Comments to ADS-B INTEROP V0.7 15.Aug 05
Comments from INTEROP #2 also included
# Author Sectio Page Line Comment Comment – Suggested Resolution – Team Discussion Status
n # Class – Please describe your issue and the Please propose a resolution to your (Open or
Choose one basis for the comment. comment including changes to text, closed)
(Editorial, Comments for MAIN BODY where appropriate.
1 Goran Haslar section low low, The information is irrelevant for the document organization. Suggested resolution: delete Note 1 Comment KK: rejected, this note has been added on closed
(=GH) 1.4.2 medium, And also not appropriate in this kind of document request of a group member. Reason: long discussions had
taken place on which technology is to be described.
high) Decision of the RFG that only the globally agreed
technology shall be described in the INTEROP. Text added
to represent that decision and avoid repeated discussions.
2 GH section editorial The list should only include the acronyms and abbreviations Suggested resolution: remove the acronyms/abbreviations Comment KK: not yet taken. We still believe that it is closed
1.4.3 that are used in the document that are not used in the document advantageous to have a list of acronyms which frequently
appears in discussions of that subject. Naturally all which
appear in the document shall appear.
3 J.Hammer 1,5 High References should include d DO-282A, DO-289. Add the appropriate reference Comment KK: not yet taken. DO-282 (UAT??) and DO-289 closed
(=JBH) (ASAS?) are they really relevant for this application????
4 Chris 2,1 Improvement IN figure 2-1, the shading used to highlight affected parts of Remove the internal shading. Comment KK: not done, as we have no problems neither on
Rossiter the architecture obscures relevant text. a colour printer nor on a black/white printer to see all text
(=CR) and the shading
5 G. Dunstone section 2.1 Editorial The words 'transmission medium' do not distinguish between Suggested resolution: Change all appearances of Comment KK: done for version V0.8 closed
(=GD) link technologies; e.g.: UAT & Mode S use 6the same band 'propagation medium' into 'link technology'
6 CR 2,1 minor Last line of paragraph 2: I would have interpreted Change "propagation medium" to "datalink protocol". Comment KK: see comment GD above. I believed solved closed
"propagation medium" as the atmosphere for which we Same comment also applies elsewhere within the with the modification done in v0.8
cannot specify requirements. document.
7 CR 2,1 minor NOTE 1: Suggest changing the wording of "… does not New wording: "…is not intended to imply a specific Comment KK: changed in v0.8 closed
impose any architecture,". architecture,"
8 JBH 2,2 Minor alerting list is incomplete Add conflict alert and MSAW to the list Comment KK: I rejected that comment as this comment bring back
should be made against the OSED for this application
9 GH section 2.2 low Add information that are beneficial for the surveillance, e.g. Suggested resolution: add parameters that could improve Comment KK: rejected. Copy from OSED. Comment has to bring back
velocity, ground track and aircraft status the NRA application be made against OSED
10 CR 2,3 minor In the information list, the 24 bit address is repeated on each Remove the reference to the 24 bit address from the second Comment KK: rejected. The 24bit in all info transferred to the closed
bullet. and third bullets. This is section is identifying information ATC processing system is considered vital for association
NOT messages. tasks; in addition this is copied from OPA
11 JBH 2.3.1 low last S 1st P does not make sense. correct it Comment KK: Improvement attempted in V0.8 closed
12 GD section Editorial The concept of defining when the receive system should Suggested solution: delete closed as per red lines 9-20-05. closed
126.96.36.199 start composing is unnecessary
13 CR 188.8.131.52 minor There is a word missing after "ADS-B". Change "ADS-B" to "ADS-B reports" Comment KK: done in v0.8 closed
14 Chris 184.108.40.206 minor Change "shall" to "should" - this is a recommendation. Comment KK: see comment above - done in V0.8 closed
15 GD section Editorial is done' can be better expressed Suggested solution: update text Comment KK: text of section 220.127.116.11 updated to contain a closed
18.104.22.168 'should'; Second sentence set into different subsection
16 Don Walker section??? Missing Version number should be required for DO-260A compliant Suggested resolution: add a version requirement to section 3 Comment KK: Main Body resolved by Note in section closed
?? requirement systems. Otherwise, you cannot distinguish them from DO- 22.214.171.124 and added section 126.96.36.199 reading ' A distinction
260 systems between NUC and NIC/NAC/SIL airborne implementations
shall be provided by the Transmit Aircraft Domain. ANNEX
A, see below
17 Konrad section Missing explanation time of applicability ' is not explained and the requirement Suggested resolution: add definition and requirement in Comment KK: OPEN, need help of the group. PLaceholder closed
Koebe 2.3.2 and requirement how to calculate the 'absolute time' is missing section 2.3.2 for note in section 188.8.131.52 and new section 184.108.40.206 added in
V0.8 (to be filled) text changed per september meeting
2 A. Warren 2.3.2 14 Need to add statement regarding max Add new statement 220.127.116.11 "The ADS-B agreed to changed text per september closed
latency of ADS-B rebroadcast function rebroadcast system shall provide a time mtg
when applicable. stamp on re-broadcast, or shall transmit
ADS-B received messages within TBD
seconds of message reception.
18 GD section 3.1 Editorial Separate out the different identification types into a), b),c). Suggested solution: change text Comment KK: disagree. We are on ground in this section, closed
Mode A is optional. The different propagation medium is not here the and/or is taken from the OSED. It is optional in
appropriate since the whole document applies to all messages, but not in the ground requirement
19 GD section Minor A note should be added to indicate that aircraft address is Suggested Resolution- add Note : Typically the aircraft Comment KK : added to V0.8 closed
18.104.22.168 used to associate ADS-B reports to each other address is used to link a new ADS-B report to
existing internal surveillance information (e.g. track).
20 CR 22.214.171.124 minor These two requirements should be recommendations. I do Comment KK: rejected: assumed vital for the proper closed
126.96.36.199 not believe that it is necessary to specify how the ground functioning of the application. Even if it is recommendation
system correlates reports with its own internal data. The two with should it has to be 2 sentences.
paragraphs could be combined into one with the
recommendation that the ground system use the
identification elements in a specific order to do its data
21 JBH 3.2.2 Medium The Transmit Aircraft Domain shall, always transmit Comment KK: similar comment received from G. Dunstone. closed
Disagree with "The Transmit Aircraft Domain shall use the barometric altitude when it is available and shall transmit Copied the text of GD into V0.8. IN addition section added
GNSS height only when barometric altitude is not available." GNSS height when barometric altitude is unavailable. Both =>OK
It should be possible to transmit both with baro as a barometric and geometric altitude may be transmitted
JBH 3.2.2 Medium more than 1 altitude may be sent: "The Transmit Aircraft Comment KK: see comment above =>OK
Domain shall indicate which closed
of the two altitude representations is provided in the ADS-B
23 JBH 3.2.2 Medium title of section is inaccurate Should be: "Altitude" Comment KK: I rejected that comment as I have used the closed
parameter names used in the OSED and OPA for the
application => title changed from baro altitude to baro
altitude or geo height
24 JBH / CM 3.2.2 Medium recommendation should be a shall Comment KK: not yet taken, to be discussed during Closed
meeting. GD also addresses that problem. BUT: OPA (6.2)
requires only > or = 100ft which seems to allow for GILHAM
Altitude data which are Gilham encoded (100ft increment) =>rejected as 100 ft increment is permitted for GA at
*shall* not be used by aircraft implementations. least
25 JBH 3.2.3 Medium text is superfluous: An HPL value of 1.0 NM also matches Substitute an appropriate reference. Comment KK: not yet changed: Comment also received closed
the presentation & draft paper by Stan Jones presented at from GD, text GD taken, but Editorial remark added that
the RFG meeting in Miami titled “ADS-B Surveillance comment shall be considered when rewriting the subsection.
Requirements to Support ATC Separation Standards” which =>all considerations concerning the minimum value
argued that HPL(NIC) <1.0 Nm is adequate to support a 5 for HPL for NRA application, reference to SPR has
nm separation standard. It also stated “SIL = 2 (1*10 -5) been inserted
risk level without an alarm require error bounds of NIC = 6
(0.5Nm) and NIC = 5 (1nm) for 3 NM and 5 NM separation
JBH 3.2.3 Medium No reason for this to be required to be cyclic: To allow the utilisation of ADS-B information for a variety of Comment KK: 'cyclically' deleted in V0.8. But note that the
"To allow the utilisation of ADS-B information for a variety of applications, the Transmit Domain shall XXcyclicallyXX closed
OPA (5.1) gives requirement for update interval for quality
applications, the Transmit Domain shall cyclically communicate accuracy and integrity indicators within an indicators => refer to SPR
communicate accuracy and integrity indicators within an ADS-B message
27 GD section3.2. In 2nd par. behind note, and shall be replaced by and/or as Suggested resolution: change to 'and/or' Comment KK: partially done in V0.8. Only retained the 'and' closed
3 sometimes it may only be NUC which is available as 'or' may give the impression that one of the items may be
omitted, which is not the case (they can be combined)
=>part completely changed, comment agreed
28 GD section use subsection numbers for requirements and Comment KK: subsection numbering implemented in V0.8 CLOSED
3.2.3 recommendations . (188.8.131.52 to 184.108.40.206 and 220.127.116.11 to 18.104.22.168), for a later
comment a section 22.214.171.124 added additionally =>editorial
will be reviewed separately
29 GD section add design requirement to use HPL Suggested resolution: text proposed by GD Comment KK: text proposed by GD implemented as 126.96.36.199 CLOSED
3.2.3 and Note following the paragraph.
30 GD section The recommendation concerning the determination of NUC/ Suggested resolution: after 'receiver' add 'or equivalent, or Comment KK: added in section 188.8.131.52 (new numbering) of CLOSED
3.2.3 NIC values shall also allow DO-229c GPS receivers DO-229c GNSS receiver' V0.8
31 GD section the description should be changed into a 'positive sense' Suggested resolution: new text proposed Comment KK: I have copied the text as modified by GD into CLOSED
3.2.3 the document, without numbering it yet. There are NO
'shalls' in his text, I doubt that we can formulate
requirements with 'may'
32 GH section3.2. medium If NUC is used alone it includes both, acccuracy and Suggested resolution: there should be an explanatory text of Comment KK: tables from DO-242 and DO-242A added to CLOSED
3 integrity information, but it does not explain how. how NUC will fullfill the requirements for accuracy and the main body with explanatory text. During meeting SG
decided to delete the tables again (copy of reference
33 CR 3.2.3 minor There is a requirement on ADS-B here where I think that Replace "ADS-B data shall be useable for 5Nm separation " Comment KK:OPEN, see other comments on section 3.2.3 CLOSED
there should be a statement of intent. with when addressing this comment. During meeeting 3.2.3
"ADS-B data is useable for 5Nm separation" completely rewritten.
Add a separate requirement to state that the ground system
shall not use ADS-B data with an HPL value of less than
TBD for 5NM separation.
3 A. Warren 184.108.40.206 16-17 NUC The NUC table is not consistent with TSO- For international interoperability, suggest During meeting table deleted again (only CLOSED
C166 Appendix 1, section (1.2) that that the more strict standard in TSO- copy from reference document)
requires selecting NUC based on HPL C166 be adopted, i.e. for both technical
only and if HPL is unknown or un- and trans-national reasons, it is highly
available, setting NUC=0. desirable to eliminate use of HFOM for
4 A. Warren 220.127.116.11 18 SIL The SIL table is different than that Replace table with that in DO-242A. During meeting table deleted again (only CLOSED
specified by DO-242A. copy from reference document)
5 A. Warren 18.104.22.168 19 Same issue in 22.214.171.124 above Delete Note 1, consistent with TSO- closed
6 A. Warren 126.96.36.199 19 Evidence that HFOM is O.K. cannot be Appropriate back-up of HPL should be closed
based on data obtained in the last few provided by use of multi-sensor data, e.g.
years when the U.S. Air Force has use of WAAS receivers or FMS/ INS
activated GPS spares as active satellites. backup to GPS during RAIM outages.
The Air Force only guarantees availability Depending on HFOM as a backup to HPL
of 24 satellites, not the 28 that are in the should not be used for Surveillance
constellation currently. In the Late 1990's where the consequences of an
there was a published incident with 7 undetected failure mode are Major level
Sats of bad geometry in which accuracy or greater. This statement should be
(HFOM) was O.K. based on best 4 Sats, replaced with a more generic statement
and HPL was very poor or unavailable. on the value of having a backup source of
Such RAIM holes are rare today, but position information to avoid loss of
recent RAIM outage rates are not a continuity of position data for ADS-B.
reliable indicator of future values.
7 A. Warren 188.8.131.52 19 One of the main reasons for approving Delete the statement beginning "In the closed
DO-242A was to tighten up on the absence of HPL, …". If a particular state
standards for integrity assessment. The wants to adopt a weaker criterion than
use of HFOM for encoding NUC was felt that of the international standard, there is
by SC-186 committee to be a bad nothing preventing them from doing so.
practice, since the receiver cannot tell The international standards for NRA
whether NUC is an accuracy or integrity should be based on DO-242A and
parameter. If we use FMS or non-GPS consistent with current best practices.
based navigation solutions as a backup, These standards, such as DO-289 call
then there is no generally usable out the use of NIC and NACp values for
relationship between accuracy metrics each ADS-B application. The
(EPU) and containment radius (Rc). The compromise adopted in TSO-C166 to
receiver of ADS-B data will not be able to use legacy DO-260 equipment is as far
tell whether the source of NIC/NUC is a as the international community should go
GPS sensor or not. in accomodating existing equipment.
34 GD section I disagree with the comment that ICAO sets a requirement Suggested resolution: change text Comment KK: I have not taken this advise. The text does closed
3.3.1 for systems in the referenced Annex 22. Interestingly, not say that there is a system requirement. An ATS
maybe Annex 11 will need to add more once ADS-B is used! requirement is cited which is to be taken over for the NRA
application - and that is as per OSED.
35 GD section The distinct indicators need to be used by the ATM system - Suggested resolution: change text Comment KK: I have not taken that over. I believe that all closed
184.108.40.206 but this can only occur if they are received. Some aircraft what is commented here is addressed in the preceding
will transmit the distinct indicators and others will (not). sections.
36 GD section 3.4 A number of ground requirements have already been listed Suggested resolution: add 'other' to the title of the section Comment KK: done for V0.8, but renumbered to 3.5 due to closed
insertion of another section
37 JBH All section Minor See red-lined copy for editorial changes Comment KK: editorials incorporated into V0.8, but 'area' not closed
changed into 'airspace' as CASCADE programme
description says 'area' and changes in 220.127.116.11 rejected as it
is understood that not all implementation are capable to do
more than the general emergency indication.
38 GD new Medium A recommendation should be added to supervise multiple Suggested Resolution- add a subsection 18.104.22.168 with Comment KK: added in V0.8 closed
section use of aircraft addresses Recommendation: The ATC processing system should
include an algorithm to detect multiple aircraft using the
same aircraft address.
39 GD new Medium A recommendation should be added to supervise clearance Suggested Resolution- add a subsection 3.4.5 with Comment KK: added to V0.8 closed
section adherence Recommendation: The ATC Processing System should
contain a monitoring function to detect mismatches between
the ATC clearance and ADS-B reported altitude.
40 GD new Minor A recommendation for additional ground system functionality Suggested Resolution- add a subsection 3.4.6 with Comment KK: not yet taken, to be discussed during closed
section should be added A.22.214.171.124 Recommendation : Additional ATC Processing meeting. Simple reason I do not understand the text
System functionality described below can be provided to
improve the integrity of downlinked positional data, providing
additional protection against GNSS faults :
a) Implement functionality which uses signals from site
monitors to allow GNSS parameters to be monitored and for
ATC to be provided warnings regarding GNSS satellite
problems. Functionality that can be provided includes :
Ø Monitor the position reported by the site monitor
compared to the surveyed position
Ø Monitor the HPL reported by site monitors
Ø Monitor the site monitor GNSS receiver ‘s “Fault detection
and exclusion” status to provide early warning of faulty
b) Provide ATC users with predictions of inadequate HPL
based upon GNSS satellite geometry, current satellite
status and US Government NANUs.
41 KK new Minor Ground velocity is addressed in the AnneX A. In spite of the 4 renumbered to 3.5 Comment KK: section 3.4 created in main body, old section
fact that it is not mandated to be provided by datalink in the
section 3.4 renumbered to 3.5
OSED, an insert should be made in the main body to justify
Comments for ANNEX A
42 JBH ANNEX High Sections A126.96.36.199 and A188.8.131.52 are very confusing. It is not Clarify the definition of a) and b) has been added to clarify, and the closed
184.108.40.206 clear what is being referred to as "definition case a or b." sentence has been changed. See v0.72 or v0.8
43 Tom Mosher ANNEX Medium There seems to be a discrepancy regarding the use of Mode Clarify ANNEX : corrected for V0.8 closed
A.220.127.116.11 A codes. Section 18.104.22.168.2 creates a requirement to
transmit the Mode A code, if it is available and a message
format exists to represent it. However, Annex A.22.214.171.124 says
in a Note that transmitting the Mode A is optional
Don Walker section??? Missing Version number should be required for DO-260A compliant Suggested resolution: add a version requirement to section Comment KK: v 0.8: sections A.1.3.10 and A.126.96.36.199 added closed
copy ?? requirement systems. Otherwise, you cannot distinguish them from DO- 3 in Annex A
of 16 260 systems
8 A. Warren A.188.8.131.52 29 There are also non-GPS sensors that add to the back end of this line "or an accepted GNSS removed closed
could qualify for NRA. This reviewer is alternative integrity containment metric
very uncomfortable with the exclusive use such as specified in DO-242A if the ADS-
of GPS language used throughout this B data source is not a GNSS sensor."
document, e.g. the use of HPL instead of
containment radius (Rc).
9 A. Warren A.184.108.40.206 29 NEED to add statement regarding Same resolution as advised in accepted NAC added in subsection closed
encoding of accuracy metrics for comments.
position, i.e. NACp.
10 A. Warren A.220.127.116.11 30 Need to add statement regarding Same resolution as advised in a note has been added in ground velocity CLOSED
encoding of accuracy metric NACv for comments. part to indicate that velocity integrity
velocity, if available. (NACv) is out of scope