Observer-Based Drag-Tracking Guidance for Entry Vehicles Considering Input Saturation Constraint
For entry vehicle guidance, this work addresses practical uncertainties and input saturation that previous methods could not handle.
This paper proposes an observer-based drag-tracking guidance law for entry vehicles that handles input saturation and uncertainties, achieving near-zero tracking error. Monte Carlo simulations demonstrate the method's advantage over existing approaches.
This paper studies the drag-tracking guidance design problem of uncertain entry vehicles. With employing a Nussbaum type function to deal with input saturation constraint, an output feedback guidance law (bank angle magnitude) with a high-gain observer is constructed that makes the drag-tracking error converge near zero in the presence of uncertainties. It is also worthy to claim that, in contrast to the existing results whose envelope of uncertainty merely depends on the drag error, the considered uncertainty is allowed to be not bigger than a function of drag error and integral term of drag error, which inevitably occurs in practice. The Monte Carlo simulation is done to illustrate the advantage of the developed method.