P294READER
P294Reader reads and processes raw navigation data from P294 files. It can understand data written by both Gator and Dolphin. It can process source airgun data with side slung arrays or up to 3 towed arrays with RGPS pods. It can also process drop positions and acoustic positioning.
The application filters raw data to attempt to eliminate bad readings, but it does not smooth data. It can process in single file or batch mode. It has a number of variable parameters and can record many vessel setups in the Position database.
When processing drop positions, it will output computed positions in SPS format. When processing acoustic data, it will output vessel positions and corrected ranges as well as other information about the run to a CSV file, which can be read and further processed by OBQC. When processing source data, it will output to both a CSV file with source COG’s and other information, and an SPS file with COG positions.
It will process depth information from the echo sounder and lay it back to either the drop position, the acoustic transducer or the source COG, depending on the data type. It will apply tide corrections if selected and if information is available.
It will check vessel node positions and speed of sound against previously read values and will alert the user if any of these values change. This can detect accidental changes to settings which sometimes occur.
The warning notice above was issued when P294Reader noticed a difference in node offsets it read from the P294 file compared to the previous readings for the same vessel. It has also detected a new acoustic transducer node that wasn’t present before.
The application will issue warnings if any data appear to be missing or erroneous and display them in the log screen. If anomalies are detected, they will also be issued to a log file for each P294 file that has anomalies. These may be viewed later if necessary.
The image above shows P294Reader after having processed 40 raw source data files in batch mode. The log screen shows that no anomalies were detected in the raw data.
P294Reader is now just used as a backup application which can produce completely unfiltered results using an independent algorithm if required. Gundog is now the main raw marine source data processing application.