Wednesday, April 5, 2017

PP792 draft 1 released: Second-generation Ku/Ka-band Aero Satcom Terminals

PP792 Satcom System

ARINC 791 characteristic provides the basis for aeronautical Ku/Ka-band satcom systems.  791 work commenced in 2008, and was largely oriented to support existing equipment suppliers with a standard provisions that could accommodate various design choices.

Ka-band satcom systems present considerable difficulty with the transmission line, favoring the installation of the transmit amplifier outside, under the radome.  Boeing 787 provisions did not provide for the 791 KRFU amplifier position at all.  Gate-Gate operations, and equipment reliability/serviceability weigh heavily upon the members.  Emerging phased array antennas will have the amplifier outside as a part of their basic design.  With this in mind, 792 moved to embrace the newest antenna features, and with that, paved the way for 792 to proceed.

791 provisions also are based on a 6/7 fitting design that was optimized for multi-gimbal antennas.  New phased-array antennas, including 2Ku, operate with tandem Transmit/Receive apertures.  The aft aperture does not fit will over 791 fittings.  792 fittings have been adjusted to allow minimum conflict with tandem apertures.

A real breakthrough with PP792 is the removal of supplier-furnished provisions.  PP792 professes an installation that is entirely standardized, and considerably smaller/lighter.  Two LRUs are removed (KRFU, APM-to be confirmed). The KANDU is reduced to a power supply, the KPSU. All the wiring is fixed, you just install the boxes, bolt on the antenna, and plug it in.

PP792 operates with PP848 to provide Ethernet interfaces electrically isolated to support passenger devices, inflight entertainment, and non-safety avionics domains.

Project Paper 792, draft 1, has been released for industry comments.  This comes three years after the project was originally conceived, with final publication to come within the next year.

In April of 2014, I presented a commentary on the emergence of flat panel antennas to the AEEC Executive Committee.

The Ku/Ka satcom subcommittee submitted an APIM for small form-factor satcom.

As has become apparent, we are pushing out publication to later this year.

We had our first meeting in Jan. 2015.

In 2015 we were deep into the “cheese plate” discussions, and wrestling with reliability of the electronics.

By 2016 we had progressed into developing and analyzing all available options, which led us to favor this configuration:

Gogo promoted a six-fitting antenna mounting to optimize the opportunity for tandem apertures. Gogo was able to gain some support in industry, to the extent that the approach was deemed viable and preferable. The failure to gain consensus in ARINC 791 Part 1 fitting locations between OEMs left the subcommittee to pursue the best “clean sheet” design that would stand as a target for future aircraft designs.

In January of 2017, SBG revealed pricing for their dual GPS/MEMS PAH sensor in the USD$5k range, making autonomous beam steering practical. That completed the last breakthrough for PP792.

In 2014, I presented this conceptual diagram for the next generation satcom.

Here is the architecture as developed in this first complete draft (pretty close to proposed).

Our next subcommittee meeting is June 14-16 in Annapolis.  Anyone can attend and is encouraged to participate.

Stay tuned!

Peter Lemme
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Follow me on twitter: @Satcom_Guru

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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 Secure Broadband IP Air/Ground Interface.

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.

1 comment:

  1. very impressive information about the Second-generation Ku/Ka-band Aero Satcom Terminals.and you are sharing the very neatly, very understandingly describe with step by step..thank you for the sharing the good idea..keep sharing..