The use of laser altimetry in the orbit and attitude determination of MarsGlobal Surveyor

Altimetry from the Mars Observer Laser Altimeter (MOLA), an instrument on b oard the Mars Global Surveyor (MGS) spacecraft, has been analyzed for the p eriod of the MGS Science Phasing Orbit-1 (SPO-1) mission phase. Altimeter r anges have been used to improve significantly the orbit and attitude knowle dge of the spacecraft by the use of crossover constraint equations derived from short passes of the MOLA data. These constraint equations differ from traditional crossover constraints and exploit the small footprint associate d with laser altimetry. The rationale for using this technique with laser a ltimetry over sloping terrain is laid out and evidence of the resulting ben efit is presented.