The present disclosure relates to location and communication systems that can be utilized for locating people, pets and other objects with a software defined radio set. A personal electronic device (PED) such as a cellular telephone, personal data assistant (PDA) or other device that include a software defined radio set can be configured for operation as a locator device. The PED transmits a signal A transponder or micro-transponder (MT) that is tagged to an object is arranged to reply to a transmission received from the PED. The PED based locator is arranged to calculate a distance between the PED and the MT using the time-of-flight (TOF) between the transmission and the receipt of a reply. The absolute geographic position of the PED can be determined using satellite navigation information, while the position of the MT relative to the PED can be determined from the TOF information.