The MER Descent Image Motion Estimation System (DIMES) is the first passive image-based system to estimate lander velocity during planetary descent. The DIMES algorithm combines sensor data from a descent imager, a radar altimeter and an inertial measurement unit in a novel way to create an autonomous, low-cost, robust and computationally efficient solution to the horizontal-velocity-estimation problem. DIMES performed successfully during both of the MER landings. During the landing in Gusev Crater, the landing system used the measurement provided by DIMES to remove a possibly catastrophic horizontal velocity.
Fig. 1: Matched image sequence from MER EDL.