Raw Delph Navigation Read-Me

The navigation was recorded in the SEG Y trace headers in both the "source coordinates" location in bytes 73-80 and also in the "unassigned" fields in bytes 181-240. However, the "unassigned" fields are erased by SU when it processes the data. The navigation data in the defined fields are accurate to 1 s of arc, or 30.8 m. The data in the "unassigned" field are accurate to the accuracy of the GPS receiver, or 3-5 m. We used Delph Seismic software to strip off the navigation from the unassigned fields and provide it here. However, this was done before the long lines were divided, and therefore some do not match the SEG Y filenames or shot numbers (Delph Seismic software is no longer available). To reconstruct them, the first 20,000 shots would belong to the linename_a.tra file. Shots 20,001 to the end of the line would be in linename_b.tra file. The navigation data are stored in the rawdelphnav folder. Each file contains nine fields separated by a space and defined as follows:

Field 1: Shotpoint Number
Field 2: Longitude (decimal degrees)
Field 3: Latitude (decimal degrees)
Field 4: Heading
Field 5: Speed
Field 6: Fix Number
Field 7: Fish Altitude
Field 8: Date
Field 9: HR:MIN:SEC (UTC)