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| Project Paper 792 System |
Project Paper 792 provides the form and fit of these second-generation satcom systems building on the baseline from ARINC 791 part 1 and using a common functional definition using ARINC 791 part 2 and Project Paper 848.
Notably, the 791 KRFU is removed entirely. The 791 KANDU converts to the 792 power supply unit, KPSU. The KPSU can access three-phase 115 VAC power and deliver as much as 1000 Watts to two (Tx, Rx) panels, for an eye-popping 2000 Watts. Thermal management and equipment reliability are paramount concerns.
Airbus has proposed a new set of 792 fitting locations that provide flexible mounting options for any sized aperture, while retaining commonality with 791 fitting locations.
The motivation for a 42" aperture comes from the need to service enormous data rates for passengers Internet access. Also, scan loss issues allow an aperture of this size to operate down to five degrees elevation, offering the largest coverage area.
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Stay tuned!
Peter Lemme
peter @ satcom.guru
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Copyright 2017 satcom.guru All Rights Reserved
Peter Lemme has been a leader in avionics engineering for 35 years. He offers independent consulting services largely focused on avionics and L, Ku, and Ka band satellite communications to aircraft. Peter chairs the SAE-ITC AEEC Ku/Ka-band satcom subcommittee, developing ARINC 791 and 792 characteristics and contributes to the Network Infrastructure and Interfaces (NIS) subcommittee developing Project Paper 848, standard for Media Independent Secure Offboard Network.
Peter was Boeing avionics supervisor for 767 and 747-400 data link recording, data link reporting, and satellite communications. He was an FAA designated engineering representative (DER) for ACARS, satellite communications, DFDAU, DFDR, ACMS and printers. Peter was lead engineer for Thrust Management System (757, 767, 747-400), also supervisor for satellite communications for 777, and was manager of terminal-area projects (GLS, MLS, enhanced vision).
An instrument-rated private pilot, single engine land and sea, Peter has enjoyed perspectives from both operating and designing airplanes. Hundreds of hours of flight test analysis and thousands of hours in simulators have given him an appreciation for the many aspects that drive aviation; whether tandem complexity, policy, human, or technical; and the difficulties and challenges to achieving success.
Hello Peter-
ReplyDeleteI found your article very useful. Could you help me with the meaning of "BI" in the diagram you posted?
Thank you,
Salvador
Bulkhead Interface.
DeleteThe connector interface that spans the pressure vessel, the fuselage.
Hello Peter-
ReplyDeleteWhat is the driver for packacing the KRFU as part of the antenna? Isn't this counter to the desire to have a low profile antenna to reduce drag?
Some phased array antennas, and other antenna designs, use an embedded amplifier in the aperture assembly. There is no KRFU for these antennas.
DeleteKa-band transmission line is very lossy, inside to outside path too long.
No room for KRFU (B787).
None of this raises the profile.
The issue is time to repair, where equipment under the radome takes more effort to replace. 792 commentary professes a need for a two-hour time from ready to remove radome to ready to return to service if simple LRU replace.