Accuracy and limitations

Accuracy and limitation can be captured in the Abstract and/or Lineage, although the ISO19115 MD_Resolution (Spatial resolution) provides a rough guide to the precision and accuracy of a resource.

The accuracy and limitations are inherited from the navigation and MRU sensors used. These vary from sensor to sensor and are available from their respective fact sheets. Teledyne Caris provides summary of all known sensors in their website (https://www.teledynecaris.com/en/products/total-propagated-uncertainty/ ). While horizontal resolution is ancillary sensor dependent, the vertical resolution of the soundings is frequency dependent of the multibeam echosounders used.

Examples:

POS MV WaveMaster & WaveMaster RM

Main Specifications (with Differential Corrections):

Roll, Pitch accuracy: 0.03° (1 sigma with GNSS or DGNSS), 0.02° (1 sigma with RTK)

Heave Accuracy: 5 cm or 5% (whichever is greater) for periods of 20 s or less

Heading Accuracy: 0.03° (1 sigma) with 2 m antenna baseline, 0.015° (1 sigma) with 4 m baseline

RTK Positioning Accuracy: Horizontal:±(8 mm + 1 ppm x baseline length), Vertical:±(15 mm + 1 ppm x baseline length), Note: RTK accuracies assume 1 m IMU-GNSS antenna offset

DGPS Positioning Accuracy: 0.5 - 2 m (1 sigma) depending on quality of differential corrections

Velocity Accuracy: 0.05 m/s horizontal

These uncertainty values are required by the processing software (e.g. Caris) in their vessel configuration (Figure 1) to compute total propagation uncertainty (TPU) which is required when creating L3 using CUBE algorithm.

Figure 1. Example uncertainty entries in Caris vessel configuration for the above POSMV example.