曝光台 注意防骗
网曝天猫店富美金盛家居专营店坑蒙拐骗欺诈消费者
Note.- The term "broadcast" when applied to extended squitter; refers to u spontaneous transmission by the transponder: This
is distinct from the Comm-B broadcast protocol.
2.3.2 AIRBORNEP OSITION J!ORMAT
Type
code
22
The airborne position squitter format shall be formatted as specified in the definition of BDS 0,5. Additional details are specified
in the following paragraphs.
95% Containment radius,
p and v, on horizontal and
venical position error
p210rnorv~15rn
2.3.2.1 COMPACT POSITION REPORTING (CPR) FORMAT (F)
23
24
25 - 27
28
29
30
3 1
Format
Airborne position
In order to achieve coding that is unambiguous worldwide, CPR shall use two format types, known as even and odd. This I-bit
field (bit 22) shall be used to define the CPR format type. F = 0 shall denote an even format coding, while F = I shall denote an
odd format coding (2.6.7).
Altitude type
(2.3.2.4)
GNSS height (HAE)
Reserved for test purposes
Reserved for surface system status
Reserved
Extended squitter aircraft status
Currentlnext trajectory change point
Aircraft operuional coordination
Aircnft operational status
Horizontal protection limit,
(HPL)
HPL 2 25 rn
This 1-bit field (bit 21) shall indicate whether or not the time of applicability of the message is synchronized with UTC time. T = 0
shall denote that the time is not synchronized to UTC. T = 1 shall denote that the time of applicability is synchronized to UTC time.
Synchronization shall only be used for airborne position messages having the top two horizontal position precision categories
(formal types codes 9, 10, 20 and 21).
NUC-P
Resewed
When T = 1, the time of validity in the airborne position message format shall be encoded in the 1-bit F ficld which, in addition to
CPR format type, idicates the 0.2 second time tick for UTC time of position validity. The F bit shall altcrnale between 0 and 1 for
successive 0.2 second time ticks, beginning with F = 0 when the time of applicability is an exact even-numbered UTC second.
The latitude/longitude field in the airborne position message shall be a 34-bit field containing the latitude and longitude of the
aircraft airborne position. The latitude and longitude shall each occupy 17 bits. The airborne latitude and longitude encodings shall
contain the high-order 17 bits of the 19-bit CPR-encoded values defined in 2.6.
Note.- The unambiguous range for the locul decoding of airborne messages is 666 knt (360 NM). The positional accurucjJ
tnaintaiized by the airbonze CPR encoding is appmximately 5.1 nzetres. The latitudehongit~idee ncodi~zgi s also a firnction of the
CPR format value (the "F" bit) described above.
281 11/02
No. 77
Part 1 Annex 10 - Aeronautical Telecommrinicatiuns
2.3.2.3.1 Extrapolating position (when T = I )
If T is set to one, airborne position messages with format type codes 9, 10, 20 and 21 shall have times of applicability which are
exact, 0.2 s UTC epochs. In that case, the F bit shall be 0 if the timc of applicability is an even-numbered 0.2 s UTC epoch, or I
if the time of applicability is an odd-numbered 0.2 s UTC epoch.
Note.- In such a case, an "even-numbered 0.2 s epoch" meum an epoch which occurs an even number of200-ms time intervals
a@er an even-nnmbered UTC second. An "odd-numbered 0.2 s epoch" means an epoch which occurs an odd number of 200-m
time i~atervalsa fter an even-numbered UTC second. Examples of even-numbered 0.2 s UTC epochs are 12.0 s, 12.4 s, 12.8 s, 13.2 s,
13.6 s, etc. Examples of odd-numbered UTC epochs are 12.2 s, 12.6 s, 13.0 s, 13.4 s, 13.8 s, etc.
The CPR-encoded latitude and longitude that are loaded into the airborne position register shall comprise an estimate of the
aircrafuvehicle (AN) position at the time of applicability of that latitude and longitude, which is an exact 0.2 s UTC epoch. The
register shall be loaded no earlier than 150 ms before the time of applicability of the data being loaded, and no later than 50 ms
before the time of applicability of that data.
This timing shall ensure that the receiving ADS-B system may recover the time of applicability of the data in the airborne position
message, as follows:
I) If F = 0, the time of applicability shall be the nearest even-numbered 0.2 s UTC epoch to the time that the airborne position
message is received.
2) If F = 1, the time of applicability shall be the nearest odd-numbered 0.2 s UTC epoch to the time that the airborne position
message is received.
Recommendation.- the airborne position register is updated at its mi~zinzum (every 200 ms), that register should be loaded
100 ms before the tinae of applicability. The register should then be reloaded, with datu upplicable at the next subsequent 0.2 s UTC
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