ED Decision 2008/004/R
Appendix 4.1: Summary of ADS-B-NRA
Air-to-ground Interoperability Requirements
The minimum set of parameters that should be provided to support the ADS-B-NRA application are summarised in the following table extracted from ED-126:[42]
|
Parameter |
BDS register |
Version 0 |
Version 1 |
||
|
ICAO Annex 10
Amendment 79, VOL III, App to chap 5 |
DO-260/ED102 |
DO-260A |
|||
|
Aircraft identification |
0.8 |
§2.3.4 |
§2.2.3.2.5 |
§2.2.3.2.5 |
|
|
SPI[43] |
0.5 |
§2.3.2.6 |
§2.2.3.2.3.2 |
§2.2.3.2.3.2 |
|
|
Emergency indicator |
0.5 |
§2.3.2.6 |
§2.2.3.2.3.2 |
§2.2.3.2.3.2 |
|
|
Barometric altitude |
0.5 |
§2.3.2.4 |
§2.2.3.2.3.4 |
§2.2.3.2.3.4 |
|
|
Quality indicator (NUC/NIC) |
0.5 |
§2.3.1 |
§2.2.3.2.3.1 |
§2.2.3.2.3.1 |
|
|
Airborne Position |
Latitude |
0.5 |
§2.3.2.3 |
§2.2.3.2.3.7 |
§2.2.3.2.3.7 |
|
Longitude |
0.5 |
§2.3.2.3 |
§2.2.3.2.3.8 |
§2.2.3.2.3.8 |
|
|
6.1 |
Table 2-97 |
§2.2.3.2.7.9 |
§2.2.3.2.7.8 |
||
|
Quality indicator (NACp) |
6.5 |
No definition |
No definition |
§2.2.3.2.7.2.7 |
|
|
Quality indicator (SIL) |
6.5 |
No definition |
No definition |
§2.2.3.2.3.1.1 |
|
|
Version Indicator[46] |
6.5 |
No definition |
No definition |
§A.1.4.10.5 |
|
Table 5:
Mandatory ADS-B-NRA Parameters
The minimum set of parameters that should be provided to support the ADS-B-NRA application are summarised in the following table extracted from ED-126:
|
Parameter |
BDS register |
Version 0 |
Version 1 |
|
|
ICAO Annex 10 Amendment 79,
VOL III, App to chap 5 |
DO-260/ED102 |
DO-260A |
||
|
Airborne Ground Velocity |
0.9 |
§2.3.5 |
§2.2.3.2.6 |
§2.2.3.2.6 |
Table 6:
Optional ADS-B-NRA Parameters
Appendix 4.2: Guidance on Encoding of
Positional Quality Indicators
In order to be able to check the compliance of the actually transmitted ADS-B data with the required quality on the recipient side, ADS-B message transmissions contain “Quality Indicators”. These are expressed for ED-102/DO-260 and DO-260A compliant ADS-B transmit systems as follows:
— ED-102/DO-260: Navigation Uncertainty Category (NUC), a combined expression of (accuracy and) integrity requirements through a single parameter;
— DO-260A: Navigation Accuracy Category (NACp) to express the position accuracy (as a 95 percentile), Navigation Integrity Category (NIC) to express the integrity containment radius and Surveillance Integrity Level (SIL) to specify the probability of the true position lying outside that containment radius without alerting.
Minimum acceptable NUC and NIC/NACp values in support of 5 NM ADS-B-NRA separation services, based on the requirements summarised in Table 2 of Appendix 4, are as follows in line with the “NIC/NACp to NUC” conversion table below.
NUC values (encoding based on HPL, with the accuracy requirements met by GNSS systems by design and in line with the related NACp values in below conversion table):
— 5 NM separation: NUC = 4;
The corresponding NIC/NACp values are as follows.
— 5 NM separation: NIC = 4, NACp = 5,
The SIL value is established to SIL≥2 in line with the combination of the position source failure and position integrity alert failure requirements, as summarised in Table 2 of Appendix 4.
Note 1: In case the SIL value is not
output by the position data sources, it is recommended that the ADS-B transmit
system provides for the static setting of SIL as part of the installation
procedure and as demonstrated for the applicable position data source
configuration.
Note 2: ED-126 provides, based on its
reference collision risk analysis only, arguments for an equally appropriate
encoding of a SIL=2 as a matter of expressing the system integrity as well. As
for the presentation of the values presented in this document, it is at the
discretion of the ATSP to decide upon the appropriate threshold values
required in support of the separation services in its airspace.
|
NUC (max Rc NM)
|
NIC (max Rc NM)
|
NACp (95%
bound) |
|||
|
9 |
(0.003) |
11 |
(0.004) |
11 |
(3 m) |
|
8 |
(0.01) |
10 |
(0.013) |
10 |
(10 m) |
|
- |
9 |
(0.04) |
9 |
(30 m) |
|
|
7 |
(0.1) |
8 |
(0.1) |
8 |
(0.05 NM) |
|
6 |
(0.2) |
7 |
(0.2) |
7 |
(0.1 NM) |
|
5 |
(0.5) |
6 |
(0.6) |
6 |
(0.3 NM) |
|
4 |
(1.0) |
5 |
(1.0) |
5 |
(0.5 NM) |
|
3 |
(2.0) |
4 |
(2.0) |
4 |
(1 NM) |
|
- |
3 |
(4.0) |
3 |
(2 NM) |
|
|
- |
2 |
(8.0) |
2 |
(4 NM) |
|
|
2 |
(10) |
1 |
(20) |
1 |
(10 NM) |
|
1 |
(20) |
1 |
(20) |
1 |
(10 NM) |
|
0 |
(no integrity) |
0 |
(> 20) |
0 |
(unknown) |
Table 7: NUC
conversion to NIC and NACp
[Amdt 20/3]
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