Geodetic Research Laboratory, Department of Geodesy and Geomatics Engineering Workshop, October 27 – 28, 2006, Quebec city, Quebec Sükeová, Liliána 1 L2C Data Collection and Analysis using a Trimble R7 GPS Receiver Liliana Sükeova Department of Geodesy and Geomatics Engineering University of New Brunswick Fredericton, NB

Geodetic Research Laboratory, Department of Geodesy and Geomatics Engineering Workshop, October 27 – 28, 2006, Quebec city, Quebec Sükeová, Liliána 2 Conclusion Outline Background and objectives Project description Observations and their analysis

Geodetic Research Laboratory, Department of Geodesy and Geomatics Engineering Workshop, October 27 – 28, 2006, Quebec city, Quebec Sükeová, Liliána 3 Background  GPS Modernization a new open civil signal available on L2 frequency – L2C – currently broadcast by Block IIR-M satellites: PRN 17 since PRN 31 since  L2C signal tracking network L2C capable GPS receivers deployed to existing and new stations  Trimble R7 receiver on loan to UNB Establishing UNB3 as a part of the L2C tracking network

Geodetic Research Laboratory, Department of Geodesy and Geomatics Engineering Workshop, October 27 – 28, 2006, Quebec city, Quebec Sükeová, Liliána 4 Objectives  General objective to analyze the modernized L2C signal  Specific objectives to establish a station using Trimble R7 receiver to collect the data containing the new L2C observables to test the receiver’s firmware version

Geodetic Research Laboratory, Department of Geodesy and Geomatics Engineering Workshop, October 27 – 28, 2006, Quebec city, Quebec Sükeová, Liliána 5 Project description  L2C signal tracking network  Trimble R7 at UNB becomes a part of L2C tracking network successfully tracks the modernized L2C signal

Geodetic Research Laboratory, Department of Geodesy and Geomatics Engineering Workshop, October 27 – 28, 2006, Quebec city, Quebec Sükeová, Liliána 6 Project description  Establishing UNB3 Trimble R7 connected to the same antenna used by IGS station UNB1 (currently UNBJ), by means of an antenna splitter (UNB, Fredericton, NB) L2C d ata collection since January 11 th, 2006 until October 10 th, second daily files containing the new L2C uploaded to the site at the Crustal Dynamic Data Information System (CDDIS) ftp://cddis.gsfc.nasa.gov/gps/data/l2ctest/daily/2006/

Geodetic Research Laboratory, Department of Geodesy and Geomatics Engineering Workshop, October 27 – 28, 2006, Quebec city, Quebec Sükeová, Liliána 7 Observations and their analyses  Data processing to create daily observation and navigation files program TEQC was used, v , provided by UNAVCO to accommodate the new GPS L2C pseudorange observable a new code (C2) was defined in RINEX (v. 2.11) observation files. The full command line reads: teqc +C2 -tr d +nav *.06n *.dat > *.06o

Geodetic Research Laboratory, Department of Geodesy and Geomatics Engineering Workshop, October 27 – 28, 2006, Quebec city, Quebec Sükeová, Liliána 8 Observations and their analysis Signal-to-noise ratio on L1:Signal-to-noise ratio on L2:

Geodetic Research Laboratory, Department of Geodesy and Geomatics Engineering Workshop, October 27 – 28, 2006, Quebec city, Quebec Sükeová, Liliána 9 Observations and their analysis C/A and L2C SNR – PRN 17C/A and P2 SNR – PRN deg 70 deg10 deg 80 deg 10 deg

Geodetic Research Laboratory, Department of Geodesy and Geomatics Engineering Workshop, October 27 – 28, 2006, Quebec city, Quebec Sükeová, Liliána 10 Observations and their analysis  Compute code multipath and noise level of C/A and L2C code pseudorange for PRN 17 of P2 and C/A code for PRN 11  code multipath and noise level =

Geodetic Research Laboratory, Department of Geodesy and Geomatics Engineering Workshop, October 27 – 28, 2006, Quebec city, Quebec Sükeová, Liliána 11 Observations and their analysis, std L2C = m std C/A = m  L2C and C/A code multipath and noise level – PRN 17, with the mean removed (offset by the carrier phase ambiguities)

Geodetic Research Laboratory, Department of Geodesy and Geomatics Engineering Workshop, October 27 – 28, 2006, Quebec city, Quebec Sükeová, Liliána 12 Observations and their analysis  P2 and C/A code multipath and noise level – PRN 11, with the mean removed (offset by the carrier phase ambiguities) std P2 = m std C/A = m

Geodetic Research Laboratory, Department of Geodesy and Geomatics Engineering Workshop, October 27 – 28, 2006, Quebec city, Quebec Sükeová, Liliána 13 Observations and their analysis  Analyses of code multipath and noise level According to (Simsky et al., 2006) the same level of noise and multipath is expected on C/A and L2C contrast with this assumption found in Trimble R7 => the firmware of Trimble R7 (v. 2.26, v. 2.28) does not combine CM and CL code wavelengths of the L2C signal

Geodetic Research Laboratory, Department of Geodesy and Geomatics Engineering Workshop, October 27 – 28, 2006, Quebec city, Quebec Sükeová, Liliána 14 Observations and their analysis  Other incongruities in the firmware of Trimble R7 after processing data with GAPS - found an inconsistency between carrier-phase and pseudorange measurements => a cycle-slip-like effect observations from consecutive days can not be used sequentially without re-initializing ambiguities for all satellites at each day crossover

Geodetic Research Laboratory, Department of Geodesy and Geomatics Engineering Workshop, October 27 – 28, 2006, Quebec city, Quebec Sükeová, Liliána 15 Conclusions  More advanced signal structure of L2C code over the C/A code,  SRN of L2C is higher than P2 code, values similar to SNR of C/A code  Multipath and noise level of L2C is higher than that of C/A code - contrast with the assumption  inconsistency between carrier-phase and pseudorange measurements Current work:  Analysis of data collected with different antennas, receivers (from all tracking stations) Future work:  Analysis of simulated data sets of L2C signal with Spirent simulator

Geodetic Research Laboratory, Department of Geodesy and Geomatics Engineering Workshop, October 27 – 28, 2006, Quebec city, Quebec Sükeová, Liliána 16 Acknowledgements  GEOIDE Network for funding  Cansel for loan of Trimble R7 receiver THANK YOU