Base station fixed position – how to set high precision coordinates

Q&A forumCategory: QuestionsBase station fixed position – how to set high precision coordinates
cono44 asked 3 months ago

Can anyone tell confirm how to set the high-precision coordinates for a base station set up in fixed mode? I understand from the integration manual I can sepcify the ECEF XYZ coordinates in mm using the high precision configuration items. 

The high precision option for each of the position types allows you to enter the value in mm
compared to the standard cm value.

The range of values permitted for the ECEF_X_HP, ECEF_Y_HP, ECEF_Z_HP are -99 to +99, scaled by 0.1 so the range is -9.9mm to +9.9mm

High-precision ECEF X coordinate of the ARP position. — Accepted range is -99 to +99.
This will only be used if CFG-TMODE-MODE=FIXED and CFG-TMODE-POS_TYPE=ECEF.

I am assuming I therefore need to set both the “normal” CFT-TMODE-ECED_X/Y/Z items in cm plus the CFT-TMODE-ECED_X/Y/Z_HP  items containing the mm values.

clive1 replied 3 months ago

Yes, you’d need to decompose the value into the cm and sub-mm fields. Basically compute the cm number, save that, subtract it out, and then write the 0.1 mm unit remainder. You could use the UBX-CFG-TMODE3 form if you’d prefer.

Typically you’d want to arrive at these values via post-processing

cono44 replied 3 months ago

Thanks Clive , that’s what I figured. Ended up using the UBX-CFG-TMODE3 as you suggested anyway since CFT-TMODE-ECED-Y wouldn’t update correctly for some reason.