Abstract: Some implementations herein relate to a device that receives and processes multiple spread spectrum signals corresponding to multiple linear frequency modulated (LFM) signals, including a multipath LFM signal having a directly received signal component and an indirectly received signal component. The device may estimate, based on transmission times and transmission positions of the multiple spread spectrum signals and the multiple LFM signals, a position of the device, a time at which the device was at the position, times of arrival of the directly received signal component and the indirectly received signal component, and a time difference of arrival between the times of arrival of the directly received signal component and the indirectly received signal component. The device may estimate, based on the transmission positions, the position of the device, and the time difference of arrival, a range to the surface relative to the position of the device.

Abstract: Some implementations herein related to an authentication equipment (AE) that receives an in-phase-quadrature phase (I/Q) spectrum recording of a covert data sequence indicative of received spectra of a signal over which an overt data sequence is transmitted and an overt time and position solution. The AE derives from the overt data sequence. indicating a position and a time at which the position was derived. The AE processes the I/Q spectrum recording to derive an independent time and position solution indicating another position where the I/Q spectrum recording was recorded and another time at which the I/Q spectrum was recorded at the another position. The AE determines whether the overt time and position solution and the independent time and position solution are a match. The AE authenticates the overt time and position solution based on the overt time and position solution and the independent time and position solution being a match.

Abstract: A receiver authenticates a wideband (WB) signal from global navigation satellites (GNSS) using a narrowband (NB) signal that is also transmitted from the satellites. The NB signal includes segments that are transmitted in time and frequency slots of successive transmission frames. The NB signal is less susceptible to a smart WB jammer. Also, the NB signal segments may also be transmitted at a relative power level with respect to the WB signal, where the relative power level may vary in a known pattern so as to distinguish the WB signal of the satellite from a stronger WB signal from a smart jammer.

Abstract: A receiver authenticates a wideband (WB) signal from global navigation satellites (GNSS) using a narrowband (NB) signal that is also transmitted from the satellites. The NB signal includes segments that are transmitted in time and frequency slots of successive transmission frames. The NB signal is less susceptible to a smart WB jammer. Also, the NB signal segments may also be transmitted at a relative power level with respect to the WB signal, where the relative power level may vary in a known pattern so as to distinguish the WB signal of the satellite from a stronger WB signal from a smart jammer.