Detecting UWB Radar signals with UWB communication interference

1.1 Impulse Radio (IR) Ultra Wideband (UWB) Communications Ultra wideband (UWB) communication is a fast emerging technology that offers new opportunities such as high data rates, low equipment cost, low power, precise positioning capability and extremely low interference Ghawami (2005). A wide range of possible UWB communication system applications includes radars due to UWB ultra high precision ranging at the centimeter level, wireless personal area networks (WPAN), sensor networks, imaging systems, UWB positioning systems, etc. Yang (2004), Kshetrimayum (2009). From a commercial point of view, the high data rates are the most attractive feature of UWB systems for which speeds of over 100Mb/s have been demonstrated Ghawami (2005). There exist three main types of UWB technologies: impulse radio (IR UWB), direct sequence (DS UWB), and multi-band orthogonal frequency division multiplexing (MB OFDM) Ran (2009). IR UWB communication technique is essentially different from all other communication techniques because it is carrier free and uses for communication between transmitters and receivers very narrow radio frequency (RF) pulses generated from the UWB pulse generator, while traditional transmission systems transmit information by varying the power, frequency, and/or phase of a sinusoidal wave in a modulation process Kshetrimayum (2009), Yao (2007). Consequently, complicated frequency mixers and local oscillators for carrier frequency up and down conversion are not necessary Yao (2007). IR UWB modulation techniques are especially important because the UWB spectrum has been made available by the Federal Communication Commission (FCC) and it can be used with IRs developed to date Lin (2005). Waveforms for IR UWB are designed to obtain a flat frequency response over the bandwidth of the pulse and to avoid a DC component. The large spectrum of a UWB signal may interfere with existing users. In order to keep this interference to the minimum, FCC specifies spectral masks for different applications, i.e. the allowed power output for specific frequencies Ghawami (2005). A contiguous bandwidth of 7.5GHz is available in the frequency interval of (3.1− 10.6)GHz at a maximum power output of −41.3dBm/MHz which is considered as extremely low Ghawami (2005). The power spectral density (PSD) of UWB systems defined as a ratio of the transmitted power P in watts and a signal bandwidth B in hertz is extremely low as compared to other communication systems due to the very wide bandwidth B of short pulses that are typically of nanosecond or picosecond order Ghawami (2005). The selection of the impulse signal type for IR UWB communication system is essential since it determines

The inter-vehicles communication is becoming increasingly mandatory to improve the road safety and to allow a better transport management. The concept behind an intelligent vehicle consists in equipping this vehicle with an optimum number of sensors, in order to perceive the environment surrounding it and to ensure an automatic guidance control and the communication with the infrastructure and other vehicles. Among the most often used tools for this objective, we can cite the embedded radar. Moreover, the Ultra Wide Band (UWB) communication systems are under fast development and undergo progressive implementation. The principle of UWB technology is to transmit rather low power, carrier-less, signals occupying a very broad spectrum [1]. The spectral concentration of radiated power is thus extremely low, so that the other systems perceive UWB ones like background noise. In this article, a road radar based on UWB technology is studied. The proposed device allows, in a road environment, good resolution and increased precision for detection and localization of obstacles.

Ultra-wideband (UWB) radar and impulse radar can provide new opportunities for information recovery from radar return signal analysis. If the UWB radar echo signal processing task is converted into a “black-box” system identification problem, then high order signal processing can offer increased performance in terms of characterizing radar returns for discrimination between targets/materials. The range supported the generation, transmission, and collection of the UWB signals covering the 300 to 900 MHz UHF band. The available information content of UWB radar returns can extend the potential capabilities of radar beyond range and Doppler measurements to target characterization and classification tasks. Preliminary results suggest that UWB radar responses from different materials exhibit different, and characteristic, bispectral and/or kernel signatures, which can be used for enhanced detection and classification under low signal- to-noise ratio conditions. Radar target identification from the return signal characteristics has been a radar design objective for years.

The propagation of ultra wide band (UWB) signals is analyzed. The UWB radar output signals are formed both with transmitter and antenna. Moreover, they can be substantially affected due to electromagnetic wave propagation through walls and multipath effects. Multipath effects are analyzed and simulated numerically for various cases with several heights and distances.

Ultra-WideBand (UWB) communication systems are usually classified as any communication system whose instantaneous bandwidth is many times greater than the minimum bandwidth required to deliver information. UWB communication is fundamentally different from all other communication techniques because it employs extremely narrow Radio Frequency (RF) pulses to communicate between transmitters and receivers. Utilizing short-duration pulses as the building blocks for communications directly generates a very wide bandwidth and offers several advantages, such as large throughput, covertness, robustness to jamming, and coexistence with current radio services. UWB technology offers a promising solution to the RF spectrum drought by allowing new services to coexist with current radio systems with minimal or no interference. This coexistence brings the advantage of avoiding the expensive spectrum licensing fees that providers of all other radio services must pay. In this chapter, the application of UWB technology in military areas has been summarized. Its wider applications has been evaluated over several leading technology including military technology systems, government sectors, communication systems, surveillance systems, rescuing, logistics entertainment, public transport, and others.

This paper presents a novel technique to recover the missing spectral information due to RF spectral restriction in ultra-wideband (UWB) synthetic aperture radar (SAR) imaging. We address a critical problem in UWB radar imaging: radar transmission is prohibited in reserved frequency bands specified by local frequency management agencies. We model the problem in a compressed sensing setup where a time-sparse received radar signal at each aperture is collected in the incoherent frequency domain using a stepped-frequency implementation. Using electromagnetic (EM) finite-difference, time-domain (FDTD) data of various targets and clutter objects computed at all viewing aspect angles, we show that the proposed technique can successfully recover the relevant information on targets of interest even from a large percentage of missing frequency bands.

Recently, ultra wideband (UWB) communications have received increasing interest due to the high data rate achievable in a short distance. UWB communications can have strong interference mitigation capability. A multicarrier ultra wideband (MC-UWB) system has been introduced in (A.H. Tewfik, et al., (2002)) and (E. Saberinia, et al., (2002)). In the MC-UWB communication systems, multiple symbols are transmitted over different carriers simultaneously. The same symbol is retransmitted over different frequency bands by utilizing frequency hopping (FH) techniques. Frequency hopping and multicarrier technologies smooth the average power spectrum density of the system. In this paper, the expression of the power spectrum density of the MC-UWB system is derived. The radiated emission power for UWB communication systems is limited by the spectrum mask specified by wireless communication authorities, such as the federal communications commission (FCC) in United States. Different parameters in the MC-UWB system will have different effects on the power spectrum density and the maximal achievable data rate. The analysis of impact of parameters in the system on the power spectrum density will help the system designer select proper parameter set to fit in emission power regulation and the required data rate in practical UWB systems. Some examples of parameter selection are also given to illustrate the impact of different parameters in the system on the power spectrum density.

Abstract. For indoor positioning, ultra-wideband (UWB) radar comes to the forefront due to its strong penetration, anti-jamming, and high-precision ranging abilities. However, due to the complex indoor environment and disorder of obstacles, the problems of diffraction, penetration, and ranging instability caused by UWB radar signals also emerge, which make it difficult to predict the noise and leads to a great impact on the accuracy and stability of the measurement data in the short term. Therefore, the abnormal value migration of the positioning trajectory occurred in real-time positioning. To eliminate this phenomenon and provide more accurate results, the abnormal values need to be removed. It is not difficult to eliminate abnormal values accurately based on a large number of data, but it is still a difficult problem to ensure the stability of the positioning system by using a small number of measurement data in a short time to eliminate abnormal value in real-time ranging data. Thus, this paper focuses on the experimental analysis of a UWB-based indoor positioning system. By repeatedly measuring the range , a large number of measurement data can be obtained. Using the massive data to train linear regression models, we get the parameter of the linear model of range data measured with the UWB radar. Based on the Gaussian function outlier detection, abnormal values are eliminated, and putting the new range data into the regression model trained by us, the ranging error is reduced by nearly 50 % compared with the peak and mean ranging errors in general.

Ultrawideband (UWB) is a promising technology for getting high data rate communications. UWB communications refer to the utilization of signals with a frequency range (3.1 to 10.6 GHz) on the condition of having a fractional bandwidth of 20% or absolute bandwidth of 500 MHz or higher. The limited power spectral density of − 41.3 dBm/MHz allows UWB communications to be safely deployed with existing wireless communication systems without causing any interference. Consequently, UWB communication systems have been proposed for different outdoor and indoor scenarios. A variety of applications are suitable for UWB communications ranging from infostations, wireless sensor networks (WSNs), on-body communications, in addition to consumer, medical and military applications. Recently, this technology shows a promising step for indoor positioning accuracy where the functioning of navigation systems such as Global Positioning System (GPS) or GLObal NAvigation Satellite System (GLONASS) might be degraded. In this paper, the fundamental properties of UWB communications are presented with an illustration on the present and future direction of this technology.

This paper describes a design effort in a smart tracking prototype, in an attempt to provide real-time, mobile and seamlessly indoor/outdoor location tracking for medical staff, patient or instruments in hospital environment, by integrating GPS (Global Position System) with UWB (Ultra Wideband). Ultra Wideband (UWB) technology can locate a person or asset to the accuracy of centimeters. While UWB technology is becoming popular for indoor position tracking, GPS technology has been around for some time for use in outdoor position tracking with an accuracy of 1 to 100 meters depending on the type of equipment used. It is envisaged that it is possible to combine GPS with UWB to give accurate position regardless of where the person or object is in indoor or outdoor. In view of the strong need for indoor-outdoor tracking in many environments such as hospitals, we looked into the possibility of integrating UWB and GPS to provide the target with seamless indoor-outdoor navigation capability and have developed a prototype. The system structure and experimental results will be illustrated in this paper. To our knowledge, no same system is reported yet.

In this paper, we present the results of the measurements and modeling of the propagation channel for ultra wide band (UWB) communications in large indoor environments. The selected environment is a sports center of large dimensions ($51 \times 26$ m, 7.4m height) without intermediate obstacles so that there is always direct path (DP) between TX and RX and UWB technology can be used for critical communications of sensors. On this environment, narrow band and ultra wide band measurements have been made with a high resolution pulse channel sounder (8ns) at the nominal frequency of 3.9 GHz. Narrow band measurements have been used to model path loss for the DP, while for UWB measurements, the power delay profile have been used to obtain the statistics of the multipath of the channel. Combining both models has been possible to obtain a detailed characterization of the environment. The results constitute a complete characterization of this type of indoor environments for UWB signals and can be easily extrapolated to other environments with similar characteristics, allowing the use of UWB technology for applications of critical communications for sensors and other devices.

In support of the Army vision for increased mobility, survivability, and lethality, we are investigating the use of ultra-wideband (UWB) radar technology to enhance unmanned ground vehicle missions. The ability of UWB radar technology to detect foliage-concealed objects could provide an important obstacle avoidance capability for robotic vehicles, which would improve the speed and maneuverability of these vehicles and consequently increase the survivability of the U.S. forces. This technology would address the particular challenges that confront robotic vehicles such as large rocks hidden in tall grass and voids such as ditches and bodies of water. This paper describes electromagnetic model predictions of the radar cross section of potential robotic vehicle obstacles. These model predictions will be used to guide the data collection scenarios for the Army Research Laboratory (ARL) ultra-wideband BoomSAR system. Using a combination of the models, simulations, and BoomSAR data we investigate the operating parameters (imaging angles, frequencies, bandwidth, etc.) for an obstacle-avoidance UWB radar.

This paper discusses the IVC (Inter Vehicle Communication) system using the UWB (Ultra Wideband) radar. DSUWB (Direct Sequence - UWB) signal is used for this IVC system because it has CDMA (Code Division Multiple Access) Capability. However, there is the near-far problem due to difference of signal power from each vehicles, it becomes the cause of degradation of communication characteristics and detection accuracy of the signal. In this paper, we propose the iterative detection system using the SIC (Successive Interference Cancellation) to improve detection rate of the signal and the bit error rate (BER) performance. The signals except the desired signal detected by the SIC is subtracted from the original received signal. As the result, the performance was improved.

The safety aspects of people exposed to the field emitted by ultra wideband (UWB) radar, operating both in the spatial environment and on ground, for breath activity monitoring are analyzed. The basic restrictions and reference levels reported in the ICNIRP safety guideline are considered, and the compliance of electromagnetic fields radiated by a UWB radar with these limits is evaluated. First, simplified analytical approaches are used; then, both a 3-dimensional multilayered body model and an anatomical model of the head have been used to better evaluate the electromagnetic absorption when a UWB antenna is placed in front of the head. The obtained results show that if the field emitted by the UWB radar is compliant with spatial and/or ground emission masks, then both reference levels and basic restrictions are largely satisfied.

Ultra-wideband (UWB) radar has become increasingly popular for short-range sensing applications due to the commercial availability, energy efficiency, and integration potential within existing wireless ecosystems. The widespread availability of commercial UWB chips, originally designed for secure ranging and localisation, has made radar sensing more accessible. These chips are low-cost, energy-efficient, and already integrated into many consumer devices, making them an attractive platform for developing radar-based sensing solutions. The high rate pulse repetition frequency (HRP) UWB PHY uses short pulses across a wide frequency range and allows for precise time-of-flight measurements and fine spatial resolution. This makes it well-suited for detecting small movements and resolving targets in cluttered environments. Sensing applications range from indoor localisation and gesture recognition to monitoring of vital signs. However, evaluating the sensing performance of UWB radar systems in diverse scenarios remains challenging. The complexity of real-world environments and the variability of target behaviours make it difficult to test UWB devices consistently. This paper presents a method for simulating UWB radar targets and assessing sensing performance under controlled conditions. By emulating target reflections and clutter characteristics, the proposed approach enables repeatable and scalable testing of UWB radar systems, facilitating the development and benchmarking of robust sensing solutions.