Optically pumped magnetometers (OPMs) exploiting alkali metal vapours for accurate, precise magnetometry have benefited from improvements in components and techniques in recent years. Microfabrication of alkali cells and chip-scale lasers allow mass-production of compact sensors, and feedback an spin-preparation techniques, such as light-narrowing, allow enhanced performance, comparable with cryogenic SQUID magnetometers. I will introduce two OPM modalities developed at Strathclyde for geomagnetic operation- the digital alkali-spin maser and geophysical free-precession magnetometer. I will discuss the potential impacts of using these sensors for geophysical applications, including Global Navigation Satellite System (GNSS)-denied positioning, monitoring of space weather and magnetic anomaly detection. I will present developments in microfabrication and digital signal processing which will enable their widespread adoption.