get_lun,unit
file='bolide_SVS_output.xdr'
nsteps=0l & nparcels = 0l

;** open data file
  openr,unit,file,/xdr

;** read array dimensions
  readu,unit,nsteps,nparcels

  time = fltarr(nsteps) ;** time array

;** read time vector
  readu,unit,time
  
;** define the lat, lon, and altitude arrays  
  lonsave = fltarr(nsteps,nparcels) & latsave=lonsave & zsave=lonsave

;** read arrays
  readu,unit,latsave,lonsave,zsave

close,unit,/all
free_lun,unit

end