Comments to ADS-B INTEROP V0.7 15-Aug-05
Comments from INTEROP #2 also included
# Author Section Page Line Comment Comment – Suggested Resolution – Team Discussion Status
# Class – Please describe your issue and the basis Please propose a resolution to your (Open or
Choose one for the comment. comment including changes to text, closed)
(Editorial, Comments for MAIN BODY where appropriate.
1 Goran Haslar section low The information is irrelevant for the document organization. Suggested resolution: delete Note 1 Comment KK: rejected, this note has been added on request closed
(=GH) 1.4.2 And also not appropriate in this kind of document of a group member. Reason: long discussions had taken place
on which technology is to be described. Decision of the RFG
that only the globally agreed technology shall be described in
the INTEROP. Text added to represent that decision and avoid
2 GH section editorial The list should only include the acronyms and abbreviations Suggested resolution: remove the acronyms/abbreviations that Comment KK: not yet taken. We still believe that it is closed
1.4.3 that are used in the document 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 a
Rossiter the architecture obscures relevant text. colour printer nor on a black/white printer to see all text and
(=CR) the shading
5 G. Dunstone section 2.1 Editorial The words 'transmission medium' do not distinguish between Suggested resolution: Change all appearances of 'propagation Comment KK: done for version V0.8 closed
(=GD) link technologies; e.g.: UAT & Mode S use 6the same band medium' into 'link technology'
6 CR 2.1 minor Last line of paragraph 2: I would have interpreted "propagation Change "propagation medium" to "datalink protocol". Comment KK: see comment GD above. I believed solved with closed
medium" as the atmosphere for which we cannot specify Same comment also applies elsewhere within the document. the modification done in v0.8
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 to
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 the Comment KK: rejected. Copy from OSED. Comment has to bring back to
velocity, ground track and aircraft status 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 NOT ATC processing system is considered vital for association
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 start Suggested solution: delete closed as per red lines 9-20-05. closed
126.96.36.199 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 requirement 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 22.214.171.124 closed
?? systems. Otherwise, you cannot distinguish them from DO- and added section 126.96.36.199 reading ' A distinction between
260 systems NUC and NIC/NAC/SIL airborne implementations shall be
provided by the Transmit Aircraft Domain. ANNEX A, see
17 Konrad section Missing explanation time of applicability ' is not explained and the requirement how Suggested resolution: add definition and requirement in Comment KK: OPEN, need help of the group. PLaceholder for closed
Koebe 2.3.2 and requirement to calculate the 'absolute time' is missing section 2.3.2 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 mtg closed
latency of ADS-B rebroadcast function rebroadcast system shall provide a time
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 not Comment KK: rejected: assumed vital for the proper closed
126.96.36.199 believe that it is necessary to specify how the ground system functioning of the application. Even if it is recommendation
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 correlation.
21 JBH 3.2.2 Medium The Transmit Aircraft Domain shall, always transmit Comment KK: similar comment received from G. Dunstone. closed
barometric altitude when it is available and shall transmit Copied the text of GD into V0.8. IN addition section added
Disagree with "The Transmit Aircraft Domain shall use the GNSS height when barometric altitude is unavailable. Both =>OK
GNSS height only when barometric altitude is not available." barometric and geometric altitude may be transmitted
It should be possible to transmit both with baro as a minimum simultaneously.
22 JBH 3.2.2 Medium more than 1 altitude may be sent: "The Transmit Aircraft Comment KK: see comment above =>OK closed
Domain shall indicate which
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 meeting. Closed
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 least
*shall* not be used by aircraft implementations.
25 JBH 3.2.3 Medium text is superfluous: An HPL value of 1.0 NM also matches the Substitute an appropriate reference. Comment KK: not yet changed: Comment also received from closed
presentation & draft paper by Stan Jones presented at the GD, text GD taken, but Editorial remark added that comment
RFG meeting in Miami titled “ADS-B Surveillance shall be considered when rewriting the subsection. =>all
Requirements to Support ATC Separation Standards” which considerations concerning the minimum value for HPL for
argued that HPL(NIC) <1.0 Nm is adequate to support a 5 nm NRA application, reference to SPR has been inserted
separation standard. It also stated “SIL = 2 (1*10 -5) risk level
without an alarm require error bounds of NIC = 6 (0.5Nm) and
NIC = 5 (1nm) for 3 NM and 5 NM separation respectively.
26 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 closed
"To allow the utilisation of ADS-B information for a variety of applications, the Transmit Domain shall XXcyclicallyXX OPA (5.1) gives requirement for update interval for quality
applications, the Transmit Domain shall cyclically communicate accuracy and integrity indicators within an ADS- 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
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 Suggested resolution: after 'receiver' add 'or equivalent, or DO- Comment KK: added in section 188.8.131.52 (new numbering) of CLOSED
3.2.3 NUC/NIC values shall also allow DO-229c GPS receivers 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
32 GH section3.2. medium If NUC is used alone it includes both, acccuracy and integrity Suggested resolution: there should be an explanatory text of Comment KK: tables from DO-242 and DO-242A added to the CLOSED
3 information, but it does not explain how. how NUC will fullfill the requirements for accuracy and main body with explanatory text. During meeting SG decided
to delete the tables again (copy of reference document only)
33 CR 3.2.3 minor There is a requirement on ADS-B here where I think that there Replace "ADS-B data shall be useable for 5Nm separation " Comment KK:OPEN, see other comments on section 3.2.3 CLOSED
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-C166 copy from reference document)
requires selecting NUC based on HPL only be adopted, i.e. for both technical and trans-
and if HPL is unknown or un-available, national reasons, it is highly desirable to
setting NUC=0. eliminate use of HFOM for encoding
4 A. Warren 220.127.116.11 18 SIL The SIL table is different than that specified Replace table with that in DO-242A. During meeting table deleted again (only CLOSED
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-C166. 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 years provided by use of multi-sensor data, e.g.
when the U.S. Air Force has activated GPS use of WAAS receivers or FMS/ INS
spares as active satellites. The Air Force backup to GPS during RAIM outages.
only guarantees availability of 24 satellites, Depending on HFOM as a backup to HPL
not the 28 that are in the constellation should not be used for Surveillance where
currently. In the Late 1990's there was a the consequences of an undetected failure
published incident with 7 Sats of bad mode are Major level or greater. This
geometry in which accuracy (HFOM) was statement should be replaced with a more
O.K. based on best 4 Sats, and HPL was generic statement on the value of having a
very poor or unavailable. Such RAIM holes backup source of position information to
are rare today, but recent RAIM outage avoid loss of continuity of position data for
rates are not a reliable indicator of future ADS-B.
7 A. Warren 188.8.131.52 19 One of the main reasons for approving DO- Delete the statement beginning "In the closed
242A was to tighten up on the standards for absence of HPL, …". If a particular state
integrity assessment. The use of HFOM for wants to adopt a weaker criterion than that
encoding NUC was felt by SC-186 of the international standard, there is
committee to be a bad practice, since the nothing preventing them from doing so.
receiver cannot tell whether NUC is an The international standards for NRA should
accuracy or integrity parameter. If we use be based on DO-242A and consistent with
FMS or non-GPS based navigation current best practices. These standards,
solutions as a backup, then there is no such as DO-289 call out the use of NIC and
generally usable relationship between NACp values for each ADS-B application.
accuracy metrics (EPU) and containment The compromise adopted in TSO-C166 to
radius (Rc). The receiver of ADS-B data will use legacy DO-260 equipment is as far as
not be able to tell whether the source of the international community should go in
NIC/NUC is a GPS sensor or not. accomodating existing equipment.
34 GD section I disagree with the comment that ICAO sets a requirement for Suggested resolution: change text Comment KK: I have not taken this advise. The text does not closed
3.3.1 systems in the referenced Annex 22. Interestingly, maybe say that there is a system requirement. An ATS requirement is
Annex 11 will need to add more once ADS-B is used! 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 what closed
184.108.40.206 but this can only occur if they are received. Some aircraft will is commented here is addressed in the preceding sections.
transmit the distinct indicators and others will (not).
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 section Medium A recommendation should be added to supervise multiple use Suggested Resolution- add a subsection 18.104.22.168 with Comment KK: added in V0.8 closed
of aircraft addresses Recommendation: The ATC processing system should
include an algorithm to detect multiple aircraft using the same
39 GD new section 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
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 section Minor A recommendation for additional ground system functionality Suggested Resolution- add a subsection 3.4.6 with A.22.214.171.124 Comment KK: not yet taken, to be discussed during meeting. closed
should be added Recommendation : Additional ATC Processing System Simple reason I do not understand the text
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 ranging
b) Provide ATC users with predictions of inadequate HPL
based upon GNSS satellite geometry, current satellite status
and US Government NANUs.
41 KK new section 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 CLOSED
fact that it is not mandated to be provided by datalink in the 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 A Clarify ANNEX : corrected for V0.8 closed
A.220.127.116.11 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 requirement Version number should be required for DO-260A compliant Suggested resolution: add a version requirement to section 3 Comment KK: v 0.8: sections A.1.3.10 and A.126.96.36.199 added closed
copy ?? systems. Otherwise, you cannot distinguish them from DO- in Annex A
of 260 systems
8 A. Warren A.188.8.131.52 29 There are also non-GPS sensors that could add to the back end of this line "or an accepted GNSS removed closed
qualify for NRA. This reviewer is very alternative integrity containment metric
uncomfortable with the exclusive use of such as specified in DO-242A if the ADS-B
GPS language used throughout this 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 encoding Same resolution as advised in comments. accepted NAC added in subsection closed
of accuracy metrics for position, i.e. NACp.
10 A. Warren A.220.127.116.11 30 Need to add statement regarding encoding Same resolution as advised in comments. a note has been added in ground velocity CLOSED
of accuracy metric NACv for velocity, if part to indicate that velocity integrity (NACv)
available. is out of scope