Described are computer-based methods and apparatuses, including computer program products, for position determination. In some examples, the method includes receiving, by a device, position information from at least one other device. The method further includes modifying, by the device, an initial position based on the position information from the at least one other device to form a refined position. The method further includes transmitting, by the device, the refined position to the at least one other device. The method further includes revising, by the device, the refined position based on refined position information received from the at least one other device to form a final position.