Research News

Research Uncovers the Potential and Challenge of Iridium L-Band Burst Transmission for Opportunistic Navigation

Oct 31, 2023

A research team affiliated with the Aerospace Information Research Institute (AIR) of the Chinese Academy of Sciences (CAS) are delving into the Iridium L-band downlink burst transmissions to explore their potential as Signals of Opportunity (SoOP) for navigation. These bursts are comprehensively evaluated in both single-burst and multiband multi-burst modes to assess their suitability and capabilities for enhancing and supplementing the standard Global Navigation Satellite System (GNSS).

The study was published in Electronics Letters on Oct 30.  

Without prior knowledge or frame verification, Iridium bursts are collected and analyzed for the study. A critical component of the study is the Ambiguity Function (AF) characterization, which provides insights into waveform features such as resolution and sidelobes in both the Doppler and delay domains.
The findings reveal those single bursts, despite reaching a maximum duration of 20.32 milliseconds, exhibit potential but fail to meet the requirements for optimal performance in navigation applications. Nevertheless, the implementation of the multiband mode substantially enhances both time delay and Doppler resolution, albeit at the expense of some AF sidelobe degradation.

As scientists continue to explore the potential of Iridium L-band downlink burst transmissions, this study is expected to boost the resilient navigation via signals of opportunity in GNSS-denied environments.