l
41
DP Message Types (Continued)
Rolls-Royce Custom DP String
The Rolls-Royce Custom DP String adopts NMEA0183 conventions with a minimum length of of 82 characters. When multi-target tracking, multiple messages are emitted per rotor
revolution: one for each target in the tracking group.
$PGNRR,T,YYYY MM DD,HH MM SS.SSS,…N,…I,S,…R.RR,Z
R
.Z
R
Z
R
,…B.BB,Z
B
.Z
B
Z
B
,…Q,±…r.r,±…p.p,…A,XXXX*CC<CR><LF>
Where:
•
$PGNRR
Proprietary header
6 chars
•
T
Type field for CyScan [C]
1 char
•
YYYY MM DD
Real-time clock date at message transmission to DP
10 chars
•
HH MM SS.SSS
Real-time clock time at message transmission to DP
12 chars
•
[NNNN]N
16-bit revolution counter in decimal
1–5 chars
•
[IIII]I
CyScan Responder id [1-5] or RadaScan 16 bit Responder ID
1–5 chars
•
S
Status [V]oid or [N]avigating
1 char
•
[RRR]R.RR
Range in metres
4–7 chars
•
Z
R
.Z
R
Z
R
Range standard deviation in metres
4 chars
•
[BB]B.BB
Bearing in degrees (clockwise from bow)
4–6 chars
•
Z
B
.Z
B
Z
B
Bearing standard deviation in degrees
4 chars
•
[Q]Q
Target brightness [%]
1–2 chars
•
±[r]r.r
Sensor roll in degrees at time of measurement
4–5 chars
•
±[p]p.p
Sensor pitch in degrees at time of measurement
4–5 chars
•
[AAA]A
†
Age of measurement in ms at transmission time
1–4 chars
•
XXXX
Reserved – 16 bit flags in hex
4 chars
•
*
Delimiter
1 chars
•
CC
Checksum
2 chars
•
<CR><LF>
Carriage return and line feed
2 chars
†
The ‘age’ is the accumulated time in milliseconds from the
moment the measurement was made until the moment the
message string is constructed, prior to being transmitted
to the DP system. It effectively gauges the lag through the
system, which may not be constant. Having a value for the
lag allows for subsequent correction of the measurement.
Summary of Contents for CyScan
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