Due to the multiple effects of GPS signal attenuation and ground interference in some areas, from February, 2020, the Insight-HXMT satellite, which uses GPS signals as its primary time reference, has experienced time restoration errors in some events data. The effect is mainly on two aspects: local events shift and whole segment events loss. The former manifests itself as a small piece of data shift to the adjacent time, and the latter shows as an overall loss of data in a long period of time (ranging from a dozen to several hundred seconds).
We are very sorry for not identifying and handling these issues in time until the end of 2021. Since then, we have made an upgrade to the software and re-produced all data of this period.
After several months' efforts, the data for the period from January 2020 to March 2022 are now fully generated and the products on the data archive website have been updated to the latest version. Above-mentioned errors have been corrected. Please see the attachment below for a comparison of the data volumes between the old and new versions. Users who have previously used HXMT data to obtain scientific results are also advised to use the new data again to verify the previous results. We expect that the new version of the data will have little impact on the energy spectrum analysis, with the possibility of obtaining more good time intervals from data which were previously lost, thus improving the statistics for a specific observation. For timing analysis, the timing or phase delay related analyses may be affected to some extent. This update only involves the data of HE and LE telescope but not ME data.
In order to avoid version confusion，during the data upgrade, we suspended the release of data products, including the data distribution of guest observations and the public data outside the proprietary period. The data release has been resumed as normal since last week. We apologize to those who were unable to access the data in a timely manner. If any user is still unable to obtain the data you need, please contact us (firstname.lastname@example.org).
Appendix: Event Data Comparision Downloads