Time Of Flight - Distance measurement

gbrault
Posts: 4
Joined: Fri Apr 10, 2015 11:05 pm

Time Of Flight - Distance measurement

Postby gbrault » Wed May 20, 2015 4:51 am

In order to use radio technology for real time location system, it seems measurement of Time of Flight is one of the best way.
Some people acheive 50cm repetability with moving target of few meters/sec (5 or so).

Basically, a node A send a message asking to node B to send back the message (don't need to be very long). Node A is able to estimate the Time to process the packet TPP and measure the Round Trip Time.

The Time of Flight is then Round Trip Time - TPP.

If c is the speed of light

d = c * ToF / 2

Few questions:
0- Is it a good idea to implement such a thing? (i.e.: any chance to get a good result)
1- Do you think ESP8266 EX could be able to measure TOF?
2- Do you have any plan to implement such a function?
3- Could you have a function in the SDK to get the result (and trigger the measurement)?

Thanks

gbrault
Posts: 4
Joined: Fri Apr 10, 2015 11:05 pm

Re: Time Of Flight - Distance measurement

Postby gbrault » Wed May 20, 2015 2:47 pm

Please, find a reference about using TOF for distance measurement http://www.eecs.berkeley.edu/~dzats/time-of-flight.pdf.

It shows TOF is much better than RSS for distance measurement

ESP_Faye
Posts: 1623
Joined: Mon Oct 27, 2014 11:08 am

Re: Time Of Flight - Distance measurement

Postby ESP_Faye » Thu May 21, 2015 1:24 pm

hi,

this is a really sharp question. thanks.
yes, we did implement a TOA algorithm within our chip. Yes, in ESP8266. We may enable this at a suitable time.
But beware that TOA is very sensitive to multi path effects, i.e. in TOA algorithm in ESP8266 per se, has only basic mitigation against multi-path now.
Thanks.

The Espressif Algorithm Team

jboden
Posts: 1
Joined: Fri Mar 18, 2016 7:01 pm

Re: Time Of Flight - Distance measurement

Postby jboden » Fri Mar 18, 2016 7:06 pm

Hello how can I access the TOF (Time Of Flight) measurement data between two ESP8266's. Or maybe this was a measurement to the AP. It sounds like it was implemented but I am not sure how I can access it in code.

Thank you in advance.

dearwind153
Posts: 49
Joined: Sun Feb 28, 2016 7:47 pm

Re: Time Of Flight - Distance measurement

Postby dearwind153 » Wed Apr 06, 2016 5:48 pm

mark for new technology

loba
Posts: 1
Joined: Sun Sep 18, 2016 12:31 am

Re: Time Of Flight - Distance measurement

Postby loba » Sun Sep 18, 2016 12:34 am

Hello,
is there any news about TOF in esp8266?
That feature would be very powerful!
Let us know if we can hope or not. ;)
Thank you.
Davide

JackDeCosta
Posts: 1
Joined: Sat Dec 24, 2016 7:41 am

Re: Time Of Flight - Distance measurement

Postby JackDeCosta » Sat Dec 24, 2016 7:44 am

There is a project which offers you the possibility to code your own TOF algorithm:
https://github.com/ernacktob/esp8266_wifi_raw

However, a native implementation would be nice though.

Hemamali
Posts: 4
Joined: Thu Jul 27, 2017 12:49 am

Re: Time Of Flight - Distance measurement

Postby Hemamali » Thu Jul 27, 2017 2:25 am

Dear espressif technical support team, is this feature enabled in latest ESP8266 SDK versions? if yes, can you please give proper guidelines on how to use that feature? i am looking for a precise WiFi receiver time-stamp through Time of Arrival(using Physical Channel State information) for one of my customer's project. your prompt reply highly appreciated.

Thanks & Regards,
Hemamali

Hemamali
Posts: 4
Joined: Thu Jul 27, 2017 12:49 am

Re: Time Of Flight - Distance measurement

Postby Hemamali » Wed Aug 02, 2017 12:34 am

Dear Espressif Dev. team,
can you please respond regarding when it will be enabled on ESP8266 SDK? it's really urgent for me to know this, since one of my customer is waiting to make decision regarding the WiFi chip set to be used for Human Tracking for his Indoor Location application, i suggested him to go with your ESP8266 chip since it's cost effective & power efficient and wide open source support but they want time based location system than RSSI based ones, given location accuracy and robustness is one of the key specs.

Thanks & Regards,
Hemamali
hema@trakray.com
+91-9972152311

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