Field test campaign of Chandrayaan-3 radar altimeter

Chandrayaan-3 is the third mission in the series of lunar exploration missions of the Indian Space Research Organisation.The mission demonstrates an end-to-end capability for safe landing and roving on the lunar surface.The lander was equipped with many sensors for a safe landing.One of the prime sensors for precise altitude estimation was the Ka-band radar altimeter (KaRA).The KaRA is designed to cover a large altitude range of 10 km to 10 m.To ensure its reliability, the KaRA go through an extensive verification and validation process, including a series of field tests designed to mimic the lander's expected descent trajectory.These tests used different platforms, such as a crane, a helicopter, and an aircraft, to simulate various flight profiles.In addition to field experiments, KaRA was subjected to hardware-in-loop simulations and laboratory testing.KaRA performed exceptionally well across all forms of evaluation.The present study discusses the comprehensive field test campaign, the challenges encountered, the outcomes achieved, and innovative strategies employed to enhance the robustness of the algorithms integral to KaRA operation.