Altimetry and transponder ground simulation experiment

We have designed and built a compact demonstrator unit for the investigation of altimetry and transponder applications. A small light-weight breadboard carries a compact frequency doubled Nd:YAG pulse laser, an afocal beam expansion optics, a small receiver telescope with spectral and spatial filter arrangements and a sensitive photo-detector. The output laser energy can be as high as 45 mJ with a pulse-width of 3 ns and the telescope aperture is 10 cm. Simulations [Degnan, J.J., 2006. Simulating interplanetary transponder and laser communications experiments via dual station ranging to SLR satellites. In: Proceedings of the 15th International Workshop on Laser Ranging, Canberra, Australia, pp. 457-462] suggested that the link margin for low Earth orbiting satellites (LEO) is comfortable. Successful satellite laser ranging from this dual-station experiment in several different configurations was achieved up to the MEO orbit in a 10 day provisional installation.