Cyclone Global Navigation Satellite Syst

  Jan 04, 2017

What is CYGNSS?
The Cyclone Global Navigation Satellite System (CYGNSS) is a space-based system developed by the University of Michigan and Southwest Research Institute with the aim of improving hurricane forecasting by better understanding the interactions between the sea and the air near the core of a storm.
 The Science of CYGNSS
The same GPS technology that helps people get where they're going in a car will soon be used in space to impact hurricane forecasting. The technology is a key capability in a NASA mission called the Cyclone Global Navigation Satellite System (CYGNSS).
The CYGNSS mission will use eight micro-satellites to measure wind speeds over Earth's oceans, increasing the ability of scientists to understand and predict hurricanes. Each satellite will take information based on the signals from four GPS satellites.
 
​CYGNSS is taking a novel approach to calculate wind speeds that both reduces the mission's cost and gathers more data as well.
Typically, measuring wind speed over the oceans from space uses a technique called scatterometry. A radar instrument aboard a satellite sends a signal to the ground, and measures the signal strength reflected back to it. Building both sending and receiving capabilities into a single instrument, however, is more expensive than the method being used on CYGNSS.
The CYGNSS satellites will only receive signals broadcast to them from GPS satellites already orbiting the Earth and the reflection of the same satellite’s signal reflected from the earth. The CYGNSS satellites themselves will not broadcast, that will result in significant cost savings.
 
Better coverage
The use of eight satellites will also increase the area on Earth that can be measured. The instruments will be deployed separately around the planet, with successive satellites passing over the same region every 12 minutes. As the CYGNSS and GPS constellations move around the earth, the interaction of the two systems will result in a  new image of wind speed over the entire tropics every few hours, compared to every few days  for a single satellite.
Another advantage – the CYGNSS orbit is designed to measure only in the tropics, where hurricanes are most often found. Traditional polar-orbiting  weather satellites measure the whole globe because they are trying to capture all types of data. The focus on tropical activity means the CYGNSS instruments will be able to gather that much more useful data on weather systems exclusively found in the tropics.
Science goal
The CYGNSS science goal is to understand the coupling between ocean surface properties, moist atmospheric thermodynamics, radiation, and convective dynamics in the inner core of a tropical cyclone. To achieve this goal, the system will measure ocean surface wind speed in all precipitating conditions, including those experienced in the eyewall. The mission will also measure ocean surface wind speed in the storm's inner core with sufficient frequency to resolve genesis and rapid intensification. As secondary goal, the project will support the operational hurricane forecast community by producing and providing ocean surface wind speed data products.