Appendix 4
Vi Vi ih N i ihbh HFOMh HFOMhb N bNTS 0 1 samples ofnumber 1 , 1 ,,
A4-6. Vertical Velocity Accuracy Test Conditions Commensurate with NACV = 1.
a. Ensure the simulator scenario has enough GPS satellites to provide a vertical dilution of precision (VDOP) of 3.0 or less.
b. One satellite shall be set at maximum power (including maximum combined satellite and aircraft antenna gain), and the other satellites shall be set at minimum power (including minimum antenna gain).
c. Broadband GNSS test noise (IGNSS,Test) of spectral density as defined in RTCA/DO-229D, paragraph 2.5.8, broadband external interference (Iext,test) and thermal noise contribution from the sky and the antenna (Nsky,antenna) shall be simulated.
Note: In RTCA/DO-229D, paragraph 2.5.8.2 step 2, replace -173.0 dBm/Hz with -172.8 dBm/Hz for total GNSS noise (IGNSS) when running separate GPS/SBAS testing for accuracy verification and/or GPS/SBAS message loss rate data.
d. The airborne equipment shall be initialized with the appropriate position and time.
It is assumed that the receiver has obtained a valid almanac for the simulator scenario to be tested prior to conducting the test.
e. Platform dynamics for the vertical velocity accuracy test shall be as defined in Table 13 below.
A4- 5
Appendix 4
Time (s) Start Jerk (g/s) End Jerk (g/s) From To Dynamics North East Down Total North East Down Total 0 T Static 0 0 0 0 0 0 0 0 T+1 T+71 0.58g longitudinal acceleration to 411 m/s
0.xx Note 1
0.xx Note 1 0 0.25 0.xx Note 1
0.xx Note 1 0 0.25 T+72 T+130 Straight and level un-accelerated flight 0 0 0 0 0 0 0 0 T+131 T+131+X Climb, increasing the vertical climb rate from 0 to 21 m/s, then decrease the rate back to 0 m/s and repeat this increasing and decreasing pattern until the time out.
0 0 0.xx Note 1
0.25 0 0 0.xx Note 1
0.25 T+132+X T+192+X Straight and level un-accelerated flight 0 0 0 0 0 0 0 0 T+193+X T+193+2X Descend, increasing the vertical descent rate from 0 to 21 m/s, then decrease the rate back to 0 m/s and repeat this increasing and decreasing pattern until the time out.
0 0 0.xx Note 1
0.25 0 0 0.xx Note 1
0.25 T+194+2X T+274+2X Straight and level un-accelerated flight 0 0 0 0 0 0 0 0 Table 13. Platform Dynamics for Vertical Velocity Accuracy Test
Note 1: The components of the jerk in the north and east direction depends on the heading chosen in the scenario.
The total jerk is not to exceed the vector combination of north, east, and down jerk components. The maximum total jerk to quickly achieve the desired dynamics should be used, but the jerk should not exceed the normal maneuver total jerk requirement of 0.25 g/s.
Note 2: The actual times may vary based on the simulator scenario control settings.
Note 3: The value of X must be at least 63 seconds to have enough samples during vertical acceleration.
f. Signal and RFI conditions can be modified during the static period to aid acquisition. Ensure the receiver enters the desired operation mode before dynamics and A4-6
Appendix 4
appropriate signal and interference conditions are applied.
g. Use the simulator velocity truth data ( truthvertical iV _ ) and the GNSS receiver velocity data ( vertical iV ) to determine the vertical velocity error ( iv ) after the GNSS receiver has entered the desired navigation mode with the specified signal and RFI conditions:
vertical i truthvertical ii VVv _
A4-7. Vertical Velocity Accuracy Pass/Fail Determination.
a. The 95% vertical velocity accuracy statistic shall be computed using the formula given below. The equipment shall be considered pass only if the statistic is less than or equal to 50-LSB ft/s.
N i i N i VDOP v 1 2 3 *2
Where:
vi = vertical velocity error (ft/sec).
VDOPi = vertical dilution of precision at epoch i.
N = number of sample points used.
b. For this test, the number of samples shall include all samples where the receiver is in the desired navigation mode.
Note: The minimum number of samples is 420 for a 1 Hz solution and 2100 for a 5 Hz solution.
A4-8. Vertical Velocity Figure of Merit Pass/Fail Determination.
The receiver velocity data and the vertical figure of merit - velocity (VFOMV) data shall be used to determine the percentage of samples bounded by the VFOMV as shown below. The test passes if bvTS , is greater than or equal to 0.95.
Vi Vi iv N i ivbv VFOMv VFOMvb N bNTS 0 1 samples ofnumber 1 , 1 ,,
A4-7
Appendix 4
A4-9. Additional Tests to Demonstrate Accuracy Commensurate with NACV = 2.
The following procedure is one acceptable means for equipment capable of better accuracy performance to demonstrate compliance with the horizontal velocity error requirement of less than 3 m/s.
a. Run the scenario in Table 13 with all satellites set at high power and no RFI.
b. This accuracy evaluation shall only include those data samples collected during the acceleration period.
c. Find the particular ih (noted as accT ) so that 95% of ih samples are less than or equal to accT .
d. Re-run the scenario in Table 13 with the same satellite and RFI conditions as the 10 m/s (NACV=1) test.
e. This time only the data samples during the non-acceleration period with the specified signal and RFI conditions are used.
f. Compute:
accnon N i accnoni accnoni accnon N HDOP h T accnon _ 1 2 __ __ _ _ 5.1 *2
Where:
accnoniHDOP __ and accnonN _ are the HDOP values for each sample i and the total number of samples (non-acceleration period), respectively.
g. The test passes only if accnonacc TT _ is less than or equal to 3-LSB m/s.
h. The velocity figure of merit is evaluated in the same way as for the 10 m/s test, i.e., the samples during acceleration and non-acceleration periods of the above 2 runs are evaluated together against the 0.95 threshold.
i. The vertical velocity requirement of 15 ft/s should be tested using the exact same philosophy as the test of 3 m/s above but with the scenario in Table 13.
A4-8
Appendix 4
A4-10. Test to Demonstrate HAE Output and Vertical Position Accuracy Metric.
a. The following procedure is one acceptable means for equipment to demonstrate compliance with the HAE and 95% vertical position accuracy output requirements needed to support ADS-B. This parameter is commonly called the vertical figure of merit (VFOM) and should not be confused with the vertical velocity figure of merit (VFOMV) from the velocity accuracy tests. All GNSS TSO equipment should use this test to demonstrate both HAE and 95% vertical position accuracy outputs.
b. The HAE output must be calculated using the general least squares position solution of DO-229D appendix J.1 (or any mathematically equivalent linear combination of range measurements). There is no restriction on the choice of the weight matrix W (including nonweighted solutions), and using the LNAV/VNAV, LP, LPV approach weight (wi = 1/σi2) is optional.
c. The HAE accuracy must be tested using the procedure of DO-229D section 2.5.8.3.
The σi2 used to compute the variance dU2 must be greater than or equal to those listed in appendix J when the equipment uses SBAS-provided integrity and greater than or equal to those listed as an acceptable means for FDE-provided integrity in section 2.1.2.2.2.2 when the equipment does not use SBAS-provided integrity. A fixed sigma of 33.3 m is considered a sufficient over-bound when using FDE-provided integrity. For equipment that uses SBAS- provided integrity, testing only in the highest mode attainable for its declared Operational Class as specified in the test itself is acceptable.
d. Performing the test described in paragraphs A4-10.a through A4-10.c confirms that the σi and dU used to compute the VFOM accuracy metric provides a sufficient error overbound. The vertical position accuracy metric must be greater than or equal to 1.96 dU where dU is computed using the same σi employed during the HAE accuracy test procedure. This VFOM calculation does not require any specific additional testing.
Note 1: The scaling factors for the vertical position accuracy metric can be rounded to 2 decimal places but there is no intention to prohibit the use of a more accurate number.
Note 2: The vertical position accuracy metric listed above is the standard metric used to provide a minimum of 95% containment under the assumption that a Gaussian distribution with a sigma of σi over-bounds the error of the range measurements. The use of a general least squares position solution (or mathematical equivalent) results in a jointly Gaussian distribution for the components (North, East, Up) of the position error. Any accuracy metric that can be mathematically demonstrated to provide a minimum 95% containment in the position domain under this Gaussian assumption is also acceptable.
A4-9
Appendix 4
A4-11. Test to Demonstrate Horizontal Position Accuracy Metric.
a. The following procedure is one acceptable means for equipment to demonstrate compliance with the 95% horizontal position accuracy output requirements needed to support ADS-B. This parameter is commonly called the horizontal figure of merit (HFOM) and should not be confused with the horizontal velocity figure of merit (HFOMV) from the velocity accuracy tests. TSO-C145/C146 revision ‘b/c’ and TSO-C196(AR) equipment already satisfy this parameter by meeting the TSO requirements. TSO-C145a/C146a and TSO-C129(AR) equipment should use this test to demonstrate the HFOM output.
b. The horizontal position output must be calculated using the general least squares position solution of DO-229D appendix J.1 (or any mathematically equivalent linear combination of range measurements). There is no restriction on the choice of the weight matrix W (including non-weighted solutions), and using the LNAV/VNAV, LP, LPV approach weight (wi = 1/σi2) is optional.
c. The horizontal position accuracy must be tested using the procedure of DO-229D section 2.5.8.3. The σi2 used to compute the variance d2major must be greater than or equal to those listed in appendix J when the equipment uses SBAS-provided integrity and greater than or equal to those listed as an acceptable means for FDE-provided integrity in section 2.1.2.2.2.2 when the equipment does not use SBAS-provided integrity. A fixed sigma of 33.3 m is considered a sufficient over-bound when using FDE-provided integrity. For equipment that uses SBAS-provided integrity, testing only in the highest mode attainable for its declared Operational Class as specified in the test itself is acceptable.
d. Performing the test described in paragraphs A4-11.a through A4-11.c confirms that the σi and dmajor, deast, and dnorth used to compute the HFOM accuracy metric provide a sufficient error over-bound. The accuracy metric must be greater than or equal to 1.96 sqrt(d2east + d2north) or 2.45 dmajor where dmajor, deast, and dnorth are computed using the same σi employed during the horizontal accuracy test procedure. This HFOM calculation does not require any specific additional testing.
Note 1: The scaling factors for the horizontal position accuracy metric can be rounded to 2 decimal places but there is no intention to prohibit the use of a more accurate number.
Note 2: The horizontal position accuracy metric listed above is the standard metric used to provide a minimum of 95% containment (varying from 95% to approximately
98.5%) under the assumption that a Gaussian distribution with a sigma of σi over-bounds the error of the range measurements. The use of a general least squares position solution (or mathematical equivalent) results in a jointly Gaussian distribution for the components (North, East, Up) of the position error. Any accuracy metric that can be mathematically demonstrated to provide a minimum 95% A4-10
Appendix 4
containm ent in the position domain under this Gaussian assumption is also acceptable.
A4-12. Demonstrating True Track Angle/True Track Angle Validity.
a. The true track angle/true track validity parameter is intended as a non-critical, optional parameter for airport surface operations. Since most GNSS position sources output some type of track information even during ground operations, it is recommended that GNSS manufacturers output ground track angle as the information can be useful for non-critical ADS- B surface applications. The concern is that below a certain velocity the ground track information becomes invalid, and the velocity at which this occurs is dependent upon the specific GNSS equipment design. GNSS/ADS-B integrations at the aircraft level must stop broadcasting ground track when the GNSS ground track information becomes invalid.
Note: It is possible that future ADS-B surface applications may be defined for critical functions. More stringent GNSS performance requirements and tests than what is described below will have to be developed if and when these new surface applications are defined.
b. GNSS equipment not providing a valid ground track.
GNSS manufacturers may choose to not have their equipment provide a ground track output acceptable for the ADS-B true track angle/true track validity parameter. GNSS manufacturers choosing this option need to include a statement within the equipment limitations section that the ground track information must not be used for ADS-B surface applications.
c. GNSS equipment providing a valid ground track for the true track angle/true track validity parameter.
(1) Appendix H in both RTCA/DO-229D and RTCA/DO-316 provides a recommended output for true ground track angle (ARINC 743 all revisions label 103) for those using ARINC 429 characteristics.
(2) GNSS manufacturers must indicate at what velocity the GNSS track angle 95% accuracy (derived from north/east velocity) exceeds eight degrees variance from the aircraft’s actual ground track. GNSS manufacturers must provide this data within the equipment installation instructions for the GNSS/ADS-B integrator.
(3) Optimally, the GNSS equipment will either invalidate or stop outputting the ground track information when it is no longer valid. If the sensor outputs a validity indicator for the velocity, it is sufficient to simply flag the output as invalid if the track accuracy exceeds eight degrees (95%). The GNSS manufacturer must provide information in the installation instructions describing how the sensor outputs the validity indicator if one is provided.
Alternately, it is acceptable for the GNSS manufacturer to state in the installation instructions that the track angle does not meet the required accuracy below a specified velocity and indicate the minimum acceptable velocity.
A4-11
Appendix 4
A4-12
(4) GNSS manufacturers developing data for the minimum valid velocity should consider the following assumptions:
Surface message is used during taxi, takeoff, and landing ground applications.
Surface taxi speed is less than 50 knots.
No turns; only along-track acceleration (0.58g) and jerk (0.25 g/sec).
Track angle validity is only an issue at taxi speeds.
Use the GNSS noise environment defined in the velocity test (paragraphs A4-3 through A4-8), or for sensors not originally certified to the latest noise environment standards, use a reduced environmental noise level as described in paragraphs A4-2.d(3) and A4-2d.(4).
Appendix 5
Appendix 5. Sample Airplane/Rotorcraft Flight Manual Supplement.
A5-1. Introduction.
The intent of this appendix is to provide general guidance for creating an AFMS/RFMS.
The information and structure below are not intended to cover all possible aircraft integrations or equipment capabilities and should not be construed to limit the content included in an AFMS/RFMS. Actual AFMS/RFMS language and structure must be tailored to the actual installation, equipment capabilities, and limitations. AC 25.1581-1 provides flight manual guidance information for transport category airplanes.
A5-1
Appendix 5
Installation Center/Repair Station Model XXX GPS 123 Fourth Street Navigation System Anytown, USA
FAA APPROVED AIRPLANE FLIGHT MANUAL SUPPLEMENT
ABC MODEL XXX GPS NAVIGATION SYSTEM
AIRPLANE MAKE:
AIRPLANE MODEL:
AIRPLANE SERIAL NO.:
REGISTRATION NO.:
This document must be carried in the airplane at all times. It describes the operating procedures for the ABC Model XXX GPS navigation system when it has been installed in accordance with <manufacturer's installation manual number and date>.
For airplanes with an FAA approved airplane flight manual, this document serves as the FAA approved ABC Model XXX GPS flight manual supplement. For airplanes that do not have an approved flight manual, this document serves as the FAA approved ABC Model XXX GPS supplemental flight manual.
The information contained herein supplements or supersedes the basic airplane flight manual dated <insert date> only in those areas listed herein. For limitations, procedures, and performance information not contained in this document, consult the basic airplane flight manual.
FAA APPROVED
_____________________ Title Office Federal Aviation Administration City, State F A A A p p r o v e d P a g e < > o f < > Date: ________ A5-2
Appendix 5
Sample Airplane/Rotorcraft Flight Manual (Continued)
Installation Center/Repair Station Model XXX GPS 123 Fourth Street Navigation System Anytown, USA
Table of Contents
SectionPage
1 General.............................................< >
2 Limitations........................................< >
3 Emergency/Abnormal Procedures....< >
4 Normal Procedures...........................< >
5 Performance......................................< >
6 Weight and Balance..........................< >
7 System Description...........................< >
FAA Approved Page <> of <> Date: ________ A5-3
Appendix 5
Sample Airplane/Rotorcraft Flight Manual (Continued)
Installation Center/Repair Station Model XXX GPS 123 Fourth Street Navigation System Anytown, USA
SECTION 1 - GENERAL <Include the appropriate statement to describe the equipment capability:>
GPS TSO-C129<appropriate revision>: The installed ABC system complies with AC 20-138C for IFR navigation using GPS for enroute, terminal area, and non-precision approach operations. Non-precision approach operations include those based on conventional navigation aids with “or GPS” in the title and those with “GPS” and “RNAV(GPS)” in the title to “LNAV” minimums.
GPS/SBAS TSO-C145 or C146<appropriate revision> Class 3: The installed ABC equipment complies with AC 20-138C for navigation using GPS and GPS/SBAS (within the coverage of a satellite-based augmentation system complying with ICAO Annex 10) for enroute, terminal area, non-precision approach, and approach procedures with vertical guidance operations.
Non-precision approach operations include those based on conventional navigation aids with “or GPS” in the title and those with “GPS” and “RNAV(GPS)” in the title to “LNAV” and “LP” minimums. Approach procedures with vertical guidance includes “RNAV(GPS) to “LNAV/VNAV” and “LPV” minimums.
Note 1: TSO-C145a/C146a Class 3 equipment is not required to perform LP approaches.
Note 2: Functional Class Delta equipment is an “ILS look-alike” that only provides LP/LPV capability on the final approach segment.
GPS/SBAS TSO-C145 or C146<appropriate revision> Class 2: The installed ABC equipment complies with AC 20-138C for navigation using GPS and GPS/SBAS (within the coverage of a satellite-based augmentation system complying with ICAO Annex 10) for enroute, terminal area, non-precision approach, and approach procedures with vertical guidance operations.
Non-precision approach operations include those based on conventional navigation aids with “or GPS” in the title and those with “GPS” and “RNAV(GPS)” in the title to “LNAV” minimums. Approach procedures with vertical guidance includes “RNAV(GPS) to “LNAV/VNAV” minimums.
FAA Approved Page <> of <> Date: ________
A5-4