Analytical performance evaluation of adaptive detection of fluctuating radar targets
A radar target whose return varies up and down in amplitude as a function of time represents the basis of a large number of real targets. This paper is intended to provide a complete analysis of CFAR detection of fluctuating targets when the radar receiver post-detection integrates M returned pulses from χ2 fluctuating targets with two and four degrees of freedom and operates in a non-ideal environment. Owing to the importance of Swerling models in representing a large number of such type of radar targets, we are interested here in adaptive detection of this class of fluctuation models. Swerling cases I and III represent scan-to-scan fluctuating targets, while cases II and IV represent fast pulse-to-pulse fluctuation. Exact expressions of detection probability are derived for all of these models. A simple and an effective procedure for calculating the detection performance of both fixed-threshold and adaptive-threshold algorithms is obtained. In the CFAR case, the estimation of the noise power levels from the leading and the trailing reference windows is based on the CA technique. The performance of this detector is analyzed in the cases when the operating environment is ideal and when it includes some of spurious targets along with the target of interest. The primary and the secondary interfering targets are assumed to be fluctuating in accordance with the four Swerling’s models cited above. The numerical results show that for strength target return the processor detection performance is highest in the case of SWIV model while it attains its minimum level of detection in the case of SWI model. Moreover, SWII model has higher performance than the SWIII representation of fluctuating targets. For weak target return, on the other hand, the reverse of this behavior is occurred. This observation is common for both fixed-threshold or for adaptive-threshold algorithms.
SWERLING, P. Probability of detection for fluctuating targets. IRE Trans. Inf. Theory, v.6, n.2, p.269-308, Apr. 1960. doi: 10.1109/TIT.1960.1057561.
RITCEY, J.A. Detection analysis of the MX-MLD with noncoherent integration. IEEE Trans. Aerosp. Electron. Syst., v.26, n.3, p.569-576, May 1990. doi: 10.1109/7.106136.
EL MASHADE, M.B. M-sweeps detection analysis of cell-averaging CFAR processors in multiple target situations. IEE Proc. Radar, Sonar and Navigation, v.141, n.2, p.103-108, Apr. 1994. doi: 10.1049/ip-rsn:19949887.
SWERLING, PETER. Radar probability of detection for some additional fluctuating target cases. IEEE Trans. Aerosp. Electron. Syst., v.33, n.2, 698-709, Apr. 1997. doi: 10.1109/7.588492.
EL MASHADE, M.B. Performance analysis of the excision CFAR detection techniques with contaminated reference channels. Signal Processing, v.60, n.2, p.213-234, Aug. 1997. doi: 10.1016/S0165-1684(97)80007-2.
EL MASHADE, M.B. Partially correlated sweeps detection analysis of mean-level detector with and without censoring in nonideal background conditions. AEÜ, v.53, n.1, p.33-44, Feb. 1999.
EL MASHADE, M.B. Target multiplicity performance analysis of radar CFAR detection techniques for partially correlated chi-square targets. AEÜ, v.56, n.2, p.84-98, Apr. 2002. doi: 10.1078/1434-8411-54100077.
EL MASHADE, M.B. M-Sweeps exact performance analysis of OS modified versions in nonhomogeneous environments. IEICE Trans. Commun., v.E88-B, n.7, p.2918-2927, July 2005.
EL MASHADE, M.B. Performance evaluation of the double-threshold CFAR detector in multiple-target situations. Journal of Electronics (China), v.23, n.2, p.204-210, March 2006. doi: 10.1007/s11767-004-0085-3.
EL MASHADE, M.B. Performance comparison of a linearly combined ordered-statistic detectors under postdetection integration and nonhomogeneous situations. Journal of Electronics (China), v.23, n.5, p.698-707, Sept. 2006. doi: 10.1007/s11767-004-0213-0.
HAYKIN, SIMON, Adaptive Radar Signal Processing. John Wiley & Sons Inc., 2006.
EL MASHADE, M.B. Analysis of cell-averaging based detectors for χ2 fluctuating targets in multitarget environments. Journal of Electronics (China), v.23, n.6, p.853-863, Nov. 2006. doi: 10.1007/s11767-005-0067-0.
EL MASHADE, M.B. Analysis of CFAR detection of fluctuating targets. PIER C, v.2, p.65-94, 2008. doi: 10.2528/PIERC08020802.