scholarly journals Accuracy Bounds for Array-Based Positioning in Dense Multipath Channels

Sensors ◽  
2018 ◽  
Vol 18 (12) ◽  
pp. 4249 ◽  
Author(s):  
Thomas Wilding ◽  
Stefan Grebien ◽  
Ulrich Mühlmann ◽  
Klaus Witrisal
Keyword(s):  
Error Bound ◽  
Antenna Arrays ◽  
Estimation Error ◽  
Position Estimation ◽  
Position Error ◽  
Time Of Arrival ◽  
Angle Of Arrival ◽  
Multipath Interference ◽  
Positioning Systems ◽  
Performance Loss

The accuracy of radio-based positioning systems will be limited by multipath interference in realistic application scenarios. This paper derives closed-form expressions for the Cramér–Rao lower bound (CRLB) on the achievable time-of-arrival (ToA) and angle-of-arrival (AoA) estimation-error variances, considering the presence of multipath radio channels, and extends these results to position estimation. The derivations are based on channel models comprising deterministic, specular multipath components as well as stochastic, diffuse/dense multipath. The derived CRLBs thus allow an evaluation of the influence of channel parameters, the geometric configuration of the environment, and system parameters such as signal bandwidth and array geometry. Our results quantify how the ToA and AoA accuracies decrease when the signal bandwidth is reduced, because more multipath will then interfere with the useful LoS component. Antenna arrays can (partly) compensate this performance loss, exploiting diversity among the multipath interference. For example, the AoA accuracy with a 16-element linear array at 1 MHz bandwidth is similar to a two-element array at 1 GHz , in the magnitude order of one degree. The ToA accuracy, on the other hand, still scales by a factor of 100 from the cm-regime to the m-regime because of the dominating influence of the signal bandwidth. The position error bound shows the relationship between the range and angle information under realistic indoor channel conditions and their different scaling behaviors as a function of the anchor–agent placement. Specular multipath components have a maximum detrimental influence near the walls. It is shown for an L-shaped room that a fairly even distribution of the position error bound can be achieved throughout the environment, using two anchors equipped with 2 × 2 -array antennas. The accuracy limit due to multipath increases from the 1–10-cm-range at 1 GHz bandwidth to the 0.5–1-m-range at 100 MHz .

scholarly journals Joint clock synchronization and position estimation in time of arrival–based passive positioning systems

2018 ◽  
Vol 14 (11) ◽  
pp. 155014771878689 ◽  
Author(s):  
Shenghong Li ◽  
Lingyun Lu ◽  
Mark Hedley ◽  
David Humphrey ◽  
Iain B Collings
Keyword(s):  
Clock Synchronization ◽  
Likelihood Estimation ◽  
Least Square Method ◽  
Position Estimation ◽  
Least Square ◽  
Time Of Arrival ◽  
Positioning Systems ◽  
Reference Node ◽  
Localization Scheme ◽  
Wireless Signal

A widely used scheme for target localization is to measure the time of arrival of a wireless signal emitted by a tag, which requires the clocks of the anchors (receivers at known locations) to be accurately synchronized. Conventional systems rely on transmissions from a timing reference node at a known location for clock synchronization and therefore are susceptible to reference node failure. In this article, we propose a novel localization scheme which jointly estimates anchor clock offsets and target positions. The system does not require timing reference nodes and is completely passive (non-intrusive). The positioning algorithm is formulated as a maximum likelihood estimation problem, which is solved efficiently using an iterative linear least square method. The Cramér–Rao lower bound of positioning error is also analyzed. It is shown that the performance of the proposed scheme improves with the number of targets in the system and approaches that of a system with perfectly synchronized anchors.

Performance Evaluation of Geolocation Based Opportunistic Spectrum Access in Cloud-Assisted Cognitive Radio Networks

2016 ◽  
Vol 4 (1) ◽  
pp. 24-41
Author(s):  
Swetha Reddy ◽  
Isaac Cushman ◽  
Danda B. Rawat ◽  
Min Song
Keyword(s):  
Cognitive Radio ◽  
False Alarm ◽  
Estimation Error ◽  
Time Of Arrival ◽  
Spectrum Access ◽  
Angle Of Arrival ◽  
Secondary Users ◽  
Probability Of False Alarm ◽  
Computing Platform ◽  
Overall Performance

The popularity of cloud-assisted database-driven cognitive radio network (CRN) has increased significantly due to three main reasons; reduced sensing uncertainties (caused by the use of spectrum scanning and sensing techniques), FCC mandated use of a database for storing and utilizing idle channels, and leveraging cloud computing platform to process big data generated by wideband sensing and analyzing. In database-driven CRN, secondary users periodically query the database to find idle channels for opportunistic communications where secondary users use their geolocation (with the help of Global Positioning System - GPS) to find idle channels for given location and time. Use of GPS makes the overall CRN vulnerable where malicious users falsify their geolocations through GPS spoofing to find more channels. The other main drawback of GPS is estimation error while finding location of users and idle bands. Due to this there will be probability of misdetection and false alarm which will have its effect on overall performance and efficiency of the system. In this paper, the authors present a three-stage mechanism for detecting GPS spoofing attacks using angle of arrival, received signal strength and time of arrival. They also evaluate the probability of misdetection and probability of false alarm in this system while detecting location of secondary users. The authors evaluate the performance of the proposed approach using numerical results.

scholarly journals Aircraft position estimation using angle of arrival of received radar signals

2020 ◽  
Vol 9 (6) ◽  
pp. 2380-2387
Author(s):  
Freeha Majeed Amjad ◽  
Ahmad Zuri Sha'ameri ◽  
Kamaludin Mohamad Yusof ◽  
Paulson Eberechukwu
Keyword(s):  
Antenna Arrays ◽  
Estimation Algorithm ◽  
Position Estimation ◽  
Computational Time ◽  
Angle Of Arrival ◽  
Estimation Errors ◽  
Multiple Signal Classification ◽  
Active Research ◽  
Increasing Demand ◽  
Bearing Number

With increasing demand of air traffic, there is a need to optimize the use of available airspace. Effective utilization of airspace relies on quality of aircraft surveillance. Active research is carried out for enhancements in surveillance techniques and various methods are evaluated for future use. This paper evaluates the use of multiple signal classification (MUSIC) based angle of arrival (AOA) estimation along with multiangulation for locating aircrafts from their electromagnetic wave emission. The performance evaluation of the system is presented by evaluating the AOA estimation errors and position estimation (PE) errors. The errors are evaluated by comparing the estimated value to the actual value. An analysis on the system parameters, AOA error and PE error are presented in the end. AOA errors are affected by the AOA value (emitter bearing), number of array elements, SNR and resolution of AOA estimation algorithm. Errors in AOA estimation lead to PE errors. The simulation results show small errors for short ranges. The system performance can be improved at the expense of computational time by using higher MUSIC resolution and larger antenna arrays

scholarly journals Dynamic Adjustment of Weighted GCC-PHAT for Position Estimation in an Ultrasonic Local Positioning System

Sensors ◽  
2021 ◽  
Vol 21 (21) ◽  
pp. 7051
Author(s):  
José Manuel Villadangos ◽  
Jesús Ureña ◽  
Juan Jesús García-Domínguez ◽  
Ana Jiménez-Martín ◽  
Álvaro Hernández ◽  
...  
Keyword(s):  
Indoor Localization ◽  
Weighting Factor ◽  
Position Estimation ◽  
Correlation Technique ◽  
Time Of Arrival ◽  
Dynamic Adjustment ◽  
Positioning Systems ◽  
Positioning Errors ◽  
Local Positioning System ◽  
Cross Correlation Technique

Ultrasonic local positioning systems (ULPS) have been brought to the attention of researchers as one of the possibilities that can be used for indoor localization. Acoustic systems combine a suitable trade-off between precision, ease of development, and cost. This work proposes a method for measuring the time of arrival of encoded emissions from a set of ultrasonic beacons, which are used to implement an accurate ULPS. This method uses the generalized cross-correlation technique with PHAT filter and weighting factor β (GCC-PHAT-β). To improve the performance of the GCC-PHAT-β in encoded emission detection, the employment is proposed of mixed-medium multiple-access techniques, based on code division and time division multiplexing of beacon emissions (CDMA and TDMA respectively), and to dynamically adjust the PHAT filter weighting factor. The receiver position is obtained by hyperbolic multilateration from the time differences of arrival (TDoA) between a reference beacon and the rest, thus avoiding the need for receiver synchronization. The results show how the dynamic adaptation of the weighting factor significantly reduces positioning errors from 20 cm to 2 cm in 80% of measurements. The simulated and real experiments prove that the proposed algorithms improve the performance of the ULPS in situations with lower signal-to-noise ratios (SNR) than 0 dB and in environments where the multipath effect makes it difficult to correctly detect the encoded ultrasonic emissions.

scholarly journals Analysis of the Position Estimation Error of a Local Positioning System utilizing Mobile Anchors

2018 ◽  
Author(s):  
Sang C. Lee ◽  
Syamsul Rizal ◽  
HeungJu Ahn
Keyword(s):  
Real Time ◽  
Estimation Error ◽  
Gaussian Model ◽  
Target Position ◽  
Position Estimation ◽  
Position Error ◽  
Positioning System ◽  
Target Node ◽  
Local Positioning System ◽  
Anchor Nodes

This paper proposes a real-time local positioning system (RT-LPs) utilizing a mobile platform equipped with three anchor nodes placed in a right-angle triangle formation for a real-time locating system (RTLS). After deriving an analytic formula to calculate the target position utilizing the measured distances among anchor nodes and the target node, we find that four parameters have an effect on the position error of the target node. The spacing between anchors is a design parameter that must be large enough to the reduce position error. However, the distance from the anchor node to the target node is an operation parameter that must be small enough to reduce the position error. Additionally, the measured ranges among the anchors and the target node have probabilistic distributions with a mean and variance, which are dominant parameters that have effects on the position error. A comparison study was conducted to determine the effects of the parameters of the target position in both a simulation and an experiment, showing rates of approximately 4% ~ 10%. These findings indicate that our simulation can work properly with the proposed method after assuming that the distance error is a Gaussian model.

scholarly journals Hybrid Precoding/Combining for single-user and Multi-Usersin mm-Wave MIMO systems

2019 ◽  
Vol 9 (2S3) ◽  
pp. 134-139
Keyword(s):  
Antenna Arrays ◽  
Mimo Systems ◽  
Matching Pursuit ◽  
Bench Mark ◽  
Angle Of Arrival ◽  
Multiuser Mimo ◽  
Parallel Transmission ◽  
Performance Loss ◽  
Hybrid Precoding ◽  
Single User

mm-Wave is one of the potential 5G technology predominant at high frequency. The antenna arrays allows parallel transmission to the multiple users. Due to the constraints in hardware in mm-Wave systems,it is difficult to implement conventional multiuser MIMO precoding techniques at mm-Wave. In this paper initially Hybrid mm-Wave MIMO capacity is compared with conventional MIMOperformance, the simulation results demonstrates that the performance loss is due to assumption of the quantized angle of arrival and departures in dictionary which is very small using OMP algorithm and the capacity approaches the conventional MIMO performance. Then the Hybrid Precoding(HP)at mm-Wave is formulated as a sparse optimization problem in which the hybrid MIMO precoders and combiners are used as the measurement matrices.Here transmit precoding and combining at the receiver is considered with a limited feedback as knowledge of channel may not be practically available.Orthogonal matching Pursuit(OMP) algorithm is used for single-user case and alsoin Multi-user case using simultaneous Orthogonal matching pursuit(SOMP) algorithm. In single user case numerical results are presented which shows that the proposed algorithm approach is closer to their unconstraint performance even after considering hardware constraints. Multi-user precoding results illustrates that the proposed HP method offers higher Spectral efficiency (SE) compared to analog –only beamforming (AB) and is close tothe performance bench mark of optimal digital beamformer

Collaborative Filtering for Position Estimation Error Correction in WLAN Positioning Systems

2011 ◽  
Vol E94-B (3) ◽  
pp. 649-657 ◽  
Author(s):  
Shigeaki TAGASHIRA ◽  
Yuhei KANEKIYO ◽  
Yutaka ARAKAWA ◽  
Teruaki KITASUKA ◽  
Akira FUKUDA
Keyword(s):  
Error Correction ◽  
Collaborative Filtering ◽  
Estimation Error ◽  
Position Estimation ◽  
Positioning Systems

scholarly journals ENHANCING THE COVERAGE OF INDOOR RADIO LOCALIZATION BY DISTRIBUTED COMPUTATIONS

2014 ◽  
pp. 248-258
Author(s):  
Andreas Fink ◽  
Helmut Beikirch
Keyword(s):  
Estimation Error ◽  
Position Estimation ◽  
Location Estimation ◽  
Sensor Data ◽  
Positioning Systems ◽  
Distributed Computations ◽  
Indoor Radio ◽  
True Position ◽  
Weighted Centroid Localization ◽  
Achievable Accuracy

The prevalent evaluation criterion for indoor local positioning systems (ILPS) is the achievable accuracy in terms of Euclidean distance between estimated and true position. Systems relying on received signal strength (RSS) ranging often use a distributed collection of RSS sensor data at reference nodes and a centralized position estimation. For this direct remote positioning, the accuracy is dependent on the reference node density and thus, is indirect proportional to the achievable coverage. To split up the dependency between these two criteria, we propose a distributed weighted centroid localization (dWCL) strategy with a hierarchical sensor data field bus. Accuracy and coverage of centralized and distributed WCL algorithms are compared for a one-dimensional tracking simulation and 196 reference nodes, arranged in up to 28 gateway segments. Using distributed computations, the localization system’s coverage is increased by factor ten while the location estimation error increases only slightly.

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