A low-cost radio communication system has been developed for the university microsatellite project ALMASat-1, which is currently scheduled for launch onboard the VEGA Maiden Flight. The communication system consists of a full-duplex low data-rate link at VHF-UHF bands and a high data-rate S-band downlink. The UHF downlink system includes a main and a backup transmitter (in cold redundancy) realizing analog FM modulation, a hybrid coupler that produces four 90-degrees phase shifted signals and a vase turnstile configuration antenna system. The VHF uplink system includes a monopole antenna and a main and a backup receiver (in hot redundancy). The S-band downlink system consists of a modulator driving a frequency synthesizer that carries out a direct digital Frequency Shift Keying (FSK) modulation. A Quadrifilar Helix Antenna (QHA) is used in order to perform a right handed circular polarization. All systems have been fully assembled and before their integration on the spacecraft (SC) a very intensive test campaign is necessary in order to evaluate the per-formance of the whole communication system and estimate the reliability of the link budgets, simulating typical and critical operational conditions. Packet Error Rate (PER) tests in free-space condition for each link, matching tests of non-commercial components and functional tests of the hybrid coupler were performed and are thoroughly described.
F. Antonini, D. Cinarelli, P. Tortora (2009). ALMASAT-1 Communication System Architecture and Test Campaign. MILANO : AIDAA.
ALMASAT-1 Communication System Architecture and Test Campaign
ANTONINI, FABIO;TORTORA, PAOLO
2009
Abstract
A low-cost radio communication system has been developed for the university microsatellite project ALMASat-1, which is currently scheduled for launch onboard the VEGA Maiden Flight. The communication system consists of a full-duplex low data-rate link at VHF-UHF bands and a high data-rate S-band downlink. The UHF downlink system includes a main and a backup transmitter (in cold redundancy) realizing analog FM modulation, a hybrid coupler that produces four 90-degrees phase shifted signals and a vase turnstile configuration antenna system. The VHF uplink system includes a monopole antenna and a main and a backup receiver (in hot redundancy). The S-band downlink system consists of a modulator driving a frequency synthesizer that carries out a direct digital Frequency Shift Keying (FSK) modulation. A Quadrifilar Helix Antenna (QHA) is used in order to perform a right handed circular polarization. All systems have been fully assembled and before their integration on the spacecraft (SC) a very intensive test campaign is necessary in order to evaluate the per-formance of the whole communication system and estimate the reliability of the link budgets, simulating typical and critical operational conditions. Packet Error Rate (PER) tests in free-space condition for each link, matching tests of non-commercial components and functional tests of the hybrid coupler were performed and are thoroughly described.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
