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.
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Set up Base module, and receive corrections from CORs.
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Wait for “Fix”
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Have reach “Average” the “Fix” position for 15mins.
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Manually enter “Averaged” coordinates for Base Module and turn off CORs corrections to Base, this is now my “known location” for RTK.
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Set up Rover module, and receive corrections from Base module.
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Wait for “Fix”.
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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…
- Set up Base module, and receive corrections from CORs.
- Wait for “Fix”
- 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 raw_201801282138_UBX.zip (1.2 MB)
Base Correction: Rinex3.03 from BASE MODULE base_201801282138_rtcm3.zip (647.1 KB)
Screen shot: Shows difference in outcomes