This is most likely due to a bit transition in the navigation data. PRN 32 may not be acquired in the first millisecond of the record. These GPS L1 signals are present in this record (sorted from the strongest to the weakest): PRN The record length is approximately 1 second and it was made in 2008. In this record one signal sample is stored as one signed byte (int8). The intermediate frequency is 4130400 Hz. The signal sampling frequency is 16367600 Hz. However they will be useful for someone who wants to verify the GNSS signal acquisition and tracking algorithms. These records are too short for the regular GNSS positioning algorithms. On this page a few samples of GNSS signal records will be provided.