In this paper, the detection of a fault in the Global Positioning System (GPS) measurement is addressed. The class of faults considered is a bias in the GPS pseudorange measurements. This bias is modeled as an unknown constant. The fault could be the result of a receiver fault or signal fault such as multipath error. A bias bank is constructed based on set of possible fault hypotheses. Initiall...

This paper addresses the issue of designing a fault accommodating control algorithm which, after a sensor fault occurrence, takes information about the degraded sensor into account and drives the system such that performance recovery is achieved. A general class of single input nonlinear systems is considered, containing also a disturbance term. An observer is used to reconstruct the degraded s...

fault tree analysis (fta) as a probabilistic risk assessment (pra) method is used to identify basic causes leading to an undesired event, to represent logical relation of these basic causes in leading to the event, and finally to calculate the probability of occurrence of this event. to conduct a quantitative fta, one needs a fault tree along with failure data of the basic events (bes). someti...

A fault-tolerant controller is a controller that drives the plant to satisfy control specifications under both nominal operation and after the occurrence of faults. This paper introduces a framework that ensures the fault-tolerance of a discrete-event system (DES) plant, which includes: (i) a nominal supervisor with respect to the nominal plant to ensure the control specification that is prior ...

From a partial observation of the behaviour of a labeled Discrete Event System, fault diagnosis strives to determine whether or not a given “invisible” fault event has occurred. The diagnosability problem can be stated as follows: does the labeling allow for an outside observer to determine the occurrence of the fault, no later than a bounded number of events after that unobservable occurrence ...

Most of the attacks attempt an initial activation which means the first occurrence of an error provoked by the fault. If its unable to stop the propagation, a fault will be transformed into a failure, causing consequences. This paper presents an exploratory research about the integration of fault tolerance aiming defenses against malicious inputs. When a fault occurs, these techniques provide m...

A strategy of fault diagnosis and tolerance for asynchronous sequential machines is discussed in this paper. With no synchronizing clock, it is difficult to diagnose an occurrence of permanent or stuck-in faults in the operation of asynchronous machines. In this paper, we present a fault detector comprised of a timer and a set of static functions to determine the occurrence of faults. In order ...

This paper discusses the problem of fault diagnosis under multiple sequential faults occurrence. In industrial applications this type of fault is the most common since the continuous operation of systems/processes is required. The fault diagnosis algorithms should cope with such type of multiple faults, but degradation in their fault isolation capabilities is introduced until the point that the...