Benchmark report for the atsc alpha vms computer


PROCESSING AND DATA ANALYSIS



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6.0 PROCESSING AND DATA ANALYSIS

6.1 General


The Processing and Data Analysis Software is listed in Table 6.1.


Software

Input

Output

CDPLP

LMT 88-byte

(Multiple)

Generic Normal Points

Merit II Full-rate

(Multiple)

GEODYN – G2E

(Multiple)

Interface, obs. file

GEODYN – G2S

Interface, sat obs

(Multiple)

Polyquick

Merit II Full-rate




Version “M”

.zip file

(Multiple)

Table 6.1 Processing and Data Analysis Software

6.2 Crustal Dynamics Project Laser Processor

6.2.1 Description


The Crustal Dynamics Project Laser Processor (CDPLP) accepts LMT 88-byte data received from the sites and produces six output format types. The CDPLP processing software generates station/satellite tracking statistics utilized for performance analysis.

6.2.2 Software Modifications


Numerous routines in the CDPLP required modifications for Year 2000 compatibility. Routines were changed for:

To determine the correct century, given a 2-digit year field, the Year 2000 Algorithm (Section 1.3) was used.


In addition to the Year 2000 software modifications, the CDPLP was modified extensively, to redesign the output graphics capabilities. The new output graphics files are in a format used for creating IDL graphics.

The new version of the CDPLP is 8.2.


6.2.3 Test Procedures


The CDPLP processor was verified by running each data set from the benchmark data set through the CDPLP processor version 8.2. All output files generated from the CDPLP processor was hand checked for accuracy and Y2k compliance.

6.2.4 Data Set


The Year 2000 benchmark data set, described in Table 2.1, was used for testing of the CDPLP. In addition, problem data from previous benchmarks of the CDPLP will be included in the CDPLP benchmark data set, to verify the software handles problem data.

6.2.5 Results


Each data set described in Table 2.1 was processed utilizing the CDPLP V8_2 processor.


  • All test files were successfully processed and found to be Y2K compliant.

  • All expected output files were produced with associated results identified as accurate and Y2k compliant.

6.3 Generic Normal Points

6.3.1 Description


The Generic Normal Point software was extensively rewritten with new algorithms to improve the normal point generation. The Y2K modifications were included in this rewrite of the software. This software now allows for the creation of CSTG format normal points on the VAX. Only Merit II normal points were created before.

6.3.2 Software Modifications


An extensive rewrite, mostly not related to Y2K, was done on the Generic Normal Point software.

6.3.3 Test Procedures


The Y2K data set was processed by the new generic normal point software. The redulting Merit II normal points were visually compared to the normal point data generated by the field normal point software.

6.3.4 Data Set


The data set generated and tested is provided in Table 2.1.

6.3.5 Results


  • The results for the non-Y2K verification are shown in the benchmark report (Appendix A) for the new software. The Y2K tests found the Generic Normal Point software to be compliant.

6.4 GEODYN

6.4.1 Description


GEODYN is the basis for all of the orbit determination performed on the VAX. The version of the software is 9310. This software is maintained by GSFC, and ATSC ports the UNIX version of the software to the VAX.

6.4.2 Software Modifications


The version of GEODYN that was being used was version 9310, and was found to be non-compliant. The most recent operational version maintained by GSFC is version 9708, which is Year 2000 compliant.

6.4.3 Test Procedures


The software was compared against the previous version 9310, using all of the operational satellites. The punch files were compared visually, and the ephemeris files were compare via software that is used routinely for this purpose. Once this benchmark was completed, a test was performed checking the GEODYN ephemeris crossing from 12/31/1999 to 1/1/2000. The dates, times, vectors and Greenwich hour angles were visually checked for discontinuities. For the rest of the test data set, a check was performed to be sure that the dates agreed.

6.4.4 Data Set


The initial data set included present day 1998 quicklook data. The Y2K data set is presented in Table 2.1.

6.4.5 Results


  • The GEODYN software was successfully executed generating ephemerides using the Y2K Benchmark Data Set that contain continuous data that starts in the year 1999 and ends in the year 2001

  • The software was compared against the previous version 9310, using all of the operational satellites. The punch GEODYN files were compared visually, and the ephemeris files were compare via software that is used routinely for this purpose. Once this benchmark was completed, a test was performed checking the GEODYN ephemeris crossing from 12/31/1999 to 1/1/2000. The dates, times, vectors and Greenwich hour angles were visually checked for discontinuities. For the rest of the test data set, a check was performed to be sure that the dates agreed. Sample Lageos iv, irv, iv difference and irv difference files are available in Appendix A.

  • A very minor discrepancy was found in the inertial vector, and was traced back to the Greenwich hour angle. This difference was on the order of about 1.0 e –12. This was about 2.5 millimeters at the range of LAGEOS. The IRVs were compared with no differences. Since the vectors used to track are the IRVs, and the IRVs are used to determine the predicted ranges, this difference has no impact in the orbit determination performed on the VAX. The Y2K aspects of the test found no errors (see Appendix A).

  • The GEODYN software was found to be Y2K compliant.


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