A Beginner ’ s Guide to Space Weather and GPS

This brief paper is written for GPS engineers or systems designers who need to know about space weather. Just as an architect might need to know about hurricanes or tornadoes, characterizing space weather enables designers to understand vulnerabilities in their designs, to create more robust designs, and to determine how best to avoid risk. Space weather is a somewhat arcane topic studied by a few space scientists who, by and large, lack a working knowledge of GPS signals and receivers. On the other hand, GPS and GNSS comprise a growth industry limited only by the imagination and are populated by engineers with little knowledge of space weather. Cornell University’s faculty are award-winning experts in both space weather and GPS receiver design and have an international reputation for their work at the intersection of space weather and GPS. These perspectives motivated the creation of this beginner’s guide. The objective is to advise the practicing engineer of when and how GPS systems may be affected by space weather. The high-level description below is adequate for determining whether further investigation is required. For those wanting to probe the subject more deeply, the bibliography at gps.ece.cornell.edu is recommended. The paper’s organization consists of an overview of space weather, how the ionosphere affects GPS signals, a description of ionospheric climate and weather, and strategies for mitigating the effects of space weather.