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Prego Operator’s Manual
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I N T R O D U C T I O N
Principles of Operation
appropriate coaxial 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, the
broadcast navigation data is retrieved from the navigation frame.
After the receiver locks on to four or more satellites, it is possible to solve
the so-called “absolute positioning problem” and compute the receiver’s
coordinates and time (in WGS-84). All this information is stored in the
receiver’s memory, which can be downloaded later onto a computer and
processed using a post-processing software package. When the receiver is
run in RTK mode, raw data measurements are recorded into the receiver’s
internal memory. This allows the operator to double check real-time results
obtained in the field.
The Prego receiver has the following operation modes:
• Stand-alone positioning
• Relative (differential) positioning with two or more receivers running
simultaneously and post-processing of collected raw data
measurements.
• Code differential (DGPS)
• Real-time kinematic (RTK)
Differential measurements, processed later, can be collected in the
following three modes:
• Static
• Stop-and-Go
• Kinematic
In differential mode, one receiver is static, and is referred to as the
Reference or Base receiver. The other receiver can be either static or
moving, and is called the Rover. The Base and Rover receivers use
transmitting and receiving radio modems to communicate with each other
and calculate differential corrections in the following formats:
• RTCM
• CMR
• CMR+
• JNS
Summary of Contents for Prego
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