This paper presents a method for on-orbit calibration of photodiodes for sun sensing in an attitude determination system. The calibration estimates the scale factors and alignment angles of the photodiodes, resulting in higher attitude determination accuracy than achieved with the pre-flight calibration parameters. The calibration is implemented with an extended Kalman filter to simultaneously ...

A priori information given by the complete modelling of the ballistic behavior of a projectile is simplified to give a pertinent reduced evolution model. This model is composed of quasi-static and dynamic models. An extended Kalman filter is designed to estimate dynamic part of the 3 attitude angles (roll in [0, 2π], angle of attack and side-slip in the range of few milliradians) from measures ...

In this paper a sensor fusion algorithm is developed and implemented for detecting orientation in three dimensions. Tri-axis MEMS inertial sensors and tri-axis magnetometer outputs are used as input of fusion system. A Kalman filter is designed to compensate the inertial sensors errors by combining accelerometer and gyroscope data. A tilt compensation unit is designed to calculate the heading o...

We report on the design, calibration and in-flight performance of a sun sensor, which is used to determine the attitude of a balloon-borne telescope. The device uses a position-sensitive detector (PSD) in a pinhole camera. By determining the position of the image of the Sun on the PSD, the orientation of the sun sensor and the boresight of the telescope relative to the Sun can be determined. Th...

Accurate estimation of localized occupancy related information in real time enables a broad range of intelligent smart environment applications. A large number of studies using heterogeneous sensor arrays reflect the myriad requirements of various emerging pervasive, ubiquitous and participatory sensing applications. In this paper, we introduce a zero-configuration and infrastructure-less smart...

BACKGROUND Modern Elekta Neuromag MEG devices include 102 sensor triplets containing one magnetometer and two planar gradiometers. The first processing step is often a signal space separation (SSS), which provides a powerful noise reduction. A question commonly raised by researchers and reviewers relates to which data should be employed in analyses: (1) magnetometers only, (2) gradiometers only...

The sensitivity of the magnetic sensor is important for many electromagnetic Non Destructive Evaluation (NDE) applications. Nevertheless, for successful defect detection, properties such as high linearity, large dynamic range and good spatial resolution are required. One solution comes in good using improved solidstate magnetic sensors based on Giant MagnetoResistance (GMR). In this way, we hav...

Advances in the field of quantum sensing mean that magnetic field sensors, operating at room temperature, are now able to achieve sensitivity similar to that of cryogenically cooled devices (SQUIDs). This means that room temperature magnetoencephalography (MEG), with a greatly increased flexibility of sensor placement can now be considered. Further, these new sensors can be placed directly on t...

The operation and test of a multi-spot digital sun sensor for precise sun-line determination is described. The image forming system consists of an opaque mask with multiple pinhole apertures producing multiple, simultaneous, spot-like images of the sun on the focal plane. The sun-line precision can be improved by averaging multiple simultaneous measures. Nevertheless, the sensor operation on a ...