How does the Global Positioning System work? Group of answer choices GPS receivers transmit radar signals into space that are reflected back to Earth by satellites. Receivers calculate positions as a function of the difference in time between the original radar pulse and the echo. GPS satellites broadcast radio signals. GPS receivers calculate positions as a function of the difference in time between the radio broadcast and the receipt of the broadcast signal by the receiver. GPS receivers send signals to satellites; satellites reply with receiver's position. GPS receivers calculate their positions relative to the locations of three or more nearby cell phone towers