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Unmanned Spaceflight.com _ Phoenix _ SSI camera pointing, first 4 sols
Posted by: jmknapp May 30 2008, 08:18 PM
I've been playing with the ftp://naif.jpl.nasa.gov/pub/naif/PHOENIX/kernels/ for Phoenix. These can be used to among other things determine where the instruments are pointing to at a given time. Here are some results looking at where the SSI camera has been pointing for the first few sols:
It looks like so far they been using the SSI around 10-12pm UTC every day. The code to generate the plots samples the pointing info every ten seconds. Here are some detail views of each period of activity. It's kinda fun to try to figure out what their objective is in each run:
Kind of artistic, some of them.
The left eye shows much less activity--maybe it's only used for stereo imaging.
PS Sorry for all the large images--I don't know how to scale them down more.
Posted by: djellison May 30 2008, 09:48 PM
Those are very cool - I'm going to see if I can put together an animation or something based on them in some way. Which files, specifically, do you use within that FTP server.
(And SSI is the opposite of Pancam. SSI is right eye for colour imaging, left to add stereo)
Doug
Posted by: jmknapp May 30 2008, 10:13 PM
Working with the SPICE kernel files and library is maddening but at least there are a lot of examples and http://neptun.umea.irf.se/~peje/spice/req/index.html. It's really tricky to figure out which kernel files are needed, so I ended up putting in all the Phoenix "CK" (instrument pointing) files, as well as "SPK" (ephemeris) files. In addition, a "frames" kernel is needed which defines the spacecraft/instrument frames and the ftp://naif.jpl.nasa.gov/pub/naif/PHOENIX/kernels/fk/phx.tf is at least worth looking at for the cool ASCII art of the spacecraft and instruments. There's also a "SCLK" (clock) kernel and an "LSK" (leap second) kernel. In short, it's kind of a bear.
As for the code, it goes something like this
utc2et_c(DATE,&et); // convert UTC string to ephemeris time et
sce2s_c(PHX,et,MAXCHAR,sclkch); // convert et to spacecraft clock ticks sclkch
scencd_c(PHX, sclkch, &sclkdp ); // convert sclkch string to double sclkdp
ckgp_c(PHX_SSI_LEFT_EYE,sclkdp,tol,"PHX_TOPO",cmat,&clkout,&found); // see if camera pointing is defined for this sclkdp
if (found) {
vequ_c(cmat[2],vinert); // pointing vector in PHX_TOPO frame is the 3rd column of cmat
reclat_c(vinert,&r,&az,&el); // changes rectangular coords to latitudinal
az *= dpr_c(); // convert to degrees
el *= dpr_c();
et2utc_c(et,"ISOC",0,MAXCHAR,utc); // get UTC string for this et
printf("%s %.6f %.6f %.6f\n",utc,r,az,el); // print the record
Maybe if you say what data you need for the animation I could make a windows app to produce it.
Posted by: djellison May 30 2008, 10:56 PM
Well - you pulled that data into an XLS didn't you - they look like Excel '07 graphs. The XLS would do fine. I THINK ( but I'm not sure ) that 3ds max can import text (which I could make from the XLS) to do animation - if not I could animate it by hand fairly easily. The one that starts 27.8280 would be a nice start - it's 144 seconds worth I think. I could do it at 5x or 10x speed to show the bobbing camera motion for taking mosaics. I'll need to make a model of the SSI to start with though 
Doug
Posted by: jmknapp May 31 2008, 01:11 AM
Doug
OK, here's a comma-delimited file:
http://marsdigg.com/righteye.txt
That's an animation I'd like to see!
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