Implements digital filter based on Duffing

As we know Duffing equation works only in analog domain. But in practice it's completely usefulness, we need digital filter which works like Duffing. I try to do it with Volterra series.

Duffing - incoming phase problem

As we all know, Duffing equation go to grate scale period when incoming signal fit to some criterion (sinusoidal and amplitude of resulting signal must be greater than some constant - one can give constant from Lyapunov exponent method). In theory all seems great...

Duffing oscillator with GPS signal

I've read several articles about using chaos theory in GPS. One of them about using Duffing oscillator to detecting periodic signal. As you know GPS carrier is a periodic cosine signal.

DMA noise estimation

Let's talk about "Delay-and-multiply approach" algorithm. It proposed in [Lin] and in the book [Tsui]. But I can't find evaluation of an impact of this algorithm to SNR. In the book wrote that this impact is significant and need further investiogation. Let's try to make some noise about it =)

Double correlation question

On the last week I think about GPS algorithms. And one idea came into my mind.

[UPD] fix in math part

=) After 4 weeks while I was off from trainings I return to a climbing gym.



But geek part of me still alive) I found very useful archive of articles of the section GNSS Solutions in the InsideGNSS magazine. It's real usefull for everyone who works with GPS SDR. They have articles about theory and practice as well.

Now I have some tasks. TODO:
1) understand how to intercept a voice in android like this GSM-intercepter-speaker/microphone

2) investigate ability of implementing GPS SDR on python with GUI as reference receiver.

3) Finish book about neuro networks and start "Hacker delights"

Software Defined Receiver (SDR) for GPS

SDR it's a very popular thing today. I have one project with GPS and need reference SDR for compare. I have git repo with some

Many of them on C/C++ (not so cool to implement POC code on C/C++). But I found one on python

The main idea on python that you can use multithread application with pretty GUI with good library scipy (matrix operation, filters and many other tasty things). You cant get all this things on Octave or Scilab. If you have Matlab you need multithread toolbox aswell. It's very interesting to have tool where one can relatively simple implement his/her idea and integrate it in the current project. I need some time to investigate this project on python and maybe I'll write some more words about this. I want also reimplement my Octave sources with python. It's very interesting to have working SDR with UI and module structure to change modules from one to another (acquire module or tracking module, etc)

BTW if you have some more, plz write me few lines with email or in comments.

Real Signal Complex Noise (RSCN) - SNR estimation algorithm

I found one very cool article about SNR estimation in the GPS (BPSK DS-SS signals).

I implemented the RSCN algo (code in octave it may changes bcoz it's link to the my work vcs and this realisation is test, I'll stabilize the code later). The description of this algo you can find in [1, 2, 3]. The [1] is the simplest article from all others ([2, 3]). And in the [3] authors tell that this algo is very sensitive to phase. And it's pretty simple to look. For example we have GPS fronend MAX2769, 16.368Mhz is sampling freq.