13 September 1989 Optimization Of Laser Beam Spread To Maximize Laser Radar Probability Of Detection
Author Affiliations +
This paper discusses the affect on probability of detection (Pd) and probability of false alarm (Pfa) of the illuminator laser beam width. Laser radar systems are required to optimize performance while minimizing the laser energy thereby requiring the illuminated target region to be optimized with regard to the uncertainty of the target location. A beam spread much larger than the uncertainty volume of the target can have a high Pd but would require excessive laser energy. A very narrow beam spread would minimize laser energy but not have a high Pd. The optimum beam spread for laser illumination of a point target with a normal distribution for its position uncertainty has been determined for both direct and heterodyne (coherent) detection. This work assumes a Gaussian laser illuminator beam spread and a Gaussian target uncertainty distribution. Values for Pd and Pfa have been computed for both direct and heterodyne detection. The results were then averaged over the intensity distribution expected for the illuminator beam and the target uncertainty. Contour plots were computed for fixed signal-to-noise ratio (SNR), defined as the on-axis SNR for the target. The minima for each contour can be plotted for various ratios of illuminator beam spread to target uncertainty. The results determine the optimum ratio for a given Pd, Pfa, SNR, and detection technique. The affect of laser speckle was also included. This method of optimum beam size determination proves extremely useful in many strategic laser radar systems.
© (1989) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Dean H. Liskow, Joseph N. Paranto, "Optimization Of Laser Beam Spread To Maximize Laser Radar Probability Of Detection", Proc. SPIE 1103, Laser Radar IV, (13 September 1989); doi: 10.1117/12.960562; https://doi.org/10.1117/12.960562

Back to Top