# S 4 index: Does it only measure ionospheric scintillation?

> Research article (GPS Solutions, 2017) · cited 26× · AI/ML

**Wikidata**: [openalex:W2767793659](https://www.wikidata.org/wiki/openalex:W2767793659)  
**Source**: https://4ort.xyz/entity/s-4-index-does-it-only-measure-ionospheric-scintillation