In this study, the authors present a novel geometrically driven multilateration technique that is based on ultra-wideband (UWB) technology. The authors refer to their proposed solution as time ...reflection of arrival (TROA). They demonstrate in this study how the position estimation error is improved upon by carefully considering the inherent properties of the UWB technology and the reflection properties of transmitted UWB signals. By a direct comparison between TROA and two widely used multilateration techniques, the authors show that indoor position estimation can be done much more effectively using their proposed solution. They also derive a new Cramér–Rao lower bound for TROA multilateration and use it to show its level of efficiency.
Air traffic management (ATM) of manned and unmanned aerial vehicles (AVs) relies critically on ubiquitous location tracking. While technologies exist for AVs to broadcast their location periodically ...and for airports to track and detect AVs, methods to verify the broadcast locations and complement the ATM coverage are urgently needed, addressing anti-spoofing and safe coexistence concerns. In this work, we propose an ATM solution by exploiting noncoherent crowdsourced wireless networks (CWNs) and correcting the inherent clock-synchronization problems present in such non-coordinated sensor networks. While CWNs can provide a great number of measurements for ubiquitous ATM, these are normally obtained from unsynchronized sensors. This article first presents an analysis of the effects of lack of clock synchronization in ATM with CWN and provides solutions based on the presence of few trustworthy sensors in a large non-coordinated network. Secondly, autoregressive-based and long short-term memory (LSTM)-based approaches are investigated to achieve the time synchronization needed for localization of the AVs. Finally, a combination of a multilateration (MLAT) method and a Kalman filter is employed to provide an anti-spoofing tracking solution for AVs. We demonstrate the performance advantages of our framework through a dataset collected by a real-world CWN. Our results show that the proposed framework achieves localization accuracy comparable to that acquired using only GPS-synchronized sensors and outperforms the localization accuracy obtained based on state-of-the-art CWN synchronization methods.
Multilateration based on a laser tracker (LT) requires the measurement of a set of points from three or more positions. Although the LTs' angular information is not used, multilateration produces a ...volume of measurement uncertainty. This paper presents two new coefficients from which to determine whether the measurement of a set of points, before performing the necessary measurements, will improve or worsen the accuracy of the multilateration results, avoiding unnecessary measurement, and reducing the time and economic cost required. The first specific coefficient measurement coefficient (MCLT) is unique for each laser tracker. It determines the relationship between the radial and angular laser tracker measurement noise. Similarly, the second coefficient is related with specific conditions of measurement β. It is related with the spatial angle between the laser tracker positions α and its effect on error reduction. Both parameters MCLT and β are linked in error reduction limits. Beside these, a new methodology to determine the multilateration reduction limit according to the multilateration technique of an ideal laser tracker distribution and a random one are presented. It provides general rules and advice from synthetic tests that are validated through a real test carried out in a coordinate measurement machine.
The serine/threonine kinase Akt1 is part of the PI3 K/Akt pathway and plays a key role in the regulation of various cellular processes such as cell growth, proliferation, and apoptosis. Here, we ...analyzed the elasticity between the two domains of the kinase Akt1, connected by a flexible linker, recording a wide variety of distance restraints by electron paramagnetic resonance (EPR) spectroscopy. We studied full length Akt1 and the influence of the cancer‐associated mutation E17K. The conformational landscape in the presence of different modulators, like different types of inhibitors and membranes was presented, revealing a tuned flexibility between the two domains, dependent on the bound molecule.
The conformational flexibility between the pleckstrin homology (PH) and kinase domain of the kinase Akt1 was investigated using multilateration of double electron resonance spectroscopy (DEER) distance restraints. Detailed structural data of wild‐type Akt1 and the cancer‐associated E17K mutation in the apo and ligand‐bound states are presented, yielding deep insights into the conformational plasticity of Akt1.
Electron paramagnetic resonance (EPR) spectroscopy in combination with site-directed spin labeling (SDSL) is a powerful approach to supplement the large toolbox of methods for protein structure ...determination. The strength of EPR spectroscopy is the ability to map flexibility of protein domains and conformational ensembles. EPR distance determination in the nanometer range and subsequent multilateration enables the three-dimensional visualization of the localization of a spin label in a protein domain. Therefore, multilateration can not only be used to represent the degree of flexibility of protein structural elements, but also track movements of whole domains. We report a detailed protocol for all needed steps, beginning with the choice of the labeling sites, the spin labeling reaction, the EPR distance measurement by double electron-electron resonance (DEER) and finally the multilateration exploiting the EPR distance restraints.
•A new impact source localization method, in a dispersive waveguide, is introduced.•The new method utilizes an accelerometer sensor network.•The power of the impact-generated wave is attenuated with ...the traveled distance.•Wave power attenuation is utilized to localize impacts (e.g., a hammer or footstep).•The new localization approach is evaluated via an experiment and using simulations.•The experiment involves localizing hammer impacts on an instrumented floor.•The experiment’s floor section is part of a corridor in an operational building.
An algorithm is introduced to solve the general multilateration (source localization) problem in a dispersive waveguide. The algorithm is designed with the intention of localizing impact forces in a dispersive floor, and can potentially be used to localize and track occupants in a building using vibration sensors connected to the lower surface of the walking floor. The lower the wave frequencies generated by the impact force, the more accurate the localization is expected to be. An impact force acting on a floor, generates a seismic wave that gets distorted as it travels away from the source. This distortion is noticeable even over relatively short traveled distances, and is mainly caused by the dispersion phenomenon among other reasons, therefore using conventional localization/multilateration methods will produce localization error values that are highly variable and occasionally large. The proposed localization approach is based on the fact that the wave’s energy, calculated over some time window, decays exponentially as the wave travels away from the source. Although localization methods that assume exponential decay exist in the literature (in the field of wireless communications), these methods have only been considered for wave propagation in non-dispersive media, in addition to the limiting assumption required by these methods that the source must not coincide with a sensor location. As a result, these methods cannot be applied to the indoor localization problem in their current form. We show how our proposed method is different from the other methods, and that it overcomes the source-sensor location coincidence limitation. Theoretical analysis and experimental data will be used to motivate and justify the pursuit of the proposed approach for localization in a dispersive medium. Additionally, hammer impacts on an instrumented floor section inside an operational building, as well as finite element model simulations, are used to evaluate the performance of the algorithm. It is shown that the algorithm produces promising results providing a foundation for further future development and optimization.
Summary
Most of the multilateration algorithms for object localization rely heavily on matrix multiplication for calculating the precise location of the target from all the reference points in a 3D ...domain. A significant disadvantage is that performing matrix multiplication can be computationally expensive, particularly for larger matrices, leading to slower performance and longer processing times. In this article, we propose a Processing‐in‐Memory (PIM) based localization approach for multilateration using a memristor crossbar array for performing faster matrix multiplication. The experiments were conducted on real‐time data collected through ultra‐wideband (UWB) chip. The simulation results demonstrate that the proposed model is around 50% faster than the fastest known localization algorithm considered for evaluation and exhibits an average of 55% improvement in localization accuracy.
Automatic dependent surveillance-broadcast (ADS-B) is an air traffic control system in which aircraft transmit their own information (identity, position, velocity etc.) to ground sensors for ...surveillance scope. The tracking of the different sensors' clocks by the use of time difference of arrival of ADS-B messages is proposed to check the veracity of the position information contained in the ADS-B messages. The method allows detecting possible on-board anomalies or the malicious injection of fake messages (intrusion) without the use of the multilateration (or any other) location algorithm. It follows that it does not need the inversion of the location problem (usually strong nonlinear and ill-posed), and, contrary to the multilateration, it works also with less than four sensors.
•Explosive sound source positioning by using modified Levenberg Marquardt algorithm.•A comparative analysis of different positioning methods.•Modified LMA performance validation through simulation ...and experimental studies.•A short and wide range of sound source positioning by varying r between 0.002 and 2.•Sound source localization for both indoor and outdoor environments.
In this paper, a modified Levenberg-Marquardt algorithm (MLMA) is proposed to localize the ‘point of burst’ of an explosive sound source over the range of (0.5–2500) m. The objective function for minimization is formulated through the time difference of arrival based multilateration approach. The developed method uses four exclusive steps to satisfy global convergence along with fast computational speed. The performance of the proposed method is validated through both indoor-outdoor experiments and simulation studies and compared to other well-known methods. The experimental results show that the non-iterative approaches perform satisfactorily only if the ratio of microphone spacing to source rangeris greater than 0.30. However, the iterative approaches outperform non-iterative approaches for anyr. It is also observed that the MLMA converges globally at least five times faster than other algorithms. The numerical simulation results also demonstrate that the MLMA provides optimal solutions at lower and higher noise thresholds.
This paper covers the design of a new multi-point kinematic coupling specially developed for a high precision multi-telescopic arm measurement system for the volumetric verification of machine tools ...with linear and/or rotary axes. The multipoint kinematic coupling allows the simultaneous operation of the three telescopic arms that are registered at the same time to a sphere fixed on the machine tool spindle nose. Every coupling provides an accurate multi-point contact to the sphere, avoiding collisions and interferences with the other two multi-point kinematic couplings, and generating repulsion forces among them to ensure the coupling’s fingers interlacing along the machine tool x/y/z travels in the verification process. Simulation presents minimal deformation of the kinematic coupling under load, assuring the precision of the sphere-to-sphere distance measurement. Experimental results are provided to show that the multi-point kinematic coupling developed has repeatability values below ±1.2 µm in the application.
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