Centimeter Precision Airborne Laser Ranging System

The Airborne Laser Ranging System (ALRS) is a proposed multibeam subnanosecond pulse laser ranging system on board an aircraft. It simultaneously measures the distances between the aircraft and six laser retroreflectors (targets) deployed on the Earth's surface with $\pm 1\mathrm{cm}$ precision. Depending on the host aircraft and terrain characteristics, the system can interrogate hundreds of small targets distributed over an area as large as $6\times {10}^4$ sq kilometers in a matter of hours. Potentially, a total of 1.3 million individual range measurements can be made in one six hour flight. Trilateration techniques are used to derive the intersite vectors between laser ground targets with precisions as high as one part in 107. Since all data is initiated, received, collected and processed in the aircraft via totally passive ground targets, there is no need for complex ground instrumentation or skilled personnel in the field. The high precision, speed, and large area coverage of the ALRS make it an attractive and highly cost effective instrument for a variety of geophysics studies and large scale surveying, engineering and land management applications, especially when combined with photogrammetric instrumentation.