Simplified Filtering Estimator for Spacecraft Attitude Determination from Phase Information of GPS Signals.

A remote sensing and control system wherein a plurality of remote sensing units are connected to a central control and monitoring console by only four interconnecting wires. A clock signal is converted to a plurality of parallel address signals at the local monitoring console and also at the remote sensing units located up the building. A sync signal is employed to synchronize all of the serial to parallel converters in the system, and each remote unit is provided with a specific code and is identified by selectively routing one or more signals through an invertor located at each unit so that the signals trigger a logic device in the particular time slot assigned to each remote unit. The input circuitry of each remote sensing unit compares two fixed microvolt reference signals derived from the least significant bit of the address signals with the return signal from the sensing device to sense for opens, grounds, normal conditions, and alarms. The system is adapted to operate with conventional computing means and programmable read only memories, as well as a multiplexer unit, for providing control signals to operate controlling device upon the occurrence of predetermined signals from the sensing device.