User Defined Data (UDD) Or EVTP

1. User Defined Data (UDD) Or EVTP

2. UDD • In the old days: • The Satellite Simulator Control Working Group (SSCWG), prepared for JPO (US Joint Program Office), something called the Enhanced Validation Test Plan. • 24th April 1999 • Test plan to be used to evaluate Satellite Signal Simulators (SSS) within the JPO office. • Purpose to provide accreditation for these SSS. • Requirement was for the Broadcast messages, and motion could be specified by user supplied files. • Original implementation in SimGEN for VMS. – Called EVTP (Enhanced Validation Test Program). • Migrated to Windows and became the UDD (User Defined Data function).

3. UDD – What's it for? • So far we have said: • SimGEN Generates the satellite orbital data, (Ephemeris) from a specified set of Almanac data. • SimGEN adds in any Ionospheric or Tropospheric effects based on its models. • Can also define Nav data errors or Modify Nav data errors in the constellation file.

4. UDD – What's it for? • UDD allows you to have much more control over: • Almanac • Ephemeris • Nav Data • Genuine SV Orbits (Verses specified orbits) • Ionosphere and Troposphere • UDD can be complicated! Lots to make sure you get right.

5. User Defined Data • Allows user to generate ASCII files to supplement the GPS Constellation file, in Part, or in Full. (except for some sections, e.g. Power, Signals being Simulated).

6. User Defined Data • Files are ASCII based and can be edited with any text editor • Operation as follows: • In normal operation SimGEN uses the information specified in the GPS Constellation file to determine the selection and signal characteristics of the satellites to be simulated when running a scenario. • When User defined Data is enabled for a scenario, the user may specify that some of the satellite control data is determined by information contained in user supplied files.

7. What do the files do? • Satellite Orbital Data: Used to define the motion of the simulated GPS satellites. (File extension is .EPH) • This is the actual RF motion of the SV’s. Time data set is valid from + SV **** Week 0893 at GPS time 601200.00 ephemeris for SV-23 *********** ID: 23 Health: 0 Issue of Data(Ephemeris): 120 Sine Harm Corr Term to Orb rad(Crs,meters): -5.25000000000e+00 Mean Motion Difference (delta n,semi-circles/sec): 1.50430423673e-09 Mean Anomaly (semi-circles): 9.91738925222e-01 Cos Harm Corr Term to Arg Lat (Cuc,radians): -2.84984707832e-07 Eccentricity: 1.18420945946e-02 Sine Harm Corr Term to Arg Lat (Cus,radians): 5.89154660702e-06 Sqrt(A)(meters): 5.15362767792e+03 Time of ephemeris (toe,seconds): 0 Cos Harm Corr Term to Angle of Incl (Cic,radians): 4.84287738800e-08 Right Ascension (omega0,semi-circles): -9.28051709197e-01 Sine Harm Corr Term to Angle of Incl (Cis,radians): -2.51457095146e-07 Inclination Angle at Reference Time (i0,semi-circles): 3.07477083988e-01 Cos Harm Corr Term to Orbit Radius (Crc,meters): 2.65062500000e+02 Arg of Perigee (w,semi-circles): -6.73587591853e-01 Rate of Right Ascension (omegadot,semi-circles/sec): -2.54385668086e-09 Rate of Inclination Angle (IDOT,semi-circles/sec): 5.07043296238e-11 C/A or P on L2 Bits (discretes): 01 HOW bit 18: 0 HOW bit 19: 1 URA Index: 0007 ISSUE OF DATA CLOCK: 0888 L2 P data flag: 0 Estimated Group Delay Differential (sec): -4.65661287308e-10 Clock Data Reference Time (sec): 0 Second order coefficient af2(sec/sec**2): 0.00000000000e+00 First order coefficient af1(sec/sec): 3.41060513165e-13 zero order coefficient af0(sec): 5.46686351299e-07 Ephemeris reference week number: 0893

8. What do the files do? • Satellite Ephemeris Data: Used to define the broadcast Navigation Data sets for satellite ephemeris and clock parameters. This file has the same format as the orbital data file. (File extension is .EPH). • This is the content of the Navigation data and not what the RF is doing. • Same format as the Orbital data file.

9. What do the files do? • Almanac Nav Data: Used to define the broadcast almanac data for the satellite orbits. (File extension is .ALM). • As ephemeris nav data, this is broadcast and not the RF. **** Week 893 at GPS time 601200 almanac for SV- 1 *********** ID: 1 Health: 000 Eccentricity: 3.85475158691e-03 Time of Applicability(s): 147456 Orbital Inclination(rad): 1.18643826563e-02 Rate of Right Ascen(rad/s): -8.04604943597e-09 SQRT(A) (m^1/2): 5153.685059 Right Ascen at TOA(rad): -1.88751916766e+00 Argument of Perigee(rad): -1.57416014892e+00 Mean Anom(rad): -2.71030399319e+00 Af0(s): 2.19345092773e-05 Af1(s/s): 0.00000000000e+00 week: 894

10. What do the files do? • Almanac Upload: Used to define the broadcast almanac data for the satellite orbits after an upload. (File extension is .ALM). • Simulates an upload of the Almanac Data. • Only 1 upload (historic). • Same format as almanac file.

11. What do the files do? • Global Nav Data: Used to define certain Navigation Data fields, in particular the UTC parameters and Ionospheric coefficients. (File extension is .GBL) ****** SV-1 GLOBAL PARAMETERS *********** UTC A0(s): 0. A1(s/s): 0. DeltatLS(s): 0 tot(s): 0 WNt(weeks): 0 WNlsf(weeks): 0 DN(days): 0 deltatlsf(s): 0 IONO a0(s): 0. a1(s/semi-circle): 0. a2(s/semi-circle^2): 0. a3(s/semi-circle^3): 0. b0(s): 0. b1(s/semi-circle): 0. b2(s/semi-circle^2): 0. b3(s/semi-circle^3): 0. REMAINING AS/SVCFG (4 BITS): 0x5 SVHEALTH (6 BITS): 0x00 SPARE BIT PATTERN (2BITS): 0x2 2 NON INFORMATION BIT PATTERN: 0x0 SPECIAL MESSAGE(22 CHAR): *1234567890123456789012*

12. What do the files do? • Ionospheric Delay: Used to define the ionospheric delay characteristics over a given period for each satellite explicitly, using a simple quadratic expression. (File extension is .ION). Iono Delay = D + Rt + 0.5At2 *WEEK 894 ! Time SVID Type Delay Rate Acceleration 0 3 1 0.6e-8 0.1e-8 0.0 24 22 1 0.1e-10 0.1e-14 0.2e-18

13. What do the files do? • Tropospheric Delay: Used to define the tropospheric delay characteristics over a given period for each satellite explicitly, using a simple quadratic expression. (File extension is .TRO). • Same format as Iono delay file.

14. What do the files do? • Nav Data Modification: Used to overwrite selected elements of the broadcast Navigation Data message for specified GPS satellites. (File extension is .NAV). • Like the Nav data editor in the constellation file. ! Header comment WEEK: 34 TOW: 123456 !The following Nav Data changes apply to all satellites SVID: 0 ! Set bits 21 and 22 to 1 in word 8 and 9 for all pages of subframe 1 SF 1:P 0:W 8:B 21-22: 00000C SF 1:P 0:W 9:B 21-22: 00000C ! Following changes apply to SV1 only SVID:1 SF 4:P 12:W 9:B 9-24: 001234 SF 4:P 12:W 10:B 1-22: 123456 SF 4:P 15:W 9:B 1-24: FFFFFF ! TOW: 123900 ! Clear all changes for all SVs SVID: 0 ! end

15. User Defined Data - Files • IEEE Hardware Control messages: • This file allows GPIB (IEEE-488) control messages to be transmitted to STR4760/80/90 and GSS7700/90 hardware during a run. • The timing and content of these messages are controlled by the user-specified file. • This file is intended for internal use by Spirent. • It may also be used by customers with special test requirements under the guidance/instruction of Spirent. • This Command would set P code on only on L1 for hardware channel 0: CHAN 0 L1CO 0

16. User Defined Data • Where User Defined Data files are specified then the information contained in these files supersedes the satellite characteristics normally applied, otherwise these are as specified by the GPS Constellation file • If only the almanac file was assigned, the satellite would be simulated as normal, except for the broadcast almanac data, which would be as defined in the user file. • All file formats described in User Manual

17. Any Questions?