Laser ranging and mapping with a photon-counting detector

We propose a new technique for remote sensing: photon-counting laser mapping. Microchannel plate detectors with a crossed delay-line (MCP/CDL) readout combine high position accuracy and subnanosecond photon timing, at event rates of 10(6) detected photons per second and more. A mapping system would combine an MCP/CDL detector with a fast-pulse, high-repetition-rate laser illuminator. The system would map solid targets with exceptional in-range and cross-range resolution. The resulting images would be intrinsically three dimensional, without resorting to multiple viewing angles, so that objects of identical albedo could be discriminated. For a detector time resolution and pulse width of the order of 10(-10)s, the in-range resolution would be a few centimeters, permitting the discrimination of surfaces by their textures. Images could be taken at night, at illumination levels up to full moonlight, from ground, airborne, or space platforms. We discuss signal to noise as a function of laser flux and background level and present simulated images.