A compact GPS receiver includes a GPS antenna composed of a patch and a ground plane to receive high frequency satellite signals, an analog circuit which processes the high frequency satellite signals into a digital signal, a digital circuit which processes the digital signal to compute positional coordinates of the GPS antenna, and an interface connector which outputs the positional coordinates to an external device. A substrate is provided to support the GPS antenna, the analog circuit, the digital circuit, and the interface connector. An EMI (electromagnetic interference) shield is provided to shield at least the digital circuit to block a noise developing at the digital circuit from interfering with the GPS antenna. The GPS antenna is mounted on the EMI shield to share the ground plane with the EMI shield, while keeping the patch insulated electrically from the EMI shield. Thus, the GPS receiver can be made compact by making the use of the EMI shield also as the ground plane of the antenna, while assuring to block the noise from interfering with the antenna and affording sufficient antenna gain with the increased ground plane.