The Study On Laser Target Identification And Communication System

This thesis discussed and analysed the technology problems for the design and development of laser target identification and communication system. Author develops a wide angle PIN photoelectric receiver and an APD tar- get echo detection system based on the weak signal detection and its processing technology. For the wide angle PIN photoelectric receiver, its main problems such as the light saturation and interference of strong backgroud light are solved. For the APD target echo detection system, a novel approach to the bi- as voltage compensation of APD detector (for example C30950E) is proposed. This novel approach makes the APD bias voltage compensation operating intel- ligently in real time through fuzzy control technique and is a key technique for the system wich can resist the background light interference . The interference of the laser emitting system to the weak signal detection system is restricted, the error rate of the system is reduced and the sensitivity of the APD echo de- tector is enhanced by the means of the electromagnetism compatible technique. The thesis presents the mathematical models for the circuit system of the PPM modulation and demodulation, PIN photoelectric receiver and APD echo detector and give out the theoretical evidence for the corresponding hardware circuit system design. A laser emitting system and a multiple single chip microprocessor infor- mation processing and controlling system which use one AT89C52 as master and multiple AT89C205 1 as slaves are also designed. Some problems such as the electromagnetism compatible design of the system as well as coding, de- coding and correcting technique of laser pulse in digital communication are discussed. The development of the proposed system was began at 1992 and final de- I sign tests were passed on Sept. 1999. The tests results indicate that the system performance has reached and exceeded the design specification requirements.