https://fis.tu-dresden.de/portal/de/publications/multifrequency-quadrifilar-helix-antennas-for-cmaccurate-gnss-positioning(383c2974-2098-4252-9467-251a1eaeb05f).html
Multi-frequency quadrifilar helix antennas for cm-accurate GNSS positioning | TU Dresden
multi frequency
https://openresearch.surrey.ac.uk/esploro/outputs/journalArticle/Satellite-MIMO-Measurement-With-Colocated-Quadrifilar/99515379402346
Satellite MIMO Measurement With Colocated Quadrifilar Helix Antennas at the Receiver Terminal -...
Jul 15, 2010 - Satellite MIMO Measurement With Colocated Quadrifilar Helix Antennas at the Receiver Terminal - University of Surrey - Journal article