Abstract: A system, non-transitory computer readable medium, and method include entering redundant oscillators and a cascaded oscillator of a spoofing resistant system into an initialization state. All but one of the redundant oscillators are disciplined to a time-and-frequency external input into normal disciplining state with the remaining one of the redundant oscillators in a holdover state. When all but one of the redundant oscillators have reached the normal disciplining state, placing all but one of the redundant oscillators into the holdover state, disciplining the remaining one of the redundant oscillators to the time and frequency external input, and disciplining the cascaded oscillator to one of the all but one of the redundant oscillators now in the holdover state. When the remaining one of the redundant oscillators and the cascaded oscillator have reached the normal disciplining state, transitioning from an initialization stage to a steady state management stage.

Abstract: A method, GNSS simulator, and non-transitory computer readable medium for providing a simulated global navigation satellite system (GNSS) signal. The method includes receiving, by a GNSS simulator, a precision timing signal and one or more items of ephemeris data from a GNSS receiver based on a decoded GNSS signal received by the GNSS receiver. The precision timing signal and the one or more items of GNSS ephemeris data are received in a digital format over a communication network. A simulated GNSS signal is generated, by the GNSS simulator, based on the received precision timing signal and one or more items of ephemeris data. The simulated GNSS signal is transmitted, by the GNSS simulator, over a coverage area. A GNSS system for providing a simulated GNSS signal is also disclosed.

Abstract: A reference management apparatus includes a reference signal housing, a fixed length propagation device, an oscillator device, and a reference management computing device. The reference signal housing having a propagation signal output and a propagation signal input. The fixed length propagation device is coupled between the propagation signal output and the propagation signal input. The reference signal management computing device is coupled to the oscillator device and the propagation signal input.

Abstract: A method, GNSS simulator, and non-transitory computer readable medium for providing a simulated global navigation satellite system (GNSS) signal. The method includes receiving, by a GNSS simulator, a precision timing signal and one or more items of ephemeris data from a GNSS receiver based on a decoded GNSS signal received by the GNSS receiver. The precision timing signal and the one or more items of GNSS ephemeris data are received in a digital format over a communication network. A simulated GNSS signal is generated, by the GNSS simulator, based on the received precision timing signal and one or more items of ephemeris data. The simulated GNSS signal is transmitted, by the GNSS simulator, over a coverage area. A GNSS system for providing a simulated GNSS signal is also disclosed.

Abstract: A reference management apparatus includes a reference signal housing, a fixed length propagation device, an oscillator device, and a reference management computing device. The reference signal housing having a propagation signal output and a propagation signal input. The fixed length propagation device is coupled between the propagation signal output and the propagation signal input. The reference signal management computing device is coupled to the oscillator device and the propagation signal input.

Abstract: A method, non-transitory computer readable medium, and apparatus that determines a GPS location includes obtaining assisted GPS data of locations of a plurality of GPS satellites, current time, and initial location data of the receiver computing device. A GPS signal from one or more of the plurality of GPS satellites within a frequency range and time range is acquired based on the obtained assisted GPS data, current time, and initial location data of the receiver computing device. The one or more acquired GPS signals are integrated over a frame period of two or more seconds. A GPS location for the receiver computing device is determined based on the one or more integrated GPS signals.