Short answer: It depends on how Colorado courts have interpreted USSC ruling in Jones. Generally speaking, a warrant is required to place a GPS tracker on a vehicle. Disclosure of the tracker is one area that has been the subject of debate.
Long answer:
According to the Supreme Court in United States v. Jones, police use of a GPS device to track a suspect’s vehicle is considered a “search” under the Fourth Amendment. This means that the police must secure a search warrant before affixing a GPS device to a person’s car for the purpose of tracking them.
Once the police secure a valid search warrant, they can attach a GPS device on the outside of a car, typically underneath the body or underneath a bumper. The device will disclose the location of the vehicle. However, this ruling was split into three separate opinions, making the application of the rule difficult.
As a result, courts throughout the states have been applying the law differently, often reaching completely contrasting conclusions over the same issues. For example, arguments are being made that the Jones case requires courts to dismiss warrantless surveillance evidence obtained by other means, such as a video camera. These arguments hinge on the idea that the Fourth Amendment protects one’s reasonable expectation of privacy, and that the court has determined that this type of long-term tracking is an invasion of that privacy.