Symmetric Double-Sided Two-Way Ranging Research Articles

Automatic Acquisition System for Mine Pressure Monitoring in Coal Mine Working-Face Footage

The existing mine pressure monitoring system has realized the online continuous monitoring of the working-face stent resistance, roadway roof offcuts, and anchor rod/rope working resistance. However, the mine pressure monitoring information of the working face currently includes only the stent resistance and the monitoring time, and there is no information on the working-face advance. The mine pressure data cannot be precisely analyzed due to a lack of measurement point locations. Mine pressure data analysis combined with the working-face feed information is the basis for safe and efficient mining and for improving the intelligence level of the comprehensive mining face. According to the special electromagnetic environment of the underground, this system adopts UWB (ultra-wide-band) technology and the SDS-TWR (symmetric double-sided two-way ranging) ranging method, with the UWB positioning base station as the core and installs positioning tags at the end supports of the working face to collect information. The data are uploaded to the host computer via Ethernet for coordinate solving, automatically collecting the working-face footage data and providing positional information for mine pressure monitoring. The application results show that the system operates normally and can collect real-time information of working-face footage and monitor mine pressure data, and meet the requirements of coal mine positioning accuracy, positioning error is less than 30 cm, the application effect is good.

Design of anti-collision device of mine trackless rubber tire vehicle

For the problem of safety accident such as the collision between equipment or between person and equipment beneath the coal mine, after analyzing the advantages and disadvantages of active safety technology now, a high precision ranging system based on UWB has been designed. This system uses Symmetric Double Sided Two-Way Ranging algorithm which can reduce the influence of clock drift, improve the ranging accuracy of the system and reduce the false alarm rate of the system. The device has the functions of personnel intrusion alarm, vehicle approach alarm, automatic shutdown of the vehicle, and so on. The results show that the maximum ranging error of the system within 20 m is ±0.13 m, which can fully meet the requirements of vehicle active safety collision avoidance. Through the research and application of preventing intrusion and proximity alarm devices, the collision accidents between vehicles and personnel as well as those between vehicles and vehicles are effectively avoided. The safety of underground personnel is improved, and the efficiency of underground auxiliary transportation is also improved.

Bias and variance of asymmetric double‐sided two‐way ranging

Asymmetric double-sided two-way ranging (ADS-TWR) is a method of range estimation through precisely time-stamped messages sent between two transceivers. In contrast to symmetric double-sided two-way ranging (SDS-TWR), ADS-TWR suppresses the errors induced by transceiver clock drifts even when the message reply delays are unequal. However, due to the nonlinearity of the ADS-TWR estimator, its mean and variance cannot be evaluated in a straightforward or exact way. This article presents an analytical approach of evaluating an approximation of bias and variance of the range estimators and applies it on an exemplary set of parameters, typical for ultra-wide band (UWB) localization systems. Moreover, the obtained results are verified by a Monte Carlo simulation. It will be proven that ADS-TWR is safe to be used in most of the present applications, and its precision is rather similar to SDS-TWR.

Numerical and Experimental Evaluation of Error Estimation for Two-Way Ranging Methods.

The Two-Way Ranging (TWR) method is commonly used for measuring the distance between two wireless transceiver nodes, especially when clock synchronization between the two nodes is not available. For modeling the time-of-flight (TOF) error between two wireless transceiver nodes in TWR, the existing error model, described in the IEEE 802.15.4-2011 standard, is solely based on clock drift. However, it is inadequate for in-depth comparative analysis between different TWR methods. In this paper, we propose a novel TOF Error Estimation Model (TEEM) for TWR methods. Using the proposed model, we evaluate the comparative analysis between different TWR methods. The analytical results were validated with both numerical simulation and experimental results. Moreover, we demonstrate the pitfalls of the symmetric double-sided TWR (SDS-TWR) method, which is the most highlighted TWR method in the literature because of its highly accurate performance on clock-drift error reduction when reply times are symmetric. We argue that alternative double-sided TWR (AltDS-TWR) outperforms SDS-TWR. The argument was verified with both numerical simulation and experimental evaluation results.

Fingerprinting Localization Method Based on TOA and Particle Filtering for Mines

Accurate target localization technology plays a very important role in ensuring mine safety production and higher production efficiency. The localization accuracy of a mine localization system is influenced by many factors. The most significant factor is the non-line of sight (NLOS) propagation error of the localization signal between the access point (AP) and the target node (Tag). In order to improve positioning accuracy, the NLOS error must be suppressed by an optimization algorithm. However, the traditional optimization algorithms are complex and exhibit poor optimization performance. To solve this problem, this paper proposes a new method for mine time of arrival (TOA) localization based on the idea of comprehensive optimization. The proposed method utilizes particle filtering to reduce the TOA data error, and the positioning results are further optimized with fingerprinting based on the Manhattan distance. This proposed method combines the advantages of particle filtering and fingerprinting localization. It reduces algorithm complexity and has better error suppression performance. The experimental results demonstrate that, as compared to the symmetric double-sided two-way ranging (SDS-TWR) method or received signal strength indication (RSSI) based fingerprinting method, the proposed method has a significantly improved localization performance, and the environment adaptability is enhanced.

WPAN에서 최대 측정거리 값을 이용한 이동객체 위치추정 보정 알고리즘

최근, 스마트폰의 GPS (Global Positioning System) 및 Wi-Fi를 이용한 위치기반서비스 (Location Based Services : LBS)에 대한 관심과 수요가 국내외에서 증가하고 있다. 위치추정 실험결과, WPAN (Wireless Personal Area Network)에서 실내 위치추정의 경우 고정노드와 이동노드간의 거리 측정 시 빈번하게 많은 오차 값이 발생함을 확인하였다. 본 논문에서는 최대 측정거리 값을 이용하여 이동객체의 위치추정 성능을 향상시킬 수 있는 위치추정 보정 알고리즘 (<TEX>$LCA_{MMV}$</TEX>)을 제안하고, 이동노드가 이동하는 상황을 3가지 시나리오로 구성하여 실험을 통해 성능을 분석하였다. 성능분석 결과, 제안한 알고리즘의 평균 위치추정 정확도는 SDS-TWR (Symmetric Double-Sided Two-Way Ranging)과 삼변측량법 보다 시나리오 1-3에서 각각 40.9cm, 77.6cm, 6.3cm 더 정확하게 측정됨을 확인하였다. Concerns and demands for the Location Based Services (LBS) using Global Positioning System (GPS) and Wi-Fi are largely increased in the world in the present. In some experimental results, it was noted that many errors are frequently occurred when the distances between an anchor node and a mobile node acre measured in indoor localization environment of Wireless Personal Area Network (WPAN). In this paper, localization compensation algorithm based on maximum measurement value (<TEX>$LCA_{MMV}$</TEX>) for moving objects in WPAN is proposed, and the performance of the algorithm is analyzed by experiments on three scenarios for movement of mobile nodes. From the experiments, it was confirmed that the average localization accuracy of suggested algorithm was more increased than Symmetric Double-Sided Two-Way Ranging (SDS-TWR) and triangulation as average 40.9cm, 77.6cm and 6.3cm, respectively on scenario 1-3.

Indoor Three-Dimensional Positioning Method Based on CSS

This paper designs a three-dimensional positioning scheme suitable for indoor, adopts Chirp Spread Spectrum (CSS) and the particular Symmetric Double-Sided Two-Way Ranging (SDS-TWR). Combining BMP085 pressure sensor to measure altitude, it can implement three-dimensional positioning of a moving object in indoor. Due to the complex indoor environment would cause multipath effect when Chirp signal being transmitted, this scheme uses Kalman filtering method to filter out mutative coordinate value, thus the positioning error can be controlled within 1 m.

Packet-Reduced Ranging Method with Superresolution TOA Estimation Algorithm for Chirp-Based RTLS

In this paper, a packet-reduced ranging method using a superresolution time of arrival estimation algorithm for a chirp-based real-time locating system is presented. A variety of ranging methods, such as symmetric double-sided two-way ranging (SDS-TWR), have been proposed to remove the time drift due to the frequency offset using extra ranging packets. Our proposed method can perform robust ranging against the frequency offset using only two ranging packets while maintaining almost the same ranging accuracy as them. To verify the effectiveness of our proposed algorithm, the error performance of our proposed ranging method is analyzed and compared with others. The total ranging performance of TWR, SDS-TWR, and our proposed TWR are analyzed and verified through simulations in additive white Gaussian noise and multipath channels in the presence of the frequency offset.

균등거리비율 및 칼만필터를 이용한 위치인식 보정 알고리즘의 성능분석

The CSS(Chirp Spread Spectrum) technology is used for developing various WPAN(Wireless Personal Area Network) application fields in general, and it can be adapted to implement localization systems especially using SDS-TWR(Symmetric Double Sided - Two Way Ranging). But the ranging errors are occurred in many practical applications due to some interferences by some experiments. Thus, the compensation algorithm for localization is required for developing localization applications. The suggested compensation algorithm that is named KF_EDR(Kalman Filter and Equivalent Distance Rate) for localization in order to reduce the ranging errors is suggested in this paper. The KF_EDR compensation algorithm for localization is mainly composed of the AEDR(Algorithm of Equivalent Distance Rate) and the Kalman Filter. It is confirmed that the improved error ratio of the KF_EDR are 10.5% and 4.2% compared with the AEDR algorithm in lobby and stadium. From the results, it is analyzed that the KF_EDR can be widely used for some localization system in ubiquitous society.

NLOS환경에서의 최소자승법을 적용한 위치인식 보정 알고리즘

The compensation algorithm for localization using the least-squires method in NLOS(Non Line of Sight) environment is suggested and the performance of the algorithm is analyzed in this paper. In order to improve the localization correction rate of the moving node, 1) the distance value of the moving node that is moving as an constant speed is measured by SDS-TWR(Symmetric Double-Sided Two-Way Ranging); 2) the location of the moving node is measured using the triangulation scheme; 3) the location of the moving node measured in 2) is compensated using the least-squares method. By the experiments in NLOS environment, it is confirmed that the average localization error rates are measured to , and by the triangulation scheme, the Kalman filter and the least-squires method respectively. As a result, we can see that the localization error rate of the suggested algorithm is higher than that of the triangulation as average 86.0% and the Kalman filter as average 16.0% respectively.

A Subspace-Based Two-Way Ranging System Using a Chirp Spread Spectrum Modem, Robust to Frequency Offset

Herein, we propose and implement a subspace-based two-way ranging system for high resolution indoor ranging that is robust to frequency offset. Due to the frequency offset between wireless nodes, issues about sampling frequency offset (SFO) and carrier frequency offset (CFO) arise in range estimation. Although the problem of SFO is resolved by adopting the symmetric double-sided two-way ranging (SDS-TWR) protocol, the CFO of the received signals impacts the time-of-arrival (TOA) estimation, obtained by conventional subspace-based algorithms such as ESPRIT and MUSIC. Nevertheless, the CFO issue has not been considered with subspace-based TOA estimation algorithms.Our proposed subspace-based algorithm, developed for the robust TOA estimation to CFO, is based on the chirp spread spectrum (CSS) signals. Our subspace-based ranging system is implemented in FPGA with CSS modem using a hardware/software co-design methodology. Simulations and experimental results show that the proposed method can achieve robust ranging between the CSS nodes in an indoor environment with frequency offset.

하이브리드형 위치인식 보정 알고리즘 성능 분석 및 평가

Abstract In this paper, the hybrid compensation algorithm(A HB ) for localization using the Compensation Algorithm distance(CA d ) and the Algorithm of Equivalent Distance Rate(AEDR) in SDS-TWR(Symmetric Double-Sided Two-Way Ranging) is suggested and the performance of the proposed algorithm is analyzed by practical experimentations. From experimentations, it is confirmed that the errors are reduced in 28 coordinates of total 32 coordinates in the experimental region and the errors are reduced about above 70% in the assigned 3 type error level ranges by A HB . Also, it is analyzed that the average localization error is reduced from 2.67m to 1.19m as 55.4% in total 32 coordinates by A HB and the error compensation capability of A HB is very excellent as above 90%. From above results, we have seen that the error reduction ratio and error compensation capability of A HB is more excellent than each CA d or AEDR. Key Words : USN, CSS, IEEE 802.15.4a, SDS-TWR, Ranging, Localization * 교신저자 : 이동명(dmlee@tu.ac.kr)접수일 10년 02월 24일 수정일 10년 04월 21일 게재확정일 10년 06월 18일

균등거리비율을 적용한 위치인식 보정 알고리즘 설계 및 성능분석

본 논문은 SDS-TWR(Symmetric Double-Sided Two-Way Ranging)의 Ranging 오차를 보정하기 위하여 균등거리비율 개념을 적용한 위치인식 보정 알고리즘인 AEDR(Algorithm for localization using the concept of Equivalent Distance Rate)을 제안하고, 위치인식 실험을 통해 위치인식 측정 성능을 분석하였다. SDS-TWR의 Ranging 오차는 실험에 의하면 비콘노드와 이동노드의 특정 거리구간에서 평균 1m~8m로 측정되었다. 그러나 제안한 AEDR에 의한 위치인식 성능은 실험을 통해 전체적으로 교내 강당과 복도 모두에서 SDS-TWR 보다 4배 정도 우수하였으며, 측정된 3~10m 이상의 위치인식 오차를 평균 2m 내외로, 3m 이내의 위치인식 오차를 평균 1m 내외로 각각 감소시킬 수 있음을 확인하였다. 특히 AEDR은 LOS(Line Of Sight) 보다 NLOS(Non Line Of Sight)에서 훨씬 더 위치인식 보정 성능이 우수함을 나타내며, 대부분의 센서 네트워크의 환경이 NLOS임을 고려할 때 AEDR이 실제환경에서의 위치인식에 큰 도움을 줄 수 있다고 판단된다. In this paper, the compensation algorithm for localization using the concept of equivalent distance rate(AEDR) in order to compensate ranging error in the SDS-TWR(Symmetric Double-Sided Two-Way Ranging) is proposed and the performance of the proposed algorithm is analyzed by the localization experiments. The ranging error of the SDS-TWR in the distance between mobile node and beacon node is measured to average 1m~8m by ranging experiments. But it is confirmed that the performance of the localization by the AEDR is better than that of the SDS-TWR 4 times in university auditorium and corridor, and the localization error of above 3~10m is reduced to average 2m and that of below 3m is reduced to average 1m respectively. It is concluded that the AEDR is superior to the NLOS(Non Line Of Sight) than LOS(Line Of Sight) in performance of ranging compensation for localization, and the AEDR is more helpful to localization systems practically considering the environment of sensor networks is under NLOS.

거리측정의 오차비율 오프셋을 적용한 보정알고리즘 연구

Abstract It is confirmed that as the distance measurements accuracy of the SDS-TWR(Symmetric Double-Sided Two-Way Ranging) based on CSS(Chirp Spread Spectrum) is considerably degraded due to frequency interference and it causes to severe errors in the localization applications. In this paper, the compensation algorithm based on error rate offset of distance measurement (  ) is proposed for the purpose to reduce the ranging errors due to by the SDS-TWR ranging problems. The   measures the distance values between two nodes by means of 1m interval about 1~25m distances in the SDS-TWR, and compensates the distance values using the parameters related to the distance compensation. From the experiments, it is analyzed that the   have reduced the distance error to average 95cm and maximum 526cm, and the distance error by the   was below about 60cm in the 25m distances. In particular, the performance of the distance measurements accuracy by the   is very high in LOS(Line Of Sight) environments.

One-Way Ranging Method Using Reference-Based Broadcasting Messages for Wireless Sensor Networks

This paper proposes a one-way ranging method using reference-based broadcasting messages. The method is based on impulse radio UWB (Ultra-wideband) for wireless sensor networks. The proposed method reduces traffic overheads and increases the ranging accuracy using frequency offsets and counter information based on virtually synchronized counters between RNs (Reference Nodes) and MNs (Mobile Nodes). Simulation results show that the proposed method can alleviate the ranging errors comparing to SDS-TWR (Symmetric Double-Sided Two-Way Ranging) method in terms of the frequency offset.