User's Manual Part 1

CL1TC-4 400W DVB-H Transmitter WEB Interface
Product Manual, Rev. 1 56
6.3.2 GPS Status
The GPS Status
page provides access to GPS receiver information including the lock status
and the number of visible satellites, as well as the exact location and time.
• GPS Common: Indicates the GPS PLL Status (Lock or Unlock), Position Altitude,
Position Latitude, Position Longitude, 3D Fix, Number of Visible and Tracked
Satellites, and Sigma Accuracy. GPS Common will also indicate if the System Clock
is updated from the GPS and it will display the System Timezone.
• Satellites: Indicates the satellite number and corresponding carrier to noise ratio.
Figure 6-7 GPS Status
After initialization, the GPS starts tracking the satellites to determine its position; the
accuracy of the GPS output signals depends on the GPS satellite reception. The GPS PLL
Status will indicate “Lock” when the quality of the received GPS signals are higher than the
minimum reception level and the minimum number of tracked satellites is reached. GPS 3D
Fix will occur when a minimum of 4 satellites are tracked. The GPS will then display Position
Latitude, Longitude and Altitude.
The output of the GPS (1 PPS and 10 MHz pulses) is fed to the Distribution Amplifiers, which
in turn feed the pulses to the modulator and up-converter.
The Controller communicates continuously with the GPS to deter-mine if the GPS is still
operating correctly and still receiving the satellite signals, etc., or if it has any alarm
(malfunction) to report.
A PLL (Phase Locked Loop) Status Unlocked event can be the result of an antenna under-
current (antenna open) or antenna over-current (short), a poor GPS 3D Fix (minimum
requirement is 4 satellites). In general, conditions that result in a poor GPS signal quality.