national traceability of gps measurements in the republic of serbia

Belgrade UniversityFaculty of Civil EngineeringDepartment for Geodesy and Geoinformatics

NATIONAL TRACEABILITY OF GPS NATIONAL TRACEABILITY OF GPS MEASUREMENTSMEASUREMENTS

IN THE REPUBLIC OF SERBIAIN THE REPUBLIC OF SERBIA

Vukan Ogrizović, Violeta Vasilić,Siniša Delčev, Jelena Gučević

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1st International Simposium RMO 2008

Serbian Time and Frequency Standard

Caesium atomic clock Agilent 5071A Nominal accuracy ±10-12

12 years warranty Expected age of the beam up to 20 years

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Agilent 5071A

Cs clock

TST 6490AMicrophase

stepper

Agilent 5087A

Distributionamplifier

TST 6460Digital clock

TST 6487Distribution

amplifier

TTS-2 GPS receiver

antenna

5 MHz

5MHz

10 MHz

1 pps

1 pps

Ref. pointUTC(ZMDM)

10 MHz

10 MHz

5 MHz

1 pps

Serbian Time and Frequency Standard

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National traceability chain

Completion of link B: Broadcast service Comparing 1PPS signals

U T C an dS I S eco n d(B IP M )

U T C(D M D M )

A

U T C(M L 1 6 0 )

B

C

D

E N DU S E R 1

E N DU S E R 2

E N DU S E R 3

. . .

1 p p sG P S

E

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Experiment setup

TRIMBLE NETRS DUT

1 pps 1 pps

HAMEG HM8123

Input A Input B

AT AR

TIMEA B’

data loggingPC

serial port

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S to p

S ta r t

T im e

1 p p s

t

Measurement of a time difference

Time interval mode Offset between start pulse and stop pulse Analysis of time differences

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Measurements

-300-200-100

0100200

0 500 1000 1500 2000 2500

time [s]

diffe

ren

ce

[n

s]

0

50

100

150

200

250

300

350

-150 -100 -50 0 50 100 150

range

frequence

Frequency histogram

Raw measurements

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Results

2

1/ 22

2 121

12, 2

2 ( 2)

M

y i i ii

x x xM

μsfor 6s, 0,267

sμs

for 8s, 0, 201sμs

for 10s, 0,159s

y

y

y

Mod

Mod

Mod

13

1

21

2222 2

13τ2

1)τ(σmod

nN

j

nj

jiininiy xxx

nNn

Allan’s variances:

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Conclusions and recommendations

Traceability from working standards to NMI and BIPM Link from ML160 to UTC(ZMDM) should be established Comparison of ML160 to UTC(ZMDM) 1PPS output 24 hours long logging session Implementation of real-time calibration procedure

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THANK YOU!

Our participation on RMO2008 is supported by:

Faculty for Civil Engineering, Belgradehtpp://www.grf.bg.ac.yu/

Metrological Laboratory ML160, Belgradehtpp://ig.grf.bg.ac.yu/metrolab/

national traceability of gps measurements in the republic of serbia

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