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Robust real-time vehicle positioning is a critical requirement for many in-vehicle technologies. However, no standalone positioning system is capable of providing uninterrupted and accurate vehicular navigation data in all environments that a vehicle could encounter. This paper presents a portable vehicular navigation system that combines high-sensitivity GPS, inertial sensors and map-matching techniques to provide uninterrupted vehicular navigation information in even the harshest environments for individual sensor technologies. This system eliminates the need for complex initialisation routines required for high-end inertial sensors, making it a truly portable system. The map-matching component establishes a link between the vehicle and spatial information useful for many more in-vehicle technologies such as route guidance and location-based services. The system performance is evaluated and presented in an urban centre with extreme levels of GPS signal degradation.

A method is proposed for predicting the internal thread height as a function of tapping process faults and relating it to the standardized thread quality tolerances. Based on the mechanistic tapping model [6], a method of estimating the magnitudes of the faults has been proposed. The effects of tap-hole axes misalignment and tap runout on thread height have been revealed by the mechanistic tapping process model. Based on this model and data obtained from the process estimated process fault values have been used to predict thread height and then predict thread pitch diameter. Using standard tolerances for pitch diameter, an assessment of thread quality can then be made. Validation experiments have been run on several materials for different combinations of process faults. Results of thread measurements showed excellent correspondence with the model predictions.

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