The Gravitational Anomaly Detector (GAD) Mine is a type of landmine invented in the Sirian Union. It is designed to disable and destroy hover vehicles, particularly hovertanks. It was designed in 3333, after Sirian military observers noted that traditional types of landmine often failed to trigger entirely when a hovertank passed over it, and when they did activate their effectiveness was much reduced.
The GAD mine is much like other types of mine, differing primarily in how it is triggered. Rather than relying upon a pressure plate, it instead has a built in GAD sensor. This constantly monitors its surroundings for changes in the local gravitational field (such as those caused by hovertanks). If a gravitational anomaly should exceed a certain threshold it detonates, sending a shaped charge up into the vehicle's vulnerable underbelly.
Although the GAD mine could theoretically be used for anti-personnel work, it would require a very sensitive GAD and would not offer any appreciable improvement in performance over pressure plate designs. Sea mine variants of the GAD mine do exist, though they are much less common than the landmine version.