Recent work has proposed a certainty trend (CT) elimination technique employed for the auto-regressive/autoregressive and moving-average (AR/ARMA) model pulse position prediction. In this paper, we investigate the intra pulse parameter estimation and pulse position prediction of the chirp and stochastic pulse position modulation (CSPPM) combined signal. The quick dechirp method is adopted to the initial frequency and chirp rate estimation. To get a stationary data series satisfying the premise condition of the AR/ARMA model prediction, a least square fitting (LSF) scheme to remove the CT term contained in pulse position sequence is presented. Compared with the classic logarithmic difference conversion (LDC) smooth method, AR/ARMA prediction performance via LSF has a significant improvement, about 70% to 96% for AR prediction and 42% to 99% for ARMA prediction. Index Terms-AR/ARMA model, prediction, stochastic pulse position modulation signal, least square fitting (LSF) I. INTRODUCTION Recently, the complex signal such as the chirp and stochastic pulse position modulation (CSPPM) combined signal is receiving more and more attention [1]-[3]. M. Kaveh and G.R. Cooper introduced the notion of the stochastic pulse position modulation (SPPM) signal in [4] and show that the removal of the velocity ambiguity requires the random delays instead of lowering the average repetition rate significantly. It is noted that CSPPM combined signal has a super low probability of intercept and anti-jamming performance by deriving its ambiguous function. Unfortunately, the surveillance of this non-cooperative signal is a challenge problem for radar reconnaissance [5], [6]. Recent years, researchers concentrated on the analysis of the SPPM signal's generation [7], distance measurement methods [8] and properties [9]. Few literatures reported the pulse position prediction for the further signal sorting and tracking. The purpose of this paper is to predict the combined signal's pulse occurrence time dependent on the live pulse position sequence, which can be treated as a discrete stationary random process in the presence of arbitrary time jitter. Inspired by that the stochastic time