Enhanced detection and identification of satellites using an all-sky multi-frequency survey with prototype SKA-Low stations

TL;DR

This study uses multi-frequency, multi-epoch observations with SKA-Low prototypes to detect and characterize satellites, reducing misidentification rates and establishing a baseline for assessing their impact on radio astronomy.

Contribution

It introduces a novel multi-frequency survey method with algorithms that significantly improve satellite detection accuracy compared to previous approaches.

Findings

Detected 152 satellites across multiple passes and frequencies.

Reduced satellite misidentification rate to less than 1%.

Identified satellites transmitting unintended electromagnetic radiation.

Abstract

With the low Earth orbit environment becoming increasingly populated with artificial satellites, rockets, and debris, it is important to understand the effects they have on radio astronomy. In this work, we undertake a multi-frequency, multi-epoch survey with two SKA-Low station prototypes located at the SKA-Low site, to identify and characterise radio frequency emission from orbiting objects and consider their impact on radio astronomy observations. We identified 152 unique satellites across multiple passes in low and medium Earth orbits from 1.6 million full-sky images across 13 selected ${\approx}1$ MHz frequency bands in the SKA-Low frequency range, acquired over almost 20 days of data collection. Our algorithms significantly reduce the rate of satellite misidentification, compared to previous work, validated through simulations to be $<1\%$. Notably, multiple satellites were detected transmitting unintended electromagnetic radiation, as well as several decommissioned satellites likely transmitting when the Sun illuminates their solar panels. We test alternative methods of processing data, which will be deployed for a larger, more systematic survey at SKA-Low frequencies in the near future. The current work establishes a baseline for monitoring satellite transmissions, which will be repeated in future years to assess their evolving impact on radio astronomy observations.