Phase Difference Measurement (AVR2151: RTB)

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Hello everyone,

recently Atmel published a new AppNote with the title Atmel AVR2151: RTB Evaluation Application - Quick Start Guide (PDF, SW).

This AppNote describes how to use the phase difference measurement (PMU) to perform distance measurements with the AT86RF233. Is that even possible with these ICs?

Does anyone have any information what precision can be achieved and up to what maximum distance the distance measurements works. Are there any constraint where this works successfully?
I would like to use the ATmega256RFR2 for this task

Unfortunaly the referenced AppNote AVR2150 and AVR2152 (Section Further Reading) are not available from the Atmel website.

Last Edited: Fri. Oct 16, 2015 - 12:21 AM
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Well, if it is described then it is possible. I'm not sure about ATmega256RFR2 though. They should have more or less the same radio hardware, but I'm not sure if PMU really works ATmega256RFR2.

In an open space accuracy is around 1 ft or so. Results vary if there is strong multipath propagation or other obstacles.

At a certain distance results from PMU will wrap around, to extend measured distanace Time-Of-Flight Module (TOM) can be used.

NOTE: I no longer actively read this forum. Please ask your question on www.eevblog.com/forum if you want my answer.

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alexru wrote:
I'm not sure about ATmega256RFR2 though. They should have more or less the same radio hardware, but I'm not sure if PMU really works ATmega256RFR2.

The datasheet of the ATmega256RFR2 mentions a PMU.

alexru wrote:
At a certain distance results from PMU will wrap around, to extend measured distanace Time-Of-Flight Module (TOM) can be used.

Are there more information available about the TOM? How is it used with the ATmega256RFR2 (or AT86RF233)?

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LoseOrc wrote:

Unfortunaly the referenced AppNote AVR2150 and AVR2152 (Section Further Reading) are not available from the Atmel website.

These documents are available in the software attachment.

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LoseOrc wrote:
Are there more information available about the TOM? How is it used with the ATmega256RFR2 (or AT86RF233)?
All the available info is in the datasheet.

NOTE: I no longer actively read this forum. Please ask your question on www.eevblog.com/forum if you want my answer.

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Hi, I have been testing the performance of the distance measurement using phase difference using ATREB233SMAD evaluation kit. Which has AT86RF233 transceiver and ATxmega256A3.
The precision was good in outdoor environment at larger distance (10m to 40m) with +/- 1m error. Although the quality is low I measured up to 90m. But since it doesn't have any collision avoidance protocol implemented, when u use it indoor with WiFi around, the result is not much satisfactory. for 2m and 4m distance, it still have an error of around 1m. But even indoor the result gets better at larger distance.
I'm a beginner in embedded programming and I'm now trying to check it's bitcloud performance and modify the code to my needs, I'm still reading how to do it. I may come back for help:)

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Performance you are getting is more or less expected. In good outdoors conditions it might be as good as +/- 30cm, but that's the best I've seen.

Indoors - it all depends, but usually absolute numbers stay the same or get slightly worse, but relative to smaller room size they perceived as very bad.

NOTE: I no longer actively read this forum. Please ask your question on www.eevblog.com/forum if you want my answer.

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I also was able to get 80m range outdoors, but to get best results I had to bump up the transmission power and pay attention to antenna orientation.

Very quick write-up here...

http://wp.josh.com/2013/05/23/first-look-at-distance-measurement-using-the-at86rf233-chip/

I hope to play with this more over the weekend and report back.

-josh

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Nice report. I think I can address some of the "bads":
1. It is my understanding that the boards are prohibitively expensive so only people who are serious about evaluating this technology are buying them. Technology is at a very early stage, it has to be ironed out before it can be used on a massive scale.
2. Requirements for extra tools has the same origins.
3. QFN package is the only option for RF, capacitance of DIP pins will kill any 2.4 GHz signal.

I'm sure when (and if, really) this technology will advance enough to be very easy to use, there will be cheap kits.

NOTE: I no longer actively read this forum. Please ask your question on www.eevblog.com/forum if you want my answer.

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hello,everyone:
I have a very Strong problems With the AT86RF233 RTB Lib.My System is Based on STM32 & AT86RF233.BUT the RTB Lib does not support the IAR FOR ARM IDE Tool! So confused! Crying or Very sad

How Can I use the RTB Lib With STM32 MCU To perform a distance measure function?

Is there any RTB Soure Code For The IAR?? Question

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There is a second thread opened to this topic, please do not cross post.
https://www.avrfreaks.net/index.p...

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Dear Atmel Team,Hello,

 

I'm a student in science computer and i working in my project with the Wirelss Distance Measurement (RTB_Eval_application). I would like to know the name of the file.c were you put the equation of the distance calculation. 

 

I will be very thankful if you will answer me .

 

Thanks.

Hello!

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All of this stuff is hidden in the library, you won't find it in the open part.

NOTE: I no longer actively read this forum. Please ask your question on www.eevblog.com/forum if you want my answer.

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Thank you for your quick reply.

where i can find this hidden parts ?

 

Thanks

Hello!

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What do you mean where? There is no code for them. They are a part of precomiled library. There is no way to get this code without signing an NDA.
 

NOTE: I no longer actively read this forum. Please ask your question on www.eevblog.com/forum if you want my answer.

Last Edited: Tue. Oct 13, 2015 - 10:58 PM
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Thank you for your quick reply yes

 

Hello!

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How i can sign an NDA?

 

 

Hello!

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I have no idea. I'm pretty sure it is impossible if you are just a student and not buying lots of parts.

NOTE: I no longer actively read this forum. Please ask your question on www.eevblog.com/forum if you want my answer.

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Hi, is this thread still alive and followed?

thank you

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Dear Atmel Team,Hello,

 

I'm working in my project with the Wirelss Distance Measurement (RTB_Eval_application). I would like to know how i can print the amplitude values of the 81 signals(2400 MHZ ,2401 .... 2480).

 

I will be very thankful if you will answer me .

 

Thanks.

Hello!

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Hi cherifmed, May be it will be a good idea to check with Atmel directly on this....