L3Harris NARDA AMS-8061, User Manual

Page: 209 / 242

SMS Messages and Commands 5-41
The 16 bit figure named Longitude
Fract
is shown as follows:
D15 D14 D13 D12 D11 D10 D9 D8 D7 D6 D5 D4 D3 D2 D1 D0
Byte
23/24
Ten thousandths of a minute
The figure named
Longitude Fract
is a
little
-endian unsigned 16 bit integer and indicates the
fractionary part of the GPS Longitude and it is expressed in Ten-thousandths of a minute.
Merging the previous data
Longitude int
and this figure the full Longitude can be obtained.
If, for example, Longitude int=0x0809 and Longitude Fract=0x16b3 then the GPS Longitude would
be: 8 degree, 09.4777 minute East.
Note that position is valid only when
Flag V of Latitude int is zero.
The figure named
NOB
is shown as follows:
OldData Reserved NOB
D07 D06 D05 D04 D03 D02 D01 D00
Byte 25 Flag 5bit unsigned integer
NOB
is a 5 bit unsigned integer which indicates how many bands have been measured and present in
the current period. Based on this figure, starting from the 33
rd
byte, then 16 bytes for each band will
follow.
If
NOB
is out of the allowed range (1-20), such in case of an empty record,
NOB
should be considered
to be 0 (no bands recorded) and thus the 33
rd
byte is in fact the 1
st
byte of the next record.
OldData
is a bit which flags whether the following data are still the same or are fresh ones.
When OldData is 0 then data have been updated since the previous record otherwise, OldData is ‘1’,
data have not completely updated yet. The latter is the case when the energy is low and the measuring
process is reduced in rate to save power.
Reserved
D07 D06 D05 D04 D03 D02 D01 D00
Byte 26
Reserved
D15 D14 D13 D12 D11 D10 D9 D8 D7 D6 D5 D4 D3 D2 D1 D0
Byte
27/28
Reserved
D15 D14 D13 D12 D11 D10 D9 D8 D7 D6 D5 D4 D3 D2 D1 D0
Byte
29/30