Transcript PowerPoint 簡報

GPS Receiver Calibration
Demostration
Jia-Lun Wang, Shinn-Yan Lin, Yi-Jiun Huang,
Huang-Tien Lin and Chia-Shu Liao
National Time and Frequency Standard Lab.,
Telecommunication Laboratories(TL),
Chunghwa Telecom Co. Ltd., Taiwan
APMP 2012
November 26, 2012
MSL
Wellington, New Zealand
Telecommunication Laboratories
GPS Receiver Calibration Exercise
 Introduction
 The Procedure for GPS Receiver Calibration
 System Setup (Hardware & Software)
 Data Record & Analysis
 Observation Data at MSL
 Calibration Trip in Asia
 GNSS Receiver
 Calibration Trip
 Detailed Principle and Data Analysis
 Summary and Discussion
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Introduction
 GPS time and frequency is one of the most accurate
techniques for comparison of remote clocks.
 To implement GPS calibration periodically is
necessary for providing accurate time transfer.
 Absolute Calibration
 Differential Calibration
 Link Calibration
 In this report, the GPS exercise demonstration and
detailed calibration procedures are presented.
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GPS Calibration System Architecture
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4
GPS Calibration System Accessories
GNSS receiver
Septentrio PolaRx4 PRO
Antenna
CRG2-DM-mini-GG choke
ring
Antenna cable
About 45m long
Personal Computer
For data record
Time Interval Counter
Aluminium Tripod
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Antenna Mounting & Cable Setup (I)
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Antenna Mounting & Cable Setup (II)
 Mounting Location Considerations
 Choose a location for the GPS antenna assuring maximum
visibility of the satellites
 The optimum location must not shaded by any structure or
by other antennas
 Spacing to Other Antennas & Equipment
 Ensure a proper spacing from other antennas to avoid
desired signal degradation because of interference
 Avoid installing antenna or routing cable around other
communications equipment generating frequencies
harmonic
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Antenna Mounting & Cable Setup (III)
 Cable considerations
 Minimizing the length of the cable from the antenna to the
receiver for maximum signal strength
 Using low loss type cable as GPS antenna cable (ex. CFD400LW 16.8 dB/100M @1.5 GHz )
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GNSS Receiver
 Multi-constellation
 GPS、GLONASS、Galileo
 Multi-frequency
 GPS L1/L2/L2C/L5
 GLONASS L1/L2
 Galileo E1/E5a/E5b/E5
 External 10 MHz reference
 To synchronize the GNSS
measurements
 Networking , remote
operation, and data logging
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GNSS Receiver Setup
 Connect the antenna cable
to the N-type connector of
receiver
 Use a RG-58 cable to input
external 10 MHz as frequency
reference input of receiver
 Use a RG-58 cable to connect
1PPS out of receiver to the input
of counter
 Connect USB cable to PC
 Power on the receiver
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Time Interval Counter Setup
 Connect 1PPS output of the receiver and Device under
test to the counter input of A and B, separately
 Make time interval measurement
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Cable Dealy Measurement
 First, connect BNC T-Connector to time interval counter (TIC)
 Second, Connect 1PPS output of the time source to one side
of T-connector
 Finally, Connect the other side of T-connector to TIC
 Make time interval measurement (Cable Delay)
1PPS input
Cable
under-test
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Software Setup (Receiver, TIC)
 Receiver software - RxControl
 Control receiver
 Log data
 Monitor navigation solution
 Time Interval Counter
software
 Measurement data record with
time tag
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Data Record & Analysis
Rinex File
CGGTTS File
Rinex to CGGTTS
Data Analysis
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Common Clock Tests (Polax4_965- Polax4_966)
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Common Clock Tests (TWTF- Polax4_965)
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Observation Data at MSL
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Calibration Trip in Asia
Ref. from ministry of foreign affairs republic of CHINA (TAIWAN)
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