Discrepancy between flatearth2lla and ned2lla outputs

I am currently running a model that uses a flat earth coordinate system as the primary reference frame but requires information from an earth-centered frame. For the conversion to geodetic coordinates (LLA), I have been using the ned2lla() function from the Navigation Toolbox; however, I would like to use the flat2lla() function from the Aerospace Toolbox or the Flat Earth to LLA block from the Aerospace Blockset instead. Both of the Aerospace blocks, however, differ in their reported altitudes from the ned2lla output, with the flat2lla altitudes being consistently lower than the ned2lla altitudes. This occurs even if I specify the WGS84 ellipsoid in the call to the flat2lla() function (the Aerospace Blockset block does not appear to have an ellipsoid option in the same way that the ned2lla function does).

Is there a way to perform the flat earth -> LLA conversion in the Aerospace Blockset/Toolbox in the same way that ned2lla uses the ellipsoid method (rather than the 'flat' method)? This would be very helpful as it would allow me to use the Aerospace functions to replace the existing Navigation function.

[Saurabh]

Hi @Thomas,

I've noticed that you're experiencing different outputs when using the "ned2lla" and "flat2lla" functions. It's important to note that both functions tend to produce similar results when the query point and the reference point are in close proximity. However, discrepancies can arise when these points are significantly far apart.

[Paul]

@Thomas

Can you provide examples that show the different results from ned2lla and flat2lla