"The Fourth Amendment provides that
"The right of the people to be secure in their persons, houses, papers, and effects, against unreasonable searches and seizures, shall not be violated; and no Warrants shall issue but upon probable cause, supported by Oath or affirmation, and particularly describing the place to be searched, and the persons or things to be seized."
"In general, the amendment prohibits the government from conducting unreasonable searches or seizures of 'the people' and their property, in most cases (subject to a number of exceptions) requiring a warrant supported by a particularized description of the object of the search or seizure.35 The term 'search' refers to a governmental infringement of an expectation of privacy that society is prepared to consider reasonable, that is, under circumstances where an individual reasonably expects that the privacy of his or her person, home, papers, or effects are protected from uninvited intrusion.36 A 'seizure' occurs when there is meaningful governmental interference in a property interest37 or intentional detention of a person.38 Searches and seizures can involve intangible as well as tangible things.39
"Government surveillance where there is no legitimate expectation of privacy does not amount to a 'search' within the meaning of the Fourth Amendment and therefore carries no requirement for a warrant, probable cause, or even any semblance of reasonableness."
Best, Richard A., Jr.; Elsea, Jennifer K., "Satellite Surveillance: Domestic Issues," Congressional Research Service (Washington, DC: Library of Congress, January 13, 2011), p. 12.