Dual antenna - lag / slow response / delay

Hello everyone,

In lack of BNO08x, I decided to try to make system with dual antennas. I ordered ESPDuino and one more f9p and made a “sandwich” of ESP+one f9p+second f9p just like mtz8302 explained in his repo (in pdf) AOG_GPS_ESP32/Dual GPS setup.pdf at master · mtz8302/AOG_GPS_ESP32 · GitHub

The problem is that the system is lagging somehow… Like it has some delay, idk…

Both modules are flashed with config file mtz8302 provided, so 8mhz refresh rate… All dimensions entered in ESP (antenna height, the distance between antennas, blah, blah), changed to USB as the operation mode (instead of UDP, I’m still using a version of agopen 5.5 I think), Web Server disable after 1 minute so ESP has more processing power… And it lags A LOT.

I compared a single antenna (with f9p directly plugged into the USB port) and then a dual antenna (over ESP), it has a delay of position update… Maybe even a 1 second or so delay…

It’s like I turn the tractor right and then after 500ms - 1s, maybe even more it starts updating the position… At this moment I’m using it without auto-steering, and it’s impossible to manually catch an AB line with such delay…

What might be a problem? Can someone help me?

The first thing I would do is open each f9p and in configuration view, open gnss. Un-tick everything except GPS, glonass, and gallileo in the enable column. They are default and won’t disable with a configuration upload. Then set rate to 10hz.
This is probably not all of the problem but will help.
Before you do that, reload the configs. A lot of times on a new f9p all of the configurations don’t transfer on the first load. I dont know why, but I’ve had it happen twice.
Then set your gnss

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might be a windows WiFi problem.
Please try the beta code it supports ethernet too (w5500).
Other possibility would be to try Franz jeep1945 code.
Other possibility would be to use USB.

Greetings Matthias

Hey, I’m already using USB (tried both USB and USB x2)… I don’t have equipment for UDP right now so I’m sticking with 5.5 AgOpen for now and USB protocol for ESP32…

Thanks for the info @Jhmach, I didn’t know that the config file can’t override constellations, there were 6 enabled and I now just left enabled GPS+GLO+GAL, also I loaded the config file 3 times again… Will see tomorrow if there is any improvement…

If not, are there any other things to do before trying jeep1945 code? Is the pinout the same as the MTZ one?

I believe MTZ and jeep1945 are same pinout.

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Sad news…

Enabling just GPS+GLO+GAL didn’t help… Also, 3 times reloading configs, didn’t help… Double-checked all measurements, and everything is correct… Tried both USB and USB x2 - didn’t help…

The position update is lagging…

Also when you are stationary, or when you stop, some weird positioning is happening, see the videos…

Anyone, please?

@MTZ8302 can you help? Also @Jhmach maybe you can help here?

Why is this happening, how can I fix this?


Data source dual in AgOpenGPS set?

I think you don’t get a heading with the 2 f9p.
Rx,tx crossed between the f9ps ( needs to be x)?

To debug:
Activate wifi hotspot at your phone, connect tablet and esp32 to the phone.
Set ssid and password and data transfer via wifi UDP at the esp. Webinterface, if access point is made by esp.
Set Agio to correct IP, don’t forget to send.
With this your USB port at esp is free to debug.
Start degugmode ubx at esp Webinterface ( Browser 192.168.x.79 ) and check with serial monitor.

Here you can see if the esp gets the data it needs.

Greetings from Germany

Yes, that was a problem… I thought there needed only TX → RX connection between the right and left antenna, didn’t know that it needs to be also from the right to the left… I also resoldered all the connections, and it started working… THANKS!

Where do you recommend placing antennas? I placed it directly above the rear axle and I’m literally unable to follow the line manually because of slow feedback (when the rear axle is off ~3cm, the front axle is off 20+cm and once I start correcting it, I overshoot the line to the other side, etc…)

Should I move antennas more forward?