Instrument Boresighting

When fitted in the aircraft the remote sensing instruments do not have a prefect nadir pointing direction. Typically this will be off by a small amount (a fraction of degree) in 3 degrees of freedom. This angular offset needs to be calculated to get precise geocorrection and positioning on the ground. To show the importance of this, for example, if there is an error of 0.5 degrees in the view vector, at an altitude of 1000m this could lead to an error of about 10m at the swath edge.

Every time the instruments are placed in the aircraft a new boresight flight has to be undertaken over the calibration site. This may just be at the start of the flying season or multiple times throughout the year. At the end of the flying season a boresight flight is undertaken to check if any change has occurred.

Hyperspectral Boresight Procedure

Flight requirements:

• Multiple flight lines taken along different flight paths
  • Opposite and overlapping: e.g. 1 line North and 1 line South
  • Parallel and overlapping: e.g. 2 lines East
  • A third direction: e.g. NorthEast

Typically we collect fully overlapping flight lines going along the compass directions: N, NE, E, SE, S, SW, W, NW

Processing technique: