Avionics
GPS-101 GPS Satellite Simulator
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• Verify operational integrity of GPS
receivers quickly
• Selectable Satellite Vehicle (SV) and
Navigation (NAV) Data
• Adjustable RF levels from -85 dBm to
-145 dBm in 1 dB steps
• Doppler control allows the operator to
select a positive or negative carrier frequency shift of approximately 4 kHz
• Stored GPS Almanac with real time clock
• Direct connect to receiver or via antenna
coupler
• Battery operated portability
Aeroflex is a leader in the design, manufacture
and marketing of Avionics test systems.
The IFR GPS-101 Global Positioning Simulator
provides accurate and repeatable testing of
Global Positioning Satellite (GPS) receivers. The
GPS-101 achieves this testing capability by simulating a Global Positioning Satellite and generating a specific Satellite Vehicle (SV) and
Navigation (NAV) data pattern. Coupled with
remotely loaded GPS almanac information and
RF levels/frequency control, the GPS-101 provides a portable test solution for verifying the
operational integrity of GPS systems.
The GPS-101 verifies the operational integrity of:
• An integrated GPS receiver - antenna system (e.g. a hand
held unit) with built-in test modes accessible by transmitting special satellite (SV) numbers and navigational (NAV)
data word that will cause an indication or received signal
strength.
• An installed GPS receiver with remote antenna system.
• Any GPS receiver or installation capable of indicating that
a single satellite with appropriate navigation data was
detected.
Operation
The GPS-101 provides dedicated front panel keys for all primary
functions. Selected parameters are displayed on a wide viewing
angle, high contrast, backlit LCD display.
MODE KEYS
RF LVL
The RF level can be adjusted from -85 to -145 dBm in 1 dB steps via
slew wheel control to verify GPS.
DPLR
The doppler control allows the operator to select a positive or negative carrier frequency shift of approximately 4 kHz to verify receiver
acquisition and lock performance.
SV
Selects the satellite vehicle to be simulated (1 through 37). The
almanac data is utilized to display an asterisk alongside the selected
satellite vehicle if the satellite is unhealthy or not available.
RF CONT
The RF control selects the modulating source for the 1575.42 MHz
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generator. The selections are RFOFF: turns carrier off, RFCW:
unmodulated carrier, RFON: C/A code and NAV data (spread spectrum signal), RFEXT: external BPSK modulation through AUX I/O
connector and RFSQR: 511.5 kHz square wave modulation (maintenance purposes).
SETUP:
Provides access to menus for setting RS-232/422 communications
port parameters, test set operational characteristics and self test.
TEST:
Selects one of three stored NAV data patterns. (Three data patterns
reserved for future use)
1. T1: NAV data that contains programmable almanac information
and GPS week and time of week fields. The almanac data is valid
for a 30 day period and may be downloaded in ‘YUMA’ ASCII text
format via the RS-232 port. Current almanac data is available from
the U.S. Coastguard Internet Web Site. The GPS-101 has an internal real time clock that keeps UTC time and is programmable by
the user.
2. T2: NAV data pattern that contains fixed GPS week and time of
week.
3. T3: Fixed 11001100.. repeating test pattern.
Select Keys: Moves cursor to selected field/parameter.
Display Keys: Contrast setting keys and display backlight on/off key.
ESC Key: Returns to main operation screen.
Slew Wheel: Allows rapid data slewing.
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Frequency
1575.42 MHz
Accuracy
Same as Master Timebase
Doppler
Selectable frequency offset ±4.0 kHz
Offset Accuracy
See Master Oscillator
Channels
Single SV simulation, selectable from 1 to 37
Phase Modulation
BPSK
PRN Code
C/A code = 1.023 MHz, 1023 bit gold code
NAV Data
50 Hz, Programmable test pattern, built-in patterns
Output Level
-85 to -145 dBm in 1 dB steps, ±2 dB accuracy into 50 Ω (AC
Coupled) Standard Cable, 4 dB loss
Spurious
<-40 dBc over the bandwidth (20 MHz)
External Modulation Input
TTL
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Standard Timebase
Frequency
10 MHz nominal (see note)
Temperature Stability
±1 ppm
Ageing Rate
±1 ppm/yr, ±5 ppm/10 yr
Uncertainty
±1 ppm
Option Timebase
Frequency
10 MHz nominal (see note)
Temperature Stability
±0.1 ppm
Ageing Rate
±0.1 ppm/yr
Uncertainty
±0.1 ppm
Note: Internal timebase frequency is a function of timebase calibration, ageing
rate, temperature stability and uncertainty.
External Reference Input
Input Level
0.25 to 6.0 Vp-p
Input Impedance
150 Ω nominal
Input Frequency
10.0 MHz
External Reference Output
Output Level
1.5 Vp-p nominal into 50 Ω
Output Frequency
10.0 MHz nominal
CCOOUUPPLLEERR
Coupling
-20 dB typical at 1575.42 MHz
Assumes
4.77 dB patch antenna gain and 4 dB cable loss
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