Deep Space PNT Instrument (DESPINA) Sensor Design

This paper describes the design of an X-ray detector for use in pulsar-based X-ray navigation in deep space. Known as the Deep Space PNT Instrument (DESPINA), it is being designed to be a compact, modular, and scalable sensor for generating an autonomous PNT (Position, Navigation, and Timing) solution. This paper discusses the design considerations and trade-offs in developing this sensor. We begin by outlining the motivation for developing the sensor, explaining the XNAV challenge, and describing the pulsar source signals we aim to utilize, as well as the background noise we need to account for. Next, we examine various detection options, discussing the pros and cons of each, and compare the leading commercially available (COTS) options. We then explore the design of a collimator for the sensor to help reduce background noise, covering key considerations such as geometry, field of view (FOV), material, and machining. Based on the trades and simulations conducted so far, we conclude that a detector design using the ADVACAM miniPIX TPX3 Flex sensor, paired with a honeycomb-shaped collimator array, offers the best opportunity to detect more pulsar targets for XNAV in deep space.