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In this paper, methods to improve a practical Time Difference of Arrival (TDOA) based source localization system are investigated. Firstly, our previous work on the development of a TDOA based source localization system using reconfigurable Software Defined Radios (SDRs) is described in detail. The system can achieve less than 100m error in a coverage of several kilometers. However, the performance...
This paper investigates the design criteria for an ultrasound positioning system used in smart tool applications. A novel range-finding system based upon low cost, ease of implementation, and an automatic gain controller (AGC) is developed. We also design several signal processing algorithms for this system, including an amplitude threshold method (ATM), a frequency threshold method (FTM), and a cross...
In this paper we detail the implementation of a Differential GPS system using only low-cost GPS receivers. The nature of the errors generated by low-cost modules is investigated and contrasted against typical error models of traditional, commercial DGPS systems. It is found that the error profile unique to low-cost GPS modules leads to a system that offers particular advantage in the horizontal plane...
Fingerprinting is the prevailing positioning method for location based service (LBS) and indoor positioning applications when compared with other methods such as cell of origin (CoO) and trilateration. It is especially more suitable for complicated indoor environments. However, higher positioning accuracy is still expected for it to match the capabilities of other mature techniques such as GPS. This...
The localization in a classical multistatic passive radar is based on finding bistatic ellipsoid crossing with at least three pairs of transmitter-receiver. The localization accuracy is dependent on the geometry and bandwidth of the illumination signal. For narrow band signals like GSM cellular phone transmission the bistatic range resolution is very poor, in a range of several kilometers. The paper...
In practical applications, the accuracy of a LPS is often affected by non-line-of-sight (NLOS) errors which disable proper locating results. In this article, a robust localization algorithm capable of minimizing the effects of NLOS errors during position estimation is presented. The robust localization algorithm uses hyperbolic multilateration in combination with proximity based grouping and final...
Indoor localization based on time difference of arrival (TDOA) has been recently a promising field of study. We consider the previously unsolved problem of locating a moving target receiver by using unsynchronized stationary beacons without requirement of manual calibration. Thus, the received signals and their time of arrival (TOA) have to be assigned to a beacon. Besides, in order to automatically...
Many indoor positioning applications focus on determining the location of a device in a particular area, like a room of a building, rather than its metric coordinates. It is common that most buildings are partitioned in more or less a regular way and discovering the relative positions of the nodes can give us an accurate estimate of the space, e.g. a room, they are located in. In this study, we have...
Indoor localization is important for logistics, industrial applications and for several consumer applications. In the area of logistics, e.g. warehouses, localization accuracy within a few meters is desired. Available radio based systems within that accuracy are neither cost effective nor easy to deploy. Distance estimation together with triangulation are one of the standard solutions for localization...
Target detection (TD) is one of the fundamental tasks in hyperspectral imagery (HSI) processing. Sparse representation (SR) as a novel tool is powerful in accurate detection of target of interest. In this paper, SR approach within disconnected spatial support is proposed for effective TD in HSI. For conventional sparse representation, an HSI pixel is represented as a sparse vector whose non-zero entries...
Spectrum prediction estimates channel future status from history statistics, which greatly improved the efficiency of spectrum sensing in cognitive radio networks. Current researches mainly focus on improving speed and accuracy of prediction. Few researches discuss the energy-efficient design of spectrum prediction. Since energy-efficient affect working hours and transmission efficiency, that is an...
Wide Area Multilateration (WAM) is a useful aeronautical surveillance system which is able to achieve high performance. However, WAM has a drawback in which position errors increase rapidly outside a constellation of receiver stations in principle. One of the solutions for the drawback is to apply a measured range between a receiver station and an aircraft to the Time Difference of Arrival (TDOA)...
Transceiver-free object localization is essential for emerging location-based service, e.g., the safe guard system and asset security. It can track indoor target without carrying any device and has attracted many research effort. Among these technologies, Radio Signal Strength (RSS) based approaches are very popular because of their low-cost and wide applicability. In such work, usually a large number...
The ADS-B position of an aircraft is generated by the aircraft itself, as opposed to e.g. the radar or MLAT position, and then broadcasted and transmitted to a tracking system via network. The intention of this paper is to discuss the necessary security mechanisms and to propose specific algorithms to safely deal with this type of position information. Furthermore, it summarizes the current implementation...
Existing methods for optimal configuration of multi-sensor suited for two dimension only or use numerical simulation to search optimal configuration, only sub-optimum solution can be realized. Based on evaluation index of Cramer-Rao lower bound(CRLB) of positioning, an universal method to obtain analytic solutions for optimal configuration is proposed. Based on this method, we derive that circularly...
This paper studies the algorithms for determining a BDS satellite's velocity using the broadcast ephemeri. Firstly, by taking the time derivatives of the Kepler orbit elements and the correction terms, the algorithm comprises close-form analysis formulas and the processing steps for directly computing a BDS satellite's instant velocity using the broadcast ephemeris is derived, and its validity is...
An enhanced version of the popular split-step Fourier method (SSFM) is presented. When used for digital backpropagation, the enhanced method allows a complexity reduction of up to one order of magnitude with respect to standard SSFM without sacrificing performance.
In this paper, an algorithm is proposed to provide position data of vehicles with high accuracy and low cost. It is to use same number of satellites or same satellites number, then calculates absolute coordination of vehicles using distance between vehicles. Finally it can enhance accuracy of relative positioning in vehicles.
This paper aims to provide the reader with a review of the main technologies explored in the literature to solve the indoor localization issue. Furthermore, some systems that use these enabling technologies in real-world scenarios are presented and discussed. This could deliver a better understanding of the state-of-the-art and motivate new research efforts in this promising field. Finally, focusing...
Localization errors can play an important role in measurements of radio propagation or spectrum utilization, especially in urban environment where GPS localization accuracy is highly varying. In this paper we present a low cost and simple method for mitigating the impact of localization errors, based on multiple GPS receivers. The presented results are based primarily on performance evaluation of...
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