Temperature dependency of ACC data TUD provides all available GPS-derived linear accelerations to VZLU End of January – end of May To be used for validation of temperature correction by VZLU  Target date: 24/06/2014 VZLU produces temperature corrected linear acceleration data Some problematic periods with large number of steps and spikes may be omitted Data sets will be made available to TUD and Ales Bezdek for validation  Target date: 02/07/2014  Does the temperature correction work well for all periods and all S/C? If not, under which conditions does it work well?  Do the parameters of the temperature correction model optimized for one period produce good results for other periods? Further decisions to be decided in teleconference ~ 04/07/2014. Note: ESA & DTU as Prime (Poul Erik) in cc ACC summary

Temperature dependency of ACC data (continued) TUM provides STR-derived angular accelerations to VZLU  End of January – end of May, all S/C  Target date: 04/07/2014 VZLU cross-checks model for temperature correction using STR-derived angular accelerations (note: priority remains on linear accelerations)  Target date: 01/08/2014 Continue to improve temperature correction Treatment of steps, etc. in L2 depends on temperature correction in L1b ACC summary

Steps, etc. Cause for sudden changes in bias (and scale factors) remains unclear Flag detected steps, spikes, pulses, etc. at L1b, but do not correct (should give indication when characterization of instrument changes) Treatment at L2 is open issue Continue to investigate steps (we do not give up!) Request for macro model Messages for scientific users New temperature correction gives promising first results, in particular for along- track axis (ongoing investigations) Swarm C provide significantly better acc data than Swarm A and B Accelerometer data contains unexpected large number of steps and other disturbances that are not understood (physical cause not clear, treatment of steps under investigation) Accelerometer data not yet ready for general user community (release date unclear) ACC summary

Recommendation for access to  house-keeping data (BUS and AOCS)  FOS daily reports (for step investigations)  Indicate location of accelerometer temperature sensors in L1b documentation  Temp. corr. Test data will be made accessible to Cal/Val teams  Processing including temperature correction needs to be documented (algorithm, input parameters, etc.)  Investigate smoothing of accelerometer data at L2 (~10s)  Action: Distribute latest version of L1b product definition Issues with data sets observed:  Data sets contain zeros at beginning and end (S/C mass, frontal area)  S/C mass show mass variations (positive and negative!), should be fixed ACC summary