Deviation Request ETSO-C146eA1#1 for Stand-Alone Airborne Navigation Equipment Using the GPS Augmented by the SBAS

Deviates from ETSO-C146eA1 §3.1, DO-229E and ETSO-C146eA1 Appendix 4, to use IS-GPS-200H instead of IS-GPS-
200D for the demodulation of GPS signals and signal processing, provided that the following features
of IS-GPS-200H and only these are used:

• Signal tracking and data demodulation limited to GPS L1C/A signals from GPS PRN 1 to 32 and to Legacy NAV (LNAV) of Block II, Block IIA, Block IIR, Block IIR-M, Block IIF and GPS III satellites.
• Data demodulation restricted to Legacy NAV (LNAV) data defined in IS-GPS-200H appendix II and to the use of the following bit fields and associated requirements:
  • Default navigation pattern
  • Null navigation pattern
  • bit 25 to 30 of all GPS words: parity
  • bit 1 to 8 of all GPS subframes: preamble
  • bit 23 of all GPS sub frames: Integrity Status Flag (optional provided Note 1 is fulfilled)
  • bit 31 to 48 of all GPS subframes: time of week, alert flag
  • bit 50 to 52 of all GPS subframe: subframe ID
  • bit 61 to 70 of GPS Subframe 1: week number
  • bit 73 to 84 of GPS Subframe 1: URA, Health, IODC MSB
  • bit 197 to 204 of GPS Subframe 1: TGD
  • bit 211 to 234 of GPS Subframe 1: IODC LSB, TOC
  • bit 241 to 264 of GPS Subframe 1: Ephem Af2, Af1
  • bit 271 to 292 of GPS Subframe 1: Ephem Af0
  • bit 61 to 84 of GPS Subframe 2: IODE, Ephem CRS
  • bit 91 to 114 of GPS Subframe 2: Ephem DeltaN, Ephem M0 MSB
  • bit 121 to 144 of GPS Subframe 2: Ephem M0 LSB
  • bit 151 to 174 of GPS Subframe 2: Ephem CUC, Ephem e MSB
  • bit 181 to 204 of GPS Subframe 2: Ephem e LSB
  • bit 211 to 234 of GPS Subframe 2: Ephem CUS, Ephem SqrtA MSB
  • bit 241 to 264 of GPS Subframe 2: Ephem SqrtA LSB
  • bit 271 to 287 of GPS Subframe 2: Ephem TOE, Ephem Fit interval flag
  • bit 61 to 84 of GPS Subframe 3: Ephem CIC, Ephem Omega0 MSB
  • bit 91 to 114 of GPS Subframe 3: Ephem Omega0 LSB
  • bit 121 to 144 of GPS Subframe 3: Ephem CIS, Ephem I0 MSB
  • bit 151 to 174 of GPS subframe 3: Ephem I0 LSB
  • bit 181 to 204 of GPS subframe 3: Ephem CRC, Ephem Omega MSB
  • bit 211 to 234 of GPS subframe 3: Ephem Omega LSB
  • bit 241 to 264 of GPS subframe 3: Ephem Omega dot
  • bit 271 to 292 of GPS subframe 3: Ephem IODE, Ephem Idot
  • bit 60 to 61 of GPS sub frame 4 and 5: Data ID Number
  • bit 63 to 68 of GPS subframe 4 and 5: SV ID
  • bit 69 to 84 of GPS subframe 4 and 5 with SV ID = 1 to 32: Alm e
  • bit 91 to 114 of GPS subframe 4 and 5 with SV ID = 1 to 32: Alm TOA, Alm DeltaI
  • bit 121 to 136 of GPS subframe 4 and 5 with SV ID = 1 to 32: Alm OmegaDot
  • bit 151 to 174 of GPS subframe 4 and 5 with SV ID = 1 to 32: Alm SqrtA
  • bit 181 to 204 of GPS subframe 4 and 5 with SV ID = 1 to 32: Alm Omega0
  • bit 211 to 234 of GPS subframe 4 and 5 with SV ID = 1 to 32: Alm Omega
  • bit 241 to 264 of GPS subframe 4 and 5 with SV ID = 1 to 32: Alm M0
  • bit 69 to 84 of GPS subframe 4 with SV ID = 56: Iono Alpha0, Iono Alpha1
  • bit 91 to 114 of GPS subframe 4 with SV ID = 56: Iono Alpha2, Iono Alpha3, Iono Beta0
  • bit 121 to 144 of GPS subframe 4 with SV ID = 56: Iono Beta1, Iono Beta2, Iono Beta3
  • bit 151 to 174 of GPS subframe 4 with SV ID = 56: UTC A1
  • bit 181 to 204 of GPS subframe 4 with SV ID = 56: UTC A0 MSB
  • bit 211 to 234 of GPS subframe 4 with SV ID = 56: UTC A0 LSB, UTC TOT, UTC WNT
  • bit 241 to 264 of GPS subframe 4 with SV ID = 56: UTC DTLS, UTC WNLSF, UTC DN
  • bit 271 to 278 of GPS subframe 4 with SV ID = 56: UTC DTLSF

Note 1: As the new definition in IS-GPS-200H is a superset of the definition in IS-GPS-200D, it is accepted to
not decode this Integrity Status Flag bit if only the IS-GPS-200D definition is used i.e. the probability of the
URE exceeding 4.42 times URA for more than 5.2 seconds, without an accompanying alert, is less than 1E-5
per hour. In this context, an "alert" is defined as any indication or characteristic of the conveying signal.