DESIGNANDDEVELOPMENTOFLOWCOSTLIDAR ANDRADARPROXIMITYFUZESENSORFOR DEFENCEAPPLICATION

Abstract

This thesis aims to design and develop a LiDAR RADAR proximity fuze that can be used in defence applications. The basic parameters established are up to 50m of detection, low cost, and to produce an optimum height of burst of 4 to 16 meters. LiDAR depends on sending a pulse of photons onto the target. The observe the return signal based on the Lambertian principle for the reflected energy. This energy is then detected with the help of an avalanche photodiode (APD) with an internal gain. Once the signal is detected, a threshold has been established to trigger a stop pulse. The time at which a pulse is sent, a start signal is registered, and a stop signal is recorded upon receiving the stop trigger. Up to four readings are taken for a single target to determine the correctness of the reading. The start and stop signals are compared to a reference time clock to get the time of flight of the light pulse. The delays in the electronic system are also taken into account while calculating the time of flight. This value is now transferred to a PC with the help of UART protocol to the LiDAR PC Utility. The LiDAR PC Utility collects this information for all the hits. The output will be in the form of comma-separated values. A number of these readings are taken over various coloured backgrounds. This data is used to design a Kalman filter to achieve a uniform range value to all the readings. This ensures a uniform range reading despite a dynamic background as the photon beam is not always pointed onto a single target due to the constant motion of the projectile. The LiDAR prototype has been realised, including the optics. A RADAR block diagram with all the parameters has been prepared. The targeted design would work in X band, and the receiver is designed to have a Gain up to 65 to 70dB.