Error Propagation Concepts Including Flight Dynamics for Total System Performance Analysis During GBAS based Initial CAT-III Approach and Landing

In order to assess the integrity risk for GBAS based automatic approach and landing, we investigated a total performance concept of a combined system consisting of an ILS look-a-like GBAS landing system (GLS) and a DeHavilland Dash-2 Beaver aircraft. We propagated four basic pseudorange errors to a position error distribution, which was then the source of position uncertainties for the GLS installed in the aircraft. Results show that the vertical total system error (TSE) in the steady state final approach lags behind the vertical navigation system error (NSE). The TSE is smoothed and preserves the general temporal sequence of the error. A reduction of 30\% of the TSE standard deviation with respect to the NSE only occurs during a period of glide slope overshoot, where the autopilot uses large and steadily declining elevator deflections to return to the desired glide path. With minor adaptations this concept can be refined and a possible error reduction may be achieved

Observer design for a class of nonlinear systems combining dissipativity with interconnection and damping assignment

A nonlinear observer design approach is proposed that exploits and combines port-Hamiltonian systems and dissipativity theory. First, a passivity-based observer design using interconnection and damping assignment for time variant state affine systems is presented by applying output injection to the system such that the observer error dynamics takes a port-Hamiltonian structure. The stability of the observer error system is assured by exploiting its passivity properties. Second, this setup is extended to develop an observer design approach for a class of systems with a time varying state affine forward and a nonlinear feedback contribution. For a class of nonlinear systems, the theory of dissipative observers is adapted and combined with the results for the passivity-based observer design using interconnection and damping assignment. The convergence of the compound observer design is determined by a linear matrix inequality. The performance of both observer approaches is analyzed in simulation examples

Amplitude control for an artificial hair cell undergoing an Andronov-Hopf bifurcation

The dynamics of an artificial hair cell is analyzed by considering the bifurcation behavior of a dominant mode model. It is shown that this model undergoes an Andronov-Hopf bifurcation similar to its biological counterpart, i.e., the hair cell in the mammalian cochlea. Consequently, this dynamical behavior is exploited to control the amplitude of the deflection of the artificial hair cell. In particular feedforward control with disturbance injection is designed based on an approximation of the oscillation using an envelope model to achieve a constant deflection amplitude. The approach is evaluated in numerical simulations

Distributed Parameter State Estimation for the Gray–Scott Reaction-Diffusion Model

A constructive approach is provided for the reconstruction of stationary and non-stationary patterns in the one-dimensional Gray-Scott model, utilizing measurements of the system state at a finite number of locations. Relations between the parameters of the model and the density of the sensor locations are derived that ensure the exponential convergence of the estimated state to the original one. The designed observer is capable of tracking a variety of complex spatiotemporal behaviors and self-replicating patterns. The theoretical findings are illustrated in particular numerical case studies. The results of the paper can be used for the synchronization analysis of the master–slave configuration of two identical Gray–Scott models coupled via a finite number of spatial points and can also be exploited for the purposes of feedback control applications in which the complete state information is required