Which Atheros chip for Distance Measuring

[Adrian Chadd]

hiya,

So the wave 2 11ac parts implement the 802.11 fine time measurement
standards. There's not yet upstream support in ath10k though. :(

As for AR9380 and the high frequency timestamp / CSI functionality - I
have half done bits in freebsd-head. The CSI parsing and stuff though
isn't in FreeBSD yet - there's an ath9k driver hack somewhere to
expose CSI data, but I haven't found any open source examples of code
parsing CSI data.



-adrian


On 11 June 2017 at 06:06, Florian Adamsky <fa-atheros at haktar.org> wrote:
> Hi all,
>
> in one of our projects we need to measure the distance between two
> 802.11 devices as accurately as possible. Our idea is to use the
> round-trip time (RTT). To avoid any delay from the operation system and
> from the network stack, our idea is to measure the arrival time of the
> acknowledgment control frame.
>
> After watching Adrias talk [1] at Defcon 22, I'm convinced that the
> Atheros chip is the best for this job. In this talk, he said that the
> AR9380 and later support various higher resolution methods for packet
> timestamps. However, in the source code it looks like that only AR6K [2]
> supports high frequency timestamp. Which chip do I need to get the high
> frequency timestamps? Maybe you even have a recommendation for a
> wireless card on which the UART pins are easily reachable or debugging.
>
> I'm grateful for any other hints for our project.
>
> Best regards
>
> Links:
> [1] https://www.youtube.com/watch?v=WOcYTqoSQ68
> [2]
> https://github.com/qca/open-ath9k-htc-firmware/blob/master/target_firmware/magpie_fw_dev/target/inc/OTUS/OTUS_soc.h#L179
> --
> Dr. Florian Adamsky
> http://florian.adamsky.it/
>
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