Hz Output - ashtech GG Surveyor Reference Manual

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The receiver has two options which affect the rate at which data output: position
update rate and Raw measurement update rate. The highest output rate supported
under different conditions is 5 Hz.

5 Hz Output

The GG Surveyor, as an option, provides the capability of 5 Hz internal receiver
update rate, allowing raw data and NMEA data to be output every 0.2 seconds. Two
options are available to control this feature: the position update rate option for NMEA
output rate, and raw measurement update rate for raw data output. See "Receiver
Options" on page 4 for more information. Because of CPU power limitation, when
this option is set, the receiver will update at 2 Hz until command $PASHS,POP,5 is
issued. When updating at 5 Hz, the receiver will use only 16 satellites in the position
solution, although it will track all available satellites. During the period while 5 HZ
update is not required, you can revert to 2 HZ and use all available satellites in the
position solution by issuing the command $PASHS,POP,2.
NMEA Outputs
As an option, the GG Surveyor allows you to output NMEA message format and
other miscellaneous messages through the serial ports. The following standard
NMEA messages are available: GLL, GXP, GGA, VTG, GSN, MSG, GSA, GRS,
GST, RMC and ZDA. Additional non-standard messages are available: LTN, AIM,
POS, SAT, RRE, TCM, and TTT. All standard NMEA messages are a string of
ASCII characters delimited by commas, in compliance with NMEA 0183 Standards
Version 2.1. All non-standard messages are a string of ASCII characters delimited by
commas, in the Ashtech proprietary response format. Any combination of these
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Typical messages might be 20 to a maximum of 79 characters in length and
generally require transmission no more often than once per second.
Proprietary
When specific information was needed, and the NMEA standard did not
contain a suitable message, Ashtech created proprietary messages in a
NMEA style format. Messages are available in ASCII.
RAW
Raw Data outputs in binary format and includes measurement data,
ephemeris data, almanac data, and position data.
When collecting data at 5 Hz, because of large amounts of data being output
through the serial ports, a 486-66 MHz or Pentium™ computer with a fast
serial and parallel port card (i.e., 16550 serial and parallel card) is recom-
mended. The serial port baud rate should be set to a baud rate above 38K.
CAUTION
GG Surveyor GPS+GLONASS Reference Manual