In United States v. Jones, 2012 U.S. LEXIS 1063* (January 23, 2012), the Supreme Court addresses the question of whether the installation of a GPS tracking device is a search under the 4th Amendment.
In Jones, a GPS tracking device was installed on a car being driven by Jones and monitored his movement for four weeks. All members of the Court agreed that the installation and monitoring of defendant’s car by GPS was a violation of the 4th Amendment, but the Court did so in three separate opinions.
The majority opinion held that the installation of the GPS was a trespass to an “effect” as the term is used in the 4th Amendment and found that the government physically occupied the property of defendant in order to obtain information about the defendant. The Court went on to state that it did not have to engage in a reasonable expectation of privacy analysis because the trespass disposed of the issue.
In the concurring opinion the court focused on the reasonable expectation of privacy articulated in Katz v. United States, 389 US 347 (1967), and also found a violation of the 4th Amendment.