UNB3 data management script assessment

1
UNB3 data management script assessment

• Thatchineswaran Thirumurthi, Landon A. Urquhart,
  Richard B. Langley, and Rodrigo F. Leandro

2
Table of Contents

• Introduction to UNB3
• Logging of UNB3 data
• UNB3 data management script
• Comparison of C2 and P2 acquisition by UNB3
• Tracking of P2 signal by UNB3 and UNBJ
• Conclusions

3
Introduction to UNB3

• UNB3 station is located at the roof of Head Hall,
  UNB, Fredericton.
• UNB3 currently uses a Trimble NETR5 receiver. It
  used to operate using a Trimble R7 receiver
  earlier.
• UNB3 receiver is owned by Trimble Navigation
  Ltd., and operated by UNB (Rodrigo, Richard,
  Liliana).
• It is part of the IGS L2C-Test network.
• UNB3 shares a Javad Antenna (JPSREGANT_DD_E
  NONE) with IGS Station UNBJ.

4
Logging of UNB3 files

• The UNB3 files are stored in a binary format
  (.t01) in Trimble NETR5 receiver.
• The data from Trimble NetR5 receiver was sent in
  real-time (RT17 format) to Cansel where using
  GPSNet, RINEX files were generated.
• It was preferred that .t01 files from Trimble
  receiver be converted into RINEX format at UNB
  and supplied to CDDIS instead of using Cansels
  GPSNet (No RT communication issues).

5
UNB3 data management script

• The data management script was modified to obtain
  the T01 hourly files directly from Trimble NETR5
  receiver and uses t012rin (an unreleased Trimble
  utility provided to UNB) to convert them into
  hourly RINEX files.
• In the Summer of 2007, the new UNB3 data
  management procedure was tested by two students,
  Landon and Thatchan.
• Assessment objective check if the new effective
  procedure was working properly.

6
UNB3 data management script

• Loss of satellite data at certain epochs were
  noticed in RINEX files produced by Cansels
  GPSNet compared to files produced by the new
  script that uses t012rin. Reason communication
  drops.

7
UNB3 data management script - FUTURE

• Trimble has provided to UNB a new utility
  (ConvertToRinex) which records SBAS data in
  addition to GNSS data.
• After successful testing, it is intended to
  replace t012rin.
• UNB has helped in the assessment of some
  unreleased Trimble utilities/firmware.

8
Comparison of C2 and P2 acquisition by UNB3

• It was found that, as expected, C2 (L2C (ML))
  signal was acquired at a lower elevation angles
  compared to P2 (semi-codeless L2 P(Y)) signal.

unb32080.07o C2 P2
PRN 12 1.68 13.05
PRN 17 4.19 13.29
PRN 31 4.64 12.72
unb32070.07o C2 P2
PRN 12 1.98 12.62
PRN 17 4.14 13.24
PRN 31 4.65 12.53
9
Tracking of P2 signal by UNB3 and UNBJ

• UNBJ tracks P2 signals at a lower elevation
  compared to UNB3 (both are semi-codeless L2
  P(Y)).
• It could be due to the splitter arrangement.

File PRN12 PRN17 PRN31
unb32780.07o 4.10º 11.20º 8.21º
unb32790.07o 9.15º 11.16º 7.95º
unb32800.07o 10.71º 11.12º 8.24º
unb32810.07o 4.12º 9.86º 6.68º
unb32820.07o 4.31º 11.06º 6.79º
File PRN12 PRN17 PRN31
unbj2780.07o 2.40º 3.88º 0.44º
unbj2790.07o 2.98º 4.09º 2.21º
unbj2800.07o 2.09º 4.12º 1.95º
unbj2810.07o 3.75º 4.17º 2.24º
unbj2820.07o 2.25º 3.94º 1.98º

• 2.8º 0.3º

• 8.3º 1.5º

10
Conclusions

• We have verified that the new data management
  works properly
• We have made a brief L2C signal tracking
  assessment, and the results are as expected
• In the near future there will be a new procedure,
  using the latest ConvertToRinex utility. The
  assessment of the new procedure is its final
  stage.