Altimeter and Velocimeter-/Optical-Aided Inertial Navigation Technology

Inertial navigation has been successfully applied in soft landing missions. The inertial navigation error is gradually increased caused by initial navigation error and inertial measurement unit (IMU) measurement error. In order to improve the navigation accuracy of the lander relative to the celestial body surface, direct measurements of the lander relative to the celestial body surface are usually used to correct inertial navigation results. Candidate sensors include altimeter, velocimeter, and optical imaging sensor. This chapter focuses on the altimeter-/velocimeter-aided inertial navigation and optical-aided inertial navigation for soft landing missions.