This read-only boolean value indicates whether the velocity figures returned by the GPS device during the last location fix are valid. An admin cares because this tells them whether to trust the accompanying heading and horizontal/vertical velocity readings, since GPS-derived speed can be unreliable under poor satellite conditions. For example, if this object reports false, the admin should disregard c3gLbsHeading, c3gLbsVelocityHorizontal, and c3gLbsVelocityVertical for that fix rather than using them to infer the device's movement.