Abstract: Improved orbit/covariance estimation and analysis (OCEAN) system and method are presented utilizing ground station observations collected from satellites passing overhead to estimate the positions, velocities, and other parameters of multiple satellites using weighted least squares (WLS) batch and/or Kalman filter smoothing (KFS) estimation algorithms to estimate each parameter, with or without a priori knowledge of the errors involved with each observed parameter.

Abstract: Systems and methods are presented for passive location of transmitters in which two or more receivers time stamp received signals from target transmitters and the time stamped data for each target signal of interest is isolated to identify a peak power time of arrival for the signal at each transmitter from which differential scan observation values are derived, and for each signal of interest a line of position curve is computed based on the differential scan observation value and corresponding receiver locations, and for each signal of interest an estimated target transmitter location is determined based on an intersection of two corresponding line of position curves.

Abstract: Systems and methods are presented for passive location of transmitters in which two or more receivers time stamp received signals from target transmitters and the time stamped data for each target signal of interest is isolated to identify a peak power time of arrival for the signal at each transmitter from which differential scan observation values are derived, and for each signal of interest a line of position curve is computed based on the differential scan observation value and corresponding receiver locations, and for each signal of interest an estimated target transmitter location is determined based on an intersection of two corresponding line of position curves.

Abstract: The orbit/covariance estimation and analysis (OCEAN) technique utilizes ground station observations collected from satellites passing overhead and estimates the positions, velocities, and other parameters of multiple satellites. It also estimates parameters for other elements, such as the locations of ground stations and measurement biases. The technique utilizes recorded observations (e.g., range, Doppler) and measurements from various sources as inputs to a weighted least squares batch estimation algorithm used in iterative fashion to estimate each parameter, with or without a priori knowledge of the errors involved with each observed parameter. The process is completed once the residual, the difference between the estimated parameter and the observed parameter, satisfies the tolerance defined by the user. Using the results of the estimation process or a predefined initial condition file, the OCEAN program can also generate a predicted trajectory (i.e.