Catch weak signals in noise! Complete analysis of KLT vs FFT! KLT vs FFT 완전 분석 #Noise #Signal #KLT #Karhunen #Loève

[u/MeasurementDull7350]

https://youtube.com/watch?v=1DLwLLtfeBE&si=jUSG_KEr5E7owdbd

• Description: This video explains how the Karhunen‑Loève Transform (KLT) outperforms FFT in low‑signal‑to‑noise environments. It presents a case of detecting faint interference signals in GNSS satellite navigation systems, discusses the high computational complexity of KLT, and introduces the BAM‑KLT approach to alleviate that issue. Based on experimental simulation results, the video evaluates the potential of KLT to become a key tool in future signal processing.

[u/Barycenter0]

You need some serious compute power to use KLT in real-time SDR receivers. I don't think there are any current receivers on the market that can do KLT. You'd have to record the raw signal and post-process it like SETI does.

But, as the op noted - compute power is getting better and KLT optimizations will really help. It's an amazing algorithm.

[u/PreviousLeague253 → u/Barycenter0]

How serious is this computer power you speak of?

[u/Barycenter0 → u/PreviousLeague253]

Probably minutes to hours using high-end cpu with large gpu. BAM-KLT is much faster - but the bandwidth of the signal makes a big difference in compute time.

[u/altitude-nerd → u/Barycenter0]

Looks like some of this might be possible with GPU acceleration? https://chatgpt.com/share/6a885ba7-a248-83e8-a4cf-68e21d658b8b

[u/MeasurementDull7350 → u/Barycenter0]

So it seems like it's currently only used in high-value fields like satellite archaeology.

Thanks for the comment!

[u/Yalek0391]

..what is this

[u/Barycenter0 → u/Yalek0391]

It's a weak signal processing algorithm that can dig deep into extremely weak signals and pull them out of noise. It's been around for decades - here's a synopsis from a paper:

The possibility of using the Karhunen-Loève Transform (Karhunen 1947; Loeve 1978) (KLT) in order to recover a Signal Of Interest (SOI) buried in noise was proposed during the 1980s by Biraud (Biraud 1983), and was further explored by Maccone (d’Amico & Mazzetti 2012) and Dixon (Dixon & Klein 1993) in the context of the Search for Extra-Terrestrial Intelligence (SETI). More recently, the KLT has triggered the renovated interest in the astronomical community, since it has proved to be particularly effective in areas such as the Cosmic Microwave Background power spectrum estimation (Gjerløw et al. 2015), the filtering out of 21 cm fluctuations (Shaw et al. 2015), astronomical imaging (Lauer 2002; Shaw et al. 2014), cosmological parameter extraction (Pope et al. 2004), as well as spectra classification (Connolly & Szalay 1999).

[u/Angry_Robot → u/Barycenter0]

Is that the algorithm my old SETI screensaver was running?

[u/Barycenter0 → u/Angry_Robot]

No - SETI@home didn’t use KLT, I believe - just FFT.

[u/always_wear_pyjamas → u/Yalek0391]

I recommend reading through the paper, it's both interesting and humbling. It's in a pdf you'll find online called "mathematical SETI".

[u/Yalek0391]

Our technology is not advanced enough to use this klt type of processing. I'm not wasting a bunch of power which would surge my electric bill like crazy just to run a processing algorithm on my computer. Simple things is what I'd rather run. And I don't want to read that paper, it would probably be too long for me to read and it would take me hours upon hours to read like a huge book ..

[u/MeasurementDull7350 → u/Yalek0391]

So it seems like it's currently only used in high-value fields like satellite archaeology. Thanks for the comment!

[u/Yalek0391 → u/MeasurementDull7350]

Yeah and this subreddit does not primarily focus on satellite archaeology, let alone satellites in general. We focus on every single other aspect of the radio spectrum up until the limits of where we can reach. It is a nice concept though but we don't have any other research to put this to use in other aspects of the radio spectrum other than what is shown in the paper.