Session
Session VIII: Ground Systems - Enterprise
Location
Salt Palace Convention Center, Salt Lake City, UT
Abstract
In January 2025, InnoCube, a 3U CubeSat was launched with the Transporter-12 mission, becoming the 31st academic satellite of TU Berlin. The technology demonstration mission is the first one at TU Berlin which uses software-defined radio to operate the satellite in the amateur UHF band. The ground station is based on software-defined radio, which has been a vital part of the development of the communication system of InnoCube. Integration into the ground segment is a logical step in the test-as-you-fly philosophy of the mission. The ground segment consists of a SDR which is paired to a power amplifier which includes the switching logic, a cavity filter and a low-noise amplifier using a high gain quad antenna. The ground station is controlled with GNURadio. The ground station paths are verified separately, for receiving, different small satellites operating over Berlin are decoded. Uplink is verified with a spectrum analyzer, vector network analyzer and ground tests. After launch, the first contact is established within 2 minutes of the satellite being in range. Initial operational challenges included TLE inaccuracy, requiring frequent updates and corrections, as well as evaluating the best station configuration to maximize link performance. This challenge is significantly reduced by using SDRs and real-time adaption of receiving and transmitting frequency, based on live transmissions. By optimizing digital signal processing, downlink capacity could be increased by over 100%. Another challenge of the mission is polarization, as satellite and ground station are both using right-handed circular polarized antennas. Polarization effects of the satellite tumbling and its implications on the link are discussed. As the signal-to-noise ratio is observed for each message, extensive data for each pass is available. Additionally, a carrier-sense is presented to increase the uplink capacity for a semi-duplex communication channel. Further analysis is discussed between calculated link budget prior to the mission and measured data, highlighting deviations and implementation losses.
Document Type
Event
Using a Software-Defined Radio Ground Station for a Small Satellite Mission
Salt Palace Convention Center, Salt Lake City, UT
In January 2025, InnoCube, a 3U CubeSat was launched with the Transporter-12 mission, becoming the 31st academic satellite of TU Berlin. The technology demonstration mission is the first one at TU Berlin which uses software-defined radio to operate the satellite in the amateur UHF band. The ground station is based on software-defined radio, which has been a vital part of the development of the communication system of InnoCube. Integration into the ground segment is a logical step in the test-as-you-fly philosophy of the mission. The ground segment consists of a SDR which is paired to a power amplifier which includes the switching logic, a cavity filter and a low-noise amplifier using a high gain quad antenna. The ground station is controlled with GNURadio. The ground station paths are verified separately, for receiving, different small satellites operating over Berlin are decoded. Uplink is verified with a spectrum analyzer, vector network analyzer and ground tests. After launch, the first contact is established within 2 minutes of the satellite being in range. Initial operational challenges included TLE inaccuracy, requiring frequent updates and corrections, as well as evaluating the best station configuration to maximize link performance. This challenge is significantly reduced by using SDRs and real-time adaption of receiving and transmitting frequency, based on live transmissions. By optimizing digital signal processing, downlink capacity could be increased by over 100%. Another challenge of the mission is polarization, as satellite and ground station are both using right-handed circular polarized antennas. Polarization effects of the satellite tumbling and its implications on the link are discussed. As the signal-to-noise ratio is observed for each message, extensive data for each pass is available. Additionally, a carrier-sense is presented to increase the uplink capacity for a semi-duplex communication channel. Further analysis is discussed between calculated link budget prior to the mission and measured data, highlighting deviations and implementation losses.
