The format of the clean??.txt files, which are the correlated and
post-processed recordings, are as follows:

The first line is 8 numbers; for example:

4 2 1 3 0 -1 -1 -2

Numbers from 1...4 indicate a good guy ID that is consistent over 20 runs
for that day.  A value of 0 indicates a bad guy.  A value of -1 indicates
a civilian.  A value of -2 indicates that track was not used.

After the first line comes the following, repeating:

time_marker  #tracks_at_this_time
track_ID    position_x    position_y   rifle_heading   helmet_heading    trigger    hit    wam_arousal   wam_aibi
......same line for each track_ID at this time
[repeat whole block at next time]

The data is recorded synchronously at 20Hz, so time between blocks is 50 ms.

track_ID is a number from 0....#tracks
position_x and position_y are in cm, measured from bottom-left of house
rifle_heading and helmet_heading are in degrees
trigger is -2 => not pulled, -1 => miss, 0...#tracks => person hit
hit is 0 => no, 1 => yes (this person was hit, not this person hit somebody)
wam_arousal is a normalized measure of heartrate variability, -4.0 ... +4.0
wam_aibi is an instaneous measure of heartrate (ms since last heartbeat)

A value of -999 means a quantity is unknown.  For example, a bad guy 
is usually not wearing a WAM, and a civilian will not be carrying a
rifle, so there will be -999's for those quantities.

A value of -1 for a heading, either rifle or helmet, means the device was
tilted outside the range +-30 degrees, and so the heading is meaningless.
Valid range for heading is 0...359.