I am using ads, f9p, ublox antena and Brick. Using 2 antena is there a big difference with accuracy?
I thought your re using dualheading.
There is no dual heading, there is a dual GPS that defines coordinates and heading
Hello, has someone experience better precision with dual antenna heading and roll ? or is it too soon to go for ?
Thx
Hello, I‘m using dual heading from AOrtner. On a flat field it works well.
When the tractor sways the heading is a little bit unstable.
On the otherside you can stop and go on and you are stable on the line.
have you seen a terrain compensation (i e you come from both side of a inclined field(hill side) and are guided on the same track ?
Thx
The reason to use 2 gps to generate a heading is so you can avoid getting the heading from a magnetometer
Magnetometers are very susceptible to error due to magnetic interference and the dual gos is not
One gos is set up in moving base the other uses a fixed base
The output of this is a fixed position and an accurate heading
That, i did understand, what i wonder is if you have 2 antennas side by side at a certain distance, then you could probably calculate a Roll as a machine never really slide much and the difference of altitude and more could give you a roll degree and so the need for a Roll sensor could also be avoided.
Yes
the dual antenna system id so accurate that if you orient the antennas at right angles to the longitudinal axis it will give you roll. It also provides position and heading
Max
any experience with AgopenGPS ?
What happened to your github repo @Aortner Aortner?
Very intrested in trying to run a dual simplertk2b setup for accurate heading, but struggling with how I can get the heading input into AOG. Thanks
sorry its active now again…
Thanks for that @Aortner , how are you getting on with it? Assume you have the two antennas mounted to the left and right of the roof? Do you just set the AOG antenna offset (side to side) to the primary F9 antenna?
It would probably be best to take the average of the two antennas. is that possible?
Always seems “wrong” settings the receiver off center with an offset, but putting them front - back would loose the ability to make roll calculations using the two which I think would be a shame.
As you say Brian an average / the center point would be ideal but guess that would have to be calculated via the Arduino being used to calculate the heading / roll using Aortner’s code…
Got dual GPS to work with 2 Ublox f9p and esp32. Data can be transferred via USB or Wi-Fi.
It corrects the position by using roll and creates a virtual Antenna position.
Just an early release.
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I see you have antenna height in set-up, what would we need to set Aog height setting?
When using two antennas do they each produce a fix at exactly the same time or close enough to? The reason I ask is because I notice you’re applying the kalman filter to the calculated roll before computing the virtual antenna position. If the two positions are computed at the same time, why is the kalman filter needed at all? After all if antenna 1 is position x, and antenna 2 is position y, then the compensated position is known to a high-ish degree of accuracy is it not? I suppose the accuracy of GPS is probably around 4cm for altitude, so after extending that to the ground, the accuracy of the fix itself could be significantly reduced, and thus noisy.
Also I’ve been wondering what value for the earth’s radius to use when doing these calculations. I looked at the UTM transforms and while they are ellipsoid, not spherical, they seem to use two value, 6378137 and 6356752.314, at least for the common WGS84 ellipsoid. I notice you used 6371000.8 metres. I suppose the best value here depends a lot on where one is in the world. I found that a value closer to the larger UTM value seemed to be pretty close to the results I got by converting first to UTM and then adjusting for roll and offsets.
[quote=“Brofarm, post:58, topic:184, full:true”]
I see you have antenna height in set-up, what would we need to set Aog height setting?[/quote]
I’m assuming zero since the sketch already compensates for roll and generates a virtual lat/lon position that’s already on the ground as it were.
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If roll is compensated before AOG gets the position set AOG antenna hight to 0.
The earth radius is the middle between those of the ellipsoid. As the virtual move is small, the miscalculation should be ok. When moving some km we should do better.
The two receivers are connected directly with the Ublox moving baseline feature. So the timing is the problem of them. I tried also calculations with GGA, the parser is in the MISC.ino. It didn’t work due to a bug in code in tan calculation (forgot to do radians) and now I didn’t test again.
Filtered roll and heading is necessary before calculation. When position changes in last digit at only 60 cm antenna distance roll/heading changes much.
Today I was driving and I reduced the filter, so it got much faster. Also the direction of virtual Antenna right was wrong.
On github now
Video of the test on YouTube
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