Jobs to do before a new flight season starts

Lever arms

If required, perform a survey of the positions of the instruments relative to the GPS antenna. We need sufficient information to compute the positions of:

• the GPS antenna(s)
• the LIDAR scanner (a measurement to the reference point on the case is sufficient)
• the RCD camera (a measurement to the reference point on the case is sufficient)
• Eagle
• Hawk
• TABI, CASI or any other imaging instrument that is installed

In all cases, a measurement to a suitable reference point on the casing of the instrument, plus an engineering diagram of the instrument, is sufficient. We have these diagrams for the Specim and Leica instruments.

These values should be recorded at:

LIDAR

Boresight calibration

Ideally we should use the Gloucester city calibration area as it has much more vertical relief. However, at the time of writing (2011), the area is not yet fully ready. Instead, we can use the Little Rissington site for the time being.

Just to add to what had been mentioned below, for the LiDAR calibration can you also ensure the correct lever arm values are entered into the flight planning software and check the scan encoder offset.

The lever arm values we currently have are (xyz): GNSS 0.019 -0.024 -1.692 IMU -0.411 0.206 -0.192 User Frame -0.142 -0.001 -0.188

In particular the User Frame values need to be correct as we have no way of adjusting these after data collection.

Scan encoder

The scan encoder measures the angle the mirror is at. At the start of the season, we should check the "centre/nadir" position is unchanged.

The procedure to check the scan encoder:

• Start up the system on the ground (no GPS or installation required)
• Run BIT mode
• Turn off 'Position In' switch on the front panel
• This will snap the mirror to the centre
• Then read F4's tick column,it should show the real scan offset and it should be within ± 500 ticks from the -10800 value
• Don't forget to switch on 'Position In' when you finish testing