ETH - Indoor Positioning & Indoor Navigation


08:15 - 08:45	Christian Robert (presenting author), Philip Tomé, Roman Merz, Cyril Botteron, Andreas Blatter, Pierre-André Farine: Low Power ASIC transmitter for UWB-IR radio communication and positioning At the Electronics and Signal Processing Laboratory at EPFL (formerly UNINE), an experimental platform has been designed and built to demonstrate the feasibility of Ultra-wideband Impulse Radio (UWB-IR) technology applied to indoor positioning [1]. This office-scale demonstrator has proven to be a valuable research tool, with the flexibility to study, test and assess the performance of various system architectures and signal processing algorithms. Based on this successful experience, a subsequent project was setup to extend the lab’s research on certain topics that could not be addressed by the office-scale demonstrator. This new R&D project pursues two main objectives: a) designing and building a large-scale UWB-based Local Positioning System (LPS), including installation, calibration and operational testing in a real industrial environment; b) conceiving and developing Application Specific Integrated Circuits (ASICs) to target cost-competitive solutions. The details related to the first objective a) are out of the scope of this paper and can be found in [2]. In turn, this paper focuses on objective b) and presents the design of a Low Power UWB transmitter ASIC that complies with ECC spectrum regulations for UWB-IR low duty cycle, as well as with FCC spectrum regulations. This transmitter has been implemented in UMC 180 nanometers CMOS technology and works with a power supply of 1.8V.

08:45 - 09:15	Paul Meissner (presenting author), Thomas Gigl, Klaus Witrisal: UWB Sequential Monte Carlo Positioning using Virtual Anchors We present a novel UWB positioning concept that performs the position estimation with a set of virtual anchor nodes, generated from a single physical anchor and floor plan information. Using range estimates to the virtual anchors, we perform multilateration to estimate the position of a receiver node. Previous work has shown the general applicability of this concept. In this contribution, we extend the concept with the introduction of a moving receiver node. Position estimation is performed using sequential Monte Carlo methods to exploit the correlation in successive receiver positions. We use approximations of the posterior probability density function of the receiver position and propagate this information from one time step to the next. A motion model for the receiver and our measurement likelihood function allow for the use of the powerful framework of Bayesian state estimation. These concepts are used to further enhance accuracy and robustness of the positioning algorithm.

09:15 - 09:45	Shuhei Fujita (presenting author), Takuya Sakamoto, Toru Sato: An accurate UWB radar imaging method using indoor multipath echoes for targets in shadow regions UWB pulse radar is promising for surveillance systems in terms of its high-range resolution. To realize a low-cost and high-quality indoor security system, we propose a UWB radar imaging system using indoor multipath echoes for targets in shadow regions. A multipath wave can be used as an approximation of an imaginary echo from a mirror image antenna to the target, except for phase rotation and attenuation. Conventional studies only dealt with locating point-like targets, not estimating the shapes. We apply interferometry using these mirror image antennas to estimate target shapes. If only this method is applied, many false image points are estimated because it is difficult to uniquely determine the corresponding mirror image antenna to each echo. We propose an effective false-image reduction algorithm to obtain a clear image. Numerical simulations show that most of the false image points are removed and the target shape is accurately estimated.

Oral Presentations (Poster Teasers)

Thursday, September 16
Auditorium D8

09:45 - 09:47

Xiaolin Meng, Joseph Ryding (presenting author, at University of Nottingham), Max Winter, Alan Dodson, Terry Moore, Bob Webb: Preliminary Results on the Latest UWB Technology for Positioning and Navigation in an Indoor Environment (Poster Teaser)
To achieve seamless positioning and navigation indoors and outdoors is a great challenge to both academic and commercial organisations around the world. The University of Nottingham has endeavoured its effort in recent years to tackle this problem. Research has been carried out in R&D of very high precision indoor positioning systems, such as pseudo-satellites, and low-cost sensor systems, such as RFID and MEMS, for mass market applications. This paper summarises our recent research efforts in using Ultra Wide Band (UWB) sensors to track indoor moving objects and assesses the overall UWB system performance such as positioning accuracy, signal availability under different observation indoor environments. In the tests up to 15 sensors were utilised and a robotic total station which could provide mm positioning accuracy was used to establish a local coordinate system and provide ground truth locations for the antenna of each of the mobile units. Future research plan is also presented in this paper.

Ultra Wide Band, Part 2

Session Chair: Christoph Steiner, ETH Zurich

10:15 - 10:45	Gunter Fischer (presenting author, at IHP-Microelectronics), Oleksiy Klymenko, Denys Martynenko: An Impulse Radio UWB Transceiver with High-Precision TOA Measurement Unit This paper describes a monolithic integrated transceiver chipset intended for impulse radio (IR) Ultra-wide band (UWB) applications including indoor communication and indoor localization. The chipset operates in the higher UWB band centered at 7.68 GHz and it is optimized for a pulse bandwidth of about 1.5 GHz. The average pulses repetition rate of 60 MHz and an octagonal pulse position modulation (8-PPM) allow for raw data rates up to 180 MBit/sec. The available high bandwidth is used for precise indoor localization employing a dedicated time-of-arrival (TOA) measurement extension. This unit runs with a system clock of 3.84 GHz, which allows a measurement accuracy of 260 picoseconds. As demonstrated this UWB transceiver chipset is well suited for two-way ranging (TWR) potentially in harsh environments. Under perfect line-of-sight conditions a spatial resolution of about 3.9 centimeter could be achieved.

10:45 - 11:15	Michal Pietrzyk (presenting author, at Fraunhofer IIS), Thomas von der Gruen: Experimental Validation of a TOA UWB Ranging Platform with the Energy Detection Receiver The ultra-wideband (UWB) technology is recognized as an ideal candidate to provide accurate localization in challenging indoor environments where other technologies, e.g. WiFi or ZigBee cannot yield good accuracy due to their signal bandwidth limitation. The energy detection receiver is currently one of the most promising low complexity non-coherent architectures that neither requires high sampling rates nor information about the channel. This paper presents results of experimental validation of the designed and implemented UWB ranging platform with the energy detection receiver. Insights into practical limits on the performance of the platform are provided. These include, among others, an analysis of the link budget and system parameters. The presented theoretical analysis is validated through laboratory measurements.

11:15 - 11:30	Jan Kietlinski-Zaleski (presenting author, at the Katayama Laboratory, Nagoya University, School of Engineering), Takaya Yamazato: UWB Positioning Using Known Indoor Features – Environment Comparison In our previous papers, [1] and [2], we presented a novel system using reflections from known reflectors to allow 3D ToA UWB indoor positioning with two receivers. The system was verified using measurement campaign data from just one example environment - a lecture room. Since then we performed measurements in two more common indoor environments – a cluttered room (laboratory) and a corridor. In this abstract we will present our positioning system results for the three environments and compare them, drawing conclusions about strengths and weaknesses of the positioning system, a short sample of our perspective paper.

11:30 - 11:45	Sivanand Krishnan (presenting author, at Infocomm Research), Lim Khoon Seong and Jefnaj Al Afif: Improving Non-Line-of-Sight Performance of UWB Localization Systems Using Neural Networks There are many UWB positioning algorithms that are able to perform at high accuracy under line-of sight (LOS) conditions. These algorithms do not perform well when blocked by objects and the environment becomes a NLOS scenario. Using machine learning techniques the ill effects of NLOS can be filtered. Neural network is a universal function estimator with good generalization properties. The neural network is trained with time difference between antennas as the training data under LOS condition. The network is targeted for strong generalization properties. When the trained network is fed with a new test data which is noisy due to NLOS condition, the network was able to filter out this noise and still output correct results. Positioning performance was significantly improved due to the use of the neural network.

Ultra Wide Band, Part 3

Session Chair: Dr. Michal Pietrzyk, Fraunhofer IIS

13:15 - 13:45	Thomas Gigl (presenting author, CISC Semiconductor), Paul Meissner, Josef Preishuber-Pfluegl, Klaus Witrisal: Ultra-Wideband System-Level Simulator for Positioning and Tracking (U-SPOT) A novel UWB positioning simulator is presented, which uses statistically defined virtual environments to enable mixed line-of-sight and non-line-of-sight simulations. A novel channel selection algorithm is presented to enable realistic simulations with experimental data. The simulator has been used for the analysis of the IEEE 802.15.4a standard with respect to its positioning capabilities with a coherent receiver. A least squares positioning algorithm is compared with a standard and an extended Kalman filter. It shows that the tracking algorithms can be used to improve the performance in NLOS scenarios significantly, by rejecting and smoothing the outliers. The full paper will contain a detailed mathematical description of the simulation framework. Also a detailed comparison of the coherent receiver and the energy detector will be presented in NLOS-intensive scenarios. A detailed analysis of the least squares positioning and the Kalman filters will be shown.

13:45 - 14:15	Amanda Prorok (presenting author), Adrian Arfire, Alexander Bahr, John R. Farserotu and Alcherio Martinoli: Indoor Navigation Research with the Khepera III Mobile Robot: An Experimental Baseline with a Case-study on Ultra-wideband Positioning Recent substantial progress in the domain of indoor positioning systems and a growing number of indoor location-based applications are creating the need for systematic, efficient, and precise experimental methods able to assess the localization and perhaps also navigation performance of a given device. With hundreds of Khepera III robots in academic use today, this platform has an important potential for single- and multi-robot localization and navigation research. In this work, we develop a necessary set of models for mobile robot navigation with the Khepera III platform, and quantify the robot's localization performance based on extensive experimental studies. Finally, we validate our experimental approach to localization research by considering the evaluation of an ultra-wideband (UWB) positioning system. We successfully show how the robotic platform can provide precise performance analyses, ultimately proposing a powerful approach towards advancements in indoor positioning technology.

14:15 - 14:45	Marcelo Segura (presenting author, at National University of San Juan, Argentina), Hossein Hashemi (at University of Southern California), Cristian Sisterna and Vicente Mut: Experimental Demonstration of Self-Localized Ultra Wideband Indoor Mobile Robot Navigation System A self-localized Ultra-Wide-Band(UWB) system is introduced, that is suitable to navigate mobile robots in indoor environments. In the proposed scheme, a number of anchor nodes are located in fixed positions in the indoor environment, and transmit synchronized 2ns pulses with Differential Binary Phase Shift Keying (DBPSK) modulation. An UWB receiver mounted on the mobile robot uses Time Difference of Arrival (TDOA) between pairs of synchronized transmitting anchor nodes for localization. Self-localization implies that position estimation algorithms run locally on the mobile robot, similar to outdoor localization systems based on Global Position System (GPS). A prototype non-coherent UWB system using off-the-shelf components is implemented where signal acquisition and localization algorithms run on a Field Programmable Gate Array (FPGA). Measurement results indicate sub-15cm positional accuracy with Line Of Sight (LOS) and Non-Line of Sight (NLOS) conditions relative to fixed anchor nodes in a typical indoor environment.

14:45 - 15:00	Rudolf Zetik (presenting author), Guowei Shen and Reiner Thomä: Evaluation of requirements for UWB localisation systems in home-entertainment applications This paper discusses basic requirements for passive ultra-wideband localization systems that aim at home-entertainment applications such as a smart audio system, which can adapt the sound according to the user location, so that an optimum listening experience is provided to the user. We have analysed over hundred thousands channel impulse responses measured by a real-time UWB channel sounder in different scenarios. Our analyses show that passive localisation systems must posses a large real-time dynamic range in order to be capable to detect a listener. We assume that the listener does not carry any tag and he is detected and localised just by electro-magnetic waves reflected from his body. Such a passive localization is demonstrated by a measurement example.

Ultra Wide Band, Part 4

Session Chair: Dr. Michal Pietrzyk, Fraunhofer IIS

15:30 - 16:00	Phillip Tomé (presenting author), Christian Robert, Roman Merz, Cyril Botteron, Andreas Blatter, Pierre-André Farine: UWB-based Local Positioning System: from a small-scale Experimental Platform to a large-scale Deployable System At the Electronics and Signal Processing Laboratory at EPFL, an experimental platform has been designed and built to demonstrate the feasibility of Ultra-wideband (UWB) technology applied to indoor positioning. This small-scale demonstrator has proven to be a valuable research tool, with the flexibility to study, test and assess the performance of various system architectures and signal processing algorithms. Based on this successful experience, a subsequent project was setup to extend the lab’s research on certain topics that could not be addressed by the small-scale demonstrator. This new R&D project pursues two main objectives: a) designing and building a large-scale UWB-based Local Positioning System (LPS), including installation, calibration and operational testing in a real industrial environment, b) conceiving and developing Application Specific Integrated Circuits (ASICs) to target cost-competitive solutions. This paper addresses the main design issues analysed during the definition phase of the large-scale UWB-based LPS requirements, considering that the new system should inherit whenever possible the design features already existing on the small-scale demonstrator.

16:00 - 16:30	Ralf Herrmann (presenting author), Jürgen Sachs, Frank Bonitz: On benefits and challenges of person localisation using UWB sensors Precise localisation of persons in their living environment is part of many upcoming applications such as wireless entertainment systems or home-based medical supervision. Ultra-wideband (UWB) sensors are especially interesting due to specific advantages over narrowband solutions. This paper lists some advantages and demonstrates challenges of implementation with a measurement example. A proposal for robust ECC-conform localisation concludes the paper.

Oral Presentations (Poster Teasers)

Thursday, September 16
Auditorium D8


16:30 - 16:32	Lukasz Zwirello, Malgorzata Janson (presenting author), Christian Ascher, Ulrich Schwesinger, Gert F. Trommer and Thomas Zwick: Accuracy Considerations of UWB Localization Systems Dedicated for Large-Scale Applications (Poster Teaser) This contribution considers the accuracy limits of ultra-wideband localization systems dedicated for large-scale-applications. Industrial environments are known for their severe fading behaviour, caused by high concentration of metal objects. In this work a detailed 3D model of the warehouse is used for wave propagation simulations. In the simulation, the transmitter is moving along the predefined path and the receiver infrastructure consists of eight base stations. The aim is to model the tracking system and asses its accuracy – firstly the accuracy upper bound is determined for the ideal case and secondly the precision estimation when including effects of hardware non-idealities is done. Effects like the the influence of pulse detection methods and geometrical configuration of base-stations are investigated. The position calculation of the mobile beacon is realized using Time Difference of Arrival approach. Eventually the accuracy of obtained results and the theoretical limit are considered based on dilution of precision evaluations.

16:32 - 16:34	Francesco Chiti, Enrico Del Re, Romano Fantacci, Simone Morosi (presenting author, at Interuniversity Consortium for Telecommunications (CNIT)), Lorenzo Niccolai, Raffaele Tucci: A system level approach for node localization in IEEE 802.15.4a WSNs (Poster Teaser) Node localization in distributed wide area WSNs is a challenging task which is becoming crucial for both scientific and industrial communities. For this purpose, the IEEE 802.15a standard has recently been proposed to achieve high accuracy within the ranging phase. This paper proposes three different algorithms based on the Time of Arrival (ToA) approach together with a technique that allows the estimation of the outcome’s reliability.

16:34 - 16:36	Shiv Ashish Kumar (presenting author), Phillip Tomé, Roman Merz, C. Robert, Cyril Botteron and Pierre-André Farine: Performance assessment of a new calibration method used for clock synchronization on impulse radio based Ultra-Wideband receivers (Poster Teaser) Some applications, such as Local Positioning Systems (LPS) based on time-of-arrival (TOA) measurements of a radio signal at several receivers at known positions, require a very accurate synchronization between the receivers. One possible approach to estimate the time offsets for all the receivers consists in placing a transmitter at a known position and estimate the TOAs of the signal at the receivers. This approach is for example used in a LPS demonstrator that has been developed in our laboratory [1]. However, this approach requires an accurate knowledge of the transmitter’s position. An inaccuracy in the transmitter’s position results in a systematic error in all the following position estimations. It has been shown that the position accuracy of our LPS is currently limited by the accuracy of the synchronization [2]. In this paper, we present a novel calibration method and assess its performance by deriving the Cramer Rao Lower Bound (CRLB). The tightness of the bound is verified by simulations and the achievable accuracy is compared to other existing methods of calibration.

16:36 - 16:38	Harald Kröll (presenting author, Integrated Systems Laboratory (IIS) at ETH Zurich), Christoph Steiner: Indoor Ultra Wideband Location Fingerprinting (Poster Teaser) Ultra Wideband (UWB) Location Fingerprinting is an attractive alternative to positioning concepts based on lateration or angulation. The high temporal resolution of multipath components of UWB channel impulse responses (CIRs) offers various opportunities for high precision and robust localization. Due to the large bandwidth the CIR of a UWB transmitter is an adequate fingerprint of the relative positions of transmitter and receiver. In order to show that the presented location fingerprinting technique is suited for high precision indoor position location with non-LoS situations an office environment measurement campaign was conducted. The performance of the measured data is evaluated under various circumstances.

16:38 - 16:40	Enrique García, Juan Jesús García (presenting author), Jesús Ureña, M. Carmen Pérez, Daniel Ruiz: Multilevel Complementary Sets of Sequences and their application in UWB (Poster Teaser) In this paper it is proposed a new algorithm to generate multilevel complementary sets of sequences. It can be considered a generalization of previous algorithms [1], by using generic multilevel Hadamard matrices. In contrast to previous works [2], it is analyzed the conditions that must satisfy the Hadamard matrix to generate not only a pair of multilevel complementary sequences but also M-Multilevel Mutually Orthogonal Complementary Sets of Sequences (M-MO-CSS), where M is a power of two (M=2m, m N - {0}). Moreover, in this work it is generated new Multilevel Loosely Synchronized (LS) sequences from two pairs of multilevel MO-CSS, being a generalization of the binary LS sequences. Finally, it is proposed the use of these multilevel sequences in a Local Positioning System based on Ultra-Wideband (UWB). An UWB link has been simulated, where the sequences are directly transmitted through the UWB channel model. At the receiver, the detection is carried out by means of the correlation between the received and transmitted sequences, and their performance is compared to chaotic sequences and binary LS sequences.

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