Accomplishments and Plans of Spire's Growing Constellation of GNSS RO CubeSats

In a relatively short time, Spire has grown from a small start-up company to the largest commercial producer of satellite-based GNSS Earth observation products. As of August 2019, and after 20 deployments, Spire now has 84, 3U Cubesats satellites operating in a variety of orbit planes, second only to Planet in the size of its nanosatellite constellation and growing with each launch. Spire satellites host three primary payloads: a dual-frequency GNSS science receiver, an automatic identification system (AIS) receiver for ship tracking, and an automatic dependent surveillance—broadcast (ADS–B) receiver for aircraft tracking. The Earth observations produced with Spire’s GNSS science receiver include atmospheric profiles performed by radio occultation (RO) and space weather observations (slant total electron content (TEC) and scintillation indices) using signals from the GPS, GLONASS, QZSS, and Galileo constellations. Spire was the only company to produce RO observations in the first NOAA Commercial Weather Data Pilot program, and since then Spire has continued to improve and grow the size and capabilities of its RO constellation.

Spire now produces thousands of RO profiles and millions of TEC observations each day with low latency, with plans for over 100 RO-producing satellites in the full constellation. Due to its agility and rapid launch cycle, averaging launches of four to eight satellites every six weeks, Spire has the unique ability to improve performance and add capabilities on-orbit that are impossible with traditional, risk-averse satellite missions. Spire has provided RO and space weather data to the second NOAA Commercial Weather Data Pilot program, the US Air Force Commercial Weather Data Pilot program, ESA, and numerous NWP centers and research institutions. Spire is also pioneering the provision of Earth observation data to NASA and ESA researchers through unique data purchase programs.

In our talk we will overview the status and capabilities of the Spire satellites and describe the collection of RO profiles from the GPS, GLONASS, Galileo, and QZSS constellations. We will also describe precise orbit determination of our low Earth orbiting satellites and inversion of the RO profiles. We will show the statistical characteristics of our products, focusing primarily on bending angle and discussing the factors affecting the quality of the profiles. We will also discuss our neural network application to the problem of wet profile retrieval. Finally, we will outline our plans for expanding the Spire constellation in the future.