A satellite laser radar in Helwan, Egypt, has been operating since 1981 with full computer control based on minicomputer system HP 2100 [1]. Between 1987-1989 IBM-PC computer and special control electronics based on Z80 microproccessors were implemented to the laser radar [2]. The control system covers all important functions for satellite ranging and calibration - two axes mount control, range and epoch counter, laser trigger, HP-IB interface for HP5270 or Stanford SR620 counters, arming and gate control. In 1999 a new laser radar control system was developed, based on a powerfull 80C188EB microprocessor operating in 1MB memory. Also special circuits for range and epoch reading are included. The control system is connected to the main station computer via fast RS232C interface based on 16550 chip. A second serial port is used for highly accurate meteorological station MET-3. Two DC servo motors (for azimuth and elevation) are controlled in closed loop feedback. Special microchips HP HCTL-1100 are used. HCTL-1100 is a high performance, general purpose motion control IC. A very precise time interval counter (resolution 20 ps) HP5370B or Stanford SR620 is connected via HP-IB interface based on NEC 7210 HP-IB microcontroller. The control system consists of one printed board built in to a Camac unit, size 14x22x30 cm. The firmware is written in C language and Assembller and it is very flexibile.

The control system will be tested in full operation on the laser radar station Helwan, Egypt, in summer 2000.

References

[2] Čech,M. - Novotný,A.: A Satellite Laser Radar Electronics Based on IBM PC Computer The Seventh International Workshop on Laser Radar Instrumentation, Matera, Italy, 1989

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