The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
In the article, a wideband, high-efficient, circular polarized(CP) antenna for COMPASS navigation satellite system is presented. It works at B1(1.561098GHz) and B1–2(1.589742GHz) frequency band and it can also be used for global positioning system(GPS) at L1(1.57542GHz) frequency band. The radiating elements are two crossed bowtie dipole with rectangular gaps in the middle of the bowtie elements....
The laser scanning based mobile mapping technology has been extensively investigated in academia in last two decades. It has been fully accepted by some traditional industries, such as surveying and forestry. However, for other traditional industries, the potential applications with such a high efficient, high speed 3D modeling technology are still underestimated. In this paper, we try to investigate...
In this paper, a range calibration and modulation sweep linearity verification method of a helicopter-borne FM-CW (Frequency-Modulated Continuous Waveform) profiling radar are presented. The radar is designed to collect backscatter signal waveforms to build target stand profiles. Various forest elements e.g. tree height; density; species, etc. can be evaluated through this profiling radar. This paper...
After the regional Chinese Beidou Navigation Satellite System (BDS) reached its full configuration of 16 operational BDS navigation satellites in November 2012, China launched the new generation Beidou satellite in March 2015. The purpose is to test new navigation signals and inter-satellite communication links and define the necessary protocols for a future network that will be capable of providing...
The topic of positioning in dense forest has attracted researchers' attention in the last few decades. Currently, accurate and robust positioning in complex forest environment is still not available by using standalone GNSS, and it is a major drawback for forestry automation. Laser scanning-based SLAM demonstrated its potential as an alternative positioning solution in dense boreal forest environment...
This paper studies sequential estimation of indoor localization based on fingerprints of received signal strength indicators (RSSI). Due to the lack of an analytic formula for the fingerprinting measurements, the Kalman filter can not be directly applied. By introducing a hidden variable to represent the unknown positioning coordinate, a state model is formulated and a constrained Kalman filter (CKF)...
Video image defogging algorithms cannot intelligently identify whether current scene has fog or not. In order to improve the intelligent defogging ability of unmanned surface vessel (USV), a classification method based on multi-feature extraction is proposed to distinguish whether a surface image is a fog image or not. A surface image sample library is first established and 8 features that are significantly...
This paper investigates an improved inertia control strategy of variable speed wind turbines, which provides with a novel approach to dynamic characteristics enhancement during frequency and oscillation events. Based on the analysis of the impacts of frequency control on inter-area power oscillation, an improved frequency control scheme of wind turbines is proposed. In this scheme, a first-order lag...
Nowadays smartphones are equipped with various sensors and powerful processing modules, and are accessible to flexible communication networks, thus enabling complex applications such as context awareness, activity recognition, health care monitoring and so forth. These applications typically require contextual information to optimize the effectiveness, e.g. indoor/outdoor identification. This paper...
This paper introduces a framework of contextual thinking in mobile devices. It is based on real-time sensing of local time, significant locations, location-dwelling states, and user states to infer significant activities. A significant activity is a well-defined activity to be inferred, for example, waiting for a bus, having a meeting, working in office, taking a break in a coffee shop et al. A significant...
In this paper, an environment knowledge-based multiple sensors indoor positioning system is designed and tested. The system integrates a LiDAR sensor, an odometer and a light sensor onto a low-cost robot platform. While, a LiDAR point-cloud-based pattern match algorithm — Iterative Closed Point (ICP) is used to estimate the relative change in heading and displacement of the platform. Based on the...
This paper proposed ambient light (ambilight) as a new type of signal sources for positioning. The possibility and methods of ambilight positioning were presented in this paper. It has been shown that two kinds of observables of ambient light can be used for positioning through different principles. Ambilight intensity spectrum measurements have highly location dependency, and they can be used for...
Microphone arrays, also known as acoustic antennas, have been extensively used for sound localization. Small-scale microphone arrays have especially been used in teleconferences and game consoles due to their small dimension and easy deployment. In this article, we present an approach to locating a sound source using a small linear microphone array. We describe the fundamentals of linear microphone...
An increasing number of WiFi and Bluetooth terminals, tags, and other mobile devices drives a growing demand for integration and coexistence of these two technologies. This paper gives the preliminary results of WiFi positioning in a WiFi and Bluetooth coexistence environment. The received signal strength indication is introduced as an observation applied to our WiFi positioning. Then, we present...
Three-dimensional personal navigation in smart phones develops in a fantastic speed nowadays. This topic has already attracts many attentions both from the scientific and industrial field. Such kind of 3D navigation application is mostly fulfilled by importing 3D models constructed in a computer into a mobile phone. However, comparing the computer platform, the mobile devices typically have the several...
Currently, GPS is the dominating technology for commercial car navigation applications, which offers acceptable navigation service for door to door navigation. However, within GPS degraded or denied areas, GPS standalone may not support sufficient accuracy and availability for a satisfactory user experience. Lane detection is an important and fundamental functionality to complete various future intelligent...
Navigation and position applications are now becoming standard built-in features in a smart phone. However, locating a mobile user in GNSS unfriendly and denied environments such as urban canyons and indoor environments ubiquitously is still a challenging task. Several self-contained sensors, such as accelerometer, digital compass, gyroscope and barometer, have been adapted as assistance augmentation...
Compared to 2D navigation, 3D navigation requires much better performance of locating and heading. In an urban environment, the signals from a built-in GPS on a smart phone are always so weak that it causes considerably low position and heading accuracy. To address this issue and improve the user experience, two contexts, Navigation and Look-Around, are defined in 3D personal navigation. The following...
This paper presents a measurement fusion approach for seamless outdoor/indoor positioning utilizing multiple sensor and network measurements in addition to computer-vision based aiding. A Kalman filter is implemented for fusing WLAN, Bluetooth, and high-sensitivity GPS positioning results with accelerometer based motion information as well as digital compass and camera derived direction. The fusion...
This paper studies indoor Bluetooth network. wireless positioning using a network of Bluetooth signals. Fingerprints of received signal strength indicators are used for localization. Due to the relatively long interval between the available consecutive Bluetooth signal strength measurements, we propose a method of information filtering with speed detection, which combines the estimation information...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.