True heading from PPK processed data output in ENU format

Hi there, have used Emlid Studio in Kinematic mode to process two RINEX files from GNSS receivers that are essentially in a moving baseline mode.

To be more specific, the GNSS receivers were mounted on a ship at the bow and stern, which whilst moored alongside a pier was subject to the effects of tide and wash of passing ships etc.

I am trying to achieve true heading by outputting from Emlid Studio in E/N/U-Baseline format, then doing some math to calculate the heading based on the dE & dN output. However, when comparing with online PPP processed data and computing azimuth from Latitude and Longitude I get some 2° bust in heading.

Normally on a UTM derived E/N output we would apply a convergence value to convert from Grid North to True North, but that is a function of the distance from the central meridian. How does one apply the equivalent of this convergence to ENU coordinates to get True Bearing? Do I need to transform the ENU coordinates into ECEF and then calculate the heading?

Any help would be much appreciated.

Hi Mark,

Welcome to our community!

I can hardly suggest something specific, but I know some of our users worked on similar setups. For instance, you can check the discussion in this thread. Maybe they can provide more details.

Hi there,

Thanks the reply. I took a look and whilst very similar, it’s not quite the same.

They are trying to calculate heading on the fly from the Lat & Long positions on the ECEF, whereas I am calculating heading from the Eastings / Northings on ENU.

Thanks for the suggestion though.

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