V A L A V I O N I C S L T D
N A V 2 0 0 0 N A V I G A T I O N S Y S T E M
I N S T A L L A T I O N A N D O P E R A T O R ’ S M A N U A L
Pre-Release Issue
Page 27 of 29
Sept. 2013
100. –100 indicates full deflection upwards, 0 indicates no reflection,
and 100 indicates full deflection downwards.
ff......................... Flags. Eight bits for HNAV and VNAV related flags, represented as
two encoded hex digits.
Bit 1 (1sb) Back Course enable (1 = enabled)
Bit 2
Localizer detect (1 = using localizer)
Bit 3
FROM flag (1 = From)
4
Bit 4
TO flag (1 = To)
Bit 5
GSI superflag (1 = valid)
Bit 6
GSI valid (1 = valid)\
Bit 7
NAV superflag (1 = valid)
Bit 8 (msb) NAV valid (1 = valid)
Example message:
$PMRRV21817??:<chksm><CR><LF>
This message indicates a full left CDI deflection (-127), a full up GSI deflection (127), both the
GSI and NAV flags/superflags are valid, TO flag set, FROM flag not set, using a localizer, with
no back course enable.
DECODED OBS SETTING
This message outputs the current OBS setting, which may be read from an external resolver or
from user input to the front panel. After power up this message will be sent at a 10 Hz rate.
Message format:
“V” ..................... Message class. This is a VHF NAV message.
“22”.................... Message identifier.
v ......................... Valid flag. “0” = OBS invalid/not present, “V” = OBS setting is valid.
ddd ..................... Three digit OBS setting, in degrees. Values are in the range of “000” to
“359”.
Example message:
$PMRRV22V170<chksm><CR><LF>
A valid OBS setting of 170 degrees.
RADIAL FROM ACTIVE VOR
This message outputs the current bearing from the active VOR station. This message will be
output even when a localizer is being tracked by the NAV receiver. In this case, the bearing will
be marked as invalid. After power up this message will be sent at a 10 Hz rate.
Message format:
“V” ..................... Message class. This is a VHF NAV message.
“23”.................... Message identifier.
v ......................... Valid flag. “0” = bearing not valid, “V” = bearing is valid.
dddf .................... Bearing to a resolution of 1/10
th
of a degree. ddd = three digit bearing
in degrees, ranging from “000” to “359”. f = 1/10
th
of a degree.
Example message:
$PMRRV23V1654<chksm><CR><LF>
A valid bearing of 165.4 degrees FROM the active VOR station.
4
The TO and From flag can not both be 1, indicating that they are both valid. They can both be zero,
indicating that neither is valid. This situation will occur whenever the receiver determines that it is within
the “cone of confusion” directly over the VOR, or when no signal is being received.
