Ultra-wideband Signals Research Articles

Galileo and BeiDou AltBOC Signals and Their Perspectives for Ionospheric TEC Studies.

For decades, GNSS code measurements were much noisier than phase ones, limiting their applicability to ionospheric total electron content (TEC) studies. Ultra-wideband AltBOC signals changed the situation. This study revisits the Galileo E5 and BeiDou B2 AltBOC signals and their potential applications in TEC estimation. We found that TEC noises are comparable for the single-frequency AltBOC phase-code combination and those of the dual-frequency legacy BPSK/QPSK phase combination, while single-frequency BPSK/QPSK TEC noises are much higher. A two-week high-rate measurement campaign at the ACRG receiver revealed a mean 100 sec TEC RMS (used as the noise proxy) of 0.26 TECU, 0.15 TECU, and 0.09 TECU for the BeiDou B2(a+b) AltBOC signal and satellite elevations 0-30°, 30-60°, and 60-90°, correspondingly, and 0.22 TECU, 0.14 TECU, and 0.09 TECU for the legacy B1/B3 dual-frequency phase combination. The Galileo E5(a+b) AltBOC signal corresponding values were 0.25 TECU, 0.14 TECU, and 0.09 TECU; for the legacy signals' phase combination, the values were 0.19 TECU, 0.13 TECU, and 0.08 TECU. The AltBOC (for both BeiDou and Galileo) SNR exceeds those of BPSK/QPSK by 7.5 dB-Hz in undisturbed conditions. Radio frequency interference (the 28 August 2022 and 9 May 2024 Solar Radio Burst events in our study) decreased the AltBOC SNR 5 dB-Hz more against QPSK SNR, but, due to the higher initial SNR, the threshold for the loss of the lock was never broken. Today, we have enough BeiDou and Galileo satellites that transmit AltBOC signals for a reliable single-frequency vTEC estimation. This study provides new insights and evidence for using Galileo and BeiDou AltBOC signals in high-precision ionospheric monitoring.

Characteristics of a distributed location system with an ultra-wideband probing signal

Using numerical simulations, the characteristics of an ultra-wideband distributed probing system for various network configurations are investigated and its optimal configuration is proposed. It is shown that the range and transverse coordinate resolutions in this case are determined by the characteristics of the probing pulse and can reach 2—3 centimeters, which corresponds to an effective angular resolution of several tens of microradians.

Development of the algorithm for determining the thickness of the structural layers of the non-rigid pavement and searching for local inclusions using sub-surface georadiolocation methods

Problem. The article is part of the authors' research in the field of road construction using GPR technologies. Ensuring a certain level of pavement reliability on highways requires the development of methods and means for continuous information acquisition and processing in real time, taking into account the parameters of structural heterogeneity, heterogeneity of physical and mechanical parameters of structures, as well as their changes over time. The solution of this problem is limited by the complexity of tasks of obtaining and interpreting the data of subsurface sensing and the associated errors in determining the parameters of structures, imperfection of methods of flaw detection of structures with subsurface inhomogeneities, multifactorial tasks of estimation of physical and mechanical parameters of multicomponent materials. Goal. Improving the accuracy and reliability of determining the boundaries of layers of non-rigid pavement structure, which have a low level of electrodynamic contrast due to interpenetration of layer materials or changes in their physical and mechanical properties. The solution of this problem is connected with the development of a method of obtaining reflected GPR signals and the improvement of algorithms for their processing. Methodology. The development of methods for the analysis of the electromagnetic field with a variable state of polarization makes it possible to assess the localization of violations of the integrity of the pavement structure at a qualitatively new level and allows the positioning of small inclusions even with a slight contrast in the dielectric constant. The proposed method of recording the reflection of an ultra-wideband GPR pulse signal at different polarizations is implemented by measuring the reflected signal from a metal sheet at oblique incidence and parallel polarization, recording the reflected pulse at perpendicular polarization, followed by measuring the reflection coefficient from the structure of the nonrigid pavement under study at parallel and perpendicular polarization. The electrophysical parameter recovery procedure is based on the solution of inverse scattering problems and ensures the accuracy of determining the low-contrast boundaries of the pavement structure and increases the accuracy of positioning subsurface heterogeneities. GPR signal processing algorithms are based on procedures for analyzing their polarization state, which allows determining the geometric parameters of subsurface heterogeneities. Practical value. The combination of the obtained results increases the accuracy and reliability of the results of GPR diagnosis and assessment of the condition of non-rigid pavement based on the most complete and reliable information about the subsu

Quasi-likelihood estimation of the arrival time of an ultra-wideband quasi-radio signal with unknown amplitude and initial phase

The problem of estimating the time of arrival of a signal is relevant in the fields of radio and hydrolocation, radio astronomy, remote observation and sensing, etc. The useful signal is often described by a quasi-deterministic function of time, which can be regular or discontinuous. In recent years, problems of processing ultra-wideband signals have been of significant interest. Among the many UWB signals, it is customary to distinguish a separate class of ultra-wideband quasi-radio signals, the structure of which is similar to the structure of narrowband radio signals, but the condition of relative narrowband for which may not be met. Algorithms for estimating the arrival time of regular ultra-wideband quasi-radio signals have been studied in the existing literature. In this case, the synthesis and analysis of an algorithm for quasi-plausible estimation of the arrival time of a discontinuous signal of finite duration and arbitrary shape is of practical interest. The purpose of the work is to synthesize and analyze a quasi-likelihood algorithm for estimating the time of arrival of a discontinuous ultra-wideband quasi-radio signal with an unknown amplitude and initial phase against a background of white Gaussian noise. In this work, closed asymptotically exact expressions for the bias and scattering of the estimate are obtained, which make it possible to study the effectiveness of the synthesized algorithm, as well as compare its effectiveness with special cases of signal models - narrowband and wideband radio and video signals. The results of the study make it possible to determine losses in the accuracy of estimation the signal arrival time due to a priori ignorance of the initial phase and shape of the modulating function of the signal. Depending on the required accuracy of estimate the time of arrival of an ultra-wideband quasi-radio signal, it is possible to optimize the parameters of the transmitted signals and determine the limits of applicability of the designed radio system.

Terminological features of the concept of signal-to-noise ratio when processing ultra-wideband signals

Currently, when processing various signals and studying various types of receivers, there are many definitions for one of the basic characteristics of radio systems – signal-to-noise ratio (SNR). At the same time, the terminological feature of the SNR concept is that any definition within the framework of a locally solvable signal processing problem is correct. However, difficulties arise when comparing the effectiveness of one algorithm with another, when studying different signal models, or when measuring the SNR in different parts of the receiving system. Some researchers ignore this fact due to the apparent absolute clarity of this issue, which leads to incorrect comparison of various processing algorithms or the formation of obviously unrealizable requirements for the designed equipment. In each locally solved problem, the determination of SNR will be individual, and comparison of efficiency at a fixed SNR must be carried out with mandatory scaling of signal energies depending on the formulation of the problem. This paper systematizes the terminological features of the SNR concept in order to ensure uniformity of its application by researchers and engineers. The purpose of the work is to systematize the definition of SNR for various signal models and conditions for measuring this characteristic, to specify the results in terms of terminological features of UWB signal processing and to propose a model for recalculating the SNR depending on the stage of the signal transmission and reception process. The paper examines the determination of SNR at the input and output of optimal and matched filters, at the output of optimal receivers operating under conditions of various a priori uncertainties, as well as when processing various classes of signals. By determining the SNR at the output of the matched filter and the SNR at the output of the maximum likelihood receiver for a rectangular video pulse, the discrepancy between the signal energies, all other things being equal, is clearly demonstrated. A connection has been established between the SNR when processing ultra-wideband signals at the output of the optimal receiver with similar devices for processing other types of signals, as well as with the SNR at the input of the receiving system. Systematization of the terminological features of the SNR concept will allow theoretical researchers to choose SNR definitions that are as close as possible to practical applications when analyzing the effectiveness of synthesized algorithms, and will allow practicing engineers to correctly interpret the results of theoretical calculations when developing or testing radio engineering systems.

3D indoor area recognition for personnel security using integrated UWB and barometer approach

Real-time location tracking is essential for personal security in industrial scenes, e.g. monitoring worker safety in power substations. Ultra wideband (UWB) technology is suitable for indoor positioning thanks to its high penetration capability, high ranging accuracy and low power consumption. However, UWB based trilateration positioning requires high workload for field deployment of base stations. Indoor complex topology results in multipath and non-line of sight (NLOS) conditions of UWB signals, and degrades the positioning performance in terms of accuracy and reliability. This paper proposes a three-dimensional (3D) area recognition solution by integrating UWB time of flight (TOF) ranging and barometer measurements. The proposed solution utilizes a multi-tier distributed joint probabilistic inference model, which accomplishes the indoor 3D area recognition exploiting multiple clustering and prediction algorithms of machine learning. The field experiments showed that the proposed method can achieve an accuracy of 3D area recognition of more than 99.2%. The proposed method improves the computing efficiency by 93%. The errors of improved differential barometric height estimation method are less than 1 m, which means a success rate of 100% for floor identification, given a floor separation of 3–4 m. The proposed solution is suitable for personnel security applications of industrial scenes, which requires reliable real-time area information rather than just coordinates.

UVIO: Adaptive Kalman Filtering UWB-Aided Visual-Inertial SLAM System for Complex Indoor Environments

Precise positioning in an indoor environment is a challenging task because it is difficult to receive a strong and reliable global positioning system (GPS) signal. For existing wireless indoor positioning methods, ultra-wideband (UWB) has become more popular because of its low energy consumption and high interference immunity. Nevertheless, factors such as indoor non-line-of-sight (NLOS) obstructions can still lead to large errors or fluctuations in the measurement data. In this paper, we propose a fusion method based on ultra-wideband (UWB), inertial measurement unit (IMU), and visual simultaneous localization and mapping (V-SLAM) to achieve high accuracy and robustness in tracking a mobile robot in a complex indoor environment. Specifically, we first focus on the identification and correction between line-of-sight (LOS) and non-line-of-sight (NLOS) UWB signals. The distance evaluated from UWB is first processed by an adaptive Kalman filter with IMU signals for pose estimation, where a new noise covariance matrix using the received signal strength indicator (RSSI) and estimation of precision (EOP) is proposed to reduce the effect due to NLOS. After that, the corrected UWB estimation is tightly integrated with IMU and visual SLAM through factor graph optimization (FGO) to further refine the pose estimation. The experimental results show that, compared with single or dual positioning systems, the proposed fusion method provides significant improvements in positioning accuracy in a complex indoor environment.

1D-CLANet: A Novel Network for NLoS Classification in UWB Indoor Positioning System

Ultra-Wideband (UWB) technology is crucial for indoor localization systems due to its high accuracy and robustness in multipath environments. However, Non-Line-of-Sight (NLoS) conditions can cause UWB signal distortion, significantly reducing positioning accuracy. Thus, distinguishing between NLoS and LoS scenarios and mitigating positioning errors is crucial for enhancing UWB system performance. This research proposes a novel 1D-ConvLSTM-Attention network (1D-CLANet) for extracting UWB temporal channel impulse response (CIR) features and identifying NLoS scenarios. The model combines the convolutional neural network (CNN) and Long Short-Term memory (LSTM) architectures to extract temporal CIR features and introduces the Squeeze-and-Excitation (SE) attention mechanism to enhance critical features. Integrating SE attention with LSTM outputs boosts the model’s ability to differentiate between various NLoS categories. Experimental results show that the proposed 1D-CLANet with SE attention achieves superior performance in differentiating multiple NLoS scenarios with limited computational resources, attaining an accuracy of 95.58%. It outperforms other attention mechanisms and the version of 1D-CLANet without attention. Compared to advanced methods, the SE-enhanced 1D-CLANet significantly improves the ability to distinguish between LoS and similar NLoS scenarios, such as human obstructions, enhancing overall recognition accuracy in complex environments.

UWB/MEMS IMU integrated positioning method based on NLOS angle discrimination and MAP constraints

A dynamic nonline-of-sight (NLOS) angle discrimination method is proposed to address the insufficiency of current research on the NLOS error characteristics of ultrawideband (UWB) signals in dynamic environments as well as the problem that UWB signals frequently suffer from occlusion, leading to poor or impossible localization. The experimental results indicate that the degree of UWB signal occlusion increases as the horizontal angle decreases, and when the horizontal angle is less than 167°, the UWB ranging error is so large that no ranging value is available. On this basis, a tightly integrated UWB/MEMS IMU positioning algorithm incorporating NLOS angle discrimination and map constraints is proposed; it employs horizontal angles to discriminate UWB ranging values in NLOS environments in accordance with the dynamic NLOS characteristics of UWB signals to assign better weights to UWB observations. Through comparative analysis of the results from both groups of experiments, the algorithm achieved northward, eastward, and planar positioning errors of 0.189 m and 0.126 m, 0.119 m and 0.134 m, 0.243 m and 0.211 m, respectively. Compared to the Robust Adaptive Kalman Filtering algorithm, the positional accuracy in the plane improved by 22.9% and 28.5%, respectively.

Modulated Radio Frequency Stealth Waveforms for Ultra-Wideband Radio Fuzes.

The increasingly complex electromagnetic environment of modern warfare and the proliferation of intelligent jamming threaten to reduce the survival rate of radio fuzes on the battlefield. Radio frequency (RF) stealth technology can fundamentally improve the anti-interception and reconnaissance capabilities of radio fuzes, thereby lessening the probability of them being intercepted, recognized, and jammed by the enemy. In this paper, an RF stealth waveform based on chaotic pulse-position modulation is proposed for ultra-wideband (UWB) radio fuzes. Adding a perturbation signal based on the Tent map ensures that the chaotic sequences have sufficiently long periods despite hardware byte limitations. Measuring the approximate entropy and sequence period shows that the Tent map with the addition of perturbation signals can maintain good randomness under byte constraints, closely approximating the Tent map with ideal precision. Simulations verify that the proposed chaotic mapping used to modulate the pulse position of an ultra-wideband radio fuze signal results in superior detection, anti-interception, and anti-jamming performance.

Detection of phase modulation disorder when processing a sequence of ultra-wideband quasi-radio signals against a background of white Gaussian noise

In conditions of a complex electromagnetic environment in communication and data transmission systems, a change in the type of modulation occurs when one or more signal parameters change abruptly, therefore the task of determining the type of signal modulation can be reduced to the task of detecting a disorder, that is, detecting the fact of a change in the type of modulation of the signal and estimation of the disorder time. The purpose of the work is to synthesize an algorithm for detecting phase modulation disorder when processing a sequence of ultra-wideband quasi-radio signals with unknown amplitude and initial phase against a background of white Gaussian noise and to analyze the effectiveness of the resulting algorithm based on the results of statistical modeling. The work synthesizes an algorithm for detecting a phase modulation disorder of a received sequence of ultra-wideband quasi-radio signals against a background of white Gaussian noise. To analyze the effectiveness of the resulting algorithm, statistical modeling of algorithm for detecting a phase modulation disorder is carried out. The dependences of the probability of detection of a disorder on the signal-to-noise ratio and the length of the sequence of received signals at a fixed moment of disorder are obtained. A comparison of the detection characteristics of phase modulation disorder of ultra-wideband quasi-radio signals and narrowband radio signals is made. It is shown that when a low-order phase modulation disorder is detected, the required values of the probability of detection are achieved at low signal-to-noise ratios, while with an increase in the modulation order and the use of its modifications, the efficiency indicators of the algorithm will deteriorate. The introduction of algorithms for detecting a disorder in radio engineering applications will allow optimizing synchronization algorithms and adaptation to interference conditions with a concomitant change in the type of modulation, as well as reducing the amount of transmitted service information in telecommunication systems.

Location-Aware Range-Error Correction for Improved UWB Localization.

In this paper, we present a novel localization scheme, location-aware ranging correction (LARC), to correct ranging estimates from ultra wideband (UWB) signals. Existing solutions to calculate ranging corrections rely solely on channel information features (e.g., signal energy, maximum amplitude, estimated range). We propose to incorporate a preliminary location estimate into a localization chain, such that location-based features can be calculated as inputs to a range-error prediction model. This way, we can add information to range-only measurements without relying on additional hardware such as an inertial measurement unit (IMU). This improves performance and reduces overfitting behavior. We demonstrate our LARC method using an open-access measurement dataset with distances up to 20 m, using a simple regression model that can run purely on the CPU in real-time. The inclusion of the proposed features for range-error mitigation decreases the ranging error 90th percentile (P90) by 58% to 15 cm (compared to the uncorrected range error), for an unseen trajectory. The 2D localization P90 error is improved by 21% to 18 cm. We show the robustness of our approach by comparing results to a changed environment, where metallic objects have been moved around the room. In this modified environment, we obtain a 56% better P90 ranging performance of 16 cm. The 2D localization P90 error improves as much as for the unchanged environment, by 17% to 18 cm, showing the robustness of our method. This method evolved from the first-ranking solution of the 2021 and 2022 International Conference on Indoor Position and Indoor Navigation (IPIN) Competition.

UWB-enabled Sensing for Fast and Effortless Blood Pressure Monitoring

Blood Pressure (BP) is a critical vital sign to assess cardiovascular health. However, existing cuff-based and wearable-based BP measurement methods require direct contact between the user's skin and the device, resulting in poor user experience and limited engagement for regular daily monitoring of BP. In this paper, we propose a contactless approach using Ultra-WideBand (UWB) signals for regular daily BP monitoring. To remove components of the received signals that are not related to the pulse waves, we propose two methods that utilize peak detection and principal component analysis to identify aliased and deformed parts. Furthermore, to extract BP-related features and improve the accuracy of BP prediction, particularly for hypertensive users, we construct a deep learning model that extracts features of pulse waves at different scales and identifies the different effects of features on BP. We build the corresponding BP monitoring system named RF-BP and conduct extensive experiments on both a public dataset and a self-built dataset. The experimental results show that RF-BP can accurately predict the BP of users and provide alerts for users with hypertension. Over the self-built dataset, the mean absolute error (MAE) and standard deviation (SD) for SBP are 6.5 mmHg and 6.1 mmHg, and the MAE and SD for DBP are 4.7 mmHg and 4.9 mmHg.

Improving the precision of time synchronization protocols in ultra-wideband networks estimating the time of flight of the radio signal

Modern applications of wireless sensor networks such as the conduction of collaborative tasks, the distributed detection of events or the alignment of data samples gathered by several nodes, require a precise time coordination of the nodes composing the network. Ultra Wide Band (UWB) technology has enabled the development of precise time synchronization protocols. The intrinsic properties of this technology allow an accurate estimation of the time of flight (ToF) of the radio signal in scenarios covering short distances. The integration of UWB transceivers in Wireless Sensor Networks (WSN) nodes is nowadays possible due to the availability of commercial chips implementing this technology. This combination facilitates the development of accurate time synchronization protocols that establish a global common clock throughout the network. In this context, the main contribution of this work is a protocol that allows the synchronization of the local clocks of these nodes with a common global reference kept in the master node. The master periodically broadcasts synchronization packets to keep the rest of the nodes synchronized. However, since the precision achieved in the time synchronization of the local clocks with UWB technology is comparable to the ToF of the RF signal for distances in the order of several meters, some considerations to estimate this delay are required. In this paper, a new algorithm is proposed that performs the estimation of the ToF of the UWB signal as well as the implementation of linear models to synchronize the local clocks of the network node, eliminating the dependence on the ToF. The experiments conducted with real devices reveal that an accuracy of tens of nanoseconds can be achieved regardless of the distance separating the network nodes.

Broadband four-shoulder sine antenna of radio monitoring and direction finding equipment with a note system of two orthogonally combined printed resistance transformers

Problem statement. The article presents material on the development of antennas used in radio monitoring and radio direction finding equipment of electronic warfare equipment. The basic requirements for the design and characteristics of antennas of radio monitoring and direction finding equipment are presented. Aspects of the fundamentals of the development of a four-arm broadband antenna powered by two orthogonally combined printed resistance transformers, which has not been used before, for the possibility of controlling polarization, are considered, the results of modeling the developed antenna are presented and recommendations for its use in the antenna array are given. Purpose. To develop a small-sized antenna that allows to increase the efficiency of the operation of radio direction finding and radio monitoring complexes in an ultra-wide frequency band, with a special power supply system of two orthogonally combined printed resistance transformers for the possibility of implementing polarization control. Results. Based on the methods of electrodynamic modeling, computational methods of technical electrodynamics, methods of full–scale experimental measurements of antenna characteristics and methods of computer processing of data of full-scale experimental measurements, an antenna has been developed that allows the control of amplitude, phase and polarization parameters in an ultra-wide frequency band. The developed antenna is based on a flat four-arm sine element with a power supply system of two orthogonally arranged printed resistance transformers. The resistance transformer significantly reduces the level of the reflection coefficient at the input and radiation losses. The use of this development in radio direction finding and radio monitoring complexes will reduce the number of sublattices of the antenna system due to the functioning of its elements in an ultra-wide frequency band. The practical significance lies in reducing the number of letters of radio direction finding antenna systems consisting of the developed antenna elements, minimizing the degree of distortion of ultra-wideband signals and ultrashort pulses of arbitrary (varying) polarization received by antenna devices and systems from the antenna presented in the article. The developed antenna and antenna devices based on it can be used for electronic warfare, as well as improving communication and remote control systems.

The application of gated recurrent unit algorithm with fused attention mechanism in UWB indoor localization

Amidst the increasing reliance on indoor positioning in areas such as large shopping malls, airports, and train stations, the precision of ultra-wideband (UWB) technology stands out for its centimeter-level accuracy. However, non-line-of-sight (NLOS) errors caused by people’s movements significantly reduce indoor positioning accuracy. In response, this paper presents an innovative blend of gated recurrent unit algorithm with fused attention mechanism (GRU_Attention). This algorithm adeptly captures the dynamism in UWB signals and intelligently focuses on pivotal features to actualize accurate three-dimensional positioning while effectively reducing NLOS error. It has been demonstrated that GRU_Attention algorithm can reach 5.6 cm accuracy level through experiments, which improved by 74.47 %, 87.44 %, 14.46 %, 43.82 %, and 29.07 % respectively compared with the backpropagation (BP), least square (LS), GRU, convolutional neural network (CNN), and fused attention mechanism convolutional neural network (CNN_Attention) algorithms. This algorithm charts a new pathway to overcome NLOS errors in indoor personnel movement scenes.

Carrier-Free Ultra-Wideband Sensor Target Recognition in the Jungle Environment

Carrier-free ultra-wideband sensors have high penetrability anti-jamming solid ability, which is not easily affected by the external environment, such as weather. Also, it has good performance in the complex jungle environment. In this paper, we propose a jungle vehicle identification system based on a carrier-free ultra-wideband sensor. Firstly, a composite jungle environment with the target vehicle is modeled. From this model, the simulation obtains time-domain echoes under the excitation of carrier-free ultra-wideband sensor signals in different orientations. Secondly, the time-domain signals are transformed into MTF images through the Markov transfer field to show the statistical characteristics of the time-domain echoes. At the same time, we propose an improved RepVGG network. The structure of the RepVGG network contains five stages, which consist of several RepVGG Blocks. Each RepVGG Block is created by combining convolutional kernels of different sizes using a weighted sum. We add the self-attention module to the output of stage 0 to improve the ability to extract the features of the MTF map and better capture the complex relationship between characteristics during training. In addition, a self-attention module is added before the linear layer classification output in stage 4 to improve the classification accuracy of the network. Moreover, a combined cross-entropy loss and sparsity penalty loss function helps enhance the performance and accuracy of the network. The experimental results show that the system can recognize jungle vehicle targets well.

Continuous ultra-wideband signal regeneration in random optoelectronic oscillators through injection locking.

By using an external injection locking method, for what we believe to be the first time, we experimentally demonstrate continuous ultra-wideband signal regeneration in random optoelectronic oscillators, achieving more adaptable signal processing capabilities than self-oscillation methods. Supported by theoretical analysis and experimental evidences, this system can regenerate any signal with sufficient gain in a random-feedback cavity, independent of cavity filters. Remarkably, enhanced phase noise performance with over 35.2 dB side mode suppression and a phase noise better than -86 dBc@1 kHz at higher injecting powers are demonstrated. Additionally, we successfully process complex multi-frequency communication signals, indicating potential applications in radar, remote sensing, and data communications.

Development of a model of received signals and algorithms for their processing for radar detection of people in rooms through a wall

The problem of developing models of received radar signals in through a wall sensing radars is considered, taking into account the properties of targets and the presence of interference clutter. In this case, the targets to be detected are people who are in a mobile or stationary state. It is assumed that the sensing is carried out using an ultra-wideband signal with step frequency modulation. The developed model should correspond to the actual received signals of the through a wall radar in terms of the proximity of statistical characteristics. Goal of article – creation of models of reflected signals corresponding to sensing with the help of through a wall radar of various rooms in the presence or absence of living people in them. Signal models have been developed that correspond to the cases of probing both an "empty" room (in the absence of people) and a room with people inside it. When developing models, the properties of real signals that were obtained during field experiments with the radar layout are taken into account. The statistical characteristics of real and model signals are compared, as a result of which the adequacy of the developed models to real signals is shown. It is also shown that the amplitude of the complex envelope of the target signal can be described using the Gauss function. The developed signal models make it possible to determine the characteristics of a matched filter, the use of which in signal processing in through-the-wall radar leads to a significant reduction in the noise component and smoothing of signals. With the help of the developed models, estimates of the effectiveness of signal processing algorithms can be obtained for various scenarios of probing rooms through a wall.

Adaptive algorithm for detecting and evaluating the parameters of ultra-wideband signals against the background of interference in sub-bands based on a multidimensional biorthogonalizer filter

Adaptive algorithm for detecting and evaluating the parameters of ultra-wideband signals against the background of interference in sub-bands based on a multidimensional biorthogonalizer filter