Title :
The ALFA constellation communications and navigation support system
Author :
Howard, Regan E. ; Jones, Dayton ; Blume, William ; Seybold, Calina
Author_Institution :
Orbital Sci. Corp., Germantown, MD, USA
Abstract :
The proposed ALFA space-based imaging interferometer mission consists of 16 identical small satellites with dipole antennas and low frequency radio receivers, distributed in a spherical array 100 km in diameter, and placed in a nearly circular distant retrograde orbit about the Earth, with a typical range of 106 km. Each satellite communicates directly with a small (11 m), low-cost antenna at each DSN site, providing parallel data paths and continuous coverage. The mission communications and navigation support system consists of an X-band frequency division multiplex (FDM) TT&C segment that uses a common 50 bps uplink channel and 17 downlink channels of 500 kbps each. The TT&C segment supports noncoherent precision Doppler ranging. Intersatellite ranging in the navigation support subsystem is accomplished by using the common four tone ranging technique over a UHF channel in the ISM (Industrial Scientific Medical) band
Keywords :
aerospace instrumentation; artificial satellites; satellite communication; satellite navigation; ALFA constellation; DSN site; Doppler ranging; ISM band; TT&C segment; UHF channel; X-band frequency division multiplexing; communications system; dipole antenna; intersatellite ranging; low-frequency radio receiver; navigation system; radio imaging interferometer; space mission; spherical array; Dipole antennas; Frequency division multiplexing; Low earth orbit satellites; Radio interferometry; Radio navigation; Receivers; Receiving antennas; Satellite antennas; Satellite broadcasting; Satellite navigation systems;
Conference_Titel :
Aerospace Conference Proceedings, 2000 IEEE
Conference_Location :
Big Sky, MT
Print_ISBN :
0-7803-5846-5
DOI :
10.1109/AERO.2000.879286
