In this article mathematical and computer models of sun sensor and magnetic sensor are considered that can be used for determination of small satellite attitude. In particular, the mathematical models of slit sun sensor and flux-gate magnetic sensor are given.

Interreflected light is known to account for a substantial amount of total illumination content in a closed environment. But often such light is colored, leading to a light environment at any point on a surface which changes spectrally depending on the orientation of the surface normal at that point. A similar effect occurs when several sources of light are present, e.g. artificial light combin...

In this paper, new attitude determination algorithms using pseudolite signal phase measurements are developed and presented with realistic simulations. Pseudolite signals are used to replace GPS signals which are often not available due to blocking by nearby large structures, for example a crew return vehicle under the International Space Station. A new observation model needs to be applied bec...

No wonder you activities are, reading will be always needed. It is not only to fulfil the duties that you need to finish in deadline time. Reading will encourage your mind and thoughts. Of course, reading will greatly develop your experiences about everything. Reading spacecraft attitude determination and control quaternion based method is also a way as one of the collective books that gives ma...

For parameter estimations, we have developed a extended kalman filter(EKF) and unscented kalman filter(UKF) for linear as well as non-linear spacecraft systems. We have described the differences of two approaches mathematical equation for modeling of the system value of mean square error, error covariance and For state estimation of satellite, two different type of filters has been described i....

This paper describes a set of numerical optimization algorithms for solving the GPS based attitude determination problem We pose the problem as one of minimizing the function tr N Q W with respect to SO where N Q andW are given matrices The method of steepest descent and Newton s method are generalized to SO by taking advantage of its Lie group structure Analytic solutions to the line search pr...

This paper presents a study using Genetic Algorithms (GA) to solve the star pattern recognition problem associated with star tracker attitude determination systems. Characteristics of the stars that are visible within the Field of View (FOV) of an imager are defined with regard to relative distances and angles. The proposed GA minimizes the discrepancy between the characteristics of the stars i...

Traditionally, the extended Kalman filter (EKF) is a well known approach for general nonlinear data fusion problem. But the unit norm constraint of quaternion vector, which is the most efficient expression of attitude, results in the singularity of error covariance matrix. To overcome this difficulty, the modified extended Kalman filter (MEKF) has been developed by Shuster (1982). In order to i...

This paper presents the results of a quaternion-based unscented Kalman filtering for attitude estimation using low cost MEMS sensors. The unscented Kalman filter uses the pitch and roll angles computed from gravity force decomposition as the measurement for the filter. The immeasurable gravity accelerations are deduced from the outputs of the three axes accelerometers, the relative acceleration...

In this paper, a new algorithm for GPS integer ambiguity resolution is shown. The algorithm first incorporates an instantaneous (static) integer search to significantly reduce the search space using a geometric inequality. Then a batch-type loss function is used to check the remaining integers in order to determine the optimal integer. This batch function represents the GPS sightline vectors in...