Summary of Session 2M Swarm 5th Data Quality Workshop 7th-10th September 2015, IPGP Paris

ASM-VFM Scalar residual ASM Vector data STR IBA Euler Angle Summary of Session 2M ASM-VFM Scalar residual ASM Vector data STR IBA Euler Angle

ASM-VFM Scalar Residual (1/2) Performance of current solution: Established and implemented model for correcting magnetic data, reducing scalar residuals between ASM and VFM to below 175 pT with good predictability in time. A/B/C disturbance model shows very similar features of α, β dependency. Disturbance directions is different across A/B/C but this is expected due to unpredictability of the generated current loops. Exact source(s) still not identified but remains the ultimate goal.

ASM-VFM Scalar Residual (2/2) Current empirical model has reached a robust and mature stage that can be improved by synergy with physical proxies, mathematical and statistical observations. Further investigate physical observations with the aim of introducing them into the model : The co-estimation of VFM parameters and Disturbance model shall result in a physical interpretation on both aspects Thermal filter to be consolidated and introduced in the model Lack of physical explanation for Sun dependent scaling, sβ. Temperature information could improve disturbance model Poor determination of y-axis related disturbance. Potential field (to constrain model) ? For plasma-induced disturbance investigations more information on the platform is needed. Continue investigations on residual distributions (why not Gaussian?) and frequency structures to relate them to physical characteristics.

ASM-Vector Boom seems to be remarkable stable ASM asymmetry to be further investigated (B-unit?, ASM-Charlie data) With fixed alignment (selected from daily estimation approach), comparison of BASM (mapped to VFM using fixed rotation) with BVFM yields dBSun(α, β) that is similar to the one determined using scalar characterization. But also presents a remaining α-dependence in the disturbance model maybe due to the inter-orbital change of rotation. Discussion on alignment approach : Alignment error budget (from industry) could help in developing a thermo elastic correction approach (e.g. fix structure parameters post-processing for thermo elastic variation taking into account also orbital variation) Possibility of building a joint model (the α, β –dependence) of VFM disturbance (residual) and mechanical distortion

STR IBA and Euler angle STR IBA Variation correlated to temperature. Physical sources under investigation. Correction model currently being developed. Euler Angle Suggested verification of the aberration correction (not connected to IBA). Estimation of VFM-STR alignment (Euler angles) reveals time dependent variations of up to 20”, strongly correlated with LT of orbit : likely caused by unmodeled external field contributions (FACs of ≈ 1 nA/m2, external fields of ≈ 1 nT). Effect to be further investigated. The Euler angles presently used in L1b processing should be updated  suggestion of having a dedicated working group to define updated Euler angles (static) for next version (re-processing) of L1b data.