As part of a multi-nation aircraft development program, HGL has been involved in providing a key element for the decoding and analysis of data recorded during flight tests.
The recorded data sets are captured using two independent recording systems, in different data formats. Dynamic signals are recorded in HDF5, and lower-rate parameters are captured using IRIG-106 format. The HDF5 data sets contain some channels recorded with fixed intervals between adjacent samples, so that spectral analysis can be easily carried out. However, a large number of the channels in the HDF5 sets are recorded with highly varying intervals between adjacent samples. Since the end user of the decoded data needed to be able to make cross-spectral comparisons from this data, it was necessary to re-sample all of the channels measured at non-constant sample intervals.
The IRIG-106 telemetry data sets also required special handling. In order to decode the streams successfully, it is necessary to be able to locate the sync word patterns in the data. However, these sync patterns were not always correctly recorded in the original flight test data. This meant that HGL had to rapidly develop sync recovery techniques for handling the data sets which were not recorded correctly.