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5.6.1.4 GPS satellites active and DOP (GSA) .
This message contains the Jupiter receiver's
operating mode, satellites used for navigation, and
DOP values. The contents of the 'GSA' message
are described in Table 3-48.
Sample message:
$GPGSA,A,3,04,16,09,24,,,,,3.33,1.96,2.70*
06
3.6.1.5 GPS satellites in view (GSV)
This message contains the number of satellites
in view, PRN numbers, elevation, azimuth,
Message ID: GSA
Rate: variable
Fields: 17
Field No.
Symbol
$_GSA
1
OP _MODE
2
FIX_MODE
3-14
SATN
15
PDOP
16
HDOP
17
VDOP
CKSUM
<CR><LF>
Note 1: Mode (operating), M = manual (forced to operate in 3D mode), A = automatic (can automatically switch between 2D and
3D).
Note 2: Mode (fix), 1 = fix not available, 2 = 2D, 3 = 3-D
Note 3: DOPs are based on the set of satellites above the elevation mask angle, this may differ from the set used for navigation.
Message ID: GSV
Rate: variable; defaults to 0.5 Hz
Fields: 19
Field No.
Symbol
$_GSV
1
MAX_MSG
2
NUM_MSG
3
NUM_SATS
4
SAT_PRN
5
ELEV
6
AZ
7
SNR
8-11
...
12-15
...
16-19
...
CKSUM
<CR><LF>
Note 1: The visible satellites may include one or more that are below the horizon. Since NMEA does not account for negative
elevation angles, the elevation field will be null for these satellites.
Note 2: Azimuth and elevation are null when the satellite is in track, but a visible list is not available.
MN002000A © 2004 Navman NZ Ltd. All rights reserved. Proprietary information and specifications subject to change without notice.
Field description
Start of sentence and address field
Mode (Note 1)
Mode (Note 2)
PRNs of satellites used in solution (null for unused fields)
Position dilution of precision (Note 3)
Horizontal dilution of precision (Note 3)
Vertical dilution of precision (Note 3)
Checksum
Sentence terminator
Table 3-48 GSA message (GPS DOP and active satellites)
Field description
Start of sentence and address field
Total number of messages (1 to 3)
message number (1 to 3)
Total number of satellites in view
Satellite PRN number (Note 1)
Elevation in degrees (90 degrees maximum) (Note 2)
Azimuth in true degrees (000 to 359) (Note 2)
SNR (C/No) 00 to 99 dB, null when not tracking
2nd satellite PRN number, elevation, azimuth, SNR (Note 1)
3rd satellite PRN number, elevation, azimuth, SNR (Note 1)
4th satellite PRN number, elevation, azimuth, SNR (Note 1)
Checksum
Sentence terminator
Table 3-49 GSV message (GPS satellites in view)
and Signal-to-Noise Ratio (SNR) values. Each
transmission identifies up to four satellites (max);
additional satellite data is sent in a second or third
message. The total number of messages being
transmitted and the number of the message being
transmitted is indicated in the first two fields. The
contents of the 'GSV' message are described in
Table 3-49.
Sample message:
$GPGSV,2,1,07,24,60,216,50,20,47,135,47,12,
40,020,47,16,36,319,46*75
Field type
Example
$GPGSA
a
A
x
3
xx,xx,....
04, 16, 09, 24...
x.x
3.33
x.x
1.96
x.x
2.70
*hh
*06
<CR><LF>
Field type
Example
$GPGSV
X
2
X
1
Xx
07
Xx
24
Xx
60
Xxx
216
Xx
50
xx, xx, xxx, xx
...
xx, xx, xxx, xx
...
xx, xx, xxx, xx
...
*hh
*75
<CR><LF>
50
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