In safety-critical applications, including firefighter and law enforcement operations, infrastructure-free localization systems are typically required. These systems must provide accurate localization in all scenarios. Seamless indoor and outdoor localization and navigation, including in dense urban environments, are needed. Multi-sensor fusion algorithms constitute an integral part in all state-of-the-art indoor positioning systems. GNSS-receivers typically provide poor estimates of their own position uncertainty in dense urban and indoor environments, where significant position errors can be expected, which makes the design of a robust sensor fusion algorithm a challenge. Sensor fusion strategies for integration of a GNSS-receiver with footmounted inertial navigation systems (INS) are described and evaluated in this work. For a loosely coupled integration strategy, we suggest to use a cut-off criteria that governs when to discard the GNSS-positions and demonstrate that it can improve the position and heading accuracy in outdoor/indoor transition regions. Similarly, for a tightly coupled integration strategy, we suggest an approach with heavy-tailed measurement noise and demonstrate its capability to suppress inconsistent data and improve performance in the same regions.
A guidance strategy for generic 2D course correcting fuzes is developed using a perturbation based trajectory prediction method together with a velocity to be gained (VTG) control formulation. The open loop dynamics for the VTG that results in the atmospheric case is a slight modification of the vacuum dynamics and similar approaches for control can be applied. We formulate and solve a time varying linear quadratic (LQ) optimal control problem to obtain a guidance strategy that makes efficient use of controls over the flight. The resulting guidance strategy requires only low complexity updates in-flight. Using simulations of a standard 155mm artillery shell with canard control in varying firing scenarios it is shown that excellent dispersion reduction can be obtained with only modest requirements on control authority.
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