Experiences with low cost M8N GPS modules?

[J0S0L0]

It seems that real world experience and hard data are not being accepted in this discussion. That was the whole point of the thread - to share real world experiences. I believe that those experiences stand on their own. The subjective opinions don't carry much weight for me. If they are important for others - that's fine. There seems to be little point in going around and around on the merits of opinion vs. hard data. People must choose the criteria upon which they make their choices on their own. I have nothing more to add.

At the end of the day, it would be more beneficial if people would bring the real world numbers to the table, and not a bunch of heresay.

Appreciate all your help, looking forward to my next project. Thanks KDan....

 

[AOtarolaR]

well just out of curiosity and despite all the advices i bought the Beitian MN-800... after some struggling installing it... i took the Solo outside just for a test (I am at a populated area so I don´t flight here) and it get 15 sats... but "red" on the controller... so.. no good HDOP, can´t say the number cuz my phone is charging (with the stock rev a gps i got good HDOP with just 7-8 sats)... but this was just a quick test... when I do a real field test i´ll let you know the results

 

[TheRedEyeBandit]

well just out of curiosity and despite all the advices i bought the Beitian MN-800... after some struggling installing it... i took the Solo outside just for a test (I am at a populated area so I don´t flight here) and it get 15 sats... but "red" on the controller... so.. no good HDOP, can´t say the number cuz my phone is charging (with the stock rev a gps i got good HDOP with just 7-8 sats)... but this was just a quick test... when I do a real field test i´ll let you know the results

my experience so far is the same... My cheap gps seems to get more stats then my rev b but it also seems like it requires more for an equal hdop and OK to fly. Takes much longer to get 'ready to fly' then my rev b as well...

That said, I've not been able to fly in an open area (I'm surrounded by tall trees and houses) and I want to take a look at my install to make sure I didn't do something that would be causing get interference...

In the couple of flights I've made I've had up to 19 sats and hoop of .7

 

[rcflyingaddict]

my experience so far is the same... My cheap gps seems to get more stats then my rev b but it also seems like it requires more for an equal hdop and OK to fly. Takes much longer to get 'ready to fly' then my rev b as well...

That said, I've not been able to fly in an open area (I'm surrounded by tall trees and houses) and I want to take a look at my install to make sure I didn't do something that would be causing get interference...

In the couple of flights I've made I've had up to 19 sats and hoop of .7

Do you use the same copper shield or are you guys putting a spacer in between?

 

[TheRedEyeBandit]

Do you use the same copper shield or are you guys putting a spacer in between?

I've got a 3dr rev 2 shield, the 3d printed mount listed at start of thread and I cut the old copper shield such the it just fit over all the components on the gps board ( I saw a video on YouTube where someone else did this.. I think they might be active on this forum. Anyway....)

Ive not made many flights with the new gps but so far I'm disappointed with the time it takes to achieve 'ready to fly' and as noted by other guy above, I need to have substantially more sats locked on before I can fly (like 10 to 12)...

Once locked on and flying, I'm getting 17 to 19 so far with hdop of .7 (which I think is pretty good?) And it seems to function as it should. I flew out of range to trigger rth and it did what it was supposed to...

All that said, with rev b, 3d printer shield/spacer and rev 2 gps shielding I get 'ready to fly' faster with 7 sats needed , lock onto 12 to 13 while flying with hdop of .7 to .8

The only reason I really wanted to upgrade was to be ready to fly faster which so far I've not seen.

I'll do some more test flights before I put rev b back in but so far that's where I'm leaning.

Maybe I got a bum chip or manufacture defect etc, as others have cited quick sat locks... idk it was $18 so IDGAS

 

[rcflyingaddict]

I'm rather impatient or should I say have gotten used to turning drone's on and flying. My two Solo's have Rev B's and both are ready to fly in under 30 seconds with 10 sat's to 13-14. I'm not sure what 17+ sat's get's you to be honest. I could see doing this if you had a rev a that did not function.

 

[TheRedEyeBandit]

I'm rather impatient or should I say have gotten used to turning drone's on and flying. My two Solo's have Rev B's and both are ready to fly in under 30 seconds with 10 sat's to 13-14. I'm not sure what 17+ sat's get's you to be honest. I could see doing this if you had a rev a that did not function.

I've got a rev a on shelf which I'll test it on before I toss it or not! I'll keep you all posted on that one too

 

[Pedals2Paddles]

Satellite quantity does not equal position quality. Neither does HDOP. The sat count and HDOP are actually not even considered by the autopilot beyond the arbitrary parameters (minimum 6 sats and 2.4 HDOP). Neither of those numbers mean a thing. The GPS being usable to the autopilot is all about position quality, which boils down to velocity stability and drift compared to the accelerometers. A quality GPS with good hardware and good filtering can and will have more stable position with less sats and higher HDOP than a piece of junk cell phone GPS with better looking numbers on the screen. So if you're shopping solely based on price and sat count, expect to get what you pay for.

 

[skyhax]

I've got a 3dr rev 2 shield, the 3d printed mount listed at start of thread and I cut the old copper shield such the it just fit over all the components on the gps board ( I saw a video on YouTube where someone else did this.. I think they might be active on this forum. Anyway....)

Ive not made many flights with the new gps but so far I'm disappointed with the time it takes to achieve 'ready to fly' and as noted by other guy above, I need to have substantially more sats locked on before I can fly (like 10 to 12)...

Once locked on and flying, I'm getting 17 to 19 so far with hdop of .7 (which I think is pretty good?) And it seems to function as it should. I flew out of range to trigger rth and it did what it was supposed to...

All that said, with rev b, 3d printer shield/spacer and rev 2 gps shielding I get 'ready to fly' faster with 7 sats needed , lock onto 12 to 13 while flying with hdop of .7 to .8

The only reason I really wanted to upgrade was to be ready to fly faster which so far I've not seen.

I'll do some more test flights before I put rev b back in but so far that's where I'm leaning.

Maybe I got a bum chip or manufacture defect etc, as others have cited quick sat locks... idk it was $18 so IDGAS

Tape the GPS to a foam pad.
Micro vibrations are murder on all GPS chips but maybe even worse on the cheaper ones.

 

[jca]

Satellite quantity does not equal position quality. Neither does HDOP. The sat count and HDOP are actually not even considered by the autopilot beyond the arbitrary parameters (minimum 6 sats and 2.4 HDOP). Neither of those numbers mean a thing. The GPS being usable to the autopilot is all about position quality, which boils down to velocity stability and drift compared to the accelerometers. A quality GPS with good hardware and good filtering can and will have more stable position with less sats and higher HDOP than a piece of junk cell phone GPS with better looking numbers on the screen. So if you're shopping solely based on price and sat count, expect to get what you pay for.

Hey P2P, did the open solo update (excellent video BTW) but am wondering what to do about my compass. I had a bad leg compass so purchased a cheap GPS with compass and changed the compass orient parameter like in the here video and everything's been working great. With the open solo update it wouldn't let me load the here parameters (recognized I didn't have a here), do I have to do the mission planner thing again? Thanks for any advice.

 

[Pedals2Paddles]

With the open solo update it wouldn't let me load the here parameters (recognized I didn't have a here), do I have to do the mission planner thing again? Thanks for any advice.

Just try again. Solex does not know whether you have a HERE or not. There is no means by which to even tell that. With that being said, I do not know what the orientation of whatever cheap GPS/Compass you got is. It is probably the same as the here (0). But who knows.

 

[J0S0L0]

After weeks of waiting, I finally received my second Beitian BN-800 GPS. The plan was to do an antenna swap using the taoglas antenna off the the stock rev. a board. The transplant went great with no issues. After a few flights, I will post my findings...

 

[cynfab]

If you are planning on using that BN-800 with GPS & Glonass, you will not have as good a signal level as with a real GPS/Glonass antenna.

http://www.taoglas.com/wp-content/uploads/2015/04/GP.1575.25.4.A.02.pdf --> original Solo & mRo
vs.
http://www.taoglas.com/wp-content/uploads/2015/04/CGGBP.25.4.A.02.pdf --> Antenna designed and specified for GPS/Glonass service.

It will work and receive Glonass sats, but not as well as it could.

Digikey has the GPS/Glonass ones for about 5 bucks + shipping +tax

CGGBP.25.4.A.02 Taoglas Limited | RF/IF and RFID | DigiKey

 

[jca]

Just try again. Solex does not know whether you have a HERE or not. There is no means by which to even tell that. With that being said, I do not know what the orientation of whatever cheap GPS/Compass you got is. It is probably the same as the here (0). But who knows.

It did take the Here settings yesterday. Flying today, will see how it works....

 

[J0S0L0]

If you are planning on using that BN-800 with GPS & Glonass, you will not have as good a signal level as with a real GPS/Glonass antenna.

http://www.taoglas.com/wp-content/uploads/2015/04/GP.1575.25.4.A.02.pdf --> original Solo & mRo
vs.
http://www.taoglas.com/wp-content/uploads/2015/04/CGGBP.25.4.A.02.pdf --> Antenna designed and specified for GPS/Glonass service.

It will work and receive Glonass sats, but not as well as it could.

Digikey has the GPS/Glonass ones for about 5 bucks + shipping +tax

CGGBP.25.4.A.02 Taoglas Limited | RF/IF and RFID | DigiKey

Good information... Thanks!!

 

[jca]

It did take the Here settings yesterday. Flying today, will see how it works....

Flew great today.

 

[J0S0L0]

Swapping out the stock Bn-800 antenna for the taoglas worked out better than expected. The gps lock is amazing...

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[KDan]

Swapping out the stock Bn-800 antenna for the taoglas worked out better than expected. The gps lock is amazing...

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Great work. I knew the stock antenna on the BN-800 was likely holding it back a little. Still, even with the original antenna it easily outperforms the stock 3DR units on both of my Solos.
Also - for those who think the ReadytoFlyQuads Mini-8 is better (it isn't, it's identical to the BN-800), you can now buy it at RTFQ's for even less. The Mini-8 is now just $17 - shipped from Florida. You can even order extra cables.
I just got one of the Micro uBlox M8N's from them for $15. It's only 18mm square and weights 6 grams. I'm using it in the 3D printed Mavic clone I'm currently working on.

 

[AOtarolaR]

Swapping out the stock Bn-800 antenna for the taoglas worked out better than expected. The gps lock is amazing...

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can you put the link to that GPS chip?
thanks!

 

[John Githens]

I think that putting any GPS on a mast is going to make a big difference on a Solo. The location of the stock GPS seems to be the cause of much of the issues.
I believe that 3DR let the styling take precedence over the engineering design. The GPS is too close to the electronics, and not located completely above everything that could partially block the GPS antenna view of the sky.
I've built DIY quad's with older Neo-7 modules that have much better GPS performance than the Solo. The difference is the GPS mounting location.

I agree with your assessment of the location of the stock Solo GPS receiver. FWIW, I went the route of installing two mRo GNSS receivers in impconcepts masts. And an earlier Drotek GNSS receiver in an impconcepts mast. A bit of DIY drilling and cable extension work, but all three work very well, given the local trees, buildings, hills and other location attributes. For reference in the field (or just outside) I check the GPS Plan app on my iPhone to see which satellites are possible for the GNSS receiver to lock to at my current location (and assuming a flat, uncluttered landscape which it almost never is on my jobs), and as allowed by the elevation mask setting. The most sats I have seen locked to-date is 28, but that is rare. On the app, the two views I use are the bird's eye view of the globe, then I swipe to see the optimal time of day to launch. Nifty to see the change from hour to hour in forecasted DOP values based on which satellites are visible. I tried one of the cheap GNSS products, but I'd rather not take the risk on a paying job.