A system is disclosed that provides a sonar system featuring combined spatial and temporal correlation array processing. The disclosed system merges spatial-based velocity errors with temporal-based velocity errors by using a combining algorithm that is based on the optimization criteria that the output after combining has no bias error and has a minimized mean square error. With these criteria, the combining algorithm takes the form of a weighted summation of the spatial data stream and temporal data stream inputs with the weights being a function of the relative velocity errors. In combining spatial and temporal processing in this manner, the disclosed system provides improved velocity measurements for a wider range of ship's speeds. In particular, the system achieves performance levels of a spatial correlation sonar for low ship's speeds for which a temporal correlation sonar solution might not be available. The system also achieves performance levels of a temporal correlation sonar for high ship's speeds for which a spatial correlation sonar solution might not be available.