GNSS Radio Occultation Sensors on Nanosatellites

As nanosatellite (satellites ⪅10 kg) technology matures, more science and operational missions are looking to utilize these platforms. Thus, there is a great need for payloads that can operate within a nanosatellite’s available resources and capabilities, as well as provide high-impact observations and quality data products. One of the more ideal types of sensor for this platform is a Global Navigation Satellite System (GNSS) radio occultation (RO) instrument. Since the first demonstration mission GPS-MET in 1988, GNSS RO data have been shown to produce invaluable data products. In the lower atmosphere (0 to ≈30 km), RO provides temperature, water vapor, and pressure profiles. In the ionosphere (90 to ≈1000 km), total electron content (TEC) and amplitude/phase scintillation are provided. This chapter is intended as an overview of RO sensor design principals, data products, recent missions hosting RO payloads, lessons learned, and future trends. References are included for those interested in greater technical details.