Viavi 87339, Operation Manual

Page: 91 / 198

Testing
4 -10
STEP PROCEDURE
6. Reduce the RF level in 0.1 dB increments until the specified C/N0 is displayed on
the receiver test page or read from the receiver using the NMEA-183 protocol.
Fig. 4-3 Simulation Function Window
4.1.6.B Acquisition Sensitivity
Perform the following steps for acquisition sensitivity test.
STEP PROCEDURE
1 If connecting GPSG-1000 via Antenna Coupler, perform Antenna Coupler
Installation procedure Section 4.1.1. If directly connecting GPSG-1000 to GPS
receiver under test, proceed to step 2.
2. Perform Setup procedure Section 4.1.2.
3. Select Launch Bar tab to display launch bar. Select SV PRN function key to
display the SV PRN Function Window. The GPS SV’s in view will be displayed in a
table.
4. Turn ON all SV’s by selecting ON/OFF field to ON in each SV line, then select
Apply
. Select the close icon to close the Function Window. On the Setup
Simulation Function Window Select PRN Signal drop down menu. Select
VARIABLE
to ensure the relative SV signal levels are set proportional to the
respective pseudo ranges
5. Select RF Level and set to -136 dBm.
NOTE:
This is 6 dB above the typical GPS receiver positional tracking sensitivity of
- 142 dBm. If the active antenna is not in circuit, the gain of the antenna should be
subtracted from these figures.
6. Increase the RF Level in steps of 0.5 dB, until positional fix is displayed on the
receiver or read from the receiver using the NMEA-183 protocol. Allow several
minutes at each power level.
7. Increase the
RF Level
in steps of 0.5 dB until the positional fix is displayed on the
receiver or read from the receiver using the NMEA-183 protocol. Allow several
minutes at each power level.
NOTE:
This is 6 dB above the typical GPS receiver positional tracking sensitivity of
- 142 dBm. If the active antenna is not in circuit, the gain of the antenna should be
subtracted from these figures.