SelfieStick: Towards Earth Imaging from a Low-Cost Ground Module Using LEO Satellites

Vaibhav Singh, Osman Yagan, Swarun Kumar

Abstract: Real-time access to overhead Low-Earth Orbit (LEO) satellite imagery from a handheld device can have transformative applications: tracking wild-fire, natural disasters and weather events. Today, real-time access to images from LEO satellites overhead is challenging to obtain. LEO satellite ground receivers are bulky, expensive and sparsely deployed in the world. Despite the exponential increase in LEO small satellites orbiting the planet today-there is a significant time gap between an image capture on such a satellite and users who need it the most in remote and ecologically-sensitive regions. This paper presents SelfieStick, a novel satellite receiver system that explores reducing this barrier of access to real-time satellite imagery data using a single low cost (< $ 30) tiny receiver. SelfieStick's core approach takes advantage of the multiplicity of overhead Low-Earth Orbit satellites due to their exponential rise in recent years. While signals from such satellites may be individually weak, especially at a low-cost receiver, SelfieStick stitches together noisy RF captures containing underlying images of the same part of the Earth across many such satellites to generate clean Earth images. This is made possible by combining weak signals in the RF domain (rather than the traditional image domain) after appropriately transforming and aligning the RF signals accounting for different satellite perspectives, their orbits and wireless channels. A detailed experimental evaluation on the RTL-SDR platform on satellite captures from the NOAA constellation demonstrates a PSNR improvement of 5 dB through combining of images across 10 satellites.