A stable clock has been developed for synchronising transmitter and receiver in a bistatic sonar system. The hardware for this GP&TS (Global Positioning and Time Synchroniser) has been described in a previous FOA report ("A GPS Based Time Synchroniser", 1999). The present report describes the GP&TS software, especially the PC Visual Fortran program, but also the assembler program in the clock itself and the communication protocol between clock and PC. It also gives a review of the electrical inputs and outputs of the clock. The report is intended to be used as a user manual and it contains a lot of screen dumps from the PC program. Some new applications for the clock are also pointed out.