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I'm of the opinion that I can do this reasonably effectively with a pair of NEO-M8P's acting as the secondary and tertiary units against the ZED-F9P primary.
On our autofarm 5001, they use a L1/L2 on the primary antenna and the other 2 are L1 only for tilt & pitch. I don't know whether they save on cheaper receivers for the L1 only antennae. I have an open box I could look at.
 

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On our autofarm 5001, they use a L1/L2 on the primary antenna and the other 2 are L1 only for tilt & pitch. I don't know whether they save on cheaper receivers for the L1 only antennae. I have an open box I could look at.
Yes, I've happened upon some of those units in searching around the interwebs. Would be interested in seeing the innards if you take some pictures.
My guess would be they do have low cost receivers, because L2 is very expensive due to the lack of off-the-shelf stuff to implement it. Whether it is the antennas, the RF down converters, or the ASICs.
The ZED-F9P actually has two receiver chips in it, one for each band.
I have several Ashtech ADU units that took four antennas, used 4x G12 or Sensor cards ganged up, and a 68K series CPU/FPU solving for the four sets of raw measurements. Sort of thing I could probably build better with 4x uBlox LEA-M8S and an STM32H7 chip, and have a BOM cost under $100.

Given the proximity and sightlines on the L1 antennas, one should be able to keep lock pretty well, and a real-time RTK Float solution should be quite good, and easy to validate via the short fixed baseline between them. Hardwired data link means no loss of observations.
The L1/L2 at the primary gives rapid RTK on the location, and the others are fixed/constrained vector math and geometry.

What's the diameter of the ground plane discs on those things? Eyeballing the images I'd guess 12-14"
 

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Is there enough vertical accuracy to use tri-gps for heading/tilt/roll? I haven't done the math nor the google search. I have 4 rtk2b-F9P and 2 M8T to experiment with, but so far 2 F9P are locked up in base-lora-rover setup. And, frankly, I am kind of fed up with pulling every detail out of the GPS-neckbeards of the internet.
 

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I already have a rpi 3 with a 7" touch screen. Way, way to small to do anything useful with.

I'd suggest 10" minimum is needed.
 

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Yes, I've happened upon some of those units in searching around the interwebs. Would be interested in seeing the innards if you take some pictures.
My guess would be they do have low cost receivers, because L2 is very expensive due to the lack of off-the-shelf stuff to implement it. Whether it is the antennas, the RF down converters, or the ASICs.
The ZED-F9P actually has two receiver chips in it, one for each band.
I have several Ashtech ADU units that took four antennas, used 4x G12 or Sensor cards ganged up, and a 68K series CPU/FPU solving for the four sets of raw measurements. Sort of thing I could probably build better with 4x uBlox LEA-M8S and an STM32H7 chip, and have a BOM cost under $100.

Given the proximity and sightlines on the L1 antennas, one should be able to keep lock pretty well, and a real-time RTK Float solution should be quite good, and easy to validate via the short fixed baseline between them. Hardwired data link means no loss of observations.
The L1/L2 at the primary gives rapid RTK on the location, and the others are fixed/constrained vector math and geometry.

What's the diameter of the ground plane discs on those things? Eyeballing the images I'd guess 12-14"
Here are a few pics, I threw broken/spare parts into a box so that you can see the arrangement.

The tractor's array ground planes are 14", the mobile base ant plane is 15".

I can also share a dump of the files on the system/os CF card if anyone is interested.
 

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Is there enough vertical accuracy to use tri-gps for heading/tilt/roll?
Going to experiment to find out. The correlators are resolving the carrier to sub-mm levels. How rigidly you can mount stuff is going to play into things.
Ground vehicles tend to stick with the dual configuration, and pick a front-back or left-right mounting depending on which specific angle is critical to their application.
On planes/boats you can typically move things far enough apart that you can get usable precision.
An array of other sensors can be fused to do dead-reckoning.

And, frankly, I am kind of fed up with pulling every detail out of the GPS-neckbeards of the internet.
The internet is certainly full of tools and trolls, providing support is a thankless task, be grateful when you find people whose answer isn't RTFM.
 

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Here are a few pics, I threw broken/spare parts into a box so that you can see the arrangement.
Thanks for those. Yes, so the larger canned board is an L1/L2 receiver implementation. The four-up devices look to be an CMC/Allstar (Plessey/Zarlink?) type 12-channel GPS L1 implementation. Sharing a common TCXO for local clock.

Got some of those 900 MHz FreeWave radio modems, off eBay and scrapped out of some Motorola police car radio network devices I think. Running at 9600 or 19200 baud?

Ok seeing you annotated the Zarlink GP parts on another image. The baseband/correlator part having an ARM7

J9 Probably ARM JTAG Header
U5 Probably ATMEL AT91FR40162 or similar part, ARM7 with FLASH
http://www.keil.com/dd/docs/datashts/atmel/at91x40.pdf

RF Down and Analog to Digital Converters (AD9288 high speed) under large can, Baseband/correlators likely in XILINX FPGA
 

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Cool, What about using three F9P's then you get heading roll and pitch
I'm waiting for my three-up shield board to arrive because frankly I think I need a bigger power supply, and I'm running out of UARTs

I'm of the opinion that I can do this reasonably effectively with a pair of NEO-M8P's acting as the secondary and tertiary units against the ZED-F9P primary.

Anyhow I have the parts, and will build both ways, the firmware is the same either way.
I have four simpleRTK2B LR.
One as base and the last ones as rovers.
I currently don’t use them because I’m still working on the tractor. I think it would be a very good solution to use the simpleRTK2B units. I know it’s not a cheap solution but they come as prebuilt and easy to mount and replace on a nice three-up shield. So I’m very interested in your the project:)
 

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Did anybody in Canada order one of these boards and have to pay DHL a $69.17 customs fee? I thought international shipping fee would have waived this. I emailed Ardusimple about this but haven't heard back yet.
 

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Did anybody in Canada order one of these boards and have to pay DHL a $69.17 customs fee? I thought international shipping fee would have waived this. I emailed Ardusimple about this but haven't heard back yet.[/QUOTE
I don't think arduSimple charged me anything extra other then international shipping and I had to pay DHL for importing it.
 

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I don't recall paying anything extra for my Ardusimple boards. I don't recall how they were shipped either. I can't find any email receipts for duties paid. I don't think I was charged any.

That reminds me my repaired boards are stuck in the DHL system somewhere. I should call them tomorrow and find out what happened to it.
 

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Wow that looks so great. Are you using the ESP? What is the idea with the extra sockets for the Xbee.
I'm using STM32 processors, I had some boards built with F750, F756 and H743 parts. At some point might port Micro-Python over.
The MikroE and XBee on the main board can support Cellular modems, we can route 5V to XBee supply for those boards supporting higher voltage/current.
Janus XF Cellular Modems
At that point we can implement an "RTK Bridge"

The board has CAN, and a header option for a WaveShare Ethernet module.

Just a note to other posters, ArduSimple is not responsible for customs/tariffs levied by local authorities, they won't have charged you VAT at EU rates, and would have stated the value on the shipping declarations. They aren't going to mark stuff as "Gifts" and frankly the customs guys are clearly aware of such dodges and are X-Raying everything. Carriers like DHL/FedEx will balance bill you to release the packages.

Working to get USA/NA distribution
 

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@clive1
How's the triple board working out?


I have two simpleRTK2B boards that I'd like to use in a moving base setup (for heading & tilt compensation) with rtcm corrections from my piksi multi base.
At what rate do I need to feed them the rtcm corrections? Do I have to do the tilt calculations myself externally? How about heading? Are there configurations available online to download?
 

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Hello



Well the ArduSimple boards don't contain micro-controllers, so the relative antenna positions is pulled from a NED vector (North, East, Down from UBX-NAV-RELPOSNED). The math involved is high school level geometry, early teens stuff in my rough recollection of UK schools, probably late teens in USA.

I know people who've spent a lot of money on electronic compass solutions, and been very highly dissatisfied. The simple dual antenna arrangement is quite effective, especially if one can decide on a left-right, front-back orientation for the vehicle, based on the angle you've got critical interest in. Precision comes from the separation you can achieve between the antennas.

Not sure I'd build a 3-antenna system with ZED's, I'd probably opt for an L1 NEO-M8P solution for the secondary and tertiary antennas, would likely be fine on a tractor with a large open field. It doesn't even need a full RTK fixed/float solution to get a good vector model.

I do have a 3-shield motherboard on it's way.

Thank for your answer, I did not know the NED vector bedore. But I still doest understood how the NED vector is generate by the 2 boards without micro-controleur : you still need a micro-controleur to calculate the NED vector based on the data of the 2 antena ?


Thank,


Math
 
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