[Hackrf-dev] <DKIM> Re: TIME OF ARRIVAL OF CW SINGAL in Nanoseconds with HackRf

Mon Mar 14 10:34:00 EDT 2016

Hello, 

Look at what is achievable with state of the art fully hardware assisted solutions. Nanosecond accuracy is even not available at the ouput of your GPSDO. 
You want the same on the fly with simple on the shelf hardware and full software solution on computer with IRQ latency of at best a few µS and OS with big jitter. 

The only sensible way in your/our context is to HW timestamp with the CPLD and post process in gnuradio as suggested. 
This is a lots of work in the sense that it is not something already implemented in the whole chain, but perfectly doable. 

Emmanuel. 
--- 

----- Mail original -----

De: "ERNEST MATEY" <ernestmatey310 at gmail.com> 
À: "n0p [Luis Bernal]" <lbernal at gmail.com> 
Cc: "hackrf-dev at greatscottgadgets.com >> hackrf-dev" <hackrf-dev at greatscottgadgets.com> 
Envoyé: Lundi 14 Mars 2016 14:34:54 
Objet: <DKIM> Re: [Hackrf-dev] TIME OF ARRIVAL OF CW SINGAL in Nanoseconds with HackRf 

Hi Luis, 

Thank you for the reply. 
I have a GPSDO to use as clock in. 
However I see the WX scopes and analysis toolsin Gnuradio can only measure is Micro-seconds. That is my concern. The time scales I see are in milliseconds and microseconds in function. 

So, with what I want to do ( CW burst time of arrival) in Gnuradio. Which method do you advice I use to achieve this. Which blocks arrangement?‎ 
And which measuring blocks will give Nanoseconds reading? 

Also I observe my CPU drags at high sampling rate though sometimes Ok at 10MHZ. Does it count in my Nanoseconds reading? 

Thank You 
Ernest. 

Sent from my BlackBerry 10 smartphone. 
From: n0p [Luis Bernal] 
Sent: Monday, March 14, 2016 12:57 PM 
To: ERNEST MATEY 
Cc: hackrf-dev at greatscottgadgets.com >> hackrf-dev 
Subject: Re: [Hackrf-dev] TIME OF ARRIVAL OF CW SINGAL in Nanoseconds with HackRf 

To achieve this you will need to use a high precision 10Mhz clock and timestamp the signal in the CPLD of the hackrf because the USB bus will add a somewhat random delay to your signal 

2016-03-13 7:59 GMT+01:00 ERNEST MATEY < ernestmatey310 at gmail.com > : 

Hi all, 

I am working on a Project to determine the Time of arrival of CW signal. 

I am using HACKRF on gnuradio. 

How best can I do this. I have my HackRf radio, gps-clock for external reference and a fast-autocorrelation block on Gnuradio. 

How can I achieve this? I want to work in Nanoseconds. How do I realize this in Gnuradio. 

Ernest 

Sent from my BlackBerry 10 smartphone. 

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