Computing Total Propagated Uncertainty

Total Propagated Uncertainty (TPU) is derived from a combination of all individual error sources. The following errors (among others) contribute to TPU:

• nav/gyro/heave/pitch/roll/tide errors

• latency error estimate

• sensor offset error estimates

• individual sonar model characteristics

TPU is essential for the following functions:

• creating S-44 or S-57 compliant datasets

• calculating surfaces weighted by uncertainty (see Uncertainty Weight)

Static values are stored in the vessel file for the survey. Sonar error values are stored in the DeviceModels.xml file in ...\HIPS\System. Other static errors can be directly entered in the Compute TPU dialog box. For some formats, real-time errors are stored for each line.

The following sonar error-models in the DeviceModels.xml have been tested by the University of New Hampshire (UNH).

• Atlas Hydrosweep DS

• Elac Nautik 1180

• Seabeam 2112

• Teledyne Reson SeaBat 8101

• Teledyne Reson SeaBat 9001

• Teledyne Reson SeaBat 9003

• Teledyne Reson SeaBat 8125

• Kongsberg EM300

• Kongsberg EM1000

• Kongsberg EM1002

• Kongsberg EM3000

• Kongsberg EM3000D

Other sonars listed in the file may make assumptions that could produce less rigorous results than these error models supplied by UNH.