The following data comes directly from S1B_IW_SLC__1SDV_20180426T063818_20180426T063845_010651_013707_1395.SAFE\annotation\s1b-iw1-slc-vv-20180426t063819-20180426t063844-010651-013707-004.xml:

-

2018-04-26T06:38:19.750001

GM2000

2.048773e-01

3.932928e-01

3.003435e-01

8.444761e-01

-5.878133015357889e-05

-9.468332864344120e-04

-4.792133113369346e-04

-6.302749733477862e+00

-5.238290812737592e+01

4.225907254185638e+01

I can not find *any* set of equations to convert from the provided quaternions (q0-q3) to pitch,roll,yaw and vice-versa. Yes, I have started with all of the ESA published documents and then expanded out to multiple other documents on the web. I have coded every variant I have encountered in Matlab, but am unable to get numbers that agree to even to the ones digit. I have even tried to use different application sequences (instead of just the published 3-2-1 order).

Worse from a documentation point of view, I believe that here Q3 is the magnitude, but almost all Sentinel-1 documentation defines Q0 to be the magnitude of the quaternion. I get that it is generally not consistent and/or both are acceptable - BUT a given system should be self-consistent.

As you might expect, this is a key step to being able to associate each formed image pixel with an exact ground coordinate. Without an understanding of how to apply (q0-q3) to be pitch,roll,yaw it is clear any attempt I take to use them for vehicle rotation/orientation will be wrong. "Close" isn't good enough - I need the full, exact understanding so I can precisely apply the vehicle orientation to my image formation.

Please, don't just point me to Wikipedia or some web page - try the numbers first - I have.

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