1. FGM report 9 th Cross Calibration Workshop Paul French, Elizabeth Lucek, Chris Carr, Patrick Brown, Tim Oddy, Andre Balogh Imperial College London March 25 th 2009 Paul French pjfrench@imperial.ac.uk

2. Presentation outline  Long term offset trends – spin plane  Long tem offset trends – spin axis  Consequences of spacecraft separation for solar wind analysis  Conclusions

3. Long term offset trends – spin plane 1/3 Of the 192 calibration parameters – the y-component for spacecraft#1 is shown for ranges 2, 3 and 4.

4. Long term offset trends – spin plane 2/3

5. Long term offset trends – spin plane 3/3 Spectrograms for the spin-plane: Cluster#1 indicating spin tone (left) Cluster#2 reduced spin tone (right)

6. Long term offset trends – spin axis 2/2 Showing the component offset for range 2, cluster#1: Unable to use solar wind analysis during main tail season - So linear interpolation is required over this period (May – Oct) Low variance within the spin-axis

7. Consequences of spacecraft separation 1/3

8. Consequences of spacecraft separation 2/3

9. Consequences of spacecraft separation 3/3

10. Conclusions We have a large volume of data and statistics spanning 8 years – these will be studied in future as time permits Initial study reveals sensor spin plane y offset drifts less than <1nT over 8 years (except S/C1) Calibration is carried out on all 4 spacecraft for data, where each instrument requires separate calibration for each range (2, 3, 4 and 5), and each range requires a calibration matrix containing 12 elements. This creates 192 (4*4*12) calibration parameters which are open to investigation.

11. Thank you