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Performance of Multi-channel Common-view. Victor Zhang National Institute of Standards and Technology Time and Frequency Division. Overview. Common-view operations at NIST GLONASS common-view GPS multi-channel common-view Summary. Common-view operations at NIST.
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Performance of Multi-channel Common-view Victor Zhang National Institute of Standards and Technology Time and Frequency Division 43rd CGSIC meeting in Arlington, Virginia, March, 2004
Overview • Common-view operations at NIST • GLONASS common-view • GPS multi-channel common-view • Summary 43rd CGSIC meeting in Arlington, Virginia, March, 2004
Common-view operations at NIST • Secondary method for contributing the NIST time scale to the computation of TAI and UTC • Global Time Service (calibrate remote clocks with respect to UTC(NIST)) • Synchronize the clocks at radio stations WWV/WWVB, WWVH to UTC(NIST) • Calibration of the two-way links between NIST and other laboratories 43rd CGSIC meeting in Arlington, Virginia, March, 2004
GLONASS common-view • GLONASS common-view with multi-channel C/A code and single channel P-code contains more transfer noise in short term due to the small number of satellites in orbit • GLONASS common-view is degraded due to the difficulties in making ionospheric delay correction 43rd CGSIC meeting in Arlington, Virginia, March, 2004
GPS multi-channel common-view • Evaluation of three different types multi-channel receivers (NISTM1, NISTM2, and NISTM3) • x 200ps @ 1day with single channel common-view • NISTM3 receiver behaves similar to the NBS-type single channel receiver • Performance of multi-channel common-view is degraded by diurnal 43rd CGSIC meeting in Arlington, Virginia, March, 2004
GPS multi-channel common-view • Distance 2,400 km • x 600 ps @ 1 day for single channel common-view (36-point everyday) • x 500 ps @ 1 day for the best multi-channel common-view (400-point everyday) • Multi-channel common-view lowers the transfer noise for averaging time from 16 minutes to a few days 43rd CGSIC meeting in Arlington, Virginia, March, 2004
GPS multi-channel common-view • Distance 7,150 km • x 800 ps @ 1 day for single channel common-view (17-point everyday) • x 600 ps @ 1 day for the best multi-channel common-view (235-point everyday) • Multi-channel common-view lowers the transfer noise for averaging time from 16 minutes to a few days 43rd CGSIC meeting in Arlington, Virginia, March, 2004
GPS multi-channel common-view • Distance 7,530 km • x 900 ps @ 1 day for single channel common-view (16-point everyday) • x 700 ps @ 1 day for the best multi-channel common-view (160-point everyday) • Multi-channel common-view lowers the transfer noise for averaging time from 16 minutes to about two days 43rd CGSIC meeting in Arlington, Virginia, March, 2004
Summary • Performance of GLONASS common-view is degraded due to the small number of satellites in orbit and the difficulties in making the ionospheric delay correction. • Multi-channel GPS common-view considerably reduces the transfer noise out to a few days. With IGS ionospheric delay and precise ephemeris corrections, the noise is 700 ps or less when averaged over 1 day. 43rd CGSIC meeting in Arlington, Virginia, March, 2004