18 U.S.C. § 3117

(a) In General .— If a court is empowered to issue a warrant or other order for the installation of a mobile tracking device, such order may authorize the use of that device within the jurisdiction of the court, and outside that jurisdiction if the device is installed in that jurisdiction. (b) Definition .— As used in this section, the term “tracking device” means an electronic or mechanical device which permits the tracking of the movement of a person or object.