Forums > Windsurfing   Gps and Speed talk

Hope for a GPS alternative

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Created by boardsurfr 5 months ago, 1 Dec 2017
FormulaNova
NSW, 6684 posts
15 May 2018 7:36PM
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decrepit said..
Pete's software is meant to set the baud rate to 9600, which seems to work with minicom.
I haven't got u-center to work yet. windows and I just don't get on.


Really? 9600 is fine for 1hz updates but it won't be anywhere near fast enough for 10hz UBX updates. I wouldn't be surprised if it uses a higher baudrate as 9600 won't be enough.

You can't get u-center to work? Its a piece of cake. As long as you have your serial driver working, it will work fine.

decrepit
WA, 8231 posts
15 May 2018 7:08PM
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Hopefully a dongle will arrive this week and I can dispense with the converter.

boardsurfr
487 posts
15 May 2018 9:35PM
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decrepit said..
Pete's software is meant to set the baud rate to 9600, which seems to work with minicom.
I haven't got u-center to work yet. windows and I just don't get on.


Don't know where you got that from. You need 115200 baud for logging to work reliably at > 1 Hz. The rate is set to 115200 by the logger software, and that works with the VK162/172 USB dongles. Theoretically, this might not work with your converter (although I think that's unlikely).

I'd suggest you try setting this in ucenter, as FormulaNova's suggests, and then save the settings in the configuration view. After saving the settings, I'd disconnect the dongle ("Receiver" menu), then unplug it, plug it back in, and connect again. Then check the baud rate, and check that you can see stuff coming across in the packages view or the binary view.
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decrepit said..
watching the file in pilogger it starts as expected, but stops as soon as the GPS starts seeing satellites, just a bit before it gets a fix.


I don't think the fix changes anything with regards to the data being sent (I'm sure that is true for NMEA data, and 98% sure for UBX). It's more likely to be some other problem, e.g. a communication issue. Also, if you're watching the file size, keep in mind that it may grow in irregular intervals (from file system buffering), and that the size shown in windows may not be updated.

There is also a file "PiLoggerSettings.txt" that may contain additional information. It should be in the PiLogger folder. You can send it to me by PM. In normal operation, it will show a stack trace with an exception when you disconnect the dongle. If you encounter a different error, it may show up in there, too.

decrepit
WA, 8231 posts
15 May 2018 10:09PM
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I tried this a few times. If I started the PI with the GPS with a sky view I only got a small file around 10kb. When I "hid" the dongle inside the house, under a heavy metal tray, the file kept growing for several minutes, about 150kb. After exposing the antenna to the sky, the logging stopped shortly before the green light started flashing. This is quite repeatable.

I'm making progress with u-center, managed to get it going with a fairly poor fix. I could see the sats and the packet, binary and text views with data flowing. I just have to figure out the config thing.

boardsurfr
487 posts
15 May 2018 10:29PM
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Looks like this may be a converter/adapter/driver thing. I just tried the Stratus GPYes, and see problems similar to yours. I'll look into it more. Check the "stdout.txt" file in the pi/Documents folder for error messages.

boardsurfr
487 posts
15 May 2018 10:49PM
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Looks like different USB-to-serial converters behave differently. The Stratus GPYes worked fine after I set the GPS baud rate to 115200 and saved the config in ucenter. That's not required for the VK172 dongles.

The logger program currently sets the baud rate for the "serial" USB port to 115200 baud. For the VK172, that seems to make no difference (after all, a USB port has no baud rate), but for the GPYes, it has to match the rate that the GPS is set to.

That probably can be fixed with an auto-bauding routine. I'll look into that, but it may take a few days. For now, try to get ucenter to work with your setup so you can set the rate yourself, and save the configuration afterwards. You'll need Configuration View => Ports => UART1, and then CFG to save.

decrepit
WA, 8231 posts
16 May 2018 11:15AM
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Don't stress over it Peter, I'm happy to know I'm not going crazy. The VK172 should arrive in a few days, that should make things a lot easier.

But it's good we are discovering these things, I'm sure it will all help down the track.

decrepit
WA, 8231 posts
16 May 2018 11:41AM
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Thanks Peter, it appears I've managed to change to 115200 and set to ubx.
This is a sample of what I now get from u-center
7CE0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
7CF0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
7D00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
7D10 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
7D20 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
7D30 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
7D40 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
7D50 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
7D60 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
7D70 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
7D80 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
7D90 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
7DA0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
7DB0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
7DC0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
7DD0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
7DE0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
7DF0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
7E00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
7E10 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
7E20 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
7E30 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
7E40 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
7E50 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
7E60 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
7E70 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
7E80 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
7E90 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
7EA0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
7EB0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
7EC0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
7ED0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
7EE0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
7EF0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
7F00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
7F10 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
7F20 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
7F30 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
7F40 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
7F50 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
7F60 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
7F70 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
7F80 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
7F90 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
7FA0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
7FB0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
7FC0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
7FD0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
7FE0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
7FF0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
8000 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
8010 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
8020 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
8030 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
8040 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
8050 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
8060 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
8070 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
8080 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
8090 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
80A0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
80B0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
80C0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
80D0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
80E0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................


That doesn't look like a lot of info.
It says I have a 2D fix
The connection icon next to COM3 at the bottom is now red and flicking whereas with 9600 it was green.

So now I'll try minicom set to 115200

decrepit
WA, 8231 posts
16 May 2018 12:06PM
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Well that didn't work, nothing happening at 115200 and I still get NMEA at 9600. I'm not really confident I actually save it. I went to CFG but couldn't see a "save" button.

And here's the "stdout.txt" file. Hope that helps.


Using settings file '/home/pi/Documents/PiLogger/PiLoggerSettings.txt'
Port names: [/dev/cu.usbmodem1411, /dev/ttyUSB0, /dev/ttyACM0]
*** Found GPS port /dev/ttyUSB0
Initialized GPS
Created log file /home/pi/Documents/PiLogger/2018_05_15_124749_PiLogger.ubx
java.io.IOException: Input/output error in nativeavailable
at gnu.io.RXTXPort.nativeavailable(Native Method)
at gnu.io.RXTXPort$SerialInputStream.read(RXTXPort.java:1429)
at gnu.io.RXTXPort$SerialInputStream.read(RXTXPort.java:1341)
at org.ecwindfest.io.USBReaderThread.run(USBReaderThread.java:75)
----- closeOutput ---- java.io.FileOutputStream@1ce613f
--- serialReaderThread is done! ---

Closed serial port

decrepit
WA, 8231 posts
16 May 2018 1:03PM
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And with help from the pi forum I've got samba working again.
I'll have another go with u-center, and see if I can save the config

FormulaNova
NSW, 6684 posts
16 May 2018 3:08PM
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Your text obvious has something that gets interpreted in HTML...

I am pretty sure I know what your problem is as I just checked it and got the same result as you!

Anyway, when you changed the baud rate on the GPS module, did you then save the config to flash? Normally it warns you about this when you try and change screens, which is probably why I forgot to mention it. If you don't it reverts back when you unpower it or restart the GPS module.

So in U-centre, you want View->Config View->CFG and then select Save Current Config. It should already have Battery Backed Ram (BBR) and Flash selected, so when you click on 'Send' it saves the config. Make sure that the settings in U-center for the baudrate is now set to the same as what you have just written to the GPS module, I.E. check that the receiver baudrate is set to 115200 in U-center after setting it to 115200 in the Port config.

This is the output that I got from U-center when I set the baudrates on the GPS different to U-center. It is essentially nothing. So, I am 99% sure this is what you have wrong, which is an easy fix if you just set the baud rate again and save it.


7B90 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
7BA0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
7BB0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
7BC0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
7BD0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
7BE0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
7BF0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
7C00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
7C10 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
7C20 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
7C30 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
7C40 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
7C50 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
7C60 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
7C70 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
7C80 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
7C90 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00

FormulaNova
NSW, 6684 posts
16 May 2018 3:13PM
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decrepit said..
Well that didn't work, nothing happening at 115200 and I still get NMEA at 9600. I'm not really confident I actually save it. I went to CFG but couldn't see a "save" button.




This is where it is hiding. Make sure 'save' is selected and then click on 'send'. You must have your baudrates matching when you do this as that's how the command is sent to the module. If you are getting valid looking messages on text view or packet view, then your baud rates are matching.





decrepit
WA, 8231 posts
16 May 2018 1:47PM
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Thanks formula, yes I think I got that in the end.

And the dongle just arrived!!!!!
I've changed USB0 back to ACM0 in the python script and I can now open the file with gpsresults. No data yet, but I guess it's atking a while to figure out where it is, with only a narrow view out the window.
I'll go back and check, to see if it's happened.

yoyo
WA, 1532 posts
16 May 2018 2:00PM
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Hope all this Pi GPS stuff is not putting off the finish datef your 48 too much.

decrepit
WA, 8231 posts
16 May 2018 2:00PM
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Gave up, plugged the battery in, unplugged the TV and took it outside. I can still see what's happening with samba, and I'm now getting positional data.
So I think it's time to get back to my board in the shed.

Next thing to do, is progress from the bread board, to a container of some kind so I can take it for a ride.

sailquik
VIC, 3910 posts
Thursday , 17 May 2018 12:35PM
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Perhaps of interest to some following this thread:

I just noticed that Officeworks (Australia) have a prepaid (Optus) phone for $29.50 again. It looks a lot like the Alcatel ones we bought a while back. Also looks like it would work well with GPS-Logit or windsporttracker for thise who want to give them a try on a cheap, possibly expendable phone. No need to insert the SIM card to use it.

I have not tried it yet, but I will get one and do so in the next few days when I go past an Officeworks shop.

www.officeworks.com.au/shop/officeworks/p/optus-x-play-prepaid-mobile-phone-volcano-black-4034x-op3001081#!specifications

Operating System: Android M (Marshmellow 6.0)

I am pretty sure it does not have OTG though.

yoyo
WA, 1532 posts
Thursday , 17 May 2018 7:38PM
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Andrew, whilst the Optus Play was release in 2017 it is virtually identical to the old Alcatel Pixi 3 (4) released in 2015. That is an eon in mobile phone development. The only obvious difference is Android 6.0 instead of 4.4 and bluetooth 4.0. The physical dimensions, specs and weight are identical.

Also Kmart's regular price is $39 so it is not so much a bargain.

I still use the pixi 3 (4) . Has a s**t screen but is light (110gm) and works well with Manfred's gpsLogit. It is a cheap and nasty phone but has a great gps and keeps on keeping on. That is all I need.

boardsurfr
487 posts
Friday , 18 May 2018 8:45PM
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decrepit said..
Next thing to do, is progress from the bread board, to a container of some kind so I can take it for a ride.


Here's my container:

Stuck together with velcro, double-bagged. The GPS is a Stratux GPYes, which has the larger antenna and a nice form factor. Plug & play, total cost ~$50 including the bag. Planning to take it on a windsurfing test ride today.

One thing I noticed yesterday was that the recording does not always start if the GPS is plugged in when the Pi starts up. Not sure why, could be something about the order in which things get started. Best bet is to plug the battery in, wait a couple of minutes for the Pi to finishing booting, and then plug the GPS in.


decrepit
WA, 8231 posts
Saturday , 19 May 2018 1:27PM
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Peter, looks like you have a fairly small battery in there? I was going to try for an all day battery, but now I think 2 smaller ones would be more convenient. It wouldn't be too hard to change them over at break time, and if you're doing serious distance the one just taken off can be recharging.

Is that the fake Chinese chip or is it a good one? Looks like it will give better accuracy than my dongle.

I took it for a drive today with some interesting results.


GPSVisualizer shows my tracks very well, I'm even on the right (left) side of the road most of the time.
But GPSResults wasn't as friendly, I had to untick filters to get any results and it only shows the last part of my tracks when I started to loose sky view going into the carport.




So I see it now, when I stopped and reversed into my drive, the sats went up to 9, looks like GPSResults isn't interested in 8 satellites or less.

decrepit
WA, 8231 posts
Saturday , 19 May 2018 7:19PM
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Had another play on windows with u-center, going into "printers & drivers" and adjust ting the baud rate to 115200, doesn't "stick" with either the dongle or module, it stays at 9600. I'm not sure if this is the problem though as the dongle works at 115200, but module doesn't.

The serial to USB converter manual says this.

Select to expand quote

The UART is programmable to support a variety of data formats and baud rates. The data format and baud rate
programmed into the UART is set during COM port configuration on the PC. The data formats and baud rates
available are listed in Table 6.
Table 6. Data Formats and Baud Rates

300, 600, 1200, 1800, 2400, 4000, 4800, 7200, 9600, 14400,
16000, 19200, 28800, 38400, 51200, 56000, 57600, 64000,
76800, 115200, 128000, 153600, 230400, 250000, 256000,
460800, 500000, 576000, 921600 3


So is this saying that the PC needs to set the baud rate?
Because I've just googled "setting baud rates", and most answers said the device sets the baud rate.

FormulaNova
NSW, 6684 posts
Saturday , 19 May 2018 10:44PM
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decrepit said..
Had another play on windows with u-center, going into "printers & drivers" and adjust ting the baud rate to 115200, doesn't "stick" with either the dongle or module, it stays at 9600. I'm not sure if this is the problem though as the dongle works at 115200, but module doesn't.

The serial to USB converter manual says this.





The UART is programmable to support a variety of data formats and baud rates. The data format and baud rate
programmed into the UART is set during COM port configuration on the PC. The data formats and baud rates
available are listed in Table 6.
Table 6. Data Formats and Baud Rates

300, 600, 1200, 1800, 2400, 4000, 4800, 7200, 9600, 14400,
16000, 19200, 28800, 38400, 51200, 56000, 57600, 64000,
76800, 115200, 128000, 153600, 230400, 250000, 256000,
460800, 500000, 576000, 921600 3





So is this saying that the PC needs to set the baud rate?
Because I've just googled "setting baud rates", and most answers said the device sets the baud rate.




When you want to change the baud rate of the GPS, do the following. You might have already done all these, but this is what I go through to set it:

Start with it working at whatever baudrate you need to. (Verify that you can see data coming in in TextView or Packet View. You should be able to see NMEA type data.)

Go into the config view, and change the baudrate on the PRT(ports) section, and change the setting for Target "1- Uart1". Change this to 115200.

Click on the send icon at the bottom of that window. At that point you will lose coms with the module as your PC is still talking at the old baudrate and your GPS is now using the new/faster wrong baud rate.

So, in U-centre, go back to the 'Receiver - Baudrate' tab and select 115200.

You should now be able to see data again in the text view or packet view windows.

Now, go into the 'Configuration View' window again, and select the CFG(configuration) section. In that you should see the devices highlighted in blue as 0-BBR and 1-Flash. The 'save current configuration' option should already have the checkbox marked.

Click on the send icon on the bottom of the window. This effectively sends that command to the GPS, and the command is 'write your config to RAM and Flash'. (If the baudrates were mismatched, this would not work.)

Now, you should be done, and it should be saved.


The 'Receiver - Baudrate' tab in U-centre is the PC setting the baudrate of your adapter.

Don't change it in 'printers and drivers'. I don't really know what it does there, but it probably sets a default baudrate, which I have never seen anything use anyway. I know the section you are talking about, but its not necessary.

You have two baud rate settings. One on the PC and one on the device it is trying to talk to. If they are different you either get nothing or gibberish as the receiving end interprets the data incorrectly.

You are lucky that you can no longer set different baudrates on the transmitter versus the receiver!

boardsurfr
487 posts
Saturday , 19 May 2018 9:18PM
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decrepit said..
Peter, looks like you have a fairly small battery in there? I was going to try for an all day battery, but now I think 2 smaller ones would be more convenient. It wouldn't be too hard to change them over at break time, and if you're doing serious distance the one just taken off can be recharging.

The battery is a 2500 mA battery (www.amazon.com/gp/product/B074D35CNB/). It should theoretically be good for a day ... except that these battery banks are made for charging phones, and turn off when the current drips below ~ 0.1 A. That has confused me a lot, with the Pi turning off at what seems to be rather random times. In a driving test, it was fine for hours; but in yesterday's windsurf test, the battery had turned off before I plugged in the dongle, which I did not notice.

I'll have to check this "battery turn off" behavior some more. The alternative to a USB power bank is using a LiPo battery, but that requires extra stuff for charging (and, if the GPS needs 5 V, a voltage converter). That ends up more expensive and complicated. I found a post somewhere that the batteries stay on if the current is higher every few seconds. Updating an e-ink display may just do the trick.

boardsurfr
487 posts
Saturday , 19 May 2018 9:33PM
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decrepit said..
Is that the fake Chinese chip or is it a good one? Looks like it will give better accuracy than my dongle.

The chip is a ublox 7. I don't know if it's authentic or not, that's very hard to tell. What matters is that it seems to work well.

I got a couple more GPS modules for bluetooth use, one ublox 7 and one ublox 8. The second one does not even claim to be a NEO8, and it shows up as only 32 channels in ucenter. But it is able to track GPS and GLONASS satellites at the same time, and gets way more satellites than any other chip I tried (up to 15 indoors). That's slightly surprising since it has a tiny antenna (18x18x2). But the VK172 has the same antenna, and it works well if it has a decent view of the sky. I'll test this on on top of my helmet when I get to it - maybe tomorrow.

boardsurfr
487 posts
Saturday , 19 May 2018 9:48PM
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decrepit said..
So I see it now, when I stopped and reversed into my drive, the sats went up to 9, looks like GPSResults isn't interested in 8 satellites or less.

Usually, the minimum is 5 satellites. It's possible that a different filter applies, for example SDoP - the +- values seem rather high in the graph. Too bad that GPSResults does not tell you which filter was used. But you should be able to change the filter settings on Windows (on the Max, that's a pain or not possible at all).

I usually compare test data to data from the GW-60 or GW-52. For comparing traces, I find GPSAction Replay more useful. Unfortunately, it had a bug reading SDoP values from .ubx files the last time I checked, so you can't see those. I need to contact Yann about it. I also have a little Java program I wrote myself to compare traces and numbers. Not really something I want to share since it's very "quick and dirty", though. But that's what I use mostly when I show screen shots of problem regions.

FormulaNova's instructions are once again spot-on, thanks.

decrepit
WA, 8231 posts
Saturday , 19 May 2018 9:58PM
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Thanks formula, that cleared that up. when you were talking about "both being the same. I thought one was the "printers and drivers" setting and the other was the u-center settings, I didn't realise the difference between the port setting and the receiver setting.

Anyway, I'm nw getting inteligble stuff at 115200, but it's not a constant stream like it is at 9600, it sits quite and thinks about it for a while then comes in in dribs and drabs.

So what I'll try and do now is take the GW52 with me, and then do a run with the dongle and one with the module and see what happens.

boardsurfr
487 posts
Saturday , 19 May 2018 10:08PM
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A few more things:
- If you use the USB hub during GPS tests, that may reduce the GPS accuracy. I've done some tests on a bus drive where the SDoP values roughly doubled when I used a USB hub to get data from 2 dongles at the same time. That may be hub-specific, or due to the two dongles, but your best bet is to not use a hub when recording.
- Was your test drive with the USB dongle or the converter-GPS combo? Which GPS module did you end up buying?
- Should be start uploading all our test data to ka72.com? I was curious to look at your data to see what caused the filtered points, but did not see an upload.

boardsurfr
487 posts
Sunday , 20 May 2018 4:55AM
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Update with some info about using USB battery packs at boardsurfr.blogspot.com/2018/05/almost.html

FormulaNova
NSW, 6684 posts
Sunday , 20 May 2018 7:12AM
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decrepit said..
Thanks formula, that cleared that up. when you were talking about "both being the same. I thought one was the "printers and drivers" setting and the other was the u-center settings, I didn't realise the difference between the port setting and the receiver setting.

Anyway, I'm nw getting inteligble stuff at 115200, but it's not a constant stream like it is at 9600, it sits quite and thinks about it for a while then comes in in dribs and drabs.

So what I'll try and do now is take the GW52 with me, and then do a run with the dongle and one with the module and see what happens.


Yes, I thought it was not a constant stream as well.

What you are really seeing though is that at 9600bps it has to queue all the data from the GPS to send to your PC across the serial connections. As its relatively slow, you see it all arrive as fast as it can so you see a steady rolling of data.

At 115200 though, the serial link is so much faster that you don't see it roll in, but an instant update. So much so that you sometimes have to look at the data to see that a few numbers here and there have changed. The whole stream has changed but as there are only a few numbers that change, you sometimes can't tell.

You are getting updates at exactly whatever Hz update rate that has been set. When you change it to 10, with UBX data, there is a lot of data coming at you.

You can go faster that 115200, but the danger is that some serial chipsets in the PC cannot go faster than that, so you could lock yourself out from the device you are talking to. The data you showed me from 'devices and printers' says that your adapter supports higher baudrates, but in this case 115200 is enough and the scripts seem to be set for 115200, so you are okay with that.

decrepit
WA, 8231 posts
Sunday , 20 May 2018 11:20AM
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@##@$%^%^
At the moment I have the module plugged into the Pi outside with the green light flashing, but I have no new file appearing in Pi logger.
I'm about to swap the module for the dongle and see what happens.

New file appeared straight away, so for some reason, with the module on 115200 it's no longer being seen by the Pi, but it was working OK on U-center with windows PC.

So for the moment tests with that are on hold.

decrepit
WA, 8231 posts
Sunday , 20 May 2018 11:32AM
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Select to expand quote
boardsurfr said..

- If you use the USB hub during GPS tests, that may reduce the GPS accuracy.



Thanks Peter I'll watch for that, but it's unlikely to happen, so far I've only used the hub inside when connecting to the TV. Now that samba is working I don't need to do that.
Select to expand quote

- Was your test drive with the USB dongle or the converter-GPS combo? Which GPS module did you end up buying?


The test drive was with the dongle, at that time the module was still stuck on 9600.
I bought the module Daffy recommended, the NEO-M8

Select to expand quote

- Should be start uploading all our test data to ka72.com? I was curious to look at your data to see what caused the filtered points, but did not see an upload.


OK that's not a bad idea, I'll upload it now, and all future tests



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Forums > Windsurfing   Gps and Speed talk


"Hope for a GPS alternative" started by boardsurfr