Javad Maxor, Руководство оператора

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www.javad.com Maxor Operator’s Manual 1-5
I N T R O D U C T I O N
Receiver Overview
interrupt, and weaken signals, lowering the number of available
satellites.
• Integrity – Fault tolerance allows a position to have greater
integrity, increasing accuracy. Several factors combine to provide
fault tolerance, including:
–Receiver Autonomous Integrity Monitoring (RAIM) detects faulty
GPS and GLONASS satellites and removes them from the position
calculation.
–Wide Area Augmentation System (WAAS) creates and transmits
DGPS correction messages.
–Five or more visible satellites for only GPS or only GLONASS;
six or more satellites for mixed scenarios.
–Current ephemerides and almanacs.
–Several algorithms to detect and correct faulty information.
Conclusion
GNSS users can use JNS GNSS receivers to collect data from a network
of satellites and control stations to triangulate precise points anywhere
on Earth.
This overview simply outlines the basics of GPS and GLONASS
positioning. For more detailed information, visit the JNS website (http:/
/www.javad.com).
Receiver Overview
When power is turned on and the receiver self-test completes, the receiver’s 20
channels initialize and begin tracking visible GNSS satellites. Each of the
receiver’s channels can be used to track C/A-L1, P-L1, or P-L2 signals. The
number of channels available allows the receiver to track all visible satellites at
any time and location. The antenna receives the different signals for processing.
An internal antenna equipped with a low noise amplifier (LNA) and the
receiver’s radio frequency (RF) device are connected with a 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. In addition, broadcast
navigation data are retrieved from the navigation frame.