Estimation of PRI Stagger in Case of Missing Observations

For a moving target indicating (MTI) radar system to eliminate “blind speeds” or synthetic aperture radar (SAR) to eliminate “blind ranges,” two or more pulse repetition intervals (PRIs) are often used sequentially. This article proposes a new correlation-matching algorithm to estimate the PRIs, despite the radar receiver possibly missing some time samples. This proposed algorithm operates in the orthonormal Ramanujan subspace, leading to fewer nonzero elements therein, thus reducing the computational load. This proposed algorithm employs the l
_p
-norm (instead of the l
₂
-norm) in computing the correlation coefficients, for better robustness against outliers. Simultaneously, a new divisor rule, instead of the least common multiple (LCM) rule, and an algorithm for computing the threshold are proposed to identify the frame period of the staggered pulse train in the presence of spurious peaks. This new algorithm improves estimation accuracy and is robustness to missing pulse and PRI jitter.