GRX1 Chapter 1
An internal GPS+ antenna equipped with a low noise amplifier ( LNA ) and the receiver's radio
frequency ( RF ) device are connected with a co-axial cable. The wide-band signal received is
down-converted, filtered, digitized, and assigned to different channels. The receiver processor
controls the process of signal tracking.
Once the signal is locked in the channel, it is demodulated and necessary signal parameters
( carrier and code phases ) are measured. Also, broadcast navigation data are retrieved from
the navigation frame.
After the receiver locks on to four or more satellites, its absolute position in WGS-84 and the
time offset between the receiver clock and GPS time are computed. This information and the
measurement data can be stored in the optional SD card and downloaded later onto a computer,
then processed using a post-processing software package. When the receiver operates in RTK
mode, raw data measurements can also be recorded into the receiver's internal memory. This
allows the operator to double check real-time results obtained in the field.
Depending on your options, capabilities of the receiver include:
Satellite based augmentation systems ( WAAS, EGNOS, and so forth ).
Adjustable phase locked loop ( PLL ) and delay lock loop ( DLL ) parameters
Dual- or multi-frequency modes, including static, kinematic, real-time kinematic ( RTK ),
and differential GPS ( DGPS ) survey modes ( DGPS modes include static, kinematic, and
RTK )
Auto data logging
Setting different mask angles
Setting different survey parameters
Static or dynamic modes
Getting Acquainted
The GRX1 is a 72-channel GPS receiver, which includes the following:
External, detachable batteries
One data ports
Interface for controlling and viewing data logging
External memory card slot
Internal radio modem
Bluetooth wireless technology module
Optional GSM/GPRS module
Optional CDMA module ( only with the Digital UHF radio modem )
GRX1 Chapter 1