Beginning on Jan. 8, 2023, some Cyclone Global Navigation Satellite System (CYGNSS) L1 samples with fill values for ddm_nbrcs and ddm_les did not receive a proper L1 fatal flag. This occurs only rarely from Jan. 8, 2023, to Feb. 2, 2023, and then slightly more often thereafter. Samples are affected when the spacecraft altitude is below 500 km altitude. This affects only the CYGNSS L1 data products. L2 and L3 data products have the proper quality control applied and are not affected.
Beginning with the data on March 9, 2023, the samples in the L1 files are receiving the proper quality control. The CYGNSS team is additionally working on an update to be able to calibrate these samples. The team will apply the update to the v2.1 and v3.1 algorithms after a remedy is generated. The next release of the CYGNSS data products, v3.2, will properly calibrate the samples below 500 km for the full dataset duration.