Differential X-Ray and Gamma-Ray Positioning System for Nanosatellites

Abstract

A CubeSat is a type of miniaturized satellite for space research. Utilization of a simplified infrastructure enables a low-cost platform to test the space readiness of new hardware without an exorbitant amount of prohibitive design. One of the areas where CubeSats offer promise is in the development of new satellite technology or scientific instruments for astronomical observations. We look at a CubeSat instrument which is able to pick up gamma ray bursts (GRBs) in the hard X-ray to gamma band. Implementation of this concept requires a precise characterization of incoming photons and thus requires energy detectors well suited for the energy range of interest, coupled with the most practical processing electronics. A compact CubeSat photon detector needs to be able to record fluxes with minimal dead time (time spent storing information). These fluxes make up signals which can be used to compute a position of the CubeSat relative to other CubeSats based on time difference of arrival (TDOA), similar to the operation of GNSS. Here we show the effects of signal noise on navigational accuracy, and show how a simple ripple counter circuit can improve the burst-to-background ratio of a photon-by-photon particle detector. The high-altitude ballooning team aims to push this technology forward and provide an updated template for CubeSat designs at the University of Minnesota.