Abstract: In emergency or search-and-rescue operations, user devices such as phones may transmit signals that indicate people may be located nearby. The signals can be detected by one or more rover devices, which can explore dangerous terrain for indications of people to be rescued. The user devices can activate an application that conserves battery power while emitting a signal, in some cases in a round robin configuration to further conserve power. The rover devices, or other devices that make contact with the user devices, can collect and manipulate data about the user devices to aid a rescue operation.