Interesting paper about using the GPS P3 method to identify solar cycle peaks

[M Lombardi]

This information might be well known and published elsewhere, but some of you might be interested in a paper that I recently found on-line.  It was published in June 2025, and describes how GPS P3 time transfer data can be used to graph the peak and evolution of solar cycles:

https://acta.imeko.org/index.php/acta-imeko/article/view/1969

The P3 method is used by metrologists at timing laboratories like NIST, because it allows dual-frequency GPS receivers to generate a third, independent pseudorange measurement that’s mostly free of ionospheric delays.  It's useful for time transfer applications, because it allows the ionospheric delays to be compensated for in real-time, without having to post process the data.  The uncertainty of the P3 method is almost as small as the uncertainty of post processing methods.  Using P3 data to graph the peak and evolution of the solar cycle seems like an interesting idea, and one that I hadn't heard of before.

73,

Mike Lombardi, K0WWX

[Kerry Case]

That dose sound interesting Mike 

Kerry

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From: ham...@googlegroups.com <ham...@googlegroups.com> on behalf of M Lombardi <michaela...@gmail.com>
Sent: Sunday, May 17, 2026 6:20 PM
To: HamSCI <ham...@googlegroups.com>
Subject: [HamSCI] Interesting paper about using the GPS P3 method to identify solar cycle peaks

 

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[Bruce Crandall]

Thanks, Mike.  It's an interesting topic. Aside from the details of the P3 correlation, I'm a little surprised the paper would use sunspot number instead of 10.7cm solar flux for the analysis.  Both factors are readily available; and most hams look to the solar flux rather than sunspot number for ionospheric conditions.

Bruce

KN4GDX

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73

[Roy Gertig]

Thanks Mike. /Roy, n0rg 

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