A gradiometer measures the difference in a physical field between locations, rather than only measuring the field at one point. For example, a gravity gradiometer can detect small variations in gravity that may indicate subsurface features such as cavities or tunnels. Its usefulness depends on the field being measured, instrument calibration, and how readings are interpreted.
In cyber security, a gradiometer matters when its measurements feed into connected systems used to monitor infrastructure. Attackers or faults could undermine trust in the output by altering, delaying, or replaying data, or by associating readings with the wrong device. Defenders should protect the full data path with device identities, authenticated communications, access controls, configuration logging, and monitoring. These safeguards help preserve measurement integrity; they do not imply that the sensing instrument itself has a specific vulnerability.