Signal Transmission Time Research Articles

Direct position determination algorithm based on wideband array signal model in external illuminator system

Abstract Target location and tracking are among the most critical applications for external illuminator systems. Most traditional array signal direct position determination (DPD) techniques are based on narrowband signals. With the advancement of communication technology, various wideband signals are extensively utilized in communication systems, leading to the failure of some traditional DPD techniques. To address this issue, this article proposes a new DPD algorithm for wideband array signals. First, we suppress the direct wave (DW) interference in the received signal. Then, a cost function for the target coordinate is constructed based on the Maximum Likelihood (ML) criterion, and a phase matching matrix is created for the problem of unknown signal transmission time. Finally, the position estimation is obtained from the peak of the cost function. Simulation results demonstrate that the proposed algorithm outperforms traditional two-step localization methods based on the time difference of arrival of signals, particularly in cases where DW interference is present in the received signal.

Tests of Fire Circuit Breakers (FCBs) to Assess Their Suitability for Use in Construction Objects

A fire circuit breaker (FCB) is dedicated to emergency services that can cut off the flow of electricity to all circuits, except for circuits supplying installations and equipment, the functioning of which is necessary during a fire. Theoretical research shows that there are no comprehensive studies on the FCB systems. Therefore, the aim of this study is to assess the impact of the components used (activating, signalling and executive devices) on the functionality of the entire FCB system (signal transmission time, actuation time, signalling, operational safety and resistance to various environmental conditions). This study proposes a new test scheme to evaluate the functionality of the entire FCB system, not just their individual components, which are widely known and used by electricians. However, it is only by combining them into a system, taking into account the requirements for firefighting equipment used by firefighters, that a completely new product is created. The new test scheme was properly validated by conducting a series of tests on several systems, consisting of multiple components (activating, signalling and executive devices). The tests carried out confirmed the validity of the assumptions made for the test methods and demonstrated the strong influence of the components (actuators, signalling and execution devices) on the functionality of the entire FCB system.

Time delay effect reduction on the wireless networked control system using an optimized FOPI-FOPD controller

Wireless Networked Control System (WNCS) is made up of an actuator, sensor, and controller that communicates through a wireless network rather than typical point-to-point cable connections. Lower maintenance costs, greater flexibility, and increased safety are the main WNCS advantages, so as a result, it has attracted a lot of researchers. Nevertheless, time delays and packet losses in wireless data transmission are classified as complicated problems, which impair WNCS output accuracy and may influence the overall system stability. Integer-Order PI-PD (PI-PD) and Fractional-Order PI-PD (FOPI-FOPD) controllers are proposed to reduce the impact of the control signal transmission's time delay and improve system performance. Matlab Simulink and True-time simulator are used to simulate the WNCS, and ZigBee protocol is used in transceiving the control signal between the controller and the system. Rotary Inverted Pendulum (RIP) acted as the controller's objective. The Grey Wolf Optimization (GWO) technique is utilized to evaluate the best controller parameters. Xbee S2 modules are used to implement the signal transmission process over ZigBee protocol. The FOPI-FOPD controller outperforms the PI-PD controller in the simulation and experimental results in decreasing the influence of time delay on system stability

Анализ параметров нелинейности и фазовых соотношений аналоговых окончаний телекоммуникационных сетей

The main calculation ratios for the characteristics of nonlinearity are presented: amplitude characteristic, dynamic range and coefficients of nonlinear distortions (harmonic coefficients). The examples show the order of their calculation and analysis. The article indicates that due to the diversity of reception and transmission of multi-channel transfer systems measuring the phase-frequency characteristic is extremely difficult. As a result, approaches to normalising the group transmission time are proposed. The article presents that the value deviation of the group signal transmission time in the channel from the value measured at a frequency of 1.9 kHz in a simple voice frequency channel is normalised, as well as the relative group transmission time regarding the minimum value for various types of endings built on the basis of digital transmission systems

Stability control of cyclic signal transmission in high power drive circuit

In order to reduce the influence of noise on the stability of cyclic signal transmission and improve the effect of signal control, a method to control the stability of cyclic signal transmission of high-power driving circuit is proposed. The main components of the driving circuit and the characteristics of its cyclic signal are analyzed. According to the analysis results, a cyclic signal transmission interference detection module is designed, and the source interference detection is realized by using this module; Considering the electromagnetic influence of the circulating signal and the power part, the optocoupler isolation method is used to isolate the circulating signal; On the basis of detecting and isolating the transmission interference of circulating signal, the primary pulse width modulation signal and the secondary fault feedback signal are modulated by a single pulse transformer to realize the bidirectional transmission design of circulating signal; The internal optimization design of the high-power drive circuit is carried out, the error correction of the signal transmission stability control is carried out by using the linearized small interference error compensation method, and the empirical mode decomposition method is applied to the cyclic signal analysis of the high-power drive circuit to solve the cross term interference problem in the cyclic signal analysis. Finally, the stability control of cyclic signal transmission is realized by using double quasi PR controller. The experimental results show that the signal transmission time of this method is short, the minimum value is less than 0.5 s, the signal transmission deviation is only 0.22, the transmission rate is high, the signal transmission deviation is small, and the signal waveform is stable, which fully shows that its control effect is good.

Optimization of Ultrasonic Positioning Accuracy by Hybrid Algorithm of Time Compensation Factor and Kalman Filter

In the ultrasonic positioning system, the positioning system has a certain delay due to the sequential ranging at the ultrasonic receiver, the system's decoding time and the signal transmission time, which has a great impact on the positioning accuracy. The solution is to set a time compensation factor for the speed of the object to be positioned and the positioning time of the system unit to compensate for the error, so as to achieve the same positioning accuracy when the object to be positioned is stationary; then the Kalman filter algorithm is used to correct the positioning results at different speeds, so that the positioning accuracy of the ultrasonic positioning system can be further improved. The simulation results show that the positioning accuracy can be stabilized within 2cm at a certain speed, which is able to move and position the object to be positioned at a certain speed; finally, the experiments are conducted using the Arduino Uno as the core positioning system, and the experimental results verify the simulation results and show that the solution can The experimental results verify the simulation results and show that the solution is able to improve the positioning accuracy of moving objects, especially when the object to be positioned moves at a constant speed, the positioning accuracy tends to be stable, and the object to be positioned with a certain speed can be positioned well.

Temporal differences between load and movement signal integration in the sensorimotor network of an insect leg.

Nervous systems face a torrent of sensory inputs, including proprioceptive feedback. Signal integration depends on spatially and temporally coinciding signals. It is unclear how relative time delays affect multimodal signal integration from spatially distant sense organs. We measured transmission times and latencies along all processing stages of sensorimotor pathways in the stick insect leg muscle control system, using intra- and extracellular recordings. Transmission times of signals from load-sensing tibial and trochanterofemoral campaniform sensilla (tiCS, tr/fCS) to the premotor network were longer than from the movement-sensing femoral chordotonal organ (fCO). We characterized connectivity patterns from tiCS, tr/fCS, and fCO afferents to identified premotor nonspiking interneurons (NSIs) and motor neurons (MNs) by distinguishing short- and long-latency responses to sensory stimuli. Functional NSI connectivity depended on sensory context. The timeline of multisensory integration in the NSI network showed an early phase of movement signal processing and a delayed phase of load signal integration. The temporal delay of load signals relative to movement feedback persisted into MN activity and muscle force development. We demonstrate differential delays in the processing of two distinct sensory modalities generated by the sensorimotor network and affecting motor output. The reported temporal differences in sensory processing and signal integration improve our understanding of sensory network computation and function in motor control.NEW & NOTEWORTHY Networks integrating multisensory input face the challenge of not only spatial but also temporal integration. In the local network controlling insect leg movements, proprioceptive signal delays differ between sensory modalities. Specifically, signal transmission times to and neuronal connectivity within the sensorimotor network lead to delayed information about leg loading relative to movement signals. Temporal delays persist up to the level of the motor output, demonstrating its relevance for motor control.

Relay Selection for Capacity Increase in Underwater Acoustic Sensor Network.

In long distance sensor nodes, propagation delay is the most crucial factor for the successful transmission of data packets in underwater acoustic sensors networks (UWAs). Therefore, to cope with the problem of propagation delay, we propose examining and selecting the best relay node (EBRN) technique based on checking the eligibility and compatibility of RN and selecting the best RN for UWAs. In the EBRN technique, the source node (S) creates a list of the best RNs, based on the minimum propagation delay to the midpoint of a direct link between S and the destination node (D). After that, the S attaches the list of selected RNs and transmit to the D along with data packets. Finally, from the list of selected RNs, the process of retransmission is performed. To avoid collision among control packets, we use a backoff timer that is calculated from the received signal strength indicator (RSSI), propagation delay and transmission time, whereas the collision among data packets is avoided by involving single RN in a particular time. The performance of the proposed EBRN technique is analyzed and evaluated based on throughput, packet loss rate (LR), packet delivery ratio (PDR), energy efficiency, and latency. The simulation results validate the effectiveness of the proposed EBRN technique. Compared with the existing schemes such as underwater cooperative medium access control (UCMAC) and shortest path first (SPF), the proposed EBRN technique performs remarkably well by increasing the throughput, PDR, and energy efficiency while decreasing the latency and LR in UWAs.

Research on Ultrasonic Localization Method of Moving Objects Based on Improved TOA Algorithm

In the process of ultrasonic positioning of moving objects, a position algorithm TOA is optimized and improved due to the problem of delay caused by sequential ranging of the sequential ranging of the ultrasonic transmitter and receiver, the system’s solving time, and the signal transmission time. By setting an error compensation factor for the velocity of the object to be located and the unit positioning time of the system, the error is compensated to achieve the same positioning accuracy when the object to be located is stationary. The simulation results show that the positioning accuracy can be stabilized within 3 cm at a certain speed, and the positioning can be performed well for objects to be positioned with a certain speed.

A soft sensor modeling method with dynamic time-delay estimation and its application in wastewater treatment plant

Time-delay estimation is an important step for soft sensor modeling. In practical industrial process, the transportation time of materials and the transmission time of signals are fluctuating, and the traditional static time-delay estimation (STDE) methods can no longer accurately extract the dynamic time-delay characteristics. In this paper, a weighted relevance vector machine model based on dynamic time-delay estimation (DTDE-WRVM) is proposed to realize the dynamic characteristic extraction and quality variable prediction. Firstly, a static delimitation-dynamic update (SD-DU) strategy is adopted for dynamic time-delay estimation, where the dynamic time-delay variation range can be determined based on the fuzzy curve analysis (FCA) method, and the dynamic time-delay characteristics between process variables can be captured based on improved sliding time window. Then, a weighted soft sensor model is established by setting the weights for the variables with different time-delays according to their importance to the output variable. Finally, a numerical example and a wastewater treatment plant (WWTP) case are studied to demonstrate the effectiveness of the DTDE-WRVM model. With the proposed method, the prediction accuracy of WWTP is significantly improved, e.g., the value of the root-mean-square error decreases by 55.7% from 0.0972 to 0.0431.

Wireless Power and Signal Transmission Based on Time-sharing Multiplexing for WPT System

In wireless power transfer (WPT) systems, wireless transmission of signals is particularly important for some practical applications. An effective approach of signal and energy synchronous transmission based on time-sharing multiplexing of the same coupled coil is proposed in this paper. Using the same coupled coil, the signal transmission is carried on when interruption of power transmission happens. To realize the proposed method, the relationship between power transmission time and signal transmission time is provided to obtain the optimal transmission process of the power and signal. Besides, the power transmission efficiency (PTE) and the signal transmission rate (STR) are analyzed. Finally, the effectiveness of the proposed method is verified by the experiment.

Different Characteristics of Radar Signal Attenuation Depending on Concrete Condition of Bare Bridge Deck

This paper examined the attenuation method, which is used abroad, to derive a method to evaluate the condition of bare concrete bridge decks using ground penetrating radar (GPR) technology. For this purpose, 12 GPR surveys of 10 bridge decks in public service from the beginning of its service to 25 years of service were carried out to examine the attenuation characteristics of GPR signals under various concrete conditions. The survey revealed the signal below the top rebar of concrete bridge deck under the condition of using de-icing chlorides for snow removal was not clear. Therefore, using the receiving wave signal from top rebar was reasonable when attenuation of GPR signal was to be used for bridge deck evaluation. Examining the signal attenuation by the condition of concrete, dispersion of the attenuated signal was overall large in the initial performance period. However, since this is not due to deterioration, exclusion of the large dispersion from the evaluation of bridge deck condition was desirable. The attenuation size was linearly proportional to its two way travel time (signal transmission time), i.e., the depth of the top rebar, in a sound bridge deck. Also, the dispersion of the attenuation was small and symmetric to the linear regression line. If the bridge deck was maintained adequately, the linear regression correlation was also maintained similarly for the next several years. However, if deterioration occurred to be accompanied by increased attenuation and dispersion, correlation coefficient of the linear regression line declined. Nonetheless, the upper value of the attenuation representing sound concrete condition was still tended to be linearly proportional to two way travel time. Since the attenuation quantity could result in considerable debilitation just by the construction error, it is necessary to deal with the depth-error of top rebar for evaluating the concrete condition by using the GPR signal attenuation. Calibration was carried out by deriving a linear regression line for the signal two way travel time and the upper 90th percentile values of the attenuation obtained from the top bar position of the bridge and then removing it from the total attenuation.

A Link Distance Division Based Time Division Multiple Access Protocol for Directional Aeronautical Relay Networks

In directional aeronautical relay networks, the airplane relay explores the advantages of the directional antenna, in terms of long transmission distance, low transmission power, small interference range and so on, to help the ground nodes transmitting data. However, data transmission delay extension problem occurs when the distance of the transmission link extends, where the wireless signal transmission time approximates the data transmission time such that the wireless signal transmission time cannot be omitted. To address the data transmission delay extension problem, a link distance division based time division multiple access protocol, LDD-TDMA, is proposed in this paper. Different from the traditional TDMA protocol, where the time slots are equal and are determined by the longest transmission link, the length of the time slots are different and are determined by different transmission links. Furthermore, the concept of communication coverage ring is proposed where the nodes located in the same ring communicate with the relay utilizing the same time slot length. The relationships between the number of rings, the ring radius and the transmission range of the LDD-TDMA are modelled and derived as a closed formula, where the ring radius are optimized such that the gain is maximized. Simulation results show that LDD-TDMA outperforms TDMA by 13.37% when the transmission range is 200 km and the ring number is 4.

Global Mittag-Leffler Synchronization of Fractional-Order Neural Networks With Time-Varying Delay via Hybrid Sliding Mode Control

In this paper, the global Mittag-Leffler synchronization (GMLS) for fractional-order neural networks with time-varying delay (FNNTVD) is studied based on hybrid sliding mode control (HSMC). First, a class of sliding surface is designed to study the dynamic behavior of FNNTVD by using the integer order Lyapunov direct method, which resolves the problem that the activation function of FNNTVD cannot be applied to the construction of Lyapunov function in the previous literature. Then, a new HSMC with the fixed signal transmission time delay is developed to ensure GMLS of FNNTVD. Next, based on Lyapunov direct method and the designed HSMC, some criteria are put forward to achieve GMLS of FNNTVD. Finally, two examples are given to verify the effectiveness of the proposed synchronization criteria for FNNTVD.

Indoor localization using time difference of arrival with UWB signals and unsynchronized devices

Indoor location using radio frequency (RF) signals has been traditionally focused mainly on RSSI and fingerprint techniques, because methods based on time of arrival (ToA) or time difference of arrival (TDoA) were not suitable for measuring short distances. However, the release of the IEEE 802.15.4a standard, the emergence of commercial ultra wide band (UWB) transceivers that are compliant to this norm and the integration of high frequency oscillators have permitted the design of more accurate indoor localization systems using the RF signal transmission time. In this paper, we propose an indoor localization system based on TDoA for UWB. The method implements an only one way transmission ranging algorithm to measure the time differences of arrival. This feature reduces the complexity of the tags to be localized, since tags only have to transmit but not to receive packets, and allows the implementation of low power applications that are controlled by the tag activity and the system requirements. On the other hand, the proposed localization algorithm does not require a permanent time synchronization of anchors’ clocks and the estimation of the time offsets is performed jointly with the position computation. For the estimation of the time offsets, the algorithm considers the different clock skews of the anchors’ oscillators and compensates the measured offsets accordingly. The proposed algorithm has been evaluated in two different scenarios with real devices. Results show an improvement in terms of localization accuracy that the algorithm allows compared to fingerprinting methods.

Wide-area damping state feedback and output feedback controller design strategy considering time delays and actuator saturation based on parametric Lyapunov theory

Remote signal transmission time delays are the major factors to affect the performance of wide-area damping controller (WADC) and even deteriorate stability of large-scale power system. If the physical structure and the mathematical model of the system are different, the method of mathematically dealing with time delay is not the same. From the perspective of mathematical application engineering, there are two main ways to deal with the communication time delay: linear matrix inequalities (LMI) theory and conventional time-delay predictive compensation theory. Traditional time delay damping controller based on linear matrix inequalities (LMI) suffers relatively large conservatism and complexity. Traditional time delay damping controller based on time delay compensation has no clear relation between the control parameter and the time delay. On the other hand, the saturation of actuator leads to the deterioration of control performance and even threat system stability. The existing methods for saturation are negative feedback anti-saturation after the actuator is saturated, which is an afterwards control and it is difficult to well eliminate the influence of saturation. In this paper, a novel design strategy for wide-area time-delay damping controller based on parametric Lyapunov theory is derived. The explicit expression of the controller parameter value associated with the time delay is determined. This strategy can deal with arbitrary large time-vary delay theoretically and have extremely low controller dimension, which makes it have potential capability to be applied in large-scale inter-connected power systems. The control strategy is determined according to the system stability original definition (The system energy function is finite and positive and its first derivative is negative), which avoids complex matrix inequalities cyclic solution and reduces the conservatism of the controller. Moreover, it can directly give simple and explicit control law and specific control parameters, which enable this method to adjust its parameters online according to the exact time delay obtained by GPS. In the design process, the saturation characteristics of the actuator are taken into account in the linearization model of the closed-loop system. This makes it very adaptable to actuator saturation, so that the proposed design strategy can ensure the small signal stability of the closed-loop system considering time delays and actuator saturation. Case study is undertaken based on a New England ten-machine 39-bus power system, which stands for a large scale power system to verify the feasibility and effectiveness of the proposed design strategy. Compared with the free weight matrix damping controller (FWMC), which is a kind of LMI-based design strategy with excellent performance, the advantages and superiority of the proposed control strategy are verified. The proposed design strategy based on state feedback and output feedback has better control performance than FWMC.

Heat flow due to time-delayed feedback

Many stochastic systems in biology, physics and technology involve discrete time delays in the underlying equations of motion, stemming, e. g., from finite signal transmission times, or a time lag between signal detection and adaption of an apparatus. From a mathematical perspective, delayed systems represent a special class of non-Markovian processes with delta-peaked memory kernels. It is well established that delays can induce intriguing behaviour, such as spontaneous oscillations, or resonance phenomena resulting from the interplay between delay and noise. However, the thermodynamics of delayed stochastic systems is still widely unexplored. This is especially true for continuous systems governed by nonlinear forces, which are omnipresent in realistic situations. We here present an analytical approach for the net steady-state heat rate in classical overdamped systems subject to time-delayed feedback. We show that the feedback inevitably leads to a finite heat flow even for vanishingly small delay times, and detect the nontrivial interplay of noise and delay as the underlying reason. To illustrate this point, and to provide an understanding of the heat flow at small delay times below the velocity-relaxation timescale, we compare with the case of underdamped motion where the phenomenon of “entropy pumping” has already been established. Application to an exemplary (overdamped) bistable system reveals that the feedback induces heating as well as cooling regimes and leads to a maximum of the medium entropy production at coherence resonance conditions. These observations are, in principle, measurable in experiments involving colloidal suspensions.

Transmission of Highly Stable Time Signals Over Optical Fiber Communication Lines

We present the results of investigations of an installation aimed at the transmission of highly stable 1 PPS time signals from the hydrogen time and frequency standard over a 150 km optical fiber communication line with the use of active electronic compensation of time delays. The error (mean-square deviation) of transmission of time signals does not exceed 80 psec on the daily interval of averaging. The installation enables us to guarantee the synchronization of the time scales of remote time and frequency standards included in the primary and secondary standards of time and frequency units.

Central Heating System Constrained Control with Input Delay Based on Neural Networks

An output constrained control with input delay is proposed for a central heating system. Due to the delay of signal transmission and valves opening time, an input delay is considered into the system and an auxiliary system is employed to handle this issue by converting the delayed input into a delay-free one. Moreover, to ensure the output supply water temperature within a limited range, Barrier Lyapunov algorithm is involved to achieve desired control accuracy. Finally, external disturbance and model uncertainty are incorporated into the dynamic system and neural networks (NN) are trained in an online fashion for the compensation. The stability of the control system is guaranteed through rigorous Lyapunov analysis and the excellent control performance over traditional PID control is demonstrated via numerical simulation study.

The Existence Question for Maximum-Likelihood Estimators in Time-of-Arrival-Based Localization

We investigate the existence question for maximum-likelihood estimation for a time-of-arrival-based localization problem where the signal transmission time is unknown. We have previously shown that for some inputs, the maximum-likelihood estimator (MLE) does not exist. Here we go further: under a genericity condition, we prove that there is nonzero probability that the MLE does not exist. Besides this theoretical result, we draw attention to practical issues with finding the estimator using local optimization techniques.