XYZ ECEF output Velocity FIX? Emlid XYZ output?

[PotatoFarmer]

I am trying to use the XYZ coordinates for my project but need some clarification;

the output of the Emlid looks like this;
Date YMD; Time UTC; X; Y; Z; Q; NS; Sdn; Sde; Sdu; Sdne; Sdeu; Sdun; Age; Ratio;
2020/12/22 04:09:21.000 -1428457.0271 -3517077.7930 5109034.7497 5 13 0.4026 0.2311 0.9605 0.0000 0.0000 0.0000 0.00 0.0 (END = HEX 0x0A)

What these Sigma are? Why are they relevant?
SDN?
SDE?
SDU?
SDNE?
SDEU?
SDUN?

I need to find a way to create messages including

message 1
Xvelocity?are these in the Emlid output?
YVelocity?
ZVelocity?
Bias Rate in m/s? I am guessing i will calculate this.
Time of fix GPS seconds (will have to back calculate this)

message 2
X position, in emlid output
Y position, in emlid output
X position, in emlid output
clock bias in meters? Guessing i will need to calculate of fudge this number.
Time of fix in seconds (will need to back calculate)

message 3 Sigma info
time of fix (back calculate)
rms, in emlid output "Ratio Factor?
sigma east? sde or sdeu?
sigma north?
covariance E-N? Calculate or guess
Sigma Up?
Semi major axis m? Calculate or Guess
Semi minor axis m? Calculate or Guess
orientation radians from true north? Calculate or Guess

Yes i have read the RTK lib manual, and yes it does not explain anything other than XYZ position only in the output on page 102. And Yes I have googled and searched this subject both on the web and this site.

I am on the fence if it will be easier to use xyz, llh or nmea, either way i will have to back calculate some, spoof others, and guess and check a few. I just need to find which format is the most complete.

But I really need to know the fully explained plain english description of the output fields of Emlids XYZ format please. That way i will know what messages i do not have to scavenge for.

[kseniia.suzdaltseva]

Hi @PotatoFarmer,

At the moment, I’m checking this with the team. I’ll get back to you with an answer as soon as possible.

[PotatoFarmer]

Hello @kseniia.suzdaltseva

I have checked the generic ZED F9P manual and have found all of these values explained in its configurable binaries. Then ordered a spark fun F9P board to continue developing with.

If the emulation of the 252 receiver is successful I can give you a more detailed list of the ECEF data needed by the emulator to make EMLID compatible.

But I have a feeling each generation of agricultural receiver may change its position input requirements drastically. Also looking into the newer 372, and SF6000 to see what messages are output by them for guidance.

[kseniia.suzdaltseva]

Hi @PotatoFarmer,

Let me describe what the sigmas mean so that you can double-check your findings:

• SDN, SDE, SDU - the standard deviations of the solution for North, East, and Up axes, showing how far a given point is from average.

• SDNE, SDEU, SDUN - the standard deviations for North-East, East-Up, and Up-North. Reach receivers don’t provide them, so the values are always 0 in XYZ ECEF output.

It would be great if you can provide a list of the ECEF data that allow using Reach in your setup. It will help me to check the possibility of implementing this with the team.