The PlanetiQ Difference

Technology

What is GPS-RO?

GPS Radio Occultation (GNSS-RO, when including all Global Navigation Satellite Systems) is a proven technique for measuring Earth’s atmosphere from space, improving weather forecasts, climate models, and space weather prediction.

A GNSS satellite in medium Earth orbit (from 19,000 to 23,000 km altitude) transmits signals that bend as they pass through the atmosphere before being received by a low Earth orbit (LEO) satellite (<600 km altitude). This bending, caused by atmospheric density, lengthens the signal’s path. Although the LEO satellite cannot directly see the bending angle, blocked from view (or occulted) by the atmosphere, it calculates it from the delay in signal arrival.

From the bending angle, atmospheric density is derived, enabling calculation of temperature, pressure, humidity, and electron density. With sufficient satellites, GNSS-RO delivers global profiles of these variables from near the surface to the top of the atmosphere.

Advantages of GPS-RO?

GNSS-RO can penetrate clouds and storms, unlike many observing technologies. Its global coverage and high accuracy provide major benefits, including:

  • More accurate forecasts of daily weather, hurricanes, and heavy precipitation
  • Improved climate monitoring, data collection over oceans, and space weather prediction

GNSS-RO is cost-effective, leveraging existing GNSS satellites and low-cost receivers. Independent studies by agencies such as ECMWF and UKMO confirm it as the most impactful satellite data needed to significantly improve weather forecast accuracy.

Current State of GNSS-RO

Global GNSS-RO data is available from the joint U.S.and Taiwan COSMIC missions: COSMIC-1, launched in 2006 and now past its operational life, and COSMIC-2, launched in 2019 but is limited to equatorial coverage. The latter has since been scaled back to fund commercial RO providers such as PlanetiQ. 

PlanetiQ has designed and launched five satellites, three of which remain operational in low Earth orbit, delivering the highest signal-to-noise ratio and temporal and spatial resolution among all providers.

PlanetiQ’s satellites carry the fourth-generation “Pyxis” radio occultation (RO) sensor, built on NASA heritage and regarded as the gold standard. This next-generation sensor is smaller, lighter, and more power-efficient than previous versions, yet offers nearly three times the data collection capability by receiving signals from all four global GNSS constellations (GPS, GLONASS, Galileo, and Beidou). Pyxis is the only compact GNSS-RO sensor capable of producing more than twice the data of other sensors currently in orbit, while routinely probing the lowest atmospheric layers where severe weather occurs.