Performance Metrics for Single-Photon Laser Ranging

Airborne laser swath mapping systems collect thousands of range measurements per second, enabling high-resolution surface mapping. Low-signal-to-noise-ratio (LSNR) detection techniques allow for implementation of light detection and range (LIDAR) instrumentation aboard platforms with stringent power, size, and weight restrictions. The University of Florida has developed the coastal area tactical-mapping system, which is a prototype LSNR LIDAR system that is capable of single-photon laser ranging. Laser pulses of 532 nm, 3.5 ??J, and 480 ps are transmitted at 8 kHz, with the outgoing footprint split into a 10 ?? 10 array of elements. Backscattered photons are imaged back onto separate anodes of a multistop microchannel plate photomultiplier tube. A 2-GHz event timer processes returns over the array. Ranges for known targets are accumulated for repeated laser shots, and statistical analysis is applied to evaluate performance metrics that are related to minimum separation distance, bathymetric mapping depth, and atmospheric scattering. An LSNR detection paradigm based on Poisson statistics has enabled topographic target detection and shallow-water bathymetry. Quantitative results are used to draw conclusions about feature detection in topographic and bathymetric mapping scenarios.