Appendix B B-19 B.4.13.1 TSO-C129.
Means of compliance for this TSO require GNSS manufacturers to use a manufacturer-defined test and/or analysis to determine the latency between the time satellite measurements are collated for processing and the time the equipment calculates a filtered (impulse response) position solution. For example; the receiver does not make observations at a single moment in time but instead staggers them, perhaps to reduce throughput.
In that case, the observations would need to be extrapolated to a common moment. There are many extrapolation methods but some use filtering that may induce latency. This would need to be addressed in the latency analysis. Since there are filters involved, measuring the impulse response may be one way of observing this delay. Furthermore, as another example; a receiver uses a Costas filter that has a specific bandwidth as part of the tracking loop. That bandwidth constrains the speed at which a dynamic maneuver will propagate through the tracking loop and thus to the resulting position. Again, measuring the impulse response of the Costas loop would provide insight into delay that would be observed when installed. Bearing this in mind, the equipment must meet a 500- millisecond TOM-to-time-of-applicability requirement and account for the impulse response of the position solution.
B.4.13.2 TSO-C129a.
Means of compliance for this TSO require GNSS manufacturers to use a manufacturer-defined test and/or analysis to determine the latency between the time satellite measurements are collated for processing and the time the equipment calculates a filtered (impulse response) position solution. The equipment must meet a 500-millisecond TOM-to-time-ofapplicability requirement and account for the impulse response of the position solution.
B.4.13.3 TSO-C145/146 Rev a Class 1.
Means of compliance for this TSO are defined in RTCA/DO-229C sections 2.1.2.6 and 2.1.2.6.2.
B.4.13.4 TSO-C145/146 Rev a Class 2/3.
Means of compliance for this TSO are defined in RTCA/DO-229C, sections 2.1.2.6, 2.1.2.6.2, and 2.1.5.8.2.
B.4.13.5 TSO-C145/146 Rev b/c/d Class 1.
Means of compliance for this TSO are defined in RTCA/DO-229D, sections 2.1.2.6 and 2.1.2.6.2.
B.4.13.6 TSO-C145/146 Rev b/c/d Class 2/3.
Means of compliance for this TSO are defined in RTCA/DO-229D, sections 2.1.2.6, 2.1.2.6.2, and 2.1.5.8.2.
Appendix B B-20 B.4.13.7 TSO-C196/196a.
Means of compliance for this TSO are defined in RTCA/DO-316, sections 2.1.2.6 and 2.1.2.6.2.
B.4.14 Velocity Accuracy.
The GNSS position source manufacturer must provide design data to assist the installer in setting the NACV. Scaling the reported GNSS position accuracy (HFOM and VFOM) is not an acceptable means to determine NACV.
B.4.14.1 NACV = 1.
For installations intending to support NACV = 1, the GNSS manufacturer must perform the velocity tests in AC 20-138D, appendix 4, section A4-1 through A4-8 associated with NACV = 1. The GNSS manufacturer must indicate that the equipment satisfies the requirements for NACV =1 in the installation instructions for the ADS-B integration.
B.4.14.2 NACV = 2.
For installations intending to support NACV = 2, the GNSS manufacturer must perform the velocity tests in AC 20-138D, appendix 4, sections A4-1 through A4-9 associated with NACV = 1 and NACV = 2. The GNSS manufacturer must present substantiation data that the equipment dynamically outputs HFOMv and VFOMv (refer to AC 20-138(), appendix 4, sections A4-5 and A4-8) and that the equipment velocity and accuracy outputs have passed the velocity tests associated with NACV = 1 and NACV = 2. The GNSS manufacturer must indicate that the equipment satisfies the requirements for NACV = 2 in the installation instructions for the ADS-B integration.
B.4.14.3 NACV = 3 or 4.
No standard for performance has been developed to support NACv = 3 or NACV = 4. A NACV = 3 or NACV = 4 should not be set based on GNSS velocity accuracy unless you can demonstrate to the FAA that the error contributions have been adequately modeled to meet those levels of performance.
B.4.14.4 TSO-C129.
Means of compliance for this TSO require GNSS manufacturers to provide substantiation data based on the NACV =1 and NACV = 2 test as appropriate and document the NACV in the installation instructions for the ADS-B integration. Refer to AC 20-138(), appendix 4, section A4- 2d(3) for additional guidance relative to using the noise environment in RTCA/DO-235B for the velocity tests.
B.4.14.5 TSO-C129a.
Means of compliance for this TSO require GNSS manufacturers to provide substantiation data based on the NACV =1 and NACV = 2 test
Appendix B B-21 as appropriate and document the NACV in the installation instructions for the ADS-B integration. Refer to AC 20-138() appendix 4, section A4- 2d(3) for additional guidance relative to using the noise environment in RTCA/DO-235() for the velocity tests.
B.4.14.6 TSO-C145/146 Rev a Class 1.
Means of compliance for this TSO require GNSS manufacturers to provide substantiation data based on the NACV =1 and NACV = 2 test as appropriate and document the NACV in the installation instructions for the ADS-B integration.
B.4.14.7 TSO-C145/146 Rev a Class 2/3.
Means of compliance for this TSO require GNSS manufacturers to provide substantiation data based on the NACV =1 and NACV = 2 test as appropriate and document the NACV in the installation instructions for the ADS-B integration.
B.4.14.8 TSO-C145/146 Rev b/c/d Class 1.
Means of compliance for this TSO require GNSS manufacturers to provide substantiation data based on the NACV =1 and NACV = 2 test as appropriate and document the NACV in the installation instructions for the ADS-B integration.
B.4.14.9 TSO-C145/146 Rev b/c/d Class 2/3.
Means of compliance for this TSO require GNSS manufacturers to provide substantiation data based on the NACV =1 and NACV = 2 test as appropriate and document the NACV in the installation instructions for the ADS-B integration.
B.4.14.10 TSO-C196/196a.
Means of compliance for this TSO require GNSS manufacturers to provide substantiation data based on the NACV =1 and NACV = 2 test as appropriate and document the NACV in the installation instructions for the ADS-B integration.
B.4.15 Vertical Position Accuracy.
The GNSS should output vertical position accuracy. The vertical accuracy should specify a 95-percent probability bound on the reported vertical position. No revisions of TSO-C129 or TSO-C196 have vertical accuracy or integrity requirements, and TSO-C145 /146 only has vertical accuracy requirements for certain approach modes.
None of the GNSS TSOs have a requirement to continuously output the vertical position accuracy data. If vertical position accuracy is output, it must have been qualified during design approval of the position source.
Appendix B B-22 B.4.15.1 TSO-C129.
Means of compliance for this TSO require GNSS manufacturers to provide substantiation data along with the VFOM output based on the test described in AC 20-138(), appendix 4, section A4-10.
B.4.15.2 TSO-C129a.
Means of compliance for this TSO require GNSS manufacturers to provide substantiation data along with the VFOM output based on the test described in AC 20-138(), appendix 4, section A4-10.
B.4.15.3 TSO-C145/146 Rev a Class 1.
Means of compliance for this TSO require GNSS manufacturers to provide substantiation data along with the VFOM output based on the test described in AC 20-138(), appendix 4, section A4-10.
B.4.15.4 TSO-C145/146 Rev a Class 2.
Means of compliance for this TSO require GNSS manufacturers to provide substantiation data along with the VFOM output based on the test described in AC 20-138(), appendix 4, section A4-10.
B.4.15.5 TSO-C145/146 Rev b/c/d Class 1.
Means of compliance for this TSO require GNSS manufacturers to provide substantiation data along with the VFOM output based on the test described in AC 20-138(), appendix 4, section A4-10.
B.4.15.6 TSO-C145/146 Rev b/c/d Class 2/3.
Means of compliance for this TSO require GNSS manufacturers to provide substantiation data along with the VFOM output based on the test described in AC 20-138(), appendix 4, section A4-10.
B.4.15.7 TSO-C196/196a.
Means of compliance for this TSO require GNSS manufacturers to provide substantiation data along with the VFOM output based on the test described in AC 20-138(), appendix 4, section A4-10.
B.4.16 Mode Output.
If interpretation of the integrity output of the position source can change due to a change in the position source mode, the position source must have a way of communicating that change of mode to the ADS-B equipment. Additionally, the position source manufacturer should provide a description of the modes and a description of how the position source outputs the mode indication.
B.4.16.1 TSO-C129.
Means of compliance for this TSO require GNSS manufacturers to provide installation instructions describing the modes available (if
Appendix B B-23 affecting interpretation of integrity output) and how the position source outputs the mode indication (refer to Position Integrity Limits, section paragraph B.4.7, of this appendix).
B.4.16.2 TSO-C129a.
Means of compliance for this TSO require GNSS manufacturers to provide installation instructions describing the modes available (if affecting interpretation of integrity output) and how the position source outputs the mode indication (refer to Position Integrity Limits, paragraph B.4.7, of this appendix).
B.4.16.3 TSO-C145/146 Rev a Class 1.
Means of compliance for this TSO require GNSS manufacturers to provide installation instructions describing the modes available (if affecting interpretation of integrity output) and how the position source outputs the mode indication (refer to Position Integrity Limits, paragraph B.4.7, of this appendix).
B.4.16.4 TSO-C145/146 Rev a Class 2.
Means of compliance for this TSO require GNSS manufacturers to provide installation instructions describing the modes available (if affecting interpretation of integrity output) and how the position source outputs the mode indication (refer to Position Integrity Limits, paragraph B.4.7, of this appendix).
B.4.16.5 TSO-C145/146 Rev b/c/d Class 1.
Means of compliance for this TSO require GNSS manufacturers to provide installation instructions describing the modes available (if affecting interpretation of integrity output) and how the position source outputs the mode indication (refer to Position Integrity Limits, paragraph B.4.7, of this appendix).
B.4.16.6 TSO-C145/146 Rev b/c/d Class 2/3.
Means of compliance for this TSO require GNSS manufacturers to provide installation instructions describing the modes available (if affecting interpretation of integrity output) and how the position source outputs the mode indication (refer to Position Integrity Limits, paragraph B.4.7, of this appendix).
B.4.16.7 TSO-C196/196a.
Means of compliance for this TSO require GNSS manufacturers to provide installation instructions describing the modes available (if affecting interpretation of integrity output) and how the position source outputs the mode indication (refer to Position Integrity Limits, paragraph B.4.7, of this appendix).
Appendix B B-24 B.4.17 Approach Mode Integrity.
SBAS equipment certified under any revision of TSO-C145 or TSO-C146 is required to have several modes of operation depending on the availability of augmentation. For example, when operating in an augmented mode intended for LPV approach guidance, the position source may determine HPL based on a lateral error versus a horizontal error and an exposure time based on the duration of the approach versus flight hour (refer to RTCA/DO-229D, appendix J). If the position source outputs the HPL on lateral error and approach exposure time, it is possible that the ADS-B transmitter would need to inflate the HPL by 3 percent in approach modes to ensure the integrity is appropriately bounded. GBAS equipment is required to comply with the GNSS or SBAS requirements for the output of position data. This is an integration issue between the GPS and ADS-B transmitter. The position source manufacturer must provide information to the system integrator to determine if the integrity output needs to be scaled (that is, by applying an inflation factor). Although we do not address the interface of a GBAS differentially-corrected position source in this AC, it will have similar considerations in approach modes as SBAS.
B.4.17.1 TSO-C129.
This is not applicable to this TSO as no HPL scaling is applied.
B.4.17.2 TSO-C129a.
This is not applicable to this TSO as no HPL scaling is applied.
B.4.17.3 TSO-C145/146 Rev a Class 1.
Means of compliance for this TSO are defined in RTCA/DO-229C, sections 2.1.1.13.1 and 2.1.3.2.2.
B.4.17.4 TSO-C145/146 Rev a Class 2/3.
Means of compliance for this TSO are defined in RTCA/DO-229C, sections 2.1.1.13.1, 2.1.3.2.2, 2.1.4.2.2, and 2.1.5.2.2.
B.4.17.5 TSO-C145/146 Rev b/c/d Class 1.
Means of compliance for this TSO are defined in RTCA/DO-229D, sections 2.1.1.13.1 and 2.1.3.2.2.
B.4.17.6 TSO-C145/146 Rev b/c/d Class 2/3.
Means of compliance for this TSO are defined in RTCA/DO-229D, sections 2.1.1.13.1, 2.1.3.2.2, 2.1.4.2.2, and 2.1.5.2.2.
B.4.17.7 TSO-C196/196a.
This is not applicable to this TSO as no HPL scaling is applied.
B.4.18 Track Angle Validity.
GNSS position sources can provide a track angle; however, the GNSS track angle may become invalid below a certain velocity. Optimally, the position source should either
Appendix B B-25 invalidate or remove the track angle when it is no longer valid. If the position source does not invalidate the track angle or remove the track angle when it is potentially invalid, the position source manufacturer must provide information on velocity limitations for GNSS track angle.
Note: The interference levels used to demonstrate velocity accuracy compliance can be used for track angle validity as well.
B.4.18.1 TSO-C129.
Means of compliance for TSO-C129 require GNSS manufacturers to use the test environment and guidance defined in AC 20-138(), appendix 4, section 4-12. It is recommended that manufacturers use RTCA/DO-229D, appendix H for outputting track angle (ARINC 743 all revisions, label 103) for those using ARINC 429 characteristics.
B.4.18.2 TSO-C129a.
Means of compliance for TSO-C129a require GNSS manufacturers to use the test environment and guidance defined in AC 20-138(), appendix 4, section 4-12. It is recommended that manufacturers use RTCA/DO-229D, appendix H for outputting track angle (ARINC 743 all revisions, label 103) for those using ARINC 429 characteristics.
B.4.18.3 TSO-C145/146 Rev a Class 1.
Means of compliance for TSO-C145/146 Rev a Class 1 require GNSS manufacturers to use the test environment and guidance defined in AC 20-138(), appendix 4, section 4-12. It is recommended that manufacturers use RTCA/DO-229C, appendix H for outputting track angle (ARINC 743 all revisions, label 103) for those using ARINC 429 characteristics.
B.4.18.4 TSO-C145/146 Rev a Class 2/3.
Means of compliance for TSO-C145/146 Rev a Class 2/3 require GNSS manufacturers to use the test environment and guidance defined in AC 20-138(), appendix 4, section 4-12. It is recommended that manufacturers use RTCA/DO-229C, appendix H for outputting track angle (ARINC 743 all revisions, label 103) for those using ARINC 429 characteristics.
B.4.18.5 TSO-C145/146 Rev b/c/d Class 1.
Means of compliance for TSO-C145/146 Rev b/c/d Class 1 require GNSS manufacturers to use the test environment and guidance defined in AC 20-138(), appendix 4, section 4-12. It is recommended that manufacturers use RTCA/DO-229D, appendix H for outputting track angle (ARINC 743 all revisions, label 103) for those using ARINC 429 characteristics.
Appendix B B-26 B.4.18.6 TSO-C145/146 Rev b/c/d Class 2/3.
Means of compliance for this TSO require GNSS manufacturers to use the test environment and guidance defined in AC 20-138(), appendix 4, section 4-12. It is recommended that manufacturers use RTCA/DO-229D, appendix H for outputting track angle (ARINC 743 all revisions, label
103) for those using ARINC 429 characteristics.
B.4.18.7 TSO-C196/196a.
Means of compliance for this TSO require GNSS manufacturers, using test or analysis to use the test environment and guidance defined in AC 20-138(), appendix 4 section 4-12. It is recommended that manufacturers use RTCA/DO-316, appendix H for outputting track angle (ARINC 743 all revisions, label 103) for those using ARINC 429 characteristics.
B.4.19 Time Mark.
GNSS position sources should output a UTC time mark identifying time of applicability with the successive position output. In modern sensors computing and outputting position multiple times per second, this time mark typically is associated with only one of the position outputs per second. The time mark can be used by the ADS-B equipment to reduce uncompensated latency. For 1090ES, the time mark output is not required for installations to be rule compliant. When integrating a UAT with an external GPS, the design of the hardware time mark must be interoperable. Some GPS synchronize the leading edge of the time mark to the UTC second. Other GPS let the time mark pulse be asynchronous to the UTC second and then record the time of the leading edge in the digital data along with the position solution. The UAT equipment must support the GPS time mark design. If the UAT equipment and GPS do not share a common time mark design, the UAT equipment will not be properly synchronized with the ground system and other aircraft.
B.4.19.1 TSO-C129.
Means of compliance for this TSO require GNSS manufacturers to provide installation instructions describing how the time mark relates to the position, velocity, FOM, and time of applicability.
B.4.19.2 TSO-C129a.
Means of compliance for this TSO require GNSS manufacturers to provide installation instructions describing how the time mark relates to the position, velocity, FOM, and time of applicability.
B.4.19.3 TSO-C145/146 Rev a Class 1.
Means of compliance for this TSO require GNSS manufacturers to provide installation instructions describing how the time mark relates to the position, velocity, FOM, and time of applicability.
B.4.19.4 TSO-C145/146 Rev a Class 2/3.
Appendix B B-27 Means of compliance for this TSO require GNSS manufacturers to provide installation instructions describing how the time mark relates to the position, velocity, FOM, and time of applicability.
B.4.19.5 TSO-C145/146 Rev b/c/d Class 1.
Means of compliance for this TSO require GNSS manufacturers to provide installation instructions describing how the time mark relates to the position, velocity, FOM, and time of applicability.
B.4.19.6 TSO-C145/146 Rev b/c/d Class 2/3.
Means of compliance for this TSO require GNSS manufacturers to provide installation instructions describing how the time mark relates to the position, velocity, FOM, and time of applicability.
B.4.19.7 TSO-C196/196a.
Means of compliance for this TSO require GNSS manufacturers to provide installation instructions describing how the time mark relates to the position, velocity, FOM, and time of applicability.
B.4.20 SIS Error Detection.
The position source should provide a means to detect a SIS error when the system uses a SIS. The probability of missed detection for a faulty SIS should be less than 1x10-3.
GNSS equipment provides the appropriate SIS error detection.
B.4.20.1 TSO-C129.
Means of compliance for this TSO are defined in RTCA/DO-208 change 1, section 2.2.1.13.1, referring to Table 2-1 (refer to Table 2-1, note D). However, TSO-C129 equipment has no requirement for pseudorange step detection. This requires GNSS manufacturers to provide substantiation data documenting that their RAIM algorithm includes pseudorange step detection pursuant to TSO-C129a, section (a)(3)(xv)5.
B.4.20.2 TSO-C129a.
Means of compliance for this TSO are defined in RTCA/DO-208, change 1, section 2.2.1.13.1, referring to Table 2-1 (refer to Table 2-1, note D) and TSO-C129a, section (a)(3)(xv)5.
B.4.20.3 TSO-C145/146 Rev a Class 1.
Means of compliance for this TSO are defined in RTCA/DO-229D, sections 2.1.1.3 and 2.1.1.5 for SBAS, section 2.1.1.2 for GPS health message, and section 2.1.2.2.2.2.2 for FDE.
Note: The SBAS SIS includes health monitoring/fault information, which is why these general signal processing requirements are included.
Appendix B B-28 B.4.20.4 TSO-C145/146 Rev a Class 2/3.
Means of compliance for this TSO are defined in RTCA/DO-229D, sections 2.1.1.3 and 2.1.1.5 for SBAS, section 2.1.1.2 for GPS health message, and section 2.1.2.2.2.2.2 for FDE.
Note: The SBAS SIS includes health monitoring/fault information, which is why these general signal processing requirements are included.
B.4.20.5 TSO-C145/146 Rev b/c/d Class 1.
Means of compliance for this TSO are defined in RTCA/DO-229D, sections 2.1.1.3 and 2.1.1.5 for SBAS, section 2.1.1.2 for GPS health message, and section 2.1.2.2.2.2.2 for FDE.
Note: The SBAS SIS includes health monitoring/fault information, which is why these general signal processing requirements are included.
B.4.20.6 TSO-C145/146 Rev b/c/d Class 2/3.
Means of compliance for this TSO are defined in RTCA/DO-229D, sections 2.1.1.3 and 2.1.1.5 for SBAS, section 2.1.1.2 for GPS health message, and section 2.1.2.2.2.2.2 for FDE.
Note: The SBAS SIS includes health monitoring/fault information, which is why these general signal processing requirements are included.
B.4.20.7 TSO-C196/196a.
Means of compliance for this TSO are defined in RTCA/DO-316, sections 2.1.1.2, 2.1.1.3, and 2.1.2.2.2.2.
B.5 Tightly-Coupled GNSS/IRS Position Sources.
This section provides high-level guidance on the issues that will need to be addressed to qualify a tightly-coupled Global Navigation Satellite System/Inertial Reference System (GNSS/IRS) for use in an ADS-B system. You must propose to the FAA the method to approve a tightly-coupled GNSS/IRS for use in an ADS-B system.
B.5.1 Tightly-Coupled GNSS/IRS Outputs.
The tightly-coupled GNSS/IRS outputs must meet the requirements, including validation, of either RTCA/DO-229(), appendix R, or RTCA/DO-316, appendix R.
B.5.2 Horizontal Velocity Accuracy.
The ADS-B system must address the horizontal velocity accuracy.
B.5.3 GNSS Performance.
The GNSS sensor should meet the minimum performance requirements for any revision of TSO-C129, TSO-C145, TSO-C146, or TSO-C196. Additionally, the GNSS sensor should meet all applicable GNSS requirements of this appendix as applicable.
Appendix B B-29 B.5.4 GNSS Installation.
Install the GNSS sensor(s) in accordance with AC 20-138().
B.5.5 NIC Containment Radius.
§ 91.227 requires a SIL = 3, which means the probability of exceeding the NIC containment radius should be less than 1x10-7 per hour or per sample. The tightly-coupled GNSS/IRS system should transmit the integrity quality metric on a per-hour basis. After loss of GNSS or GNSS RAIM, the hybrid system should report the integrity containment radius of 1x10-7 probability on a per-sample basis rather than on a per-hour basis. Doing so would allow the GNSS/IRS system to transmit at a probability of 1x10-7 for a longer period of time.
B.5.5.1 RTCA/DO-229D, appendix R, section 2.1 requires tightly-coupled systems to meet two integrity limits. The integrity limit for the faulted satellite case is 1x10-7. The integrity limit for fault-free (rare normal) case is 1x10-5. RTCA/DO-229D, appendix R, section 2.1.1 acknowledges that in tightly integrated systems, inertial coasting may cause the rare normal limit to be dominant over the limit for the faulted conditions in times of poor satellite coverage. If the HPL output from the tightly-coupled position source changes from the fault detection 1x10-7 basis to the fault free 1x10-5 basis, the position source needs to indicate this change to the ADS-B equipment. We recommend the position source use a 1x10-7 integrity basis in all modes.
B.5.5.2 If the integrity containment probability output of the tightly-coupled GNSS/IRS position source changes from per-hour to per sample following a loss of GNSS or a loss of GNSS RAIM, the position source must indicate this change to the ADS-B equipment (that is, SILSUPP).
B.5.5.3 If the tightly-coupled GNSS/IRS scales the inertial integrity from 1x10-5 to 1x10-7, the scaling must have been demonstrated during design approval of the position source. If the inertial basis is per-sample and is scaled to per-hour, this scaling must have been demonstrated during the position source design approval.
B.5.6 GNSS Integrity Performance in the Flight Manual.
If a tightly-coupled GNSS/IRS position source is intended to be used as an ADS-B position source after the loss of GNSS, include integrity coasting performance in the flight manual. Specifically address the following:
B.5.6.1 If inertial coasting will meet § 91.227 requirements, such as NACP = 8, NIC = 7, SIL = 3, and SDA = 2.
B.5.6.2 Estimated length of time following a loss of GNSS for which inertial coasting is expected to meet the § 91.227 requirements. The estimate should assume the system met minimum § 91.227 requirements just before the loss of GNSS or GNSS RAIM. This estimate will be helpful to
Appendix B B-30 operators in developing a means to ensure that the system can meet § 91.227 requirements during predicted GNSS degradations.
B.6 Non-GNSS Position Sources.
The FAA does not know of any currently available non-GNSS position sources that can meet the performance requirements of § 91.227. However, you may wish to integrate a backup ADS-B OUT capability in the event of loss of GNSS. Such a backup is not required. We do not expect any ATC operational advantages for systems that provide a non-GNSS backup unless that backup capability meets the performance requirements of § 91.227. This section provides high-level guidance on the issues that will need to be addressed to qualify a non-GNSS position source for use in an ADS-B system without regard to § 91.227 requirements. If you choose to integrate this capability, use the guidance below and propose to the FAA the method to approve a non-GNSS position source for use in an ADS-B system B.6.1 Distance Measuring Equipment (DME/DME).
B.6.1.1 The DME/DME Area Navigation (RNAV) system must meet the minimum performance requirements of TSO-C66c, Distance Measuring Equipment (DME) Operating within the Radio Frequency Range of 960-1215 Megahertz.
B.6.1.2 There are no industry standards for use of a DME/DME system to determine position integrity or velocity accuracy. You must propose a method to derive these parameters.
B.6.1.3 The DME/DME system must only use DME facilities listed in the Airport/Facility Directory (A/FD).
B.6.1.4 The DME/DME system must only use operational DME facilities.
The system must exclude non-operational facilities by checking the identification. Operational mitigations, such as manually excluding (blackballing) DME stations or any action that requires pilot action or monitoring of the DME/DME system, are not permissible for ADS-B qualified position sources.
B.6.1.5 Reasonableness Checks.
The DME/DME system must incorporate reasonableness checking. Refer to AC 90-100(), U.S. Terminal and En Route Area Navigation (RNAV) Operations, for additional information on reasonableness checks.
B.6.2 VOR/DME.
ADS-B position sources may not use Very High Frequency Omnidirectional Range (VOR) information. Do not interface any position solution that uses VOR information as the performance of the VOR cannot be assumed throughout the region in which the signal is received.