Rough Tracking Research Articles

Feasibility study of microsatellite laser communication pointing system based on SEEOR technology

Satellite laser communication technology is a communication method that uses laser beam as information transmission carrier to transmit information data in space. It has many advantages such as large communication capacity, long transmission distance, high bandwidth, no spectrum permission, etc,widely used at present. The beacon light direction of its typical satellite laser communication system is realized by rough tracking servo turntable platform carrying optical components, so,there are a series of shortcomings such as turntable vibration, corner error and system inertia etc. Currently, a new technology, Non-Mechanical Beam Steering (NMBS) technology, in mid-wave infrared (MWIR) which has emerged, is expected to break through above shortcomings and provide possibilities for the transmission of beacon light in satellite laser communication. This paper focuses on the application of non-mechanical beam pointing technology in satellite laser communication system. We objectively analyzed the basic principles of the Non-Mechanical Beam Steering chip work, and the feasibility of using Non-Mechanical Beam Steering to transmit beacon light in satellite laser communication theoretically. It will open up a new way for the development of microsatellite laser communication technology in the future.

MixAR

MixAR, a full-stack system capable of providing visualization of virtual reconstructions seamlessly integrated in the real scene (e.g. upon ruins), with the possibility of being freely explored by visitors, in situ, is presented in this article. In addition to its ability to operate with several tracking approaches to be able to deal with a wide variety of environmental conditions, MixAR system also implements an extended environment feature that provides visitors with an insight on surrounding points-of-interest for visitation during mixed reality experiences (positional rough tracking). A procedural modelling tool mainstreams augmentation models production. Tests carried out with participants to ascertain comfort, satisfaction and presence/immersion based on an in-field MR experience and respective results are also presented. Ease to adapt to the experience, desire to see the system in museums and a raised curiosity and motivation contributed as positive points for evaluation. In what regards to sickness and comfort, the lowest number of complaints seems to be satisfactory. Models' illumination/re-lightning must be addressed in the future to improve the user's engagement with the experiences provided by the MixAR system.

Visual servo for gravity compensation system

This paper proposed a visual servo framework for the tower-crane-like Gravity Compensation System that is widely used in various aerospace ground tests. In this framework, a real-time detection algorithm is proposed to measure the position of the target. Using this algorithm, the target's original position is marked firstly in a well-designed calibration step, and then compared to its real-time position to calculate the offset for tracking. To realize the high precision tracking, a 2-level servo mechanism is investigated, in which a large-inertia crane servo system is utilized for the rough tracking and a 2-DOF (2 Direction Of Freedom) platform is used for the precise localization. The proposed method leads to a high responding speed and low time-drift in wide range tracking, and greatly decreases the compensation error in the microgravity simulation for space manipulator and moon vehicle.

Study on the Simulation of the APT Rough Tracing System Based on the Predictive Control Technology

Laser space offers an attractive alternative in the military fields for its many advantages of wide bandwidth, high code rate, low power consumption and large capacity. Because the narrow laser beam will lead to many challenges in laser beam pointing, therefore, APT (acquisition, pointing and tracking) technology is one of key technology for the laser space communication. The ATP rough tracing servo turntable studied in this paper adopts two-axes-four-frame structure. In order to increase the tracking precision, the predictive control algorithm is adopted in the rough tracking position loop. The simulation result shows that, comparing with common PI controller, the predictive control algorithm could improve the dynamic response characteristics of the system and increase the tracking precision.

Dual-Mode Solar Tracking Controller

For the current solar tracking controller’s poor immunity, poor tracking accuracy and the traditional sensor‘s form single issue, this paper propose a dual-mode solar tracking system which is based on PLC (Programmable Logic Controller). The system combined the fixed trajectory rough tracking with the photoelectric sensor accurate tracking effectively, and improved the controller’s photoelectric sensor tracking mode. By comparing the results of experiments, it shows that the improved tracking controller can achieve tracking accuracy highly. So it can promote the utilization of solar energy.

The analysis of interface emulsion detector for the OPERA experiment in JAPAN Scanning facility

The OPERA experiment, designed to search for neutrino oscillations, started its physics run in July 2008. It is the most recent emulsion-counter hybrid experiment. In this experiment two different types of emulsion detectors are used. One is called Emulsion Cloud Chamber (ECC), and is used as a target. The other is called Changeable Sheet (CS), which is attached to the downstream side of each ECC to identify the ECC in which a tagged neutrino interaction occurred. The CS interfaces rough tracking information obtained in the electronic detectors to the ECC and therefore is a key element of the emulsion-counter hybrid experiment. As a first step, a CS selected by electronic detectors is scanned and analyzed to decide if the ECC is to be developed and analyzed in detail; a few CS are usually to be analyzed to identify an ECC for each tagged event due to the inaccuracy of the electronic detectors. The CS has a large scanning area and therefore Japan and Europe (Gran Sasso) are sharing in the CS analysis load to handle the scanning job. In this paper, the CS analysis method developed for the Japan scanning facility is described in detail.100 million tracks are read out on each CS by an automatic emulsion read-out system ( S-UTS ), most of them are so-called fake tracks mainly due to low momentum Compton electrons or random noise and a few real tracks from a tagged neutrino interaction have to be picked up among a huge background. A dedicated method to reject this background without losing real tracks has been developed on the basis of analyzing track data obtained by S-UTS and combining these data with a final selection using additional information on multiple Coulomb scattering of candidate tracks obtained by human eye check to eliminate a remaining background. Performance of this method is shown to be sufficient for the OPERA experiment.

Motion Segmentation for Time-Varying Mesh Sequences Based on Spherical Registration

A highly accurate motion segmentation technique for time-varying mesh (TVM) is presented. In conventional approaches, motion of the objects was analyzed using shape feature vectors extracted from TVM frames. This was because it was very difficult to locate and track feature points in the objects in the 3D space due to the fact that the number of vertices and connection varies each frame. In this study, we developed an algorithm to analyze the objects' motion in the 3D space using the spherical registration based on the iterative closest-point algorithm. Rough motion tracking is conducted and the degree of motion is robustly calculated by this method. Although the approach is straightforward, much better motion segmentation results than the conventional approaches are obtained by yielding such high precision and recall rates as 95% and 92% on average.

Recent Irregularities in Table II of Morbidity and Mortality Weekly Report

Table II of Morbidity and Mortality Weekly Report each week displays the cumulative year-to-date provisional number of cases of selected notifiable diseases in the United States, by state. Thus comparisons between the same weeks for different years can allow a rough rapid tracking of trends. In recent years, particularly 2004, the reported provisional cases showed incongruities. As of April 16, 2004, for example, no AIDS cases at all appeared in Table II. Responses from government public health officials (Centers for Disease Control and Prevention (CDC) and State of California) indicate instabilities and problems in the public health surveillance and reporting system. Such instabilities and problems, if serious and enduring enough, could impair detection of threats to public health.