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Numerical simulations play an essential role in the development and testing of navigation and guidance algorithms, especially when developer must keep the development costs as low as possible. Low budget development focuses mainly on utilization of numerical flight mechanics simulators including optimization and hardware in loop tests. Reliable, high fidelity results can be easily obtained by numerical simulations of flight dynamics utilizing computing power provided by a normal off‐the‐shelf home PC. However, it still requires a simple, but good and valid model of the aircraft and environment. This paper describes an approach to a numerical simulation of aircraft motion that respects the requirement for a full environment high fidelity model and keeps a good interface for further development of attitude control. The goal is achieved by directly specifying the aerodynamic angles of the vehicle in the simulation environment by the guidance system, which can later be used as input for attitude control algorithms. It is proved how an appropriate selection of reference frames and formulation of laws of motion gives very quick and reliable results by employing large integration time steps that would be difficult to achieve in 6–degree‐of‐freedom simulations. This paper also investigates the range of applicability, advantages, and drawbacks of this method. An example of an aerodynamic angle‐based guidance law for a UAV is explained and demonstrated by figures. Santrauka Straipsnyje pateiktas lektuvo slenkamojo judesio dinamikos modeliavimo efektyvus ir patikimas metodas. Ivedus konkrečias koordinačiu sistemas, šiuo metodu galima nustatyti aerodinaminius duomenis ir greičio atskaitos sistema. Tai ypač naudinga modeliuojant skrydžio valdymo ir navigacijos algoritmus, nes čia nebūtini visi aerodinaminiai duomenys. Šis metodas ir jo pritaikymas iliustruojamas BSA valdymo pavyzdžiu.

Most re-entry vehicles utilize a Descent and Landing System (DLS) for a safe descent through the lowest part of the atmosphere. It usually requires deployment in a certain suitable range of flight conditions, which has to be estimated by limited means of navigation. This paper presents a comparison of currently used trigger methods and triggering algorithms which are based on correlation between in-flight measurements and the DLS triggering conditions, where the correlations have been extracted by multiple Monte Carlo campaigns. This approach gives a significant improvement of triggering accuracy over direct measurements for a ballistic re-entry. Also a lateral g-load safety trigger is developed to prevent the angle of attack oscillation escalation. Furthermore a sensor sensitivity analysis is performed for a lifting entry trajectory in order to support an upcoming ESA re-entry mission. The velocity drift appears to be the dominant dispersion by a factor ten for Mach estimation. Finally a case study has been performed to investigate the possibility to reduce the footprint by a dynamic parachute opening window. This could be effective for Mars reentry using a parachute able to deploy beyond Mach 2.5, which would reduce the footprint by up to several tens of kilometers. Nomenclature