In this paper, the mathematical model of the S-mode of an automatic dependent surveillance-broadcast signal is established, and the realization process and theoretical accuracy of the rising edge and optimal estimation measurement algorithms in the time of arrival (TOA) estimation algorithm are analyzed. First, the theoretical implementation of the single-pulse differential matched filter is deduced and verified, and the improved algorithm of the multipulse differential matched filter for TOA measurement is analyzed based on pulse accumulation. Then, a polynomial fitting algorithm is proposed to reduce the TOA estimation error to solve the time discretization problem caused by hardware sampling in engineering practice. Finally, the TOA estimation performance of each algorithm is analyzed using simulation, and the effectiveness of different algorithms applied to the multilateration system is verified by combining them with the positioning algorithm.