Abstract:
A system and process that can be used to determine vehicle attitude with only one navigation receiver. In one embodiment, the antenna of the navigation receiver is driven with a signal that modulates sensitivity in azimuth. The received navigation signal strength is demodulated by the phase at which the antenna is sweeping and a phase angle and a magnitude for the incoming signal are calculated. Using this calculated phase angle, magnitude and antenna characteristics, the location of the user (i.e. the navigation receiver) and the location of the navigation satellite, the attitude of the antenna and hence the user or user vehicle can be determined.
Abstract:
A train control system comprising a vital brake interface unit that is disposed between the train control processors and the braking system. The brake interface unit ensures that any failure in the control processors or the interface itself is detectable and, when detected, causes the system to fail safely (i.e., the train's brakes are applied). By virtue of the use of redundant circuitry paths, the vital braking interface unit enables real-time verification of system circuitry without actually applying the train's brakes.