Minimum Operational Performance Standards for Global Positioning System/Wide Area Augmentation System Airborne Equipment
|Publication Date:||13 December 2006|
Note: The title of DO-229D changed to Minimum Operational
Performance Standards for Global Positioning System/Satellite-Bas
The original document is DO-229D issued December 13, 2006 with Change 1 (described above) issued February 1, 2013 included as Appendix V. The Change is also incorporated throughout the document and includes the errata issued July 31, 2008. This Change has been produced to reflect errata, corrections, and clarifications to requirements and test procedures for SBAS airborne equipment as a result of comments received from industry during their implementation of products conforming to the referenced standard since the standard's publication in December 2006. These changes do not alter any requirements within the original DO-229D document published in December 2006 that were not previously altered by Federal Aviation Administration (FAA) Technical Standard Orders (TSOs) C145c and C146c.
This document contains Minimum Operational Performance Standards (MOPS) for airborne navigation equipment (2D and 3D) using the Global Positioning System (GPS) augmented by the Wide Area Augmentation System (WAAS). The primary areas of change from DO-229C to DO-229D are:
1. Clarifications: Numerous changes have been incorporated to more clearly describe the meaning and intent of the requirements. To accomplish this there have been changes in the requirements text, explanatory notes added to clarify intent, or both.
2. Appendix Updates: Appendices F and I from DO-229C have been deleted and replaced with entirely new material. Appendix F now addresses SBAS capability considerations for ADS-B. Appendix I now contains mode switching process flow diagrams to aid in understanding the mode transition requirements.
There are three new appendices in DO-229D, Appendix S, Appendix T and Appendix U. Appendix S contains process flow diagrams that are examples of the computation and logic flow to meet MOPS requirements for the possible operational modes. Appendix T is a description of the tool used to determine GEO bias error in receiver correlator designs. Appendix U contains guidance information for interfacing WAAS with ADS-B equipment.
3. Corrections: There are numerous changes in DO-229D to correct errors in equations and to update references to other documents. For example, equations in several places had incorrect signs, symbols, and/or nomenclature. Some of these errors were noted in the errata sheet and TSO-C145a/C146a. The errors documented by those sources have been incorporated; and, many additional errors were found during the review.
Further, the update to DO-229D includes changes related to the changing environment for GPS and service provider experience gained thru operating SBAS systems. For example, the narrow-band geostationary satellites in the WAAS system are in the process of being replaced with wide-band satellites. A result is that major requirement changes have been incorporated in DO-229D related to noise, minimum/maximum satellite power levels, and antenna gains.
4. New Requirements: There are new requirements either embedded within previously existing requirements from DO-229C, or, captured as entirely new sections that never previously existed. Some examples are:
1. There is a new requirement for Fault Detection Prediction so that SBAS equipment provides at least the same capability as TSO-C129a equipment when operating outside of SBAS coverage.
2. There is a new GEO bias error requirement to account for the net group delay through the receiver correlator that results from the signal bandwidth of SBAS satellites compared to GPS satellites.
3. There is a requirement to only use weighted solutions for FDE algorithms.
Section 2.3 for Delta-class receivers has been extensively re-written and expanded.