“…With respect to the parameter estimation of PPSs whose orders P exceeded two, we first used PD to reduce the PPS order to two and then employed the combined dictionary algorithm to estimate the two highest-order parameters, a P and a P−1 . When considering a third-order PPS, y(n) = exp(j(a 3 (n ) 3 + a 2 (n ) 2 + a 1 (n ) + a 0 )) + υ(n) (24) where (a 3 , a 2 , a 1 , a 0 ) = (2.75e-6, 1.25e-3,π/8, π/3), the SNR varied between −10dB and 13dB, the total number of samples was set as N = 515, and the sampling interval was = 1.6477s. First, we used PD to reduce the PPS order to two, where PD 1 is defined as PD 1 [n; τ ] = exp j(6a 3 τ (n ) 2 + 4a 2 τ (n )…”