Table of Contents
Advertisement
messages can be output through any of the serial ports, and the same messages can be
output through different ports at the same time. The output rate is determined by the
$PASHS,NME,PER command, and can be set to any value between 0.2 and 999
seconds depending upon the update rate option installed (5, 2, or 1 Hz). See "NMEA
Data Message Commands" on page 129 for more information.
Raw Data Outputs
As an option, the GG Surveyor allows you to output raw data through the serial ports.
Table 4.5 outlines the different types of messages available.
All outputs are in binary format. Any combination of messages can be output through
any of the serial ports, and the same messages can be output through different ports at
the same time. The output rate is determined by the $PASHS,RCI setting, and can be
set to any rate between 0.2 and 999 seconds depending upon the raw data update rate
option installed (5, 2, or 1 Hz). See "Raw Data Outputs" on page 37 for more
information.
Signal to Noise Ratio
The GG Surveyor calculates the signal to noise ratio using one of two methods: DBH
or AMP. Select which method using the $PASHS,SNR command. The default
method is the AMP method.
The DBH method the classic method of dB*Hz units, and the result is independent of
the hardware. The result is presented in true SNR, in dB*Hz. The range is
approximately 30 to 55. The receiver can track signals with SNR > 26 dB*Hz, and
can find signals with SNR >34 dB*Hz. The algorithm is
SNR[dB*Hz] = 10*log10 (mean(I)
Advanced Operation
Table 4.5: Raw Data Messages
Message
MCA
measurement data output with Ashtech
type 3 data structure
PBN
position data
SNV
GPS ephemeris data
SNG
GLONASS ephemeris data
SAL
GPS almanac data
SAG
GLONASS almanac data
Description
2
2
2
/[mean(I
) - (mean(I)
])/(2*T)
37
Advertisement
Table of Contents
