Positioning Based on Tightly Coupled Multiple Sensors: A Practical Implementation and Experimental Assessment

During the last decade, the number of applications for land transportation that depend on systems for accurate positioning has significantly increased. Unfortunately, systems based on low-cost global navigation satellite system (GNSS) components harshly suffer signal impairments due to the environment surrounding the antenna, but new designs based on deeper data fusion and on the combination of different signal processing techniques can overcome limitations without the introduction of expensive components. Supported by a complete mathematical model, this paper presents the design of a real-time positioning system that is based on the tight integration of extremely low-cost sensors and a consumer-grade global positioning system receiver. The design has been validated experimentally through a series of tests carried out in real scenarios. The performance of the new system is compared against a standalone GNSS receiver and survey-grade professional equipment. The results show that a carefully designed and constrained integration of low-cost sensors can have performance comparable to that of an expensive professional equipment

Calibration of low-cost three axis magnetometer with differential evolution

The magnetometers are used in wide range of engineering applications. However, the accuracy of magnetometer readings is influenced by many factors such as sensor errors (scale factors, non-orthogonality, and offsets), and magnetic deviations (soft-iron and hard-iron interference); therefore, the magnetic calibration of magnetometer is necessary before its use in specific applications. This research paper describes calibration method for three axis low-cost MEMS (Micro-Electro-Mechanical Systems) magnetometer. The calibration method uses differential evolution (DE) algorithm for the determination of the transformation matrix (scale factor, misalignment error, and soft iron interference) and bias offset (hard-iron interference). The performance of this method is analysed in experiment on three axis low-cost magnetometer LSM303DLHC and then compared to the traditional method (least square ellipsoid fitting method). The magnetometer readings were obtained while rotating the sensor around arbitrary rotations. The experimental results show that the calibration error is least using DE. © Springer International Publishing AG 2017.Internal Grant Agency of Tomas Bata University in Zlin [IGA/FAI/2017/007