A Long Distance Laser Altimeter for Terrain Relative Navigation and Spacecraft Landing

• Published in: NASA Center for AeroSpace Information (CASI). Conference Proceedings
• Main Authors: Pierrottet, Diego F, Amzajerdian, Farzin, Barnes, Bruce W
• Format: Conference Proceeding
• Language: English
• Published: Hampton NASA/Langley Research Center 05.05.2014
• Subjects: Aircraft rockets; Altimeters; Flight tests; Helicopters; Laser altimeters; Lasers; Navigation; R&D; Rangefinding; Research & development; Spacecraft landing; State estimation

A high precision laser altimeter was developed under the Autonomous Landing and Hazard Avoidance (ALHAT) project at NASA Langley Research Center. The laser altimeter provides slant-path range measurements from operational ranges exceeding 30 km that will be used to support surface-relative state estimation and navigation during planetary descent and precision landing. The altimeter uses an advanced time-of-arrival receiver, which produces multiple signal-return range measurements from tens of kilometers with 5 cm precision. The transmitter is eye-safe, simplifying operations and testing on earth. The prototype is fully autonomous, and able to withstand the thermal and mechanical stresses experienced during test flights conducted aboard helicopters, fixed-wing aircraft, and Morpheus, a terrestrial rocket-powered vehicle developed by NASA Johnson Space Center. This paper provides an overview of the sensor and presents results obtained during recent field experiments including a helicopter flight test conducted in December 2012 and Morpheus flight tests conducted during March of 2014.