Abstract: Multi-stage distributed beamforming for distributed mosaic wireless networks is provided. Embodiments described herein present systems, devices, and methods that provide increased range, data rate, and robustness to interference and jamming. A distributed mosaic wireless network includes a transmitter, a receiver, and one or more distributed clusters of radios referred to herein as mosaics or relay mosaics. Each mosaic consists of several distributed, cooperative radio transceivers (e.g., mosaic nodes) that relay a signal sent by the transmitter towards the receiver. In some embodiments, a single-stage beamforming technique is implemented whereby the transmitter sends a signal to a first mosaic, which then relays this signal by beamforming to the receiver. In some embodiments, a multi-stage beamforming technique is implemented whereby the transmitter sends a signal to a first mosaic, which then relays this signal by beamforming to a second mosaic, which then relays this signal by beamforming to the receiver.

Abstract: A precise cardiac data reconstruction method is provided, which may also be referred to herein as radar cardiography (RCG). The RCG can reconstruct cardiac data, such as heart-rate and/or electrocardiogram (ECG)-like heartbeat waveform signals, wirelessly by using advanced radar signal processing techniques. For example, heartbeat and related characteristics can be monitored by isolating cardiovascular activity from strong respiratory interference in spatial spaces: azimuth and elevation. This results in significant improvements to pulse signal-to-noise-ratio (SNR) compared to conventional approaches, facilitating heart-rate variability (HRV) analysis.

Abstract: A system and method utilizes optical depth sensors to estimate heart rate of one or more subjects. A method includes obtaining optical depth video data of at least one subject; identifying a region of interest of the subject(s) from optical depth video data; segmenting the region of interest into multiple areas; identifying pixel intensity with respect to time in the areas to produce a depth signal data matrix including multiple spatial channels; decomposing the depth signal data matrix into a low-rank spatial-temporal eigenvector matrix to produce refined depth signal data streams; and projecting the refined depth signal data streams onto a selected pulsatile direction and producing a cardiac pulse signal for the subject(s).

Abstract: A radar stethoscope system (12) and method for respiration and heart sound assessment is provided. Embodiments present a method to measure acoustics related to breathing and heartbeat sounds using small-scale radars. Acoustic data derived from the radar return measurements can be based on phase changes of the radar return measurements over a period of time. The radar stethoscope (12) can capture and identify respiratory and heart acoustics as traditionally captured by a clinical stethoscope. Using advanced radar processing algorithms, these acoustic signals can be recovered from a distance and without making contact with the patient (14).

Abstract: A precise cardiac data reconstruction method is provided, which may also be referred to herein as radar cardiography (RCG). RCG can reconstruct cardiac data, such as heart rate and/or electrocardiogram (ECG)-like heartbeat waveform signals wirelessly by using advanced radar signal processing techniques. For example, heartbeat and related characteristics can be monitored by isolating cardiovascular activity from strong respiratory interference in spatial spaces: azimuth and elevation. This results in significant improvements to pulse signal-to-noise-ratio (SNR) compared to conventional approaches, facilitating heart-rate variability (HRV) analysis.

Abstract: Multi-stage distributed beamforming for distributed mosaic wireless networks is provided. Embodiments described herein present systems, devices, and methods that provide increased range, data rate, and robustness to interference and jamming. A distributed mosaic wireless network includes a transmitter, a receiver, and one or more distributed clusters of radios referred to herein as mosaics or relay mosaics. Each mosaic consists of several distributed, cooperative radio transceivers (e.g., mosaic nodes) that relay a signal sent by the transmitter towards the receiver. In some embodiments, a single-stage beamforming technique is implemented whereby the transmitter sends a signal to a first mosaic, which then relays this signal by beamforming to the receiver. In some embodiments, a multi-stage beamforming technique is implemented whereby the transmitter sends a signal to a first mosaic, which then relays this signal by beamforming to a second mosaic, which then relays this signal by beamforming to the receiver.

Abstract: Hybrid in-situ and signal of opportunity (SoOP) calibration for antenna arrays is provided. Deployment of aircraft antennae is redesigned to support multiple services with shared physical elements that conform to the exterior of an aircraft to mitigate drag. Conformal arrays are, however, susceptible to structural changes in the fuselage that manifest as pointing errors and side lobe degradation. Embodiments provide an online calibration algorithm that leverages cooperative satellites in direct line-of-sight of a radio frequency (RF) device with an antenna array (e.g., an aircraft with a conformal antenna array) to optimally steer beams. These external calibration sources supplement an in-situ source mounted on a common platform with the antenna array (e.g., placed on the aircraft's tail). Models are established for potential sources of mismatch and the hybrid calibration method is demonstrated via simulations.

Abstract: System and method for contactless vascular flow measurement are provided. Herein, a measurement circuit emits a radio frequency (RF) waveform toward a human peripheral body part and measures micro-vessel motion in an area of interest of the human peripheral body part based on reflections of the RF waveform. Accordingly, the measurement circuit can extrapolate vascular flow information in the human peripheral body part based on the measured micro-vessel motion. In a non-limiting example, the measurement circuit can detect inner organ vibrations to measure pulse rate, strength, and/or pressure caused by radial arterial blood flow changes at the human peripheral body part. By detecting and measuring the vascular flow via the RF waveform, the vascular flow measurement system provides a non-invasive approach to detect and/or prevent peripheral artery diseases. Further, the measurement circuit emits a very low power, non-ionizing RF waveform to help minimize potential health risks to a human body.

Abstract: Methods, systems, and devices for direct radio frequency (RF) signal processing for heart rate (HR) monitoring using ultra-wide band (UWB) impulse radar are presented. A radar sensor is able to directly sample a received signal at RF which satisfies the Nyquist sampling rate, preserving a subject's vital sign information in the received signal. The vital sign information can be extracted directly from a raw RF signal and thus down conversion to a complex baseband is not required. The HR monitoring performance from the proposed direct RF signal processing technique provides an improvement in continuous HR monitoring as compared against existing methods using a complex baseband signal and/or other measurement techniques.

Abstract: Position information estimation in a distributed radio frequency (RF) communications system is provided. Embodiments disclosed herein facilitate high-precision estimations of positions, orientations, velocities, and acceleration of network nodes in a distributed RF network. The distributed RF communications system incorporates a series of estimation processes which makes it susceptible to propagation of errors. To ensure robustness of the distributed RF communications system, relative positions of network nodes are tracked by iteratively tracking parameters used for estimating position information. Some embodiments take advantage of Kalman filtering algorithms by leveraging principles directed by physics. At every network node, several filtering algorithms can be employed to synchronize clocks, track delay between multiple-input multiple-output (MIMO) antennas and estimate position and orientation of other network nodes.

Abstract: Remote recovery of acoustic signals from passive sources is provided. Wideband radars, such as ultra-wideband (UWB) radars can detect minute surface displacements for vibrometry applications. Embodiments described herein remotely sense sound and recover acoustic signals from vibrating sources using radars. Early research in this domain only demonstrated single sound source recovery using narrowband millimeter wave radars in direct line-of-sight scenarios. Instead, by using wideband radars (e.g., X band UWB radars), multiple sources separated in ranges are observed and their signals isolated and recovered. Additionally, the see-through ability of microwave signals is leveraged to extend this technology to surveillance of targets obstructed by barriers. Blind surveillance is achieved by reconstructing audio from a passive object which is merely in proximity of the sound source using clever radar and audio processing techniques.

Abstract: Position information estimation in a distributed radio frequency (RF) communications system is provided. Embodiments disclosed herein facilitate high-precision estimations of positions, orientations, velocities, and acceleration of network nodes in a distributed RF network (e.g., including base stations and vehicles, such as aircraft or unmanned aerial systems (UASs)). Modern radio systems must adapt to limited spectral access by reducing spectrum demand and increasing operational efficiency. In this regard, an RF system is provided which simultaneously performs positioning and communications tasks. This system specifically addresses the issue of spectral congestion by employing an extremely efficient positioning strategy and using a joint waveform that simultaneously enables both tasks. This efficiency in turn supports more users in a given frequency allocation.

Abstract: Multi-stage distributed beamforming for distributed mosaic wireless networks is provided. Embodiments described herein present systems, devices, and methods that provide increased range, data rate, and robustness to interference and jamming. A distributed mosaic wireless network includes a transmitter, a receiver, and one or more distributed clusters of radios referred to herein as mosaics or relay mosaics. Each mosaic consists of several distributed, cooperative radio transceivers (e.g., mosaic nodes) that relay a signal sent by the transmitter towards the receiver. In some embodiments, a single-stage beamforming technique is implemented whereby the transmitter sends a signal to a first mosaic, which then relays this signal by beamforming to the receiver. In some embodiments, a multi-stage beamforming technique is implemented whereby the transmitter sends a signal to a first mosaic, which then relays this signal by beamforming to a second mosaic, which then relays this signal by beamforming to the receiver.

Abstract: A hyper-precise positioning and communications (HPPC) system and network are provided. The HPPC system is a next-generation positioning technology that promises a low-cost, high-performance solution to the need for more sophisticated positioning technologies in increasingly cluttered environments. The HPPC system is a joint positioning-communications radio technology that simultaneously performs relative positioning and secure communications. Both of these tasks are performed with a single, co-use waveform, which efficiently utilizes limited resources and supports higher user densities. Aspects of this disclosure include an HPPC system for a network which includes an arbitrary number of network nodes (e.g., radio frequency (RF) devices communicating over a joint positions-communications waveform). As such, networking protocols and design of data link and physical layers are described herein.

Abstract: Detecting abnormalities in vital signs of subjects of videos is provided. Aspects of the present disclosure include methods, apparatuses, and systems to detect and measure vital sign information of one or more human subjects of a video and detect abnormalities in the vital sign information. In some examples, such abnormalities can be used to indicate video data is likely altered or fraudulent. In this regard, imaging photophlethysmography (IPPG) and advanced signal processing techniques, including adaptive color beamforming, can be used to extract the vital signs of the video subjects.

Abstract: A vital sign monitoring system using an optical sensor is provided. The vital sign monitoring system, and related methods and devices described herein, is equipped with a camera or other optical sensor to remotely detect and measure one or more physiological parameters (e.g., vital signs) of a subject. For example, the vital sign monitoring system can detect, measure, and/or monitor heart rates and respiration rates from one or multiple subjects simultaneously using advanced signal processing techniques, including adaptive color beamforming to more accurately detect and measure the vital sign(s) of interest.

Abstract: Systems and devices for phase-accurate vehicle positioning are disclosed. These systems and devices facilitate high-precision estimations of positions, orientations, velocities, and accelerations of signal nodes in a distributed network (e.g., including base stations and vehicles, such as aircraft or unmanned aerial systems (UASs)). The positioning estimations are based on time-of-arrival estimations of low-bandwidth signals and a phase-accurate distributed coherence algorithm. In some cases, the low-bandwidth signals may further facilitate joint communications and positioning estimations between the signal nodes.

Abstract: Methods and systems for remote sleep monitoring are provided. Such methods and systems provide non-contact sleep monitoring via remote sensing or radar sensors. In this regard, when processing backscattered radar signals from a sleeping subject on a normal mattress, a breathing motion magnification effect is observed from mattress surface displacement due to human respiratory activity. This undesirable motion artifact causes existing approaches for accurate heart-rate estimation to fail. Embodiments of the present disclosure use a novel active motion suppression technique to deal with this problem by intelligently selecting a slow-time series from multiple ranges and examining a corresponding phase difference. This approach facilitates improved sleep monitoring, where one or more subjects can be remotely monitored during an evaluation period (which corresponds to an expected sleep cycle).

Abstract: Vital sign monitoring via remote sensing on stationary exercise equipment is provided. A new non-contact approach described herein uses radio frequency (RF) radar (e.g., ultra-wide band (UWB) radar) to remotely monitor vital sign information (such as heartbeat and breathing) and human activity information of subjects using stationary exercise equipment. In some embodiments, a radar sensor captures micro-scale chest motions (corresponding to the vital sign information) as well as macro-scale body motions (corresponding to movements from exercise). A signal processor receives radar signals from the radar sensor and processes the radar signals to reconstruct vital sign information from the micro-scale chest motions and/or human activity information from the macro-scale body motions using a joint vital sign-motion model, which can be trained using machine learning and other approaches.

Abstract: Terahertz wave plethysmography provides a new principle of radar-based vital sign detection. This disclosure presents new applications at terahertz (THz) frequency band for non-contact cardiac sensing. For the first time, cardiac pulse information is shown to be simultaneously extracted based on two established principles using unique THz waves. A novel concept of Terahertz-Wave-Plethysmography (TPG) is introduced, which detects blood volume changes in the upper dermis tissue layer by measuring the reflectance of THz waves, similar to the existing remote photoplethysmography (rPPG) principle. A detailed analysis of pulse measurement using THz is provided. The TPG principle is justified by scientific deduction and carefully designed experimental demonstrations. Additionally, pulse measurements from various peripheral body regions of interest (ROIs), including palm, inner elbow, temple, fingertip, and forehead, are demonstrated using a novel ultra-wideband (UWB) THz sensing system.