Taiaho Observatory: New Zealand's Premier Optical Communications Ground Station
Prof. Joseph Ashby
University of Auckland (link)
Free space optical communications (FSOC) represent a step change in the space data ecosystem. By using infrared laser light instead of conventional radio, FSOC makes possible data transfer speeds up to 10Gbits−1 and beyond in a form factor small enough to fit on a standard CubeSat. This would enable even small satellite missions to perform high data output operations, such as hyper-spectral imaging or high-resolution earth observation. The largest obstacle to the widespread adoption of FSOC is the necessity for a cloud free line of sight (CFLOS) between the satellite and an optical ground station (OGS). Therefore, one method for increasing the reliability of an FSOC network is the formation of large, geographically disparate, OGS networks. The more OGS nodes that are in a network and the further apart spread, the higher the likelihood that a given satellite will have CFLOS to at least one OGS. This is one of the motivations for the formation of the Australasian Optical Ground Station Network (AOGSN), with multiple OGSs being established across Australia and New Zealand. Taiaho observatory is the latest OGS to join the AOGSN. It has been constructed just South of Auckland, New Zealand in a collaboration between the German Aerospace Center (DLR), and the Universities of Auckland and Canterbury. Taiaho uses the latest in compact, low-cost opto-mechanical receiver technology, the DLR Small Optical Ground Stations Focal-Optics Assembly (SOFA), paired with a 30cm telescope, and a direct-drive Alt-Az mount to track and receive FSOC signals from Low Earth Orbit (LEO) satellites. This prototype observatory demonstrates the benefits of extending the AOGSN to New Zealand, and will serve as a testbed for later, larger, and more advanced OGSs to be established at sites with more favourable climatic conditions. The focus for current research at Taiaho is the characterisation of the free-space channel between the satellite and the ground station, with projects on different methods for atmospheric turbulence measurement and the effect of aerosols on bit error rate.
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