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How-to RTK Height as Tide

This document describes how to use RTK Height as Tide.

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For offshore operations the heights from a GNSS receiver can be quite accurate, but still have some noise and sometimes even an incorrect height (spike).
The solution is filtering the height and presenting this as a pseudo tide.

This option has been added to the Computation Setup under the Height tab.
In order to actually use the RTK Tide for height aiding, the 'Unreliable height' computation must have top-priority and the 'Accurate height' computation must be further down the priority list of computations.

Computation Setup

Make sure that there are two computations available, one with Unreliable Height and one with Accurate Height.


 

In order to get this working, a database should have a top-priority 'Unreliable height' computation and an 'Accurate height' computation further down the list.

The height status of each computation is shown in the Computation Priority list on the Computation Parameters dialog.
This is useful on large installations on which a number of computations are being used.


Under the Height tab, the RTK tide can be selected as Tide method.

  • Tide filter type: a Median Filter or a Mean Filter can be set to filter out spikes.
  • Tide filter length: a filter length can be set in seconds for which the average tide is calculated.
  • Maximum age tide values: the tide values may be used until the maximum age, data older than the time entered here, is disregarded.
  • Tide object : the Mean of All Objects, Master Vessel Object, or Own Vessel Object can be selected to provide the tide value.

Regardless of which tide object option is selected, only above-water objects with accurate heights will be used for the tide filter.
The Own Vessel Object option will compute RTK Tide values for each accurate object individually, whereas the first two options (Mean of all objects and Master Vessel objects) will only compute one single RTK Tide value.


Info

The option RTK tide can be used Online and also in a Replay.

Info

To get the correct result make sure that the Height above Draft Reference (in Database Setup) and online Draft (online) are entered correctly.

Adding a draft sensor will improve the final results.

See for more information about the height aiding settings: How-to Height - Tide and RTK


Displays

The RTK tide value will be stored as an Observation in the database.
This observation can be used in the same way as any other observation in Qinsy.
It can be found under Computed Height of the Object.

Example Displays

Observation Physics:


Alert:


Timeplot:

Generic Layout Editor

It is also possible to select the RTK Tide value using the Generic Layout Editor.
The value can be shown in a Display, in a Logfile or Export file and can be output to another system.

In the Generic Layout Editor select the RTK Tide Value under Observation System from Raw Data.

Info

Note that this item is the same as item Tide under Height Aiding or as the item Tide under Tide Results.

Help for Generic Display Layout Editor

More information on the use of the Generic Editor can be found in this part of the Knowledge Base: Generic Layout Editor.

Return to: How-to Computation Setup