I have the bn-220 GPS installed on my quad, and the first time I tested it it was bad and the altitude reading was all over the place, as well as the functionality of the RTH (constantly trying to climb up reaching 100+ meters when it's at 300 already, because the altitude reading was already bad in the first place).

Anyway, I read a bit and changed the GPS location to the top of the frame, far away for the other electronics and with a good view to the skies, the second and third flights were great and everything worked perfectly.

Today I went to fly it again, and not only that the altitude was all over the place and the quad didn't stop climbing up, there was another thing..
I activated RTH at 500 meters from home while flying 80kph away from the home point, the quad balanced itself, but continued to drift, and when I saw that it isn't trying to fix itself at about 1.1km I deactivated RTH and flew it back home.

I was flying with 12 satellites, GPS defaults(although I think I should maybe set it to more than 32 degrees but I don't know). What could cause it?
I flew several batteries today and experienced the same issues.

Quote:I have the bn-220 GPS installed on my quad, and the first time I tested it it was bad

That's says a lot, Other's say the same. Other's say the Matek are better, I have a Maytek gps and it works as expected it also has a compass which i like.

Maytec Gps  this one has a barometer and compass too, Which would give you better altitude reading. (but you would need to solder two extra pads for the compass.)

I guess if the altitude is off as you say, How will the flight controller perform not good, I would expect with bad data.

(29-Mar-2021, 06:27 PM)sircolin Wrote: That's says a lot, Other's say the same. Other's say the Matek are better, I have a Maytek gps and it works as expected it also has a compass which i like.

Maytec Gps  this one has a barometer and compass too, Which would give you better altitude reading. (but you would need to solder two extra pads for the compass.)

I guess if the altitude is off as you say, How will the flight controller perform not good, I would expect with bad data.

This GPS has a compass AND a barometer built in? wow, I thought for a barometer you had to have something big on your quad.

About your last sentence, my set altitude in BF is 50 meters or maximum height, and the quad just went 120 meters in the air(according to GPS, but it was higher than 120m), which is waaay higher than the maximum altitude, and it just kept on rising until I took manual control.
Seems like something related to software & the GPS giving bad data, the thing is that it worked perfectly.. so Matek is the way to go?

I have the BN220T mounted on my SourceOne above the FPV camera and I get a gps lock in under 15 seconds. Make sure you twist the wires as this helps and keep it aways from the esc and vtx.

Betaflight does not have a Return to home, it is GPS Rescue. Basically it is helpful if you lose rc control of your quad as a failsafe or you activate it if you lose video. It does not matter to me if it drifts a bit as long as it starts to fly towards me and I take manual control of the quad.

If you ensure the GPS get a lock before you arm then it will set the home position.

Also before you go long range its best to test GPS Rescue.

I always prefer a barometer onboard the FC for the quads I plan to put GPS on.

If you need good RTH functions then iNav is a better option.

(30-Mar-2021, 09:16 AM)kafie1980 Wrote: I have the BN220T mounted on my SourceOne above the FPV camera and I get a gps lock in under 15 seconds. Make sure you twist the wires as this helps and keep it aways from the esc and vtx.

Betaflight does not have a Return to home, it is GPS Rescue. Basically it is helpful if you lose rc control of your quad as a failsafe or you activate it if you lose video. It does not matter to me if it drifts a bit as long as it starts to fly towards me and I take manual control of the quad.

If you ensure the GPS get a lock before you arm then it will set the home position.

Also before you go long range its best to test GPS Rescue.

I always prefer a barometer onboard the FC for the quads I plan to put GPS on.

If you need good RTH functions then iNav is a better option.

I understand that it's not an actual RTH, and I know it's purpose is to get your video and RC signal back to take controls manually.
I stated that it drifted for 600 meters before I took manual controls to save it, and the altitude issues are probably another indicator that something isn't right.

I guess you are right though, I think a barometer, compass and GPS will give me the best results, it's just that the simple thing of going towards my general direction, it successfully failed ><

A compass and a barometer are not necessary for GPS rescue although it helps.

But a reminder that a compass is more sensitive to electrical interference and needs to be positioned away from any electrical noise else the effects are far worse.

A barometer would only provide altitude data and is more accurate compared to gps altitude. However this would not add any benefits to gps rescue direction.

But drifting 600meters is too much. Something is not right.

Do you have the Betaflight minimum number of satellites set to 8? Do you wait for a gps lock before arming? Also I prefer setting the home point to first arm in case I need to land and take off again.

While flying do you suddenly lose satellites or a gps lock?

Can you enter the GPS coordinates in Google maps on your phone to see if it locates you close enough?

Also when flying, does the home arrow on the OSD point in the right direction? Try flying straight ahead of yourself to test this.

What version of Betaflight are you using? I remember 4.1 had some issues that were fixed in 4.2.

(02-Apr-2021, 11:50 AM)kafie1980 Wrote: A compass and a barometer are not necessary for GPS rescue although it helps.

But a reminder that a compass is more sensitive to electrical interference and needs to be positioned away from any electrical noise else the effects are far worse.

A barometer would only provide altitude data and is more accurate compared to gps altitude. However this would not add any benefits to gps rescue direction.

But drifting 600meters is too much. Something is not right.

Do you have the Betaflight minimum number of satellites set to 8? Do you wait for a gps lock before arming? Also I prefer setting the home point to first arm in case I need to land and take off again.

While flying do you suddenly lose satellites or a gps lock?

Can you enter the GPS coordinates in Google maps on your phone to see if it locates you close enough?

Also when flying, does the home arrow on the OSD point in the right direction? Try flying straight ahead of yourself to test this.

What version of Betaflight are you using? I remember 4.1 had some issues that were fixed in 4.2.

I have the minimum set to 5 or 6 I think, I take off when I have minimum of 8, I had 11 at that specific flight.
I don't lose satellites midflight, it's pretty stable actually, and I have the home point set at first arm for the same reason you do.

I'll try to check the coordinates to check that, and about that arrow it was kinda off by 45 degrees at one of the flights, the others were fine enough (max 20 degrees).

I read that BF4.1 had issues and I am using the latest of 4.2.

thanks for the help, I'll check the DVR for the coordinates and the footage in general

Hi all - I recently reconfigured a quad and put a previous BN220 I was using elsewhere on it. I’m getting strange behavior where it only acquires satellites if I’m flying around and the moment I disarm again it drops to zero satellites. Has anyone ever seen this? This bn220 worked perfectly on my other quad and this quad worked just fine with another unit I had on it.

Thanks!

A friend of mine who works in the broadcast industry used this to mitigate the interference problems with the GPS serial data link to the FC
https://www.digikey.com/en/products/deta...2/13618905

it cost around $1.60 USD per foot
it is a twisted pair shielded cable ( 2 pairs inside )
so you can connect GND, VCC , TX1 and RX1 to it ( or any free UART you have on your FC like TX2 RX2 or TX3 RX3 and so on )

i made a diagram of a BN-220 connected to a MAMBA F4 FC

The pinout of the BN220 Below

check here
https://intofpv.com/t-gps-rescue-why-it-...ot-to-home
i had similar problems on bn220

on mateksys everything is fine (without compas) but i have not best place to mount it so probably thats why