Slow scan television via tactical satcoms

A system which enables near real time moving picture information in redundant scenes to be transmitted over a low data rate tactical satellite communication link is described. The prototype equipment was designed to operate from automobile based satcom terminals using 16 kbit/sec tactical voice links. With the advent of more powerful satellites (SKYNET 4) the equipment should be usable with manpack type satcom terminals. The video codec operates at a constant 16 kbit/sec data rate and is therefore compatible with any 16 kbit/sec digital communications link. The system has two modes of operation: conventional slow scan television to build up the television frame, and conditional replenishment to send the moving picture information. The majority of information in a moving picture scene is stationary and is therefore redundant information.