2050
User Guide
D.4 GSA NMEA Sentence
GPS Mode, Satellites used for navigation, and DOP Data
The GSA sentence identifies the GPS position fix modes, the SV’s used for navigation,
and the DOP values for the position fix.
Example:
$GPGSA,A,3,04,05,07,09,10,17,24,30,,,,,2.5,1.1,2.2*38
FIELD Description
1
Operation Mode
M = Manual, forced to operate in 2D or 3D
A = Automatic, 3D/2D
2
GPS Fix Mode:
1 = fix not available
2 = 2D Fix
3 = 3D Fix
3 thru 14 ID’s of GPS Satellites used in position fix
(‘null’ used for unused fields)
Note: To avoid possible confusion by repetition of satellite ID numbers
when using multiple GNSS systems, the following convention has
been adopted:
a) NavStar GPS satellites are identified by their PRN numbers,
which range from 1 to 32
b) S.B.A.S. (WAAS/EGNOS etc…) has reserved numbers which
range from 33 to 64 to identify their PRN identification which
actually range from 120 to 138. Therefor an ‘offset’ from NMEA
S.B.A.S. SV ID to PRN number is 87. Thus an ENOS PRN
number of 120 minus 87 yields a NMEA SV ID of 33.
c) The numbers 65 to 96 are reserved for GLONNASS satellites.
GLONASS satellites are identified by 64+satellite slot number.
The slot numbers are 1 through 24 for the full GLONASS
constellation of 24 satellites, this gives a range of 65 through 88.
The number 89 to 96 are available if slot numbers above 24 are
allocated to on-orbit spares.
15
Position Dilution of Precision (PDOP) value
16 Horizontal
Dilution
of
Precision (HDOP) value
17
Vertical Dilution of Precision (VDOP) value
18
Check Sum (hexadecimal representation) followed by CRLF
terminator pair
Table D. 6
GSA Sentence Fields
C-44
Summary of Contents for 2050
Page 2: ...1 2 ...
Page 8: ......
Page 14: ...2050 User Guide This Page Intentionally left blank 6 ...
Page 17: ...2050 User Guide Figure 2 2050 Front View Figure 3 2050M Only Back View 2 9 ...
Page 22: ...2050 User Guide This Page Intentionally left blank 2 14 ...
Page 34: ...2050 User Guide This Page Intentionally left blank A 26 ...
Page 42: ...2050 User Guide This Page Intentionally left blank C 34 ...
Page 43: ...2050 User Guide C 35 ...
Page 44: ...2050 User Guide This Page Intentionally left blank C 36 ...
Page 58: ...2050 User Guide This Page Intentionally left blank C 50 ...
Page 60: ...2050 User Guide This Page Intentionally left blank C 52 ...
Page 62: ...2050 User Guide C 54 ...
Page 64: ...2050 User Guide C 56 ...
Page 65: ...2050 User Guide C 57 ...