The traditional location methods for passive localization are TDOA (Time Difference of Arrival) based due to the unknown TOE (Time Of Emission).Based on Bancroft's algorithm

which was developed for GPS single-point position

the TOA least squares (TOA-LS) estimation algorithm for passive multilateration is proposed.The TOA-LS equations are composed of three linear equations whose coefficients are dependent on the target position and TOE.Using Bancroft's algorithm with some initial values

the TOA-LS algorithm solves the linear equations for new solutions and updates their coefficients.Simulation experiments demonstrate that the TOA-LS algorithm is near optimal and attaining the theoretical lower bound for targets in different geometric positions.