Physics Nature Is Weird

Your satellite internet connection is accidentally becoming the world’s most precise global weather sensor.

April 14, 2026

Original Paper

Rain Rate Estimation Bounds and Weather-Adaptive Pilot Allocation for LEO Satellite ISAC

Haofan Dong, Houtianfu Wang, Hanlin Cai, O. Tansel Baydas, Ozgur B. Akan

arXiv · 2604.10830

The Takeaway

By measuring how tiny raindrops interfere with broadband signals, researchers can track rainfall down to less than a millimeter per hour across the entire planet. It transforms the 'problem' of signal interference into a high-resolution tool for monitoring climate change.

From the abstract

Rain attenuates Ku-band satellite signals by up to 20~dB, encoding precipitation information along the Earth-space slant path. This paper derives the Bayesian Cramér-Rao bound (BCRB) for rain rate estimation from LEO broadband OFDM downlinks. Using corrected ITU-R P.838-3 coefficients, the standard CRB yields a minimum detectable rain rate $R_{\min} \approx 4.3\mmh$ for a single link at the $38^\circ$ reference elevation. We derive the prior Fisher information in closed form for log-normal rain