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This work presents the performance evaluation of an ultra-wide band (UWB) positioning system for monitoring athletes in sports. Focusing on a five-a-side football scenario, the objective of this paper is to evaluate the performance of the proposed UWB positioning system by considering three different heights of the receiver antenna: 1 m, 1.6 m and...
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... However, since portable units are typically installed by sports scientist or researchers, instead of providers, some issues should be considered during installation. Recently, a survey was published regarding the method for use of radio frequency-based technologies, which requires clustering some items when installing the system. 1 To date, the height of antennas and antennas' installation shape are considered as data affecting factors. 1 However, while the relative height of antennas have been investigated in team sports, 7 to the authors' knowledge, no studies have assessed the effects of different antenna installation shapes on the quality of recorded data, thus the need to investigate so as to further understand the impact of different antenna shape setups and topology configurations on data accuracy. ...
Ultra-wide band (UWB) technology has become one of the most promising technologies of the future. It seems that the positioning of the antenna set influences the accuracy of the player's performance. This study was aimed to assess the influence of two different antenna positioning system shapes: (i) octagonal installation and (ii) circular installation. A UWB technology was used to track a healthy and well-trained athlete's (age: 38 years, mass: 76.34 kg, and height: 1.75 m) positioning. Overall, the data measured showed high accuracy in both shape setups in all trajectories assessed in static and dynamic conditions for all speed thresholds. However, the distance covered during jogging and sprinting showed poor accuracy for both shape setups. Moreover, the data measured showed high test-retest reliability and inter-device agreement in the static condition, regardless of the antenna setup shape. In conclusion, both the octagonal and circular antenna setup shape provided accurate data, but the measurement error associated within the setup shape seemed slightly different between the two systems.
... IoT devices are an indispensable element of smart cities or industry 4.0 (e.g., intelligent parking lots that provide information about available spaces and make it easier to find a previously parked car) [1]. Such devices are also used in sports or rehabilitation [2,3]. GPS and inertial navigation are widely applied to determine the position of an object [4,5]. ...
... The other values are presented in Figure 7. The fundamental accuracy measure in positioning systems (indoor and outdoor) is a root mean square error (RMSE, (2)). For the analysed system, the mean error changes with distance without being clearly monotonous. ...
UWB is a rapidly developing technology characterised by high positioning accuracy, additional data transferability, and communication security. Low costs and energy demand makes it a system that meets the requirements of smart cities (e.g., smart mobility). The analysis of the positioning accuracy of moving objects requires a ground truth. For the UWB system, it should have an accuracy of the order of millimetres. The generated data can be used to minimize the cost and time needed to perform field tests. However, there is no UWB simulators which can consider the variable characteristics of operation along with distance to reflect the operation of real systems. This article presents a 2D UWB simulator for outdoor open-air areas with obstacles and a method of analysing data from the real UWB system under line-of-sight (LOS) and non-line-of-sight conditions. Data are recorded at predefined outdoor reference distances, and by fitting normal distributions to this data and modelling the impact of position changes the real UWB system can be simulated and it makes it possible to create virtual measurements for other locations. Furthermore, the presented method of describing the path using time-dependent equations and obstacles using a set of inequalities allows for reconstructing the real test scenario with moving tags with high accuracy.
... КЛЮЧЕВЫЕ СЛОВА: сверхширокополосные импульсные электромагнитные волны, антенна типа «бабочка», искусственная нейронная сеть, метод корреляции, система позиционирования ВСТУП Існуючі системи глобального позиціонування (GPS) можуть задовольнити більшу частину своїх користувачів, але при певних природних умовах або в закритих приміщеннях його використання сильно ускладнено [1]. Визначення положення об'єктів конче потрібне в різних сферах діяльності людини: у сільському господарстві [2], для безпеки дорожнього руху [3], для різних видів спорту [4], в сферах промислового виробництва, логістики товарів тощо. ...
Background: Global and local positioning systems have a wide area of civil and military applications. Transport, logistics, precise agriculture, industrial technologies, safety systems need a strict definition of objects position on plane or in space. Existing modern positioning systems have some drawbacks in utilization and restrictions in application. Objectives: To improve a system of local positioning on a plane that does not need a time synchronization using the impulse ultrawideband electromagnetic field of two spaced bow-tie antennas and analysis and recognition of time forms of received waves by artificial neural networks and cross correlation method. To carried out the investigation of stability of the positioning system operation in presence of an interference in the form of additive white noise. Materials and methods: The electromagnetic simulation of excitation and radiation of the antennas is carried out by finite difference time domain method. The classification of received impulse form by known samples is realized by two alternative method, i.e. correlation approach and artificial neural networks. Results: The utilization of correlation method and artificial neural networks permitted to realize the positioning system with angular resolution of 1 degree. The probability distributions of recognized angles for different levels of additive noise in received signals for these two techniques are obtained. Conclusion: The comparison of artificial neural network application and correlation method for angle recognition shows that artificial neural networks can demonstrate a better precision than correlation approach. artificial neural network gives a correct angle recognition after statistical averaging of classification results even for the signal to noise ratio 0 dB. Artificial neural networks demonstrate a in three times shorter time of numerical simulation than we need for cross correlation function calculation. The application of shorter electromagnetic impulse increases the quality of angle classification in presence of the noise for both presented methods.
... The positioning accuracy also depends on the technology used for RTT estimation. RTT computed using UWB signals is commonly more accurate with respect to the RTT computed using narrowband signals [22][23][24]. ...
Wi-Fi round-trip timing (RTT) was applied to indoor positioning systems based on distance estimation. RTT has a higher reception instability than the received signal strength indicator (RSSI)-based fingerprint in non-line-of-sight (NLOS) environments with many obstacles, resulting in large positioning errors due to multipath fading. To solve these problems, in this paper, we propose high-precision RTT-based indoor positioning system using an RTT compensation distance network (RCDN) and a region proposal network (RPN). The proposed method consists of a CNN-based RCDN for improving the prediction accuracy and learning rate of the received distances and a recurrent neural network-based RPN for real-time positioning, implemented in an end-to-end manner. The proposed RCDN collects and corrects a stable and reliable distance prediction value from each RTT transmitter by applying a scanning step to increase the reception rate of the TOF-based RTT with unstable reception. In addition, the user location is derived using the fingerprint-based location determination method through the RPN in which division processing is applied to the distances of the RTT corrected in the RCDN using the characteristics of the fast-sampling period.
... Strength training is mostly concentrated in the range of strength and strength speed. When arranging the training, we should analyze the internal needs and characteristics of the project, determine the proportion of strength, explosive force, speed and other components in the continuum of continuous change, and highlight or give priority to the components closely related to the project needs on the basis of all-round development, which is more conducive to the improvement of sports performance and the prevention of sports injury [19] . In addition, whether it is speed based events or speed strength, explosive force, strength and speed based events, different types of sports have common characteristics in strength training, that is, training must emphasize the speed and quality of action. ...
Based on the analysis of big data, this paper designs the intelligent control model of sports athletes’ training progress. By constructing the evaluation system of sports athletes’ training intensity, it improves the intelligent control algorithm of sports athletes’ training intensity, and ensures the operation effect of the intelligent control model of sports athletes’ training intensity. In order to verify the effect of the model, simulation experiments are carried out, and the results show that most of the models are effective. From the perspective of analysis, the intelligent model of athletes’ training progress has outstanding practical value. The model can quickly and accurately formulate training plans, solve the data fluctuation phenomenon under the trend of big data division, and realize intelligent operation. Moreover, the fluency and accuracy are very high, which is worth promoting and applying.
... However, this fact has not been sufficiently investigated. To the authors' knowledge, only one study has assessed the influence of relative antenna height in a sport setting [23]. Martinelli et al. [23] assessed the effects of the relative height of a UWB technology based system antenna set (i.e., four antennae). ...
... To the authors' knowledge, only one study has assessed the influence of relative antenna height in a sport setting [23]. Martinelli et al. [23] assessed the effects of the relative height of a UWB technology based system antenna set (i.e., four antennae). These authors set the antennae at heights of 1.00 m, 1.60 m and 2.00 m from the floor and looked for the most suitable antenna height during athlete motion. ...
... These authors set the antennae at heights of 1.00 m, 1.60 m and 2.00 m from the floor and looked for the most suitable antenna height during athlete motion. The results suggested that the height of the antennae should be similar to the height at which the device is located on a player's upper back (i.e., around 1.6 m height) [23]. As this study considered individually analyzed athlete movements, did not consider collective metrics and highlighted that a slight error in the computation of a player position may cause a substantial deviation from the gold standard in a collective metric, it seems to be of interest to assess the influence of the height of antennae on the measurement of collective variables [12]. ...
Ultra-wide band (UWB) based local positioning systems (LPS) are based on devices and
a portable antenna set. The optimal installation height of the antennae is crucial to ensure data accuracy. Collective variables are metrics that consider at least two pairs of coordinates, which may lead to lower precision than an individual one. Therefore, the aim of this study was to compare the influence of antenna height with collective metrics using a UWB (i.e., IMU; WIMU PRO™, RealTrack Systems, Almeria, Spain) based LPS. Data acquisition was carried out in a basketball court measuring 28 x 15 m. Five devices were used; one of which was carried by a healthy and well-trained athlete (age: 38 years, mass: 76.34 kg, height 1.70 m), while each of the remaining four was positioned on a tripod in one of the four corners of the court. Four kinds of variables were extracted: (1) static distances, (2) dynamic distances, (3) static areas and (4) dynamic areas in all antenna installation
modes of 0.15, 1.30 and 2.00 m. The results showed that the antenna of 1.30 m provided better accuracy for all measures (% difference range from 0.94 to 1.17%) followed by the antenna of 2.00 m (% difference range from 2.50 to 2.15%), with the antenna of 0.15 m providing the worst accuracy level (% difference range from 1.05 to 3.28%). Overall, the measurements of distance metrics showed greater accuracy than area metrics (distance % difference range from 0.85 to 2.81% and area % difference range from 2.50 to 3.28). In conclusion, the height of the antennae in basketball courts should be similar to the height at which the devices are attached to a player’s upper back. However, as the precision is sensitive to the magnitude of the measure, further studies should assess the effects of the relative height of antennae in team sports with greater playing spaces.
... Existen factores como la frecuencia de muestreo y el uso simultáneo de varios dispositivos (Alarifi et al., 2016;Leser et al., 2011) que limitan el uso de los LPS basados en la radio frecuencia UWB. De igual modo la altura de las antenas infl uye en el margen de error (Martinelli et al., 2019). ...
OBJECTIVES 1. To analyze the validity and reliability reported by the different indexes and variables of neuromuscular, tactical and kinematic load in semi-professional soccer.
2. To know/describre/highlight the training and competition characteristics and demands in semi-professional soccer.
3. To analyze the differences derived from the use of two types of radiofrequency technologies for the control of external load in semi-professional football.
METHODOLOGY From the perspective of the objectives, this Doctoral Thesis by compendium of publications has used a descriptive, correlational, explanatory and exploratory methodology to respond the general objectives and in each specific objectives of the scientific articles.
CONCLUSIONS Both technologies can be used, but it is recommended to use the same one always, when finding differences between the variables total distance and average speed from GNSS and LPS.
Both the Player Load and the AcelT are two valid load indexes for determining neuromuscular demands, so their use can be done indistinctly both in training and in competition.
Soccer players experience a decrease in performance over the course of minutes of play. Contextual variables such as the distribution of matches on the calendar, the location of the match (home or away), the partial result of the match, and the specific position of the player modify the external load to which the players are subjected.
A strong relationship has been found between Player Load and Power Metabolic. The similar dynamics in both load indicators offers the possibility of using them for external load quantification.
Finding differences between both technologies (GNSS and LPS) indicates that the tactical variables obtained from different technologies cannot be compared with each other.
The game phase as well as the SSG format have a direct influence on the tactical analysis variables
... The tag is held at the user's chest height of 1.4 m, and the anchors are deployed at the height of 1.8 m. The relative height difference of 0.4 m between the tag and anchor is ignored in this evaluation because it does not almost affect the 2D LS-based positioning performance [30]. In addition, to match the azimuth angle with the 2D coordinate system, a bias with a heading offset of 20 • is added when obtaining the heading yaw. ...
Some of the researches on indoor positioning have been conducted, but there are still many constraints on indoor positioning approaches. Among these approaches, ultra-wideband (UWB) provides a fast and precise positioning performance but requires a sufficient infrastructure and a clear line-of-sight (LOS) channel. However, inertial sensor-based pedestrian dead reckoning (PDR) operates without infrastructure, but it requires position initialization and has error drift problems. In this study, we propose a hybrid positioning system that fully combines UWB and PDR to overcome such constraints and improve the positioning performance. This hybrid positioning system uses a Kalman filter (KF) based fusion method that identifies non-line-of-sight (NLOS) environments and mitigates UWB errors through PDR. We also evaluated the proposed system implemented using practical testbed devices at indoor environments classified as LOS, weak NLOS, and hard NLOS. The evaluation results showed that the proposed system significantly improves the positioning performance and alleviates the positioning constraints, as compared to the single positioning system. Our system has been designed to be lightweight compared to the existing extended KF-based convergence system, but is more robust to both weak and hard NLOS environments. Eventually, it improved positioning performance by 35.5% than existing hybrid systems in the hard NLOS environments.
