I have 20 hrs of raw data and used Auspos to get ITRF cartesian co ordinates.
I have 14 sats but can still not get a fix, has about 600mm in Hz and 1.150in the V.
Any ideas on why I cant get a fix / so far out - using RTK2go as a castor and Z9 esp32 thing+.
What is your acquisition setup?
Zf9p to esp32 via wifi. Antenna is mounted on fixed pole. Sparkfun zf9 example 14
You usually need more than 14 for RTK (fewer are strictly required, but they need to be spaced out and of the same band) AFAIK
Does the antenna have anything blocking its view of the sky?
yep good view of the sky.
What I don’t get though is why are we going to cms in ecef co ords. It’s already in meters.
Does RTK2go need it in cms?
//-1280208.308,-4716803.847,4086665.811 is SparkFun HQ in ECEF coordinates so…
//Units are cm so 1234 = 12.34m
/ Units are cm with a high precision extension so -1234.5678 should be called: (-123456, -78)
(-128020830, -80, -471680384, -70, 408666581, 10,
I don’t really understand this bit.
For those trying to follow your ramblings at home, confirm you’re working through this example
The TMODE of the ZED-F9P takes ECEF coordinates to a .1 mm precision, so each axis X, Y and Z are broken into TWO integer components, as the settings don’t use floating point parameters
The fractional part is +/- 100 (10 mm or 1 cm), and the comments in the code try to explain this decomposition.
I don’t really understand this bit.
It might help if you review the Interface Manual for the ZED-F9P firmware.
https://cdn.sparkfun.com/assets/f/7/4/3/5/PM-15136.pdf#page=243
Does RTK2go need it in cms?
Not really, what it expects the Base Receiver to be sending is an RTCM3 Message 1005 which has the TMODE ECEF coordinates in it. The Base Receiver will NOT be in RTK mode, it will be in TIME mode. If the coordinates disagree with the receivers own perception of position this will degrade to NO FIX
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That is correct
Ok, then for it to work you’re going to need to edit the sketch to reflect the ECEF position of your antenna
So I have put the ECEF from my auspos into the sketch.
For example the Cartesian X from AusPos is -5036612.004 which I put into the sketch as -503661200, -40,
Have I got that correct?
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Hi @Wocky1 ,
I found this site useful for WGS84 ECEF coordinates (adjust the cookies according to taste!):
If you’re somewhere ~near Brisbane, -5036612.004 would be the ECEF-X in m:
-5036.612004 km
-5036612.004 m
-503661200.4 cm
-503661200 cm, -40 * 0.1mm
To enter that in the Example14_NTRIPServer code, you would use:
response &= myGNSS.setStaticPosition(-503661200, -40, , , , , false, VAL_LAYER_RAM);
To make the position ‘permanent’ (RAM, Battery-Backed RAM and Flash) use:
response &= myGNSS.setStaticPosition(-503661200, -40, , , , , false, VAL_LAYER_ALL);
I hope this helps,
Paul
Just for giggles:
Here are the coordinates for SF HQ copied from the Example14 code:
The antenna is indeed at about the midpoint of the SW face of the building, up on the parapet.
Enjoy!
Paul
Ah. But. A little caution is needed…
If you click on the map at that exact same location, the reported coordinates are very different:
Why? After a little head-scratching, I figured it out… When you click on the map, it is reporting the ECEF coordinates for WGS84 Altitude 0m. Not the actual altitude.
Hope this is useful,
Paul
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Very useful, thanks Paul.
I an beginning to think that I am missing something very simple like these Cartesian Co ords entered into the zed F9 and the sketch need to be in WGS84.