Position Location Systems Research Articles

A Practice of BLE RSSI Measurement for Indoor Positioning.

Bluetooth Low Energy (BLE) is one of the RF-based technologies that has been utilizing Received Signal Strength Indicators (RSSI) in indoor position location systems (IPS) for decades. Its recent signal stability and propagation distance improvement inspired us to conduct this project. Beacons and scanners used two Bluetooth specifications, BLE 5.0 and 4.2, for experimentations. The measurement paradigm consisted of three segments, RSSI–distance conversion, multi-beacon in-plane, and diverse directional measurement. The analysis methods applied to process the data for precise positioning included the Signal propagation model, Trilateration, Modification coefficient, and Kalman filter. As the experiment results showed, the positioning accuracy could reach 10 cm when the beacons and scanners were at the same horizontal plane in a less-noisy environment. Nevertheless, the positioning accuracy dropped to a meter-scale accuracy when the measurements were executed in a three-dimensional configuration and complex environment. According to the analysis results, the BLE wireless signal strength is susceptible to interference in the manufacturing environment but still workable on certain occasions. In addition, the Bluetooth 5.0 specifications seem more promising in bringing brightness to RTLS applications in the future, due to its higher signal stability and better performance in lower interference environments.

Measurements Corner

Traditional wireless position-location systems, operating using propagating waves, suffer reduced performance in non-line-of-sight (NLoS) applications. Traditional systems that use quasistatic fields have instead been limited to short ranges, progressive direction-finding applications, require RF fingerprinting, or do not provide complete immunity to dielectric obstacles (use of electric fields). These limitations impose severe restrictions in applications such as tracking an American football during game play, where position and orientation tracking may be required over long ranges, and when the line-of-sight (LoS) is blocked by groups of people. A technique using magneto-quasistatic fields and complex image theory was recently shown to circumvent these problems, and to enable accurate long-range one-dimensional and two-dimensional measurements. In this work, we present three-dimensional position and orientation measurements using the magneto-quasistatic system and complex image theory over an area of 27.43 m × 27.43 m. Inverting the theoretical expression for the voltage measured at the terminals of the receiving loops to determine three-dimensional position and orientation resulted in mean and median geometric position errors of 0.77 m and 0.71 m, respectively; inclination orientation mean and median errors of 9.67° and 8.24°, respectively; and azimuthal orientation mean and median errors of 2.84° and 2.25°, respectively.

WiFi-Based Localization in Indoor Wireless Network

Indoor positioning systems that make use of received signal strength-based location fingerprints and existing wireless local area network infrastructure have recently been the focus for supporting location-based services in indoor and campus areas. A knowledge and understanding of the properties of the location fingerprint can assist in improving design of algorithms and deployment of position location systems. However, the most existing research work ignores the radio signal properties. This paper investigates the properties of the received signal strength reported by IEEE 802.11b using KNN algorithms and used to locate the position of the movable device. Analyses of the data are performed to understand the underlying features of location fingerprints. The performance of an indoor positioning system in terms of its rescission is compared using measured data and a Gaussian model to see how closely a Gaussian model may fit the measured data different subcarrier.

Full speed ahead [precision maritime engineering

Dynamic positioning (DP) systems are used extensively in the offshore industry and have allowed operators to drill ocean wells at depths of over 3,000m. Holding a vessel in position demands the highest level of seamanship, particularly in hostile waters. So the design of automatic positioning systems has taxed the ingenuity of the control industry. To work effectively they have to take account of the erratic nature of position signals, as well as being able to distinguish cyclic rolling, heaving and pitching motions from the steady forces exerted by wind and tide.The automated positioning system will receive signals from an anemometer, gyrocompass and a range of radio and acoustic position-location systems. While the wind speed and direction will generally be used in a feed-forward control loop, a computerised system is needed to process all this data and determine the power setting of the thrusters to maintain the desired position.

A New Position Location System Using DTV Transmitter Identification Watermark Signals

A new position location technique using the transmitter identification (TxID) RF watermark in the digital TV (DTV) signals is proposed in this paper. Conventional global positioning system (GPS) usually does not work well inside buildings due to the high frequency and weak field strength of the signal. In contrast to the GPS, the DTV signals are received from transmitters at relatively short distance, while the broadcast transmitters operate at levels up to the megawatts effective radiated power (ERP). Also the RF frequency of the DTV signal is much lower than the GPS, which makes it easier for the signal to penetrate buildings and other objects. The proposed position location system based on DTV TxID signal is presented in this paper. Practical receiver implementation issues including nonideal correlation and synchronization are analyzed and discussed. Performance of the proposed technique is evaluated through Monte Carlo simulations and compared with other existing position location systems. Possible ways to improve the accuracy of the new position location system is discussed.

Overview of spatial channel models for antenna array communication systems

Spatial antenna diversity has been important in improving the radio link between wireless users. Historically, microscopic antenna diversity has been used to reduce the fading seen by a radio receiver, whereas macroscopic diversity provides multiple listening posts to ensure that mobile communication links remain intact over a wide geographic area. In later years, the concepts of spatial diversity have been expanded to build foundations for emerging technologies, such as smart (adaptive) antennas and position location systems. Smart antennas hold great promise for increasing the capacity of wireless communications because they radiate and receive energy only in the intended directions, thereby greatly reducing interference. To properly design, analyze, and implement smart antennas and to exploit spatial processing in emerging wireless systems, accurate radio channel models that incorporate spatial characteristics are necessary. In this tutorial, we review the key concepts in spatial channel modeling and present emerging approaches. We also review the research issues in developing and using spatial channel models for adaptive antennas.

Large HF bearing errors for propagation paths tangential to auroral oval

Large electron density gradients in the ionosphere associated with the walls of the midlatitude trough produce tilted reflecting surfaces which lead to HF signals propagating over paths well displaced from the great circle. Measurements are presented of signals propagating over two paths along the midlatitude trough for which bearings deviations of up to 100° from the great-circle path, i.e. the expected direction of arrival, were frequently recorded. The times of occurrence and magnitude of these large deviations are consistent with the known features of the midlatitude ionospheric trough. Such large deviations of the measured bearing from the great-circle path, which far exceed the instrumental errors, have serious implications for the operation of position location systems operating within the HF band.

Position location using wireless communications on highways of the future

With the advances in wireless communications and low-power electronics, accurate position location may now be accomplished by a number of techniques which involve commercial wireless services. Emerging position location systems, when used in conjunction with mobile communications services, will lead to enhanced public safety and revolutionary products and services. The fundamental technical challenges and business motivations behind wireless position location systems are described, and promising techniques for solving the practical position location problem are treated.

Navigation and Position Location Systems

Navigation and Position Location Systems