Gravity, Magnetic and Electromagnetic Gradiometry (Second Edition)

Gradiometry is concerned with the extraction of useful information from the spatial variation of the gravity, magnetic and electric fields that exist naturally on Earth and other planets. It is a complex multidisciplinary area that combines theoretical and applied physics, ultra-low noise electronics, precision engineering, and advanced signal processing. With applications including the search for oil, gas, and mineral resources, GPS-free navigation, defence, space missions and medical research there has been considerable investment into the development of various types of gradiometers driven by the extremely valuable type of information they reveal.

This book describes gravity gradiometers, magnetic gradiometers, and electromagnetic (EM) gradiometers. The first two do not require any active sources of the primary physical fields whose gradients are measured, such as gravity and ambient magnetic fields. EM gradiometers do require a primary EM field, pulsed, or sinusoidal, which propagates through media and creates a secondary EM field, which contains information about the non-uniformness of electromagnetically active media such as conductivity and magnetic permeability contrasts. These anomalies are the boundaries of mineral deposits, oil and gas traps, underground water reserves, buried artefacts, unexploded ordnance, nuclear submarines, and even cancerous human tissue.

The author provides readers with a comprehensive and up to date overview of the history, applications, and current developments in relation to some of the most advanced technologies in the 21st Century, especially regarding future challenges in natural resource exploration in the changing energy supply environment and a post COVID world. This new edition also incorporates the most important new directions bringing fresh ideas into the field, including quantum or quantum-enabled sensing and miniaturization of the operational environment in which gradiometers should function.