Time Of Flight - Distance measurement

[gbrault]

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]

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]

Hi,

This is a really sharp question. thanks.
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.
So sorry that it is not supported now, but if there is any update, we will let you know.

Sorry for the inconvenience.

[jboden]

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]

mark for new technology

[loba]

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]

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]

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]

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

[BladeGalen]

Yes, we did put into effect a TOA set of rules inside our chip. Yes, in ESP8266. We may additionally enable this at a appropriate time.