Cheap GPS option

[peabody124]

So I've been talking to a guy that is testing OP-GPS against this module http://www.goodluckbuy.com/crius-cn-06-gps-receiver-v2-0-module.html and the second module is smaller and has comparable or better position deviation.  It might be a good option if anyone needs another GPS.  I've ordered two and will report back with testing results.

[Kenn Sebesta]

I'd be very glad to see Dale test one of these on his linear slides. For my purposes, the GPS velocity precision is much more important than the position precision.

[AlPackin]

I saw this a while back and thought it sure looked compatible

[Edouard Lafargue]

What was the final word on the MKT OP GPS? I saw Adafruit is selling it too with their own adapter, it is basically the firmware we got from GlobalTop plus a few additions, so it should be compatible, but if my memory serves me well, velocity filtering on those GPS made them unsuitable for use on our platform. Is that the case?

[peabody124]

I think latency was the main killer with it.  UBlox was a lot better.  Also talking to this guy further the CN-06 has firmware 7.0 instead of OP-GPS which is 6.0.  That according to other people makes a BIG difference in performance.  So I'm excited to try out the one from GLB.

[peabody124]

Holy shit: 5mm/s resolution?

http://diydrones.com/profiles/blogs/proof-of-concept-test-extremely-accurate-3d-velocity-measurement

[Lilvinz]

ordered two of those...

[AlPackin]

I think witespy stocks the same thing in the US ?

http://witespyquad.gostorego.com/flight-controllers/ublox-6m-gps-module.html

[jabram]

I am not sure whitespy has exactly the same thing, it uses NEO-6M but his antenna looks different, the antenna on CRIUS CN-06 V2.0 beats all the much larger supposedly better GPS antennas I have tried on the same NEO-6M module.. I got a few from Rctimer.

[msev]

What about guys which have old, inferior gps's like Global top PA6B (http://www.flytron.com/osd-headtrackers/15-simpleosd-gps-module.html) ? Will this kind of gps's also be supported?

[AlPackin]

I just ordered 2 from GLB as per the original link

[Lilvinz]

Got mine. Can anyone shed some light on how to properly setup those modules (besides baudrate)?

[Kenn Sebesta]

You basically only need to configure it as UBX output and then turn on just the four or five messages that the firmware reads. I can't remember the exact message names, but you can see them quite clearly in UBX.c. There's no need to add anything else.

P.S. To do this, use the u-center software package.

[AlPackin]

Did anyone have any luck with these? This was a few weeks ago but I could not download the ubx.txt file without a huge number of errors.  I tried editing one parameter at a time and after a while I got it so screwed up that I can't connect at any baudrate.  The second one works fine with U-Center but I can't even successfully change the baudrate from 9600.  I configured the OP gps by just downloading the file and it still works ok.  I did a comparison between the OP gps config and the MW config in the gps I have working with quanton..  I'm kind of gun shy about trying to download Werner's ubx.txt, I'd hate to screw this new one up.  I would like to get it working as UBX rather than NMEA based on James comment today. 

 It looks like main differences are in MSG(Messages), PRT(Ports) (maybe I just have to change the Protocol out) and the SBAS Settings. 

[Menno]

I also have the one from GLB and spend about 3 evenings in U center trying to configure the gps. What a horrible program. Mine also gives a lot of warnings when loading configuration files and it refuses to save any baudrate higher than 38400 to the flash memory.

If you still have ome with the factory settings. Could you please write a configuration file from it? I cant find the factory settings on the Internet.

[@mundsen]

Hi!

I have configured this module from rctimer.com
http://www.rctimer.com/index.php?gOo=goods_details.dwt&goodsid=763&productname=

I guess it's the same module?

I was able to configure it to work with my Quanton controller running at 38400

Is it ok to use 115200? - I have not tested setting the baudrate higher.

If anyone is interested, I can try to document how i configured it using U Center ?

[Kenn Sebesta]

It should be okay to use 115200. In theory, there's a tradeoff between speed and latency:

*  The faster the transmission, the less lag there is between when the data is measured and when the flight controller receives the updated data. NMEA at 57600 can just barely do 10Hz (I think that the UBX protocol is much more efficient), so that would mean that each packet is around 100ms late. That's quite a lot.

*  The slower the transmission, the more time the flight controller (FC) has to get individual bytes from the transmission queue. Since new bytes overwrite old bytes, if the FC has not had time to fetch the old byte it will be lost from the stream. Missing data corrupts the message, so you don't want to go too fast.

What's too fast? I don't know that anyone's tested it, but on the Quanton "too fast" is probably in the hundreds of thousands of baud. So I wouldn't worry about it.

If anyone is interested, I can try to document how i configured it using U Center ?

Yes, please. It sounds as if this is being a hit or miss proposition for a lot of people, which to me means that there's a non-intuitive "gotcha" in the setup process.

[AlPackin]

@Menno  Tonight after work I will see if I can get a config file from the one that still works

[AlPackin]

ahh, just what I was looking for to figure out this GPS config stuff

http://dlnmh9ip6v2uc.cloudfront.net/datasheets/Sensors/GPS/760.pdf

[AlPackin]

looks like significant changes made between fw ver 6.02 and 7.01 ... probably why the OP config file throws so many aeeors

[AlPackin]

errors that is

[JamesL]

as far as I know.. Ublox works pretty well.. seems non-USA area will prefer 6H due to its better coverage from other sattlite system... if only in USA... 6M is sufficient

i dont know if this piece of info will help or not....I used 6m managed to maintain within 1m pos hold and RTL to exact launch position (with MWC) in 1.5m/s wind

also..it is possible to configure the gps with fc so every time booting the any of the gps will be at the same page

JamesL

[AlPackin]

the openpilot gps is a 6Q, with an older fw ver, 6.02 I believe.  The Crius and the MW2 version from witespy are 6M and are fw ver 7.01 if I recall

[@mundsen]

Hi all, 

Anyonte tested this one?
http://witespyquad.gostorego.com/flight-controllers/ublox-6m-gps-w-mounting-backplane.html

I think it have the same mounting holes as the Quanton board

Have a great weekend

[AlPackin]

yes, I have that one and it tests fine on the quanton with the GCS but I haven't been able to fly it yet.  Another foot of snow today. :(

[AlPackin]

I made the rest of the settings required to run the witespy GPS as UBX.  I was doing all the UBX>>CFG>>CFG settings but missed the UBX>>NAV settings.  Previous to that U-Center didn't even display any SVs in the world map or Skyview.  Everything looks good and I finally found what has been driving me crazy.  I have been having trouble saving settings, not all settings but some.  It turns out that when I save the settings to a file, which I do routinely after every change, a few errors are displayed and when I look back at the device the settings have changed.  I would think that the software would just poll the device for a list of settings and log the response to the file.  As long as I don't try to save to a file my settings remain correct after powering up and down.

I have the latest version of U-Center, maybe I need a FW update for the GPS.  I will look into that today

[AlPackin]

Seeing that I can't make a setup file to import into the GPS at the moment,  I have documented all the settings required to use a GPS using UBX protocol with the GCS.

[mnuapel]

Hello guys, wha is the difference between NEO6M and LEA6H chipsets? Lea 6H should support glonass but how about the prformace? GPS with lea module is twice more expensive.

http://www.hobbyking.com/hobbyking/store/__33998__UBLOX_LEA_6H_GPS_Module_w_Built_in_Antenna_2_5m_Accuracy.html

[@mundsen]

6H is firmware upgrade-able, 6M not

[Kenn Sebesta]

It seems that the LEA is more accurate, and can use the GLONASS network, although I'm not sure how much more accurate the LEA is when it's using both GLONASS and GPS.

Accuracy isn't all that counts, though, data frequency is also important. There are information theory papers that show you get better control with high frequency quantized data, vs. very accurate data at low rates. With that in mind, in some cursory reading, it's difficult for me to ascertain exactly what rate they both will give, but the NEO-6M seems to support 10Hz, which can stutter down to 5Hz, whereas the LEA6H supports 5Hz that can stutter down to 2Hz. If this is correct, then I would prefer the guaranteed 5Hz signal to the 2Hz one, even if the 5Hz is somewhat more accurate.

[JamesL]

i believe the advantage of 6h over 6m is outside USA application... it seems to me 6m works just as goon as 6h in USA.. but had multiple reports that 6m does not provide enough accuracy in other areas.. I suspect the GPS focuses more in US territory than other countries.. so that glonass and other positioning systems might assist to provide better coverage/accuracy 

 

[Olivier Damiron]

Al, thanks for this great info.

I found the data sheet for the Neo6 modules and it says max 5 Hz for all of them. I notice you guys push it to 10. 

Can it actually do 10 Hz with this chipset?

[@mundsen]

Have been testing this module http://witespyquad.gostorego.com/flight-controllers/ublox-6m-gps-w-... on a quanton controller the last days (inside the house while configuring the controller..).

At daytime I was able to get 3D fix inside the house, but in the evening I get no GPS signal at all.

When I test using my 3DR GPS LEA6 module (using my VRBRAIN controller), I got 3D Fix and 8 sats inside the house without any problems, and very fast (at the same place where I tested ublox-6m)

So my experience is that the LEA6 is superior compared to 6M

Is the LEA6 able to use other/more GPS satellites then 6m?

I live in Norway

[peabody124]

See the comment about by JamesL.  Probably outside the US it's more important to use a LEA module.

@Oliver: I don't think it can compute at 10 Hz but it does output at 10 Hz.  I'm not entirely sure this is appropriate but works well for me - and if it reduces the latency from computation to message that's a good thing.

[CheBuzz]

@peabody124 - I'm pretty sure that's true.  I think the "true" update rate is 2 Hz, or possibly 4 Hz at the most and the other updates are just smoothing.

[Menno]

I have spent several evenings in U-center trying to configure my crius-cn-06 module. I have tried it on a desktop computer with Windows XP and my laptop with Windows 7. I can't seem to configure the baudrate settings higher than 38.400. I will save any value below that, but not higher. I have also tried different configuration files with the same result.

Is it possible that I have an older module that does not support higher baudrates? Will it be (noticeably) less accurate if I use it at 38400?

Honestly I don't think that I have ever encountered something in the last years that was this troublesome to configure. I'm usually the guy in the family that people come to if they have a problem with there computer :-(

Perhaps there is somebody in Western Europe that I can mail the GPS to for checking/configuring?

Regards,

Menno

Op dinsdag 13 november 2012 19:28:58 UTC+1 schreef peabody124 het volgende:

So I've been talking to a guy that is testing OP-GPS against this module http://www.goodluckbuy.com/crius-cn-06-gps-receiver-v2-0-module.html and the second module is smaller and has comparable or better position deviation.  It might be a good option if anyone needs another GPS.  I've ordered two and will report back with testing results.

[CheBuzz]

Using UBX and an update rate of 4Hz, I don't think 38400 baud should be a problem at all.

[peabody124]

That's really quite odd.  I'm using 56000 on my CN-06 without issue.  I just got another one which I have to configure today or tomorrow.  I'll take a screen capture.

[Menno]

Thanks for that. It's really a strange problem. I can set the baudrate at 115200, reconnect to the board at that baudrate and you can actually see the satellite data moving by faster. once the power is disconnected and reconnected the baudrate is set to 38400 again.

If I change it to a lower value than it does store in the permanent memory, therefore I don't think it's a battery problem.

 

Op donderdag 25 april 2013 17:46:57 UTC+2 schreef peabody124 het volgende:

[Menno]

@peabody124; Is GPS hold already supported in the next or master branch (not waypoint or rth). I am rebuilding my FPV quad (don't like the v-tail after all) and would really like it to hold possition so that I can land it LOS instead of FPV.

Op donderdag 25 april 2013 18:12:34 UTC+2 schreef Menno het volgende:

[peabody124]

I would strongly recommend against trying that using next.  It's missing some fairly critical safety features.  I'll add you to the email list of people testing this stuff.  What operating system are you running?

[Menno]

32bit Windows

Op donderdag 25 april 2013 21:21:57 UTC+2 schreef peabody124 het volgende: