Guidance system

About: Guidance system is a research topic. Over the lifetime, 4282 publications have been published within this topic receiving 45964 citations.

Image Processing for Near Earth Object Optical Guidance Systems

Abstract: A feature tracking algorithm is described, which is designed to support optical navigation of autonomous spacecraft. The algorithm is based on an existing system designed for use in planetary entry, descent, and landing (EDL) scenarios and includes several extra processing steps aimed at improving the performance. The algorithm is tested against the original by processing synthetic image streams of an asteroid and a lunar-type surface, taking care to use realistic surface reflectance models. The tracked features are processed to extract estimates of the camera motion between frames, and the results are compared with the ground truth to assess the robustness and accuracy of the feature tracking.

Optimal Guidance for Aerodynamically Controlled Re-Entry Vehicles

Abstract: Linear optimal control theory is applied to develop terminal guidance laws for aerodynamically controlled re-entry vehicles. The quadratic performance function minimized includes the terminal state error, the integral of the state deviation from the nominal trajectory, and the integral of control corrections, where the weighting coefficients are trajectory dependent parameters. The vehicle is assumed to be controlled by lift acceleration magnitude and bank angle. By use of linear regulator theory, perturbation feedback control gains are calculated and used with state errors to compute corrections to the commanded nominal lift acceleration and bank angle. A four-state perturbation model is used to approximate the six-state trajectory dynamics for the derivation of the guidance feedback gain matrix. The notable feature of the approach described in this paper stems from the elimination of the velocity magnitude state in the flight dynamics perturbation model. In addition, "time" is eliminated as the independent variable in favor of distance, resulting in a four-state perturbation model. With these and other assumptions, the control variables are lift acceleration and bank angle, which are the natural ones for an acceleration controlled vehicle using accelerometers for measurement. This unique approach to modeling avoids the need for consideration of angle of attack and aerodynamic drag in the guidance equations. The guidance law implementation is thus independent of vehicle parameters such as mass and surface area, atmospheric density, and the aerodynamic coefficients of lift and drag. The resulting guidance law is evaluated using a three-degree-of-freedom simulation, in which the angle of attack and accelerations are limited and the trajectory dynamics are described by a six-state set of differential equations. Good performance is obtained for a variety of initial state errors, and off-nominal conditions in atmospheric density and vehicle aerodynamic lift and drag coefficients.

Implementation of laser navigation system using particle filter

Abstract: This paper presents a positioning method of the laser guidance with a particle filter for an AGV (automatic guided vehicle). Wired guidance and magnetic guidance system have been used mainly for AGV's guidance in industry. However, these guidance systems have an expensive installation cost and a difficult maintenance. Therefore, the laser guidance system as a wireless guidance system is increasingly used. However, this system has a number of positioning errors when the AGV turns or moves fast by the characteristics of the laser guidance which detects reflectors using a rotating header within the particular operating environment. Hence, this paper proposes a positioning method to improve the performance of the laser guidance system. The proposed system integrates two encoders, a gyro sensor and laser guidance through the particle filter. To verify the performance of the proposed positioning method, we compare the positioning accuracy of the proposed method with an existing product of the laser guidance system. The experimental results show that the proposed method is more accurate than the existing product.

Low-cost sensors based Multi-Sensor Data Fusion techniques for RPAS Navigation and Guidance

Abstract: In order for Remotely Piloted Aircraft Systems (RPAS) to coexist seamlessly with manned aircraft in non-segregated airspace, enhanced navigational capabilities are essential to meet the Required Navigational Performance (RNP) levels in all flight phases. A Multi-Sensor Data Fusion (MSDF) framework is adopted to improve the navigation capabilities of an integrated Navigation and Guidance System (NGS) designed for small-sized RPAS. The MSDF architecture includes low-cost and low weight/volume navigation sensors suitable for various classes of RPAS. The selected sensors include Global Navigation Satellite Systems (GNSS), Micro-Electro-Mechanical System (MEMS) based Inertial Measurement Unit (IMU) and Vision Based Sensors (VBS). A loosely integrated navigation architecture is presented where an Unscented Kalman Filter (UKF) is used to combine the navigation sensor measurements. The presented UKF based VBS-INS-GNSS-ADM (U-VIGA) architecture is an evolution of previous research performed on Extended Kalman Filter (EKF) based VBS-INS-GNSS (E-VIGA) systems. An Aircraft Dynamics Model (ADM) is adopted as a virtual sensor and acts as a knowledge-based module providing additional position and attitude information, which is pre-processed by an additional/local UKF. The E-VIGA and U-VIGA performances are evaluated in a small RPAS integration scheme (i.e., AEROSONDE RPAS platform) by exploring a representative cross-section of this RPAS operational flight envelope. The position and attitude accuracy comparison shows that the E-VIGA and U-VIGA systems fulfill the relevant RNP criteria, including precision approach in CAT-II. A novel Human Machine Interface (HMI) architecture is also presented, whose design takes into consideration the coordination tasks of multiple human operators. In addition, the interface scheme incorporates the human operator as an integral part of the control loop providing a higher level of situational awareness.