This is by far the most comprehensive and detailed evaluation I’ve seen. Great work.

Fantastic analysis. Thank you for revisiting this!

Brilliant work Professor 2D

Nice and detailed test, thanks for the effort you put in!

Your visualisations are very clear and informative! Great work! Thank you!

Wow...Much better details/data... Thanks Chris

This is just so interesting. Thank you for sharing, it's inspiring to see.

Wow, impressive data analysing! Great walkthrough of the errors Great job Thanks for sharing your experience with all of us 👍😀

Amazing work! Thanks for sharing.

This is amassing work. M9P is really the best choice period now. fantastic video

This is such brilliant stuff, thanks for doing this testing. I'm probably crazy, but this is actually very reassuring for how I'm using my pile of BN-180 and BN-220 units, because being within 5m is more than adequate for my uses, but knowing that the M8P would be worth it for position hold navigation is exactly what I'd want to run.

wow, what a great job of representing data! thanks for this masterpiece!

Super nice view you got down there!

your job is very good

I love how much detailed info you're able to cram into this, and yet still make it so easy to follow and understand! lol I've used several of these GPS modules for my flying over the years and never really noticed much in the way of accuracy or performance differences, other than some of them lock much quicker than others at start up. lol That said, this makes it clear to me that uBlox is probably the way to go, especially the M8N seems to be a good performer. I don't think I've seen a module targeted for FPV with the M8P, or maybe I wasn't paying attention if I did. ;) Excellent job!

No kidding Chris great data. Thanks

Awesome vid, thanks mate!

that was just what I needed thanks

Glad my comment was useful! Your comparison is now by far the best I’ve seen, loving all the visualizations. But again the poor performance of the BN-880 is surprising to me along with the decent performance of the 7M. Maybe my 7M is a fake and just a 6M? The decent performance of the BN-880Q just makes it more confusing. I guess I’ll have to look closer at my past data again. And yes, my username is a Monty Python reference as a result of my name being Tim Chant and thus I’m often called the 'electronics enchanting wizard'.

Brilliant exploring and visuals and great data set and explanations. Pretty sure the best I’ve seen. I wouldn’t say mistakes made, just the raw process of learning exposed. It’s courageous of you to put out videos that are impossible to edit once published. (youtube is an interesting and somewhat scary medium to share original content) At 13:35 you say separating into “two groups”, I see 3 distinct groups. The heat-map plots at 16:44 and 15:30 really highlight the accuracy of data collected from individual units. • Group1 { MSP, M8N, 7M } … most consistent position data • Group2 { BN180, BN880, BN880Q } • Group3 { BN220, 6M } … least consistent position data A merged overlay for each of the 3 groups would really show similarity of GPS units in each group, and contrast the 3 groups (or levels of accuracy, consistency). For “true GPS” reference position, you might want to do weighted average of the 3 groups, something like a 3, 2, 1 weight, or 2, 1, 1 weighting. This weighted average “true GPS” reference position may better highlight the inaccuracies of individual units. Weighted average would help reduce the “smudging” effects you mention at 28:57 from the less accurate GPS units. BTW: At 27:50 … Are you sure it’s the 7M that’s off, not the 6M? Like you said, I’m expecting the 6M to be one doesn’t belong in this group (Group1 as I noted above). See 7M vs 6M at 14:40 … that seems to contradict the plot(s) at 27:50. I’m a bit sad as just received 3x BN220 units that I ordered 3-4 weeks ago. Have to thank you in advance, as your results will save me some future head aches. Also thinking to set up a similar experiment to test my 3 BN220 modules for my region. Likely a winter project, as I’ll just use the units for now, having better insights. Many thanks for sharing your deep dive into GPS data.

❤ very nice!!!

18:00 I have no idea about it but that looks pretty cool 👍

We had the same crappy weather over in Qld a few days back, now it's cold as (well, for sunny Qld anyhow)

While not RTK, its incredible how good gnss has got.

19:37 - Dang! You could use the yellow/red dots to (seems like a matched pair in terms of resolution, sample-rate, lag, etc.) to also determine the absolute heading of a thing without relying on compasses

A very comprehensive and well explained video. Thanks for efforts of finding breaks in the weather. Being in Melbourne (AUST) I understand your pain this time of year. Have you thought of doing the test against an RTK setup to show the advantages of an RTK? I realise that this is quite expensive, although not as bad as it used to be. Just a thought as it would provide a good control signal. Thanks for your videos.

Couple of observations. You can do a contour histogram of position. Or if you are just looking at one of height, lat, long, you can do a histogram which shows the spread and any offsets nicely. ie. A vertical alignment of histograms, then the x-axis as a consistent range between all. The other interesting thing would be to check to see if there is any correlation between the different devices when it comes to errors. Is there a relationship where positions tend to move in the same direction. Otherwise interesting.

If you could add support for non UBX mode GPS modules, this could be a real series. There are so many different GPS chipsets out there so it would be very interesting to see a comparison. The other problem is trying to have many UARTs available to simultaneously test multiple modules. Thanks!

i alway like the video fist, because i know i'll enjoy it. Thanks

Super interesting thanks! Can you do a comparison with an M8P utilising RTK? Your previous video on RTK showed an improvement but it'd be great to see this detailed analysis.

I wonder if different gps devices use different Kalman filters. I think some units try to detect if they are stationary or moving and use different filters based on that. So, while moving, there can more or less different results. Switching to 10Hz should improve accuracy, especially when moving. (Most modules calculate and filter position at the output Hz rate. More Hz means more data and seems to give better accuracy to points at least when moving). I think at least some older Ublox modules had different modes for stationary, moving (with low change in elevation like car) and flying (where there can be a lot of height change).

One may think about the wondering or rotation of the sats in space while looking from really far away on to a point on earth?? then the ones that are wondering more probably have lock down to the farthest sats.... I do however am impressed by the M8N I mean unless that particular antenna is locked down in to the closest possible satellites "Very much directly in top?? but no because the test give you a whole 10 hours meaning that GPS antenna changed satellites at least 130 times... great work, probably not a subject for every one !!

Hi, will there be a video again soon? Your videos have always been so entertaining and instructive! I feel withdrawal symptoms ...

Goddamn that's fascinating!

Right now I'm watching a lot of your older video series again, like the Farm Rover or the ardupilot experiments. I am right to say that if you did this again, would you get significantly better results after discovering this accuracy problem? Thank you very much for sharing your experiences!

Your test data and visualization are impressive! I did have one thought to pass on. I noticed you seem to have taped some of the modules down. I'm no RF engineer, but I've always wondered about the effect that dielectric plastic coverings might have on the ceramic antennas used in these GPS modules. Would the extra capacitance the tape adds shift the center frequency of these antennas enough to matter? If so, the GPS antennas which come with tight fitting cases would presumably need be tuned to account for this effect when they are manufactured. I've always added heatshrink to bare GPS modules and hoped it wouldn't matter. Your test methods might actually be sensitive enough to answer this question in a practical way by testing identical modules with and without cases or plastic tape, then switching and testing again to control for sample differences.

Just need to mention that almost all the modules you use have a ceramic antenna patch that is usually connected to a single chip amplifier directly on the feed into the board. This basically makes "active antenna" moot.

It'd be interesting to see C/N0 and pseudorange performance metrics between the different modules. Seeing pseudorange variation for the same PRN/Frequency between the various modules would be a good indicator of the tracking loop performance for the various modules. Some of performance issues on the lower performing modules could be from bad measurements for satellites (multipath, bad Iono/tropo, etc). Checking for multipath in the measurements would be interesting. There should be a few chips of variation between the multipath signals and the regular signals (on the same PRN different Freq), accompanied by a lower than average C/N0 if they're present.

Great and comprehensive comparison! Would be awesome to see a comparison between the newer Beitian models (BK with M9 and BE with M10) and maybe also the more expensive Matek SAM-M10Q. Did you get to use any of those?

+1👍 !!💪

You should try the ATGM336H module, I've seen some good written reviews about it, but there is so little documentation about it, it can track the Chinese constellation too, some people claiming that they sometimes caught 20 satellites with it.

Good, but I miss to compare same with RTK fixed station, that should be on another level.. But need the long range wifi or other way to transmit this information to the modules tested.

Excellent comparison! I use the Matek “M8Q”...do you happen to know if that is actually a different module, or is it essentially a M8N?

Are you OK, 3 Months is a long time. We need more of your Videos.

your weather is just like england, thanks for the correction video, If you can find the fence post on google earth can you tell which gps was closest ?

hello sir, nice video thank you. Would you tell me what software u use for track visualization? its help a lot for me thank you

10:42 When rain is large drops it never lasts very long

Ah, a good ol' quantization bug. Now you know the pattern for the future at least (if that's a comfort) :P The modules have different accuracies at different refresh frequencies, you should probably see different patterns at 1Hz than at 10Hz.

Fascinating stuff! I've learned a lot from your video's so thank-you for making them. A couple of things spring to mind though...did you really get the 6M to output data at 10Hz? I thought it was only capable of 5Hz max. I'm not doubting you but would like to know how you did that. The other thing about the 6M...isn't it GPS only? I don't know about the others but to be fair it does have a disadvantage at only getting GPS data, which kind of means it didn't really do too bad considering. I'm probably wrong on both accounts but whatever....thanks again for the fantastic info, a real gold mine.

On Comma Ai's Github there is an interesting project Laika.

This is why we tend to use an offset when working with geo data, the points you're using are seldom far apart, so that way you can have high precision, even when just using floats. Also, converting between projections (wish there was just one to rule them all - *sigh*) you loose precision, even when using doubles, since there's so many intermediate calculations.

I wonder if I could ask you for some help? I have two F2s Flight controllers both of which lost their GPS pucks in crashes last year. I've tried all over but cannot get replacements unless I get one's similar that need various changes making which I don't understand about! Can I email you about this please? Best regards Nick.

Hello, Nrf and neo6m gps (tinygps library) work, but Nrf and neom8n gps (tinygps+ library) the code does not fail and loads but does not work. What do you think might be the reason. I would be very happy if you could help me. I wish you healthy days.

Nice, thank you. Are all the GPS configured in the same way?

Where we can buy legit m8p or m8n?

Did you say the M8P uses an active antenna? In your last video?

what is this visual software used for STM programming?

Now I know why my fixedwing always change circle point in loiter mode using 6m. But everytime my wireless PIR doorbell triggered it will cause my gps loses all satellites.

Floating point precision is a rake that every programmer steps on.. don`t get me started on FP equality comparison and denormals, those are equally "fun"

Man did you see that double rainbow

how you are getting 10hz from neo-6m it only support 5hz max

hi chris, I'm still using your iforce2d editor, which is great but you're website has no valid ssl certificate. Maybe you can fix that. Thank you, great content and great editor.

Looks like the M8P is doing 5hz?

Those modules are more precise than a phone's GPS, right?

This is great, but I'm now wondering if you have two identical modules, and put them head to head. Will the error be similar or not? Also you might know this but there was an experiment where precision was increased using 2 GPS devices, and one was stationary. All the errors the stationary one had, were subtracted from the moving one. As far as I remember clouds do affect the GPS location, and satellites do move fast, using the stationary GPS you negate most errors, but you need to be in the proximity of the ground station. It's nice that the modules gained accuracy while moving, but bad if you want to have a ground station. I've noticed not all drawn lines ended up in the same point. But this is something you might be interested in testing. BTW, did all the GPS modules agree on the average location?

👍👀🇭🇷

That is not normally

Hard to believe I’m the first to say thumbs up to the spermatozoa races. 😂

*metre, not meter.