| File
Name |
Approved |
Description
of the Proposed Change |
| Capitalization |
8/6/03 |
During
the review of the proposed UAT SARPS Technical manual, it has
been pointed out that there were inconsistencies in DO-282 in
the treatment of capitalization in some Tables in DO-282 that
reference the names of Fields versus those of subfields.
This comment will affect numerous field names in several
Tables and in paragraph text in future versions of DO-282. |
Flight
Plan ID
UAT-WP-14-02A |
4/7/04 |
As
directed by the FAA ATC branch, Working Paper UAT-WP-14-02A
should be implemented as detailed for adding a Flight Plan ID
reporting element to the Mode Status message.
UAT-WP-14-02A presents a proposal for the new or
revised UAT MOPS text in both the requirements and test
procedures sections and was originally agreed to, and
published by, a subgroup of Working Group 5 on 7 August 2002,
as Working Paper UAT-WP-14-02.
WG-5 agreed during Meeting #19 to make modifications to
UAT-WP-14-02 (thus producing UAT-WP-14-02A) because of
concerns raised in Working Paper UAT-WP-19-02. |
| 1.1 |
4/7/04 |
Terms
of importance in the document such as “shall” and
“should” are not defined.
Proposed
Resolution: Take the definition of these terms from the
ASA MASPS, RTCA DO-289 §2.4, and insert them into §1.1 as a
Note:
Note:
The use of “shall” in the body of this
document indicates a requirement.
The use of “should” indicates a
characteristic that is highly recommended, but is not
required. |
| 1.3 |
4/7/04 |
Descriptions
of FIS-B Services lack Detail and this document implies
multiple uses of the uplink segment including FIS-B and TIS-B.
How will capacity be allocated for those broadcast or
other services anticipated in the uplink segment?
Proposed
Resolution:
WG-5 agreed to insert a reference to the FIS-B MASPS (RTCA
DO-267) and a sentence into §1.3 indicating that: “The
allocation of Ground Uplink capacity to particular types of
broadcast information will be made by the appropriate
regulatory authority.” |
| 1.3.1 |
8/6/03 |
The
last MSO should be numbered 3951 in (1) Figure 1-1, (2)
as the last number in the paragraph following Figure 1-1, and
(3) at the end of the first sentence in the first paragraph of
§1.3.3. |
| 2.1 |
4/7/04 |
Several
subsections of §2.1
make frequent reference to ADS-b. Since ADS-B is one
service or function, such as FIS-B or TIS-B, that is supported
by the UAT equipment, should the references be "UAT"
instead of "ADS-B?"
Proposed
Resolution: Changes from "ADS-B" references to
"UAT" were made in sections 2.1.7, 2.1.9, 2.1.11 and
2.1.12. |
2.1.11
Table 2-1 |
4/7/04 |
During
the review of Table 2-1 involving a discussion of Antenna
Diversity by the ICAO ACP WG-C UAT Subgroup, it was agreed
that Table 2-1 needed to be clarified with respect to the
alternating of antennas.
Proposed
Resolutions:
(1) Change the heading of the two rightmost columns to:
“Intended Antenna Diversity (when Airborne for Classes A
& B0-B1)
(2)
In the column headed “Transmit,” replace the word
“Alternate” with the phrase “Alternating every 2
seconds.”
(3)
In the column headed “Receive,” replace the word
“Alternate” with the phrase “Alternating every
second.” |
| 2.2.2.3 |
8/6/03 |
In
the second line of Note 2, change "frequency offset"
to "frequency deviation" |
| 2.2.2.4 |
8/6/03 |
To
address an issue that arose during the discussion of the UAT
SARPS Technical Manual, it appears that for the sake of
completeness and to rule out some potential anomalous
behavior, §2.2.2.4 should be amended to include a requirement
for the horizontal dimension of the eye opening as well as the
vertical dimension.
Working Paper UAT-WP-15-01 discusses this proposed
change and suggests changing the beginning of the text in §2.2.2.4
to read: “The minimum vertical opening …”
Additionally, add a second paragraph reading “The
minimum horizontal opening of the eye diagram of the
transmitted signal (measured at 978 MHz) shall be no
less than 0.624 microseconds (0.65 symbol periods) when
measured over an entire Long ADS-B Message containing
pseudorandom payload data.” |
2.2.2.5
Figure 2-1 |
4/7/04 |
During
implementation of an operational UAT transmitter, it has
become evident that the “20 dB” corner in the upper curve
of Figure 2-1 during the ramp up and ramp down periods is
needlessly restrictive.
Relief of this restrictive requirement is being
requested.
Proposed
Resolution:
It was agreed by WG-5 during Meeting 21 that the 4 by 4 bit
periods in Figure 2-1, which identify the ramp up and ramp
down periods, would be changed to 2 by 6 bit periods during
the ramp up, and 6 by 2 bit periods during the ramp down.
Corresponding changes will be required in the text of
the requirement and in the test procedures. |
2.2.2.6
Figure 2-2 |
12/8/03 |
(1)
Numerous discussions in the UAT SARPS Subgroup regarding the
use of the terms “necessary” or “occupied” bandwidth,
led to the ultimate resolution of deleting references to
either term.
It was agreed that Figure 2-2 would however be enhanced
by adding a vertical label on the right side of the plot in
Figure 2-2 indicating “250% Boundary.”
(2)
Numerous
discussions in the UAT SARPS Subgroup regarding the use of the
terms “necessary” or “occupied” bandwidth, led to the
ultimate resolution of agreeing to replace
the Note following Figure 2-2 by breaking it into two separate
notes reading:
- 99%
of the power of the UAT spectrum is contained in 1.3 MHz
(+/- 0.65MHz).
This is roughly equivalent to the 20 dB bandwidth.
- Spurious
transmission requirements begin at
+/- 250% of the 1.3 MHz
value, therefore the transmit mask requirement extends to
+/- 3.25 MHz.
|
| 2.2.3.2.2 |
9/17/03 |
Working
Paper UAT-WP-15-08 proposed a format for Information Frames
that would contain the incremental units of information
conveyed in the UAT Ground Uplink Message. This
framework of Information Frames offers the flexibility to
support various kinds of uplink information as well as a
mixture of information types within each Ground Uplink
Message. WG-5 agreed during Meeting #16 with the
recommendations of UAT-WP-15-08 and directed that the
additions proposed in the Working Paper be made in §2.2.3.2.2
and §2.2.3.2.2.2, as appropriate. |
| 2.2.3.2.2.1.4 |
8/6/03 |
During
the review of the proposed UAT SARPS Technical Manual, it was
agreed by the UAT SARPS Subgroup that this paragraph should be
re-written for clarity as: “The “UTC Coupled” flag is a
1-bit (bit 1 of byte 7) flag used to indicate whether or not
the ground station 1 Pulse Per Second timing is valid.
An encoding of ONE represents that the Ground Station
is UTC-Coupled (§2.2.5.1).
An encoding of ZERO represents that the Ground Station
is not UTC-Coupled (§2.2.5.2).” |
2.2.4.2
Table 2-7 |
2/9/04 |
The
number of Bytes associated with the TARGET STATE (TS) Payload
Element is incorrectly stated at 5, when it should be four
(4).
Proposed
Resolution:
Change the number of Bytes for the TARGET STATE Payload
Element to four (4). |
| 2.2.4.5.1.3.2(1) |
4/7/04 |
During
a review of this section by the ICAO ACP WG-C UAT Subgroup, it
was suggested that this requirement be clarified to indicate
that the ADDRESS QUALIFIER can only be set to ONE (indicating
the use of a self-assigned, temporary address) if the
participant is NOT receiving ATC Services.
Proposed
Resolution: Revise the entire requirement paragraph to
read as follows: “An “ADDRESS QUALIFIER” value of ONE
(binary 001) shall indicate that the message is an
ADS-B Message from an aircraft that is not receiving ATC
services, and that the “ADDRESS” field holds the
transmitting aircraft’s self-assigned ownship temporary
address.
An “ADDRESS QUALIFIER” value of ONE shall not
be used when the “Receiving ATC Services Flag” (§2.2.4.5.4.13.3)
is set to ONE, indicating that the Participant is receiving
ATC services.” |
| 2.2.4.5.1.3.2(2) |
12/8/03 |
The
ground systems folks have a strong requirement that, if a
participant uses a Temporary Address, that it always be the
same address within one flight segment, regardless of how many
times the pilot toggles the ICAO versus Temporary selection.
The reason being that having multiple Temporary
addresses from the same participant in a short period of time
(less than 1 minute coast time) can cause bogus conflict
alerts on the ATC controller displays.
Proposed Resolution:
At the top of page 30 where the values of M(1), M(2)
and TIME are described: change “at
the time
the temporary address option is selected” to “ the
first time
the temporary address option is selected |
| 2.2.4.5.2.1.a |
8/6/03 |
In
paragraph (a), second line, change: “encode the latitude of
the ADS-B Transmitting System” to “encode the
latitude provided to the ADS-B Transmitting System” |
| 2.2.4.5.2.1.b |
8/6/03 |
In
paragraph (b), second line, change: “encode the latitude of
the ADS-B Transmitting System” to “encode the
longitude provided to the ADS-B Transmitting System” |
2.2.4.5.2.1.c
Table 2-12 |
12/8/03 |
Two
errors have been discovered in Table 2-12 during
implementation of the UAT Capstone GBT.
- For
the bit definition “1011 1111 1111 1111 1111 1111” the
Longitude should be “(90+LSB) degrees West”
- For
the bit definition “1100 0000 0000 0000 0000 0000” the
Latitude should be
”+90 degrees (South Pole)”
|
2.2.4.5.2.1.d
Figure 2-5 |
8/6/03 |
During
the review of the proposed UAT SARPS Technical Manual, it was
agreed by the UAT Subgroup that the following changes would be
made to Figure 2-5 for clarity: (1) In the lower half of the
figure, change "270 degrees E = 90 degrees W" to
"90 degrees W" (2) In the lower half of the figure,
add a label at the center of the globe indicating "N
Pole" |
| 2.2.4.5.2.2 |
9/17/03
and
12/8/03 |
(1)
When
transmission of Pressure Altitude is inhibited (i.e. made
not-available), does that force the Altitude Type field to
assume the '1' value (i.e. Geometric Altitude becomes
Primary)? The
question arises due to a lack of clarity in the last sentence
of the 3rd paragraph of this section (i.e. "If only one
ALTITUDE TYPE is available, then that Altitude shall be
indicated in the "ALTITUDE TYPE" field").
But note that the ALTITUDE TYPE field always refers to
both types of altitude, by assigning one of them as
"primary" (though it doesn't use that word), and the
other as the SECONDARY ALTITUDE. Proposed
Resolution: Change the last sentence of the 3rd paragraph
to: "
If
only one altitude source is available, then the use of that
Altitude shall be reflected in both the “ALTITUDE TYPE”
and “ALTITUDE” fields.”
(2)
As documented in Working Paper UAT-WP-18-01, in some cases,
the UAT MOPS text includes phrases such as "if
available" to describe the appropriate processing of
Optional Input Elements detailed in Table 2-64. A
suggested clarification to the Altitude Type Selection,
Element #5 in Table 2-64 is to modify §2.2.4.5.2.2,
third paragraph, second sentence by replacing the first five
words as follows: "A means shall be provided
If an Altitude Type Selection Input is available, it shall
be used ..."
|
| 2.2.4.5.2.4 |
2/9/04 |
As
a result of the need to ensure that a transmitting system
passes through the received NIC and NAC, it was decided during
Meeting #20 of Working Group 5 that there would be no
extrapolation of NIC or NAC.
Proposed
Resolution:
Add the following sentence on to the end of the existing
requirement in this section: “The value of the NIC parameter
shall be the highest value in
Table 2-15 consistent with the NIC Input with the
exception that if the NIC Input is consistent with a value of
“9,” “10” or “11” and the ADS-B equipment does not
support the timing requirements for the Precision condition
(§2.2.7.2.2), a NIC value of
“8” shall be transmitted.”
|
2.2.4.5.2.5.1
including
Table 2-17
through
2.2.4.5.2.5.2
including
Table 2-18 |
11/6/03 |
As
initiated by the review of the UAT SARPS Technical Manual, and
as documented in Issue Paper
71, the errors in the
determination and validation of the Air/Ground State were
originally defined in DO-260 and were carried forward to the
ADS-B MASPS (DO-242A), the UAT MOPS (DO-282), and the revised
1090 MHz ES MOPS (DO-260A).
The RTCA SC-186 Plenary on 9/18/03 established an ad
hoc working group to resolve the errors and to recommend
language for the draft ASA MASPS (DO-289).
Working Paper UAT-WP-17-03 details the text
agreed to by that ad hoc working group, and which was
additionally reviewed and agreed to by the Technical Subgroup
of the ICAO ACP WG-B SCRSP for inclusion in the revision of
the 1090 SARPS.
Proposed
Resolution:
It was recommended that the text of UAT
WP-17-03, as included
in the ASA MASPS (DO-289), be adopted to replace the text and
tables of these referenced paragraphs in DO-282 |
| 2.2.4.5.2.6.2 |
12/8/03 |
As
documented in Working Paper UAT-WP-18-01, in some cases, the
UAT MOPS text includes phrases such as "if
available" to describe the appropriate processing of
Optional Input Elements detailed in Table 2-64.
A suggested clarification to the Ground Speed Element
#12 in Table 2-64 is to modify the first sentence of §2.2.4.5.2.6.2
by changing the end of the sentence by inserting the phrase
“if Ground Speed is available.”
|
| 2.2.4.5.2.6.4 |
12/8/03 |
As
documented in Working Paper UAT-WP-18-01, in some cases, the
UAT MOPS text includes phrases such as "if
available" to describe the appropriate processing of
Optional Input Elements detailed in Table 2-64.
A suggested clarification to the Track Angle Element
#13 in Table 2-64 is to modify the end of the first sentence of §2.2.4.5.2.6.4
as follows: "if not available otherwise
Track Angle shall be encoded, if available."
|
| 2.2.4.5.2.7.1.1 |
12/8/03 |
As
documented in Working Paper UAT-WP-18-01, in some cases, the
UAT MOPS text includes phrases such as "if
available" to describe the appropriate processing of
Optional Input Elements detailed in Table 2-64.
A suggested clarification to the Geometric Vertical
Rate, Element #16 in Table 2-64, is to insert the words “if
available” after “Geometric source” in the second
paragraph of §2.2.4.5.2.7.1.1.
|
2.2.4.5.2.7.2
Table 2-35 |
8/6/03
and
12/8/03 |
Working
Paper UAT-WP-15-03 describes the request to simplify the
“Length” and “Width” Category columns by eliminating
the left side of all of the inequalities.
Working
Paper UAT-WP-18-03 further describes a change to Codes 14 and
15 as per agreement in the ASA MASPS (RTCA DO-289).
|
2.2.4.5.3
Table 2-38 |
8/6/03 |
During
the review of the proposed UAT SARPS Technical Manual, it was
requested that a “Note” be added after Table
2-38, reading: “Design of the TIS-B Ground Subsystem is
in a preliminary phase.
The message structure in Table 2-38 may evolve as this
design matures.” |
| 2.2.4.5.3.1 |
8/6/03 |
During
the review of the proposed UAT SARPS Technical Manual, it was
requested that the “Notes” in this section
be revised to be clearer.
The proposed Notes would read: “1. The “UTC”
field shown in Table 2-11 for the State Vector Element is not
provided for TIS-B transmissions.
The “UTC Coupled” status of the ground station
transmitting TIS-B information is available in the UAT Ground
Uplink Message (§2.2.3.2.2.1.4)” and
2. The application that uses TIS-B reports is assumed to make
appropriate checks for a TIS-B Site ID of value ZERO.
If the Address Qualifier shown in Table 2-10 indicates
that this is a TIS-B Message, and the TIS-B SITE ID indicates
a value of ZERO, an error condition is indicated.” |
| 2.2.4.5.4.2 |
4/7/04 |
Use
of "must" in reference to the Call Sign characters
is confusing, since it implies that the UAT equipment performs
some action.
UAT equipment does not validate the data it is
provided, and the Call Sign that is provided to the UAT is
only re-formatted into Radix-40 format.
Also, use of the term "left-most" is
non-descriptive without specifying the context.
Proposed
Resolution:
Re-write the 1st paragraph as follows:
The
Call Sign field consists of eight characters.
Each character shall be represented as Base-40 code
values as shown in Table 2-41.
The left-most character (as depicted on a cockpit
display unit) corresponds to Character #1.
Add
the following Note:
Note:
The formatting of the Call Sign field is outside the scope of
this document.
It is expected that the 'space' character will only be
used as trailing pad characters.
Any characters that are not provided to the UAT
equipment may be encoded as either the "not
available" code, or the "space" character. |
2.2.4.5.4.5
Table 2-43 |
9/17/03 |
The
UAT MOPS at present contains no requirements on use of the
MOPS Version Number field by an ADS-B receiver.
The only requirement is that it be transmitted, and
that it be the value ONE.
At a minimum, some guidance on how to use the Version
Number would be appropriate. Proposed
Resolution: Add Note 2 below Table 2-43 stating:
Note:
“It
is assumed that future changes to the UAT MOPS will be
backward-compatible with previous versions.
Given this, the function of the UAT MOPS Version Number
is to support forward compatibility with future revisions of
these MOPS. For
example, future MOPS Version UAT equipment may safely assume
that it may ignore any "reserved" data fields in
received messages from the earlier versions of these MOPS.
Also, future MOPS Version equipment should ignore the
content of all reserved fields shown in the original RTCA
DO-282, until the receiving equipment obtains a participant's
MOPS Version number. Fields
that are defined in a earlier version of these MOPS may be
relied upon to remain consistent with later MOPS versions.” |
| 2.2.4.5.4.9 |
2/9/04 |
As a
result of the need to ensure that a transmitting system passes
through the received NIC and NAC, it was decided during
Meeting #20 of Working Group 5 that there would be no
extrapolation of NIC or NAC.
Proposed
Resolution:
Add the following sentence on to the end of the existing
requirement in this section: “The value of the NACP
parameter shall be the highest value in Table 2-45
consistent with the NACP Input with the exception
that if the NACP Input is consistent with a value
of “10” or “11” and the ADS-B equipment does not
support the timing requirements for the Precision condition
(§2.2.7.2.2), a NACP
value of “9” shall be transmitted.” |
| 2.2.4.5.4.12.2 |
8/6/03 |
As
per discussion in Working Paper UAT-WP-15-04, there appears to
have been an inconsistency between the TCAS equipment
interface requirements in the ADS-B MASPS and the UAT MOPS.
This analysis is supported by discussion of the UAT
SARPS Subgroup and the proposed changes are consistent with
changes made to the UAT SARPS Technical Manual.
Following the suggested changes in UAT-WP-15-04, the
sentence in the ADS-B MASPS §3.4.4.9.1, which contains the
requirement R3.102-B, will be inserted prior to the last
sentence in the first paragraph of §2.2.4.5.4.12.2.
Additionally, in the second existing paragraph, the
last word will be changed from “ZERO” to “ONE.”
Finally, the “Note 1” from the ADS-B MASPS §3.4.4.9.1
will be inserted after the second paragraph. |
| 2.2.4.5.4.13.1 |
8/6/03 |
As
per discussion in Working Paper UAT-WP-15-04, there appears to
have been an inconsistency between the TCAS equipment
interface requirements in the ADS-B MASPS and the UAT MOPS.
This analysis is supported by discussion of the UAT
SARPS Subgroup and the proposed changes are consistent with
changes made to the UAT SARPS Technical Manual.
Following the suggested changes in UAT-WP-15-04, the
sentence in the ADS-B MASPS §3.4.4.10.1, which contains the
requirement R3.110-B, will be inserted prior to the last
sentence in the first paragraph of §2.2.4.5.4.13.1.
Additionally, in the second existing paragraph, the
last word will be changed from “ZERO” to “ONE.” |
| 2.2.4.5.4.14 |
12/8/03 |
As
documented in Working Paper UAT-WP-18-01, confusion over the
scope of this True/Magnetic Flag is easy to achieve, since it
exists in the Mode Status Element, but refers to fields in the
Target State Element in a different transmitted message.
Proposed Resolution: Change the title of §2.2.4.5.4.14
to “True/Magnetic Indicator Flag for the Target State
Element” and alter the text of paragraph one to clarify the
use of this ‘Indicator’ in support of the Target State Element. |
2.2.4.5.6.1
Table 2-52 |
12/8/03 |
As
documented in Working Paper UAT-WP-18-01, the use of “Track
Heading” is incorrect inside Table 2-52, and should be changed to “Target
Heading.” |
| 2.2.5.1 |
8/6/03 |
During
the review of the proposed UAT SARPS Technical Manual, it was
requested by the UAT SARPS Subgroup that the second sentence
of the “Note” in this section be re-written
as: “Short term GNSS outages are
mitigated by UAT ground infrastructure providing timing
information and/or by the ability of UAT avionics to prevent
Airborne UAT Transmitting Subsystems from transmitting in the
Ground Uplink Segment for a minimum of 20 minutes in the
absence of GNSS (§2.2.5.2 [d]).” |
| 2.2.6.1.2 |
8/6/03 |
In
Note 2 under Table 2-63, second line change “Trajectory
State” to “Target State” |
| 2.2.6.2.1 |
2/9/04 |
Working
Paper UAT-WP-20-03
identifies a problem with the test procedure Table 2-97 and
indicates that the problem is a need for a clarification to
the requirement in §2.2.6.2.1.
Proposed
Resolution:
As identified in Working Paper UAT-WP-20-03,
in the second paragraph of §2.2.6.2.1, which defines the
transmission timing for the current UAT frame m,
in front of the existing equation for R(m),
place the phrase “When m>=1,” and in front of
the equation for R(0), place the phrase “When m=0,” |
| 2.2.6.2.2 |
12/8/03 |
Clarification
is required as to whether the “1 second UTC epoch,”
referenced in the 3rd line of the first paragraph,
is specified as the reference point for Tx MSO timing, is the
Time Mark signal presented to the equipment, as specified in
§2.2.5 and Figure 2-6, page 64.
Using the Time Mark signal as presented to the
equipment would remove any implied requirement for the UAT
equipment to compensate for errors in an externally supplied
1PPS time mark signal.
Proposed Resolution: Insert the phrase “as
supplied to the UAT Transmitting Subsystem”
in the third line of the first paragraph after the words
‘UTC epoch.’ |
| 2.2.7.1.b |
12/8/03 |
As
documented in Working Paper UAT-WP-18-01, §2.2.7.1
provides the requirements text for Table 2-64.
Subparagraph "b" describes how the
"Optional" input elements are handled. As
written, the text is most applicable to Data Elements that
have a corresponding Field in the transmitted message
payload. The text of "b" does not provide
sufficient guidance for Input Elements that are used by the
UAT Transmitting Subsystem, but do not necessarily map
one-for-one into a transmitted Field.
Proposed
Resolution: Change the period ending the sentence of
subparagraph "b" into a comma and to the end add the
phrase: "or be processed using the 'data unavailable'
procedures related to that element." |
2.2.7.1
Table 2-64 |
(1) 8/6/03
(2) 12/8/03
|
(1)
Element
#13 (Track Angle) is listed as Mandatory for Class A1L.
The requirement in §2.2.4.5.2.6 is that while in the
GROUND state, the State Vector data includes Ground Speed and
either Heading or Track Angle.
It makes little sense for Ground Speed and Heading
interfaces to be Optional, but a Track Angle interface to be
Mandatory, as shown in Table 2-64. Proposed
Resolution: Mark the Track Angle interface as Optional for
A1L.
(2)
As documented in Working Paper UAT-WP-18-01, the existing text
of §2.2.4.5.2.7.2 does not define any “data unavailable”
condition for the Aircraft/Vehicle Length and Width Code, and
the Position Offset Applied fields.
This is consistent with Table 2-64 showing a “n/a”
in the Data Lifetime column, since this is a static data for a
given A/V.
However, these Input Data Elements are designated as
Optional for the A0 and A1L equipment classes.
Though the ADS-B MASPS (DO-242A §3.4.4.6) allows
certain participants (Length < 25 meters and Width <= 34
meters) to not transmit the A/V Length and Width Code, the UAT
MOPS as written makes no provision for not sending these
codes.
In addition, the UAT MOPS does not provide any guidance
for the use of these codes in the case where these inputs are
Optional and not provided.
Proposed Resolution: Modify Table 2-64 to make
A/V Length, Width and POA Fields Mandatory for all aircraft
equipment classes. |
| 2.2.7.2.2 |
1/12/04 |
Subparagraph
‘a’ requires the Time of Applicability of the ALTITUDE
field, when in the Precision condition, to be the current 0.2
second epoch.
However, many aircraft do not have encoding pressure
altimeters that output at a 5 Hz rate.
Since current encoding pressure
altimeters do not provide Time of Applicability, the practical
effect of this requirement might be to preclude the
implementation of the Precision condition completely.
This would largely dilute the benefits for surface
operations available from use of WAAS-enabled GPS. This
problem is further discussed in Working Paper UAT-WP-19-11.
Proposed
Resolution:
Revise subparagraph ‘a’ by inserting the phrase
“when it conveys a Geometric Altitude” after reference to
the “ALTITUDE” field.
Revise subparagraph ‘b’ by deleting the reference
to the LATITUDE, LONGITUDE and ALTITUDE fields, and simply
state that “All other ADS-B Message fields that are provided
at the ADS-B equipment …” |
| 2.2.7.2.3 |
(1)
2/9/04
(2) 4/7/04
|
(1)
As
a result of the need to ensure that a transmitting system
passes through the received NIC and NAC, it was decided during
Meeting #20 of Working Group 3 that there would be no
extrapolation of NIC or NAC when the system is in the
“Non-UTC Coupled” condition.
Proposed
Resolution:
(1) Delete subparagraph “b,” and combine subparagraph
“a” with the entry sentence. (2) Modify
the first sentence of the Note to read: “A UAT Transmitting
Subsystem that is capable of meeting the timing requirements
of §2.2.7.2.2 makes no adjustment to the NIC or NAC
that it receives as inputs.”
(2)
During
a review of the proposed change to this section by the ICAO
ACP WG-C UAT Subgroup, it was agreed that first sentence of
the Note should not be deleted, but rather should be
changed to be clarified.
Proposed
Resolution:
Modify the first sentence of the Note to read: “A UAT
Transmitting Subsystem that is capable of meeting the timing
requirements of §2.2.7.2.2 makes no adjustment to the
NIC or NAC that it receives as inputs.” |
| 2.2.8.2.1.1 |
(1) 8/6/03
(2) 2/9/04
|
(1)
In the title, change “is Desired” to “As Desired"
(2)
In §2.2.8.2.1.1, as identified in Working Paper UAT-WP-20-05A,
the receiver sensitivity requirement is specified under three
simultaneous worst-case conditions of signal degradation.
This triple-worst-case specification is an
unnecessarily tight constraint, since only a statistically
small number of participants will operate on all three margins
simultaneously.
Proposed Resolution: (a) In the first paragraph, delete
the word “simultaneous.”
(b) Replace both subparagraphs with relaxed text. |
| 2.2.8.2.1.2-1 |
8/6/03 |
In
the title, change “is Desired” to “As Desired” |
| 2.2.8.2.1.2-2 |
(1) 8/6/03
(2) 2/9/04
|
(1)
To conform to a proposed addition to the UAT SARPS Technical
Manual, insert a new paragraph entitled “Basic UAT ADS-B
Message As Desired Signal.”
Copy the existing text of §2.2.8.2.1.1 for “long”
and change the desired signal level to “-94dBm.”
(2)
In §2.2.8.2.1.2, as identified in Working Paper UAT-WP-20-05A,
the receiver sensitivity requirement is specified under three
simultaneous worst-case conditions of signal degradation.
This triple-worst-case specification is an
unnecessarily tight constraint, since only a statistically
small number of participants will operate on all three margins
simultaneously.
Proposed Resolution: (a) In the first paragraph, delete
the word “simultaneous.”
(b) Replace both subparagraphs with relaxed text. |
| 2.2.8.2.1.3 (new) |
(1) 8/6/03
(2) 2/9/04
|
(1)
The
existing §2.2.8.2.1.2 will be renumbered to §2.2.8.2.1.3.
However, in the published §2.2.8.2.1.2, in order to
have consistency with the ICAO VDL documentation, it is
proposed that subparagraph (a) be changed from a value of 600
knots to a value of 850 knots, and that a Note
be added under (a) stating that:
Note:
The 850 knot ground station closure rate is derived from a 600
knot true air speed, added to a 250 knot worst-case wind
velocity.
The 1200 knot air-to-air closure remains valid because
both aircraft are assumed to be within the same air mass, so
the wind velocity makes no difference to the closure rate.
(2)
In the new §2.2.8.2.1.3, as identified in Working Paper UAT-WP-20-05A,
the receiver sensitivity requirement is specified under three
simultaneous worst-case conditions of signal degradation.
This triple-worst-case specification is an
unnecessarily tight constraint, since only a statistically
small number of participants will operate on all three margins
simultaneously. Proposed Resolution: (a) In the
first paragraph, delete the word “simultaneous.”
(b) Replace both subparagraphs with relaxed text.
|
| 2.2.8.2.2 |
2/9/04 |
As
identified in Working Paper UAT-WP-20-05A,
there is a need to clarify that the stated dynamic range
requirement applies to reception of Long ADS-B Messages only.
Proposed
Resolution:
Insert the words “for Long ADS-B Messages” after
the word “rate” in the first line of the initial
paragraph. |
| 2.2.8.2.3 |
2/9/04 |
As
identified in Working Paper UAT-WP-20-05A,
there is a need to clarify that the desired signal for this
requirement is the Long ADS-B Message.
Additionally, it is necessary to reduce the minimum
rejection ratio for the +1.0 MHz case in Table 2-65 by 3 dB
(from 18 dB to 15 dB). |
| 2.2.8.2.7 |
11/6/03 |
The
requirements for processing ADS-B sync Trigger events do not
provide a minimum requirement for the time interval between
overlapping message events. (i.e. gives no guidance on the
rate of overlapping messages).
This implies that all successful messages may be
overlapping messages.
The test procedure (§2.4.8.3.3, page 252) presents
without justification that 100 overlapping messages per second
is sufficient to validate this requirement.
Proposed
Resolution:
Working Paper UAT-WP-16-02
raised the issue of whether or not there should be an addition
to the UAT MOPS to cover minimum requirements for processing
synchronization trigger events at a high rate.
Working Paper UAT-WP-17-02
recommended that a new requirement be added at §2.2.8.2.7and
that a new test procedure be added at §2.4.8.2.7. |
| 2.2.8.3.1.1 |
2/9/04 |
The
requirement of subparagraph “a” indicates that if the Reed
Solomon decoder determines that there are no residual errors
after completing the decoding process “AND any of the
first 5 bits of the payload has a non-zero value,”
then a Successful Message Reception shall be declared.
During Meeting 20 of WG-5, it was agreed that the
requirement requiring any of the first five bits to be
non-zero was not a valid requirement.
Proposed
Resolution:
Remove the text of the requirement in subparagraph “a”
that is shown above as underlined and bold.
Add a note explaining this as note #2 in the set of
notes at the end of these requirements. |
| 2.2.8.3.5 |
12/8/03 |
During
the review of the UAT SARPS Technical Manual, it was agreed by
the UAT SARPS Subgroup that in writing this requirement, we
forgot about the reference point for the measurement.
Therefore, to conform to a proposed change to this
requirement in the UAT SARPS Technical Manual, it is proposed
to revise subparagraph (c) to read: “Accuracy of +/- 500
nanoseconds relative to the optimum sample point of the first
bit of the synchronization sequence applied at the receiver
terminals for UAT equipment using either an internal or
external UTC Coupled time source.” |
| 2.2.12 |
(1)
12/8/03
(2)
1/12/04
(3)
4/7/04
|
(1)
During
the review of the UAT SARPS Technical Manual, it was agreed by
the UAT SARPS Subgroup that the title of this requirement in
the Tech Manual would be changed to “Mutual Suppression
Pulses,” and that the text of this section will be changed
to be:
a.
UAT equipment shall
provide an output suitable for sending suppression signals.
b.
UAT equipment shall
not respond to suppression signals.
Note:
UAT equipment is not to inhibit or delay its transmissions
based on suppression signals.
There is no need to desensitize the UAT receiver based
on suppression signals.
(2)
As documented in Working Paper UAT-WP-19-04, it becomes
necessary to provide a boundary around the suppression
pulse. Proposed Resolution: Add the following on
to the end of subparagraph 'a:' "The suppression
duration shall begin no later than the start of the
ADS-B Message Transmission Interval defined in §2.2.2.5
and no earlier than 2 microseconds prior to the start of the
ADS-B Message Transmission Interval. The suppression
duration shall end 10 +/- 1 microseconds from the end
of the ADS-B Message Transmission Interval."
(3)
After further Working Group discussion, it was agreed that the
first paragraph should be revised and replaced in its
entirety, as follows:
“UAT
equipment shall provide an output signal suitable for sending
suppression signals. The UAT equipment shall provide a mutual
suppression signal whenever the transmitter output power
exceeds -20 dBm. In
addition, the suppression signal shall not become active prior
to 5 microseconds before the start of the ADS-B Message
Transmission Interval defined in §2.2.2.5, and the
suppression signal shall not remain active later than 5
microseconds after the end of the ADS-B Message Transmission
Interval defined in §2.2.2.5.”
|
| 2.2.14.3 |
1/12/04 |
An
option to use a frequency diplexer is provided to allow
sharing of a single antenna on an aircraft between the ATCRBS/Mode
S Transponder and the UAT Subsystem. New requirements
are provided in 2.2.14.3, with the appropriate test procedures
provided in 2.4.14.3 and further supporting information in
Appendix E. |
| 2.2.15.2.1.3 |
1/12/04 |
The
existing text of this section appears to be a cut-and-paste
from §2.2.15.1.1.3, and it appears that it was not completely
edited for content, because it still includes references to
“data input interfaces” that are required for the report
assembly function, and that does not make a lot of sense.
Proposed
Resolution:
Replace the text of this section with the following:
”The ADS-B Receiving Subsystem input processing function shall
be capable of efficiently processing all necessary interfaces
as required for Receiver Message Processing and Report
Assembly, as defined in §2.2.8.3, §2.2.9 and §2.2.10.” |
2.3.1
Table 2-70 |
8/6/03 |
To
conform to a proposed addition to the UAT SARPS Technical
Manual, it is proposed that we add a new paragraph §2.3.2.12
entitled “Basic UAT ADS-B Message As Desired Signal.”
Indicate appropriate tests for the new §2.3.2.12.
Increase all of the following paragraph numbers in the
2.3.2.13 through 20 range. |
| 2.3.2.11 |
8/6/03 |
In
the title, change “is Desired” to “As Desired” |
| 2.3.2.12-1 |
8/6/03 |
In
the title, change “is Desired” to “As Desired” |
| 2.3.2.12-2 |
8/6/03 |
To
conform to a proposed addition to the UAT SARPS Technical
Manual, it is proposed that we add a new paragraph entitled
“Basic UAT ADS-B Message As Desired Signal.”
Reference the correct test procedure paragraph. |
| 2.4.2.1 |
12/8/03 |
Working
Paper UAT-WP-15-13 raises concerns about using the root raised
cosine filter when setting up the Vector Signal Analyzer for
this test procedure.
Further investigation will be performed by various
individuals and reported on during the 17 September 2003 WG
Meeting #16 so that a conclusion may be reached on what
change, if any, to apply here.
Proposed Resolution: For the measurement filter
selection, replace "root raised cosine" with
"low pass". |
| 2.4.2.4 |
(1) 8/6/03
(2) 12/8/03 |
|
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