Results from Phase-1, Phase-2 and Phase-3 Kirari Optical Communication Demonstration Experiments with the NICT optical ground station (KODEN)

[Abstract] Bi-directional ground-to-satellite laser communication experiments between the optical ground station developed by the National Institute of Information and Communications Technology (NICT) located in Koganei of downtown Tokyo and a low earth orbit (LEO) satellite, the Optical Inter-orbit Communications Engineering Test Satellite (OICETS) called “Kirari”, were successfully performed in March, May and September, 2006. The Kirari Optical Communication Demonstration Experiments with the NICT optical ground station (KODEN) was conducted in cooperation between the Japan Aerospace Exploration Agency (JAXA) and NICT. The ground-to-OICETS laser communication experiment is the first in-orbit demonstration with respect to the LEO satellite. Phase-1 laser communication experiment was conducted in March, 2006 and the downlink bit error ratio (BER) of around 1e-5 was measured. Phase-2 laser communication experiment was done in May, 2006 but there was no significant improvement due to bad weather. The uplink and downlink BERs of 1e-4 ~ 1e-7 were simultaneously measured in Phase-3 in September, 2006 with an uplink of 2 Mbps and a downlink of 50 Mbps, respectively. Eighteen trials over the course of three months were conducted during the test campaign. There were eleven successful passes out of all the trials. Acquisition and tracking of the OICETS satellite were always successful when partly clear skies were predominant, showing the optical link was successfully established by 100 % without bad weather conditions. For the uplink, multi-beam laser transmission was used from the optical ground station to the OICETS satellite in order to reduce the intensity fluctuation of the optical signal due to atmospheric turbulence. The fluctuation of the received signal power was well minimized by using four-beam laser transmission. The applicability of the onboard optical terminal was demonstrated, aiming not only for geostationary earth orbit (GEO)-LEO links but also for ground-to-LEO optical links. This paper presents the results of Phase-1, Phase-2 and Phase-3 KODEN experiments.