What type of tracking method is best for a senior who is prone to wandering: radio frequency, GPS, or cellular?

Yes ,I my self would like to know where I can find out more information on this radio frequency signal??????????????????????

where can a find the device/deices being used with project lifesaver for my father

where do i find the devise being used with project life saver for my father

Unlike cellular and GPS technology, the radio frequency signal does not rely on fragile cellular networks or satellite signals that are weather dependent. Radio Frequency technology is reliable and can track an individual who wanders during adverse weather conditions, in water, in a densely wooded area, in a concrete or steel structure, or in a building.