GSV messages will be generated. Total number of messages being transmitted and the
number of the current message are indicated in the first two fields of the message. If
multiple GPS, GLONASS, etc. satellites are in view, then separate GSV messages with
Talker ID GP for GPS satellites in view, GL for GLONASS and GA for GALILEO satellites will
be generated.
GLL – Geographic Position – Latitude/Longitude. The GLL message contains the latitude
and longitude of the present position, the time of the position fix and the status.
3.5 GNS – GNSS Fix Data. The GNS message contains Time, Position Fix and related data
for single or combined navigation satellite systems (GNSS). If the data is calculated from
multiple satellite systems in differential mode then several GNS messages are generated.
The first message with Talker ID “GN” will be followed by separate messages with Talker
ID “GP”, “GL” etc. to report the data calculated from the individual systems. Only one GNS
message is generated in differential mode with SBAS.
ZDA – Time & Date. The ZDA message provides UTC, day, month, year and local time zone.
The Local time zone is presented by the number of hours and minutes that have to be
added to local time in order to get the UTC time. Local zone is generally negative for East
longitudes with local exceptions near the International Date Line.
GBS – RAIM GNSS Satellite Fault Detection. The GBS message provides results of the
Receiver Autonomous Integrity Monitoring (RAIM) function. Given that the GNSS receiver
is tracking sufficient satellites to perform integrity checks on the positioning quality of the
position solution, a message is required in order to report the output of this process to
other systems and advise the system user. With the RAIM function in the GNSS receiver,
the receiver can isolate faults to individual satellites and not use these in its position and
velocity calculations. Also, the GNSS receiver can still track the satellite(s) and easily judge
when returned within tolerance. This message is used for reporting such RAIM
information. To perform this integrity function, the GNSS receiver must have at least two
observables in addition to the minimum required for navigation. Normally these
observables take the form of additional redundant satellites. If only GPS, GLONASS, etc. is
used for the reported position solution the Talker ID is “GP”, “GL”, etc. and the errors
pertain to the individual system. If satellites from multiple systems are used to obtain the
reported position solution the Talker ID is “GN” and the errors pertain to the combined
solution.
DTM – Datum Reference. The DTM message provides the current local geodetic datum
and datum offsets from the reference datum. The reference Datum cannot be changed
and is always WGS 84 for the NV08C receiver.
GNSS System Compatibility Mode. To allow you to use software developed for interfacing
GPS-only receivers a Compatibility mode is included in the communication protocol. In
this mode the Talker ID of GGA, RMC, DTM, GLL, VTG and ZDA messages is set to “GP”
regardless of which system satellites are used for the reported position.
JSNAV APPLICATION
JSNav is a GPS/GNSS application that lets you easily collect waypoints or track data.
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