Two different elevations; did i doing something wrong...?

I usually never post process only because i can recieve corrections via CORs. Here is my “normal” workflow, and then ill explain my issue later.

  1. Set up Base module, and receive corrections from CORs.

  2. Wait for “Fix”

  3. Have reach “Average” the “Fix” position for 15mins.

  4. Manually enter “Averaged” coordinates for Base Module and turn off CORs corrections to Base, this is now my “known location” for RTK.

  5. Set up Rover module, and receive corrections from Base module.

  6. Wait for “Fix”.

  7. Start survey/project/etc.

This next test was done in my front yard. Alittle about my yard… Large trees in all directions, powerlines about 5’ above reach antenna but 30’ to the north, tv coax cable about 5’ above reach antenna but 25’ to the north, my house is within 6’ of the tripod; single story home but still rises above antenna.

Heres what i did tonight…

  1. Set up Base module, and receive corrections from CORs.
  2. Wait for “Fix”
  3. Turned on Raw(ubx) logging, and Base Corrections(rinex3.03)

Elevation Mask: 18*
SNR Mask: 33*
GPS, Glonass only
Position: Kinematic
GPS AR: Fix-and-Hold
GlonassAR: OFF
Update: 1hz

(((Averaged Coords: 40.8267354162 , -81.9279369104 , 303.039 - (ant:1.905m) = 301.133)))
***These above coordinates were from a 15min average using the Base reach module “Averaging Tool”, the Base was receiving CORs corrections to get this “Fixed Average”.

Next i ran the logs through rtklib convert, post, plot…
I will attach the logs during that time; after changing the time stamps to remove the float signals at the beginning, here is the averaged coords…40.826748784 , -81.927946701 , 298.1505 .

It is showing an elevation of 298.1505 without an antenna correction. With my antenna height it would be corrected to 296.2445.

That is a difference of about 4.8895m.

So, did i do something wrong with my post processing(again, i dont usually have to but thought id try)? Or is something else going on?

Please help.

Raw Data: UBX from BASE MODULE (1.2 MB)

Base Correction: Rinex3.03 from BASE MODULE (647.1 KB)

Screen shot: Shows difference in outcomes

First thing i notice is Q=1. If you select all, does float or any other status apper?
If this screen is the same as the one you used to average it would also calculate all solutions.
So just selecting Q=1 doesnt unselect the other when average is done.

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Yes, if selecting ALL a few random floats appear. I adjusted my time stamps in processing to remove as many Float signals as possible(the ones at the beginning before it reached a “fix”). I only see about two inside the green area “Fix” area. I’ll keep adjust my time stamps/samples to get those removed to see if it helps any.

I understand by selecting Q-1 it still averages ALL points. I will try to adjust my time samples to the same as my actual 15min Reach Average and not the whole log time, or I’ll try to adjust and remove any remaining floats signals that are still lingering.

I’ll try again after work, thanks!

Also, check that RTKPOST is set to ellipsoidal height.

I get the same as this. Try deleting RTKpost config file and process again, Also, did you use Rinex header in base coordinates?

I will try again after work.

To be honest, the Rinex Header I’m not sure about. I will also have to confirm this later.

Thanks for all your help. It must just be me, haha. I’ll grasp this eventually!

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