Kamel, Ahmed M., Renaudin, Valerie, Nielsen, John, and Lachapelle, Gérard
International Journal of Navigation & Observation. 2013, p1-17. 17p.
INERTIAL navigation systems, FUZZY logic, GLOBAL Positioning System, GUIDED missiles, BANDWIDTHS, PHASE-locked loops, and RADIO interference
Autonomous Navigation Systems used in missiles and other high dynamic platforms are mostly dependent on the Global Positioning System(GPS). GPS users face limitations in terms of missile high dynamics and signal interference. Receiver's tracking loops bandwidth requirements to avoid these problems are conflicting. The paper presents a novel signal frequency and phase tracking algorithm for very high dynamic conditions, which mitigates the conflicting choice of bandwidths and reduces tracking loop measurement noise. It exploits the flexibility of fuzzy control systems for directly generating the required Numerically Controlled Oscillator (NCO) tuning frequency using phase and frequency discriminators information and is labeled Fuzzy Frequency Phase Lock Loop (FFPLL). Because Fuzzy Systems can be computationally demanding and an InertialNavigation System (INS) is often onboard the vehicle, an assisted INS Doppler version has been designed and is also proposed. Assessment of the new GPS trackingmethod is performed with both simulated and experimental data under jamming conditions. The main enhancements of the proposed system consist in reduced processing time, improved tracking continuity and faster reacquisition time. [ABSTRACT FROM AUTHOR]
ERROR probability, BALLISTIC missiles, INERTIAL navigation systems, MONTE Carlo method, and FLIGHT simulators
A circular error probability (CEP) metric in ballistic missile science is an experimental indicator of the accuracy of a missile system. There are a lot of error sources that cause a ballistic missile to deviate from its ideal trajectory, and that causes a deviation from required CEP. This work discusses the problems of dispersion of ballistic missiles due to inertial navigation system (INS) errors. INS deterministic errors are usually calibrated and compensated using some proper techniques. However, INS stochastic errors can be modeled and analyzed. In this study, a chosen missile is thoroughly analyzed using the six degrees-of-freedom missile flight trajectory simulator. A Monte Carlo simulation is used to generate a large number of flight trajectories to inspect the effect of INS stochastic noise on missile CEP. Moreover, a strategy for selecting an adequate sensor according to mission requirements and its corresponding sensor errors is introduced. [ABSTRACT FROM AUTHOR]