Design and Implementation of a Deception Jamming System for Laser Receivers

摘要

Laser jamming has two forms: passive and active jamming. In this paper we compare between the passive, active and passive-active deception techniques from the functional point of view. Passive jamming techniques are used with highly absorptive or diffusive materials on the body of the equipment. These passive techniques decrease the intensity of the reflected laser pulses and hence decrease SNR. Active jamming techniques are used to deceive and puzzle laser receivers. A high energy pulse with delay time is transmitted with each reflected pulse then the receiver will confuse between the two pulses. Active jammers need higher energy pulses to provide high jammer to signal ratio. In this paper we will compare received pulses using passive technique only, active technique only and passive-active technique. We use Q-switched Nd:YAG Laser source with wavelength of 1064 nm, energy of 80 mJ, pulse width of 200 μs and repetition rate 10-20 Hz. The intensity of the incident laser pulse is reduced by a factor of 80 % using an absorptive material, at the same time an electronic circuit receives the laser pulses and use it to trigger high-power LEDs with the same laser wavelength that make phase shift and signal distortion to the received pulses. The results show that the passive-active technique is the optimum one and solve the two disadvantages of each passive and active technique as individual. It decreases the reflected signal amplitude and hence the jammer to signal ratio can be obtained with lower power sources and increases the complexity for the DSP-based systems.