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TOPIC: NMEA Bluetooth To Tablet For Wireless Operation

NMEA Bluetooth To Tablet For Wireless Operation 4 years 6 months ago #9037

  • longjohn119
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Terrible45 wrote:
Good blog and nice job John !!!

Thanks .... I'll be putting some more stuff on there in a very near future about this new GPS system as well as I finally got good enough with 3D CAD software that I've redesigned my little mapping aquabot that is based on an Open Source design called the Jalcboat and which I've renamed the W.A.S.P. - The Wireless Aquatic Science Platform.

I just received my ID and password for the Iowa NTRIP network, now all I have to do is read a hundred pages of tech literature so I can configure the NEO-M8N to receive and use the correction data. I even found a nice Android app from a guy that lives about 60 miles away from me here in Iowa to help access the NTRIP network and set up the phone's Bluetooth to send the data to the GPS. I don't expect too many problems as the state is using the Leica Geosystems 'SpiderNet' RTN system and Leica uses uBlox GPS and Class 1 (100 meter) Bluetooth modules in their ruggedized Windows tablets and handheld GIS data collectors and both companies are based out of Switzerland. "Precision Farming" has become a big buzzword here in Iowa and I think driverless automated tractors and combines will be common in the next 10 years even before we see driverless cars ..... Out in a field you don't have to worry about some idiot coming at you at 60 mph while trying to text his girlfriend or someone running a stop sign or slamming on the brakes in front of you.

"Assuming the standard GPS RTK protocols and best practice methods are employed for maximum precision i.e. good satellite coverage, good geometry of precisions, low multipath environments etc, IaRTN typically achieves an RTK accuracy of 1-2 cm horizontally and 2-3 cm height. "

Cripes I'd be tickled to death to achieve 20-30 cm precision ..... In fact I'd probably have a nerdgasm .....
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NMEA Bluetooth To Tablet For Wireless Operation 4 years 6 months ago #9080

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Unfortunately this isn't going to work as I had hoped because the NEO-M8N only supports RTCM 2.3 and only a small subset (4 commands) and rather than true RTK you have simple DGPS BUT when you enable NTRIP/RTCM it shuts down SBAS/WAAS and the result ends up being a wash or maybe even slightly worse for me. However this might still be useful for those places that don't have a decent reception of an SBAS system like WAAS in North America and EGNOS in Europe. Also enabling RTCM on the NEO-M8N kills all the GLONASS and Galileo satellites which lowers the precision even more so I was actually getting lower precision with RTCM than using WAAS with the Russian and EU sats.

However the NEO-M8N is still a damned good device and well worth the upgrade, last night in my "Adverse Conditions Test Setup" I had locked 9 US birds, 1 WAAS bird, 4 Russian birds and 4 EU birds and was getting a HDOP of 0.7 and a PDOP of 1-1.1 ..... out in the open I'm going to be able to lock even more birds from all 3 constellations plus all 3 WAAS satellites (I'm smack dab in the middle of North America and get 3 WAAS birds easily) and expect these Dissolution of Precision numbers to drop even further .... Also note that I'm using active patch antennas that aren't really 'cut' for GLONASS and only cost me 5 bucks so they aren't exactly optimal although as long as you use an antenna with a 'patch of 25mm x 25mm or greater the antenna should have enough bandwidth to get the Russian birds with only a slight loss, it will depend mainly on the SAW filter and the SAW filter on a 5 buck active patch antenna likely isn't all that steep and they are mainly used to eliminate interference from frequencies below 1575 Mhz not above it . Using the NEO-6 module I've been using for the last couple of years only netted 6-7 US birds and no WAAS sats which shows how much more sensitive the NEO-M8N module is

I can get a centimeter resolution from this module but I'd have to buy another and set up my own base using RTKLIB as a RTK server and then have to 'phone in' to it. On the boat end I would have to also run the module through RTKLIB using my Windows tablet tethered to my smartphone but that wouldn't allow me to get it into the Elite 7 Ti and the range of accuracy is only about 10 miles from the server. It is something I may play around with later in the season but right now it's too much of a hassle to be useable and besides this thing already outperforms anything I have used previously since I can use more than just the US GPS constellation but also the Russian and EU ones .... More birds = a more accurate position solution. It effectively increases the precision 2-3 fold and that is nothing to scoff at even it is isn't 'centimeter resolution' .... To be able to effectively use the Iowa NTRIP network I'd have to get a NEO-M8P precision module which looks to be about 200 bucks but it does work with RTCM3.1 and would get you centimeter resolution 'out of the box' but that kind of defeats the idea of a low cost system although for under $300 I could build an RTK Rover with built-in in Class 1.5 Bluetooth 4.0/LE and a GSM cell modem that would rival a professional RTK Rover costing several thousand ..... Maybe next year, I'm already way over 'budget' since I just had to have one of those new Bluetooth enabled Minn Kota iPilot trolling motors .... I can't wait to geek out on autopilot and auto anchoring without throwing out and hauling back in my anchors .....
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NMEA Bluetooth To Tablet For Wireless Operation 4 years 6 months ago #9102

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Just to give you an idea of what I mean by adverse conditions here is a google maps shot and note not only the trees but the fact it's sitting on the sill plate of a basement wall with a two story house above and to the east

Adverse Conditions test spot
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