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GPS ANTENNA
GPS is a line of sight system, which means in order for the receiver to track the satellites there must
be an unobstructed path directly to them. Buildings, trees, machinery, and human bodies are common
obstructions. When locating the antenna/receiver find a place where the antenna will have an unob-
structed view of the sky. Items such as electrical motors, generators, alternators, strobe lights, radio
transmitters, cellular phones, microwave dishes, radar, active antennas, etc., all generate electrical
and magnetic fields which can interfere with the GPS or WAAS signal. Mount the Antenna/receiver
away from such potential sources of interference.
The GPS can be de-tuned by close proximity to other objects. For example, if you place the antenna
under fiberglass its performance could be degraded. Usually, if the antenna/receiver is lowered so that
at least a quarter of an inch gap is made between the antenna/receiver and the covering plastic or
fiberglass, acceptable performance can be achieved. Metal or other dense materials will completely
block the GPS signals.
OPERATION
Initial startup
Both the internal GPS and WAAS receiver must perform a COLD START the first time the system is
powered up. The GPS receiver will search the sky for satellites and download data necessary for
operation. The WAAS receiver will wait until the required almanac data is received. The cold start will
take up to 15 minutes but is only required during the initial power up.
Connect the serial cable provided between the Invicta 115 and the computer, apply power. Allow the
receiver to operate while installing the software program on the computer. Turn off all unnecessary
electrical equipment to minimize electrical noise interference.
NORMAL OPERATION
Upon completion of the initial "cold start", the receiver begins to operate in "normal mode". The unit
should be operating in full DGPS mode within a few minutes of power up.
All configuration and WAAS data is stored in nonvolatile memory inside the Invicta 115. Configuration
changes are made with utility software.
Be aware of possible satellite obstructions, which may interfere with GPS operation.
TROUBLESHOOTING
·
Make sure the antenna is mounted so that it has a clear view of the sky and is as far away from
electrical noise sources as possible.
Attempt to isolate all problems as either:
·
Receiver/Antenna
·
Power
·
Transmitting Site
·
Serial Communications
·
Peripheral Device
6
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