LPS^2 prototypes in the lab

justinlee wrote 04/01/2017 at 01:59

hi, so cool, how to implement the AOA with the board ?

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Göran Nordahl wrote 04/01/2017 at 08:57

Two boards separated a bit from each other. Here is a little video showing our test rig for Angle of Arrival (AoA):

https://youtu.be/D9BWkx_0Sz8
Some explanations:
* Distance between receiver boards (two modified LPS boards to handle external clock and synk + better antenna) is 300 mm.
* The x axis shows time.
* The y axis shows difference in distance to the tag.
* The blue dots are individual measurements and the green line is the mean value.
* Both TDoA and TOF can be used, i.e. both angle and distance to the tag can be measured.
* In the bottom of the screen values for TDOA, TOF (if enabled) and RSSI are shown.
* At 0:20 a slider in the web interface controls the rig orientation. Much easier to rotate the rig than running around with the tag.
* At 1:30 an additional degree axis is activated in the settings menu.
* At 2:28 TDOA+TOF is deactivated, so that only TDOA is shown in the bottom of the screen. This allows for higher update rate.
* At 3:03 txpower settings are played around with, with resulting changed RSSI seen at the lower part of the scrren. All DW1000 settings are available via the settings tab, making test and evaluation easy.
* The UI was recorded in Brisbane, Australia and the webcam in Stockholm, Sweden. Hence the delay and artifacts - sorry about that.

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Göran Nordahl wrote 12/20/2016 at 05:46

The 2.4 GHz antenna in the upper left or the UWB antenna in the lower right?

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Hasan Yavuz Özderya wrote 12/21/2016 at 07:56

I've just noticed the upper left one, now I'm interested in both :D

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Göran Nordahl wrote 12/21/2016 at 08:01

Antennas are interesting creatures :-) Have you seen this one from Molex? It can stand on a GND plane, i.e. no need for cut-outs in the GND plane!

https://www.instagram.com/p/BNeIGXABxtE/

http://www.molex.com/molex/products/datasheet.jsp?part=active/0479480001_ANTENNAS.xml

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Hasan Yavuz Özderya wrote 12/21/2016 at 08:11

That Molex antenna indeed looks crazy : )

I'm wondering if the shape of the upper left antenna is arbitrarily drawn (with some rules of course) or each curve is carefully calculated?

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Göran Nordahl wrote 12/21/2016 at 08:15

Will have to ask my former boss, who designed it.

Also Johanson Technology have an interesting antenna to be placed above a GND plane:

http://www.johansontechnology.com/datasheets/antennas/2450AT42E0100_Web.pdf

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Hasan Yavuz Özderya wrote 12/20/2016 at 05:44

What kind of antenna is this?

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oshpark wrote 12/21/2016 at 23:19

Yeah, the pattern is very interesting. Wonder if that is for functional reason or just aesthtics?

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What is not in the CAD is solved with patch wire

Cranberry

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