SPIKE Orbit Model Update Tools Requirements
A. Vick, W. Kinzel, G. Soutchkova,W. Workman
Overview:
The purpose of these tools is to provide updates to the tables SPIKE used for determining a target’s orbital viewing. These parameters come from the SPSS orbit model and must be updated at least once per year depending on
the degradation of the HST orbit.
Specific and Generic Capabilities Needed:
• The Tool Must:
• read hst orbit fits from the SPSS database
• calculate TJD (Truncated Julian Date) for all fits
• plot semi-major axis vs. time
• have a way to identify the fit interval and other locations on the plot
• fit the semi-major axis with a linear and quadratic function of time
• plot the semi-major axis data with the linear and quadratic fits superimposed
• produce the "error quality plot", (difference in RA of Ascending node of model and spike model vs.
time)
• calculate spike constraint set parameters, and write them to a file
It Would be Nice For the Tool to Have:
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all capabilities merged into one tool
an interactive plotting tool, such that you could
- highlight a fit interval
- highlight a plot interval
- read the mouse position in graph coordinates
an option to print plots to paper or screen
constraint set parameters written out in spike syntax
output that was a complete spike constraint set file. (would need to copy the old file, so another input is
not needed)
the time scale in yyyy.ddd format instead of TJD on plots
legends on all graphs
a user interface using yyyy.ddd time format instead of TJD
the tool read only the latest hst orbit fit per epoch out of the database
the tool use definitive instead of 10 week predictive hst orbit fits
Tool Can Live Without:
• changing the planning interval in the spike constraint set file, (would need to be a multiple of 7 days)
• having the tool check the linearity of the precession rate vs. time
(just a consistency check on the SPSS fit data.)
SPIKE Orbit Model Update Tools Requirements
May 10, 2001
1
User Interface Features:
• inputs needed are fit_start, fit_end, projection_end (in time), possibly the name of the old constraint file, possibly a parameter to print plots.
Exisiting Algoritms:
• list_hst_orbit_fits, fit_hst_orbit, fit_orbit1.for in [LRP.TOOLS]
• list_hst_orbit_fits.sql in [LRP.TOOLS.SQL]
SPIKE Orbit Model Update Tools Requirements
May 10, 2001
2