Active vs Passive (Gravity)

Since the GZG universe uses a Grav technology, it would seem reasonable that
a gravity field detector/mapper would also be invented.

Yes, I agree that the gravity produced by a ship or even a group of ships
would be miniscule compaired to a planet or large asteroid.

However, the grav technology appears to be directional. This would be
necessary to create the gravity decks on ships. It would also make sense that
the Grav drive units of ships would also be directional. Perhaps this
non-natural patterns of Gravity would be able to be detected.

And I will conceed that these units could be turned off for a ship that is
trying to hide from sensors.

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