GPS investigation and right of the target. It intrudes the “privacy”?

Using the new technology such as Global Positioning System (GPS) in criminal investigation poses the problem relating to the target’s right. This past March, the Japanese Supreme Court’s grand bench ruled that the collection of GPS data by police threats target’s “privacy” and is the mandatory investigation required a warrant because of its unique features of GPS investigation. However, there is no consensus as to what “privacy” exactly means in the field of criminal law. Does it overlap with the right protected from unreasonable search and seizure, property rights, or any other rights? It can be still disputable to consider what is the right infringed by the GPS investigation. This paper focuses on the issues related to the scope of what we call as “privacy” and the limits of using GPS devices.