UTCAP is similar to UCAP, but a time/date stamp is automatically inserted into the output file every 10 minutes. This enables the program to be run unattended, allowing the user to check whether OSCAR-11 is transmitting or is silent.
TIME_DIFF is a Windows program for calculating the clock error. It performs the same function as TIME_ERROR, but reduces the amount of typing for repeat calculations.
The magnetometer calibrations have steadily changed during the many years in orbit. Although the changes are small and are not noticeable on a plot of individual channels, they do have a considerable effect when the total magnetic field is calculated.
Yoshi Hashida of UoS has now supplied some recent calibrations for the magnetometer channels, optimised for the WOD dated 06-October-2000. These give good results with the current data. The new calibrations are -
BX = 0.152*N - 69.8
BZ = 0.146*N - 65.3
BY = 0.155*N - 71.0
where N is the WOD value. BX, BZ, BY are the magnetic fields along the X, Z, Y axes respectively, in micro-Tesla.
These calibrations should be used for the current data. The previous calibrations should be used for data several years old. Thanks Yoshi.
The failure is in the conversion of two digit year number used in the Keplerian elements to the four digit form used in PLAN13.
The problem is the subroutine Save_kep. The line
YE = YE + 1900
Was changed to -
IF YE < 70 THEN YE = YE + 2000 ELSE YE = YE + 1900
The second modification was to change the FIX instructions to INT as described in the corrections to PLAN13QB below. This change did not have any effect on the output from SATILL and ORBILL. However the output of ORBMAG was slightly changed, although not noticeable on a plot. The revised output should be more accurate, and may help with recalibration of the magnetometers.
1. Replacement of FIX functions by INT. During development of the program I had replaced the INT functions by FIX in order to cure a problem. It didn't work, and I forgot to remove the modification! The mod causes the program to generate some negative values for MA, which is used in the output display, and processing for ORBMAG.
2. Replacement of leading spaces in hours & minutes of time display by zeros.
3. Addition of an extra digit to display of Doppler shift (RR).
Many thanks John for your feedback.
I have also updated the file BBC2QB. This was done for another project, and now goes beyond the needs of the PLAN13 conversion. However it may be of interest.
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