EIRP degradation due to the D3LS approach to STAP based on the random position errors.