Hi
I have a dual gps system but both gps are basically trash. One is a decent m8n which can get 10sats and other is 7m
I have decided to replace the 7m with a m10n gps and will keep the m8n as secondary.
Does anyone have suggestions on which brand to use? I was primarily thinking of the radiolink se100 gps because it can get good sats and also has an ist8310 compass?
Another option was hglrc m100pro but for some reason I haven’t seen any Ardupilot users using these gps. By budget is a little tight, under 40 dollar at max.
Holybro hardware is great but expensive and mostly it uses can bus which might or might not work on pixhawk 2.4.8
Unfortunately, i live in India where even the m9 mini gps costs 8000 rupee (around 81 US dollars )
Mateksys hardware is just unavailable on all sites from where i can buy.
A friend of mine is running the se100, and it locks around 25 sats in a normal park and hdop is 0.7. I think these are pretty good. Size is not a concern.
The larger units like normal gps that are commonly used seem to have far larger antenna and direct interface (I dont mind soldering though)
You mismatching probably m9 mini and m10 mini on holybro. The m9 is a more powerfull device as a M10 and it is by this double in price.
The HDOP value you are asking for says nothing. This value is depending to the actual satellite constellation at the time and location you are looking for. Same for satcount.
You can still get a bad fix with high satcount due to misconfiguration.
So if your budget is so small than best is to invest your time (for free) to check what you really need. So one question for me is, why you need a dual gps system.
Simply as bigger the ceramic antenna as better is GPS quality with the same chipset and same design. A 25 x 25 mm ceramic patch antenna is low end for a good drone.
The shown receivers differ in antenna size. Bigger patch antennas are better then the smaller ones.
Apart from this these modules are just average. I can only recommend the SAM-M10Q because this is developed by ublox as a stand alone module, no additional HF-components involved.
Other cheap receivers are put together with various parts from unknown sources (use small receiver chips from ublox without integrated HF parts in a questionable design. Some work other don’t.
I have a bunch of these small GPS modules incl some Matek units. All the Matek units work well, a cheap one from Micoair works pretty well, one from Flywoo works but not very well. I would guess all the cheap units are coming from the same factories with different labels applied.
This is not a high requirement and can be done by both the old m7 as well as the better m8, but I don’t think that you need two GPS for this requirement. If the GPS fails mostly it is not a wrong or defective GPS module, it is more a not optimal built (wiring, setup etc).
If you have a high value professional drone it might be different but so far I can read from your posts you are looking just more for low budget hobby drone.
So again I only can recommend to invest more time to learn and understand the functionalities.
For example in most cases it is not necessary to use all available GNSS systems. All these kind of low cost receivers use only one GNSS system at a time to calculate the fix. So it is not necessary that thios receiver uses its power to track satellites from other systems. This only takes calculation power.
I have one of these. It works fine and likely outperforms most of the other cheap options mentioned here except for the other M-10 based modules, which should be about equivalent.
I can only suggest to do some more digging into details.
Hook the module to an UART→ USB converter and connect it to ublox ucenter (first generation, not “2). Select COM Port and activate autobauding.
Open a new message view tab and observe SAT reception in an open space.
Keep distance to USB3 devices and all RF-transmitters and step down/up power cricuits in the first step. For example the ELRS receivers might influence GNSS L1 signals up to a complete deny of fixing.
The M7 should see about 8-10 SATs in GPS mode, the M8 around 16-20 depending on configuration at current constellation at your place. Use GPS + GALILEO or GPS + Beidou.
Wait up to 30 minutes to have the ALMANACH fully downloaded. If its still performing badly, reset the module to DEFAULTS and try again for up to 30 minutes.
Screenshot is from a cheap M10 module inside shortly after configuration reset. C/Noise is quite bad because of poor reception. Should be around 30-40 for a lot of SATs outside. When i switch on my Speedybee 2,4Ghz ELRS NANO receiver at 10mW transmit power, it completely loses fix.
Just did a small test with an pretty old ublox NEO-M8Q (vers. 2.01, not upgradable) which was laying around for years. Took a few minutes to fix (inside the house because of bad weather)
