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Scanner Position

by Mats Holmström last modified Apr 21, 2015 09:26 AM

The scanner position for ASPERA-3 and ASPERA-4 as a function of time

The scanner position is reconstructed as a function of time for ASPERA-3 and ASPERA-4. The input data is the scanner position counter from instrument housekeeping (HK). The result is available as text files for MEX/ASPERA-3 and VEX/ASPERA-4 with two columns. The first column is UT time. The second column is scanner position in degrees (computed by multiplying the raw scanner counter with 90/116.625). The scanner position at times not given in the file should be computed by linear interpolation. The same information is also available as SPICE kernel files for MEX/ASPERA-3 and VEX/ASPERA-4

The above data files are updated nightly using the latest HK available.

NOTE This is an experimental product at this stage. It is automatically produced from all available HK packets. There are known problems, e.g., some positions are greater than 180 degrees, the conversion from scanner position counter to degrees is inaccurate, the time resolution is sometimes low (8 sec), and the MEX full scan sessions needs manual reconstruction.

Note also that the last position in the files corresponds to the last position available from TM.

The scanner position is also incorporated into our field of view plots for MEX and VEX If you find a text like "scanner at 10 deg HK" at the top of the plot, it means that scanner position information was available at the requested time and used for the plot.

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