A Microwave Anticipatory Crash Sensor for Automobiles

A Multi-phase continuous-wave (CW) Doppler Radar is proposed for measuring small periodic displacement. Multi-phase local oscillator (LO) signals are incident to quadrature mixers to simultaneously generate multiple arcs on the complex plane. Multiple arcs obtained from synchronized data at the same time can be provided in the circle fitting method to compensate for DC offset voltages on the radar. A 5.8 GHz CW Doppler radar with four-phased LO signals, which are generated by a passive balun and two hybrid couplers, is implemented on an FR4 PCB for measuring the periodic displacement at the distance of 0.5 m. Compared to the conventional CW Doppler radar based on a single arc, measurement results show a lower root mean square error (RMSE) and that the RMSE is effectively reduced by more than three times at displacements less than 2 mm.

본 논문에서는 기상 제약이 많은 CCTV 보완을 위해 CW 도플러 레이더를 사용하는 감시 시스템에서 두 개 이상의 물체 접근 또는 이탈 정보를 감지하기 위한 모니터링 프로그램을 개발하였으며, 물체의 접근 또는 이탈 정보를 효율적으로 감지하기 위한 알고리즘을 제안하였다. 제안하는 알고리즘은 CW 도플러 레이더에서 수신한 신호를 FFT 처리하여 실수부와 허수부로 분리 후 각 동일 주파수 마다 진폭을 합산하여 이들의 위치를 통해 접근 또는 이탈을 판단하는 방식이다. 이를 시뮬레이션 및 실험을 통해 검증하였으며, 두 개 물체의 접근 또는 이탈을 감지한 결과 정상적으로 감지하는 것을 확인할 수 있었다. The CCTV is limited by weather conditions. To overcome this limitation, we develop a monitoring program that can sense the approach or recede of two or more objects within a surveillance system that uses a continuous-wave (CW) Doppler radar, and we proposed an algorithm to efficiently detect the approach or recede information of the object. The proposed algorithm separates the signal received by the CW Doppler radar into the real and imaginary parts using Fast Fourier Transform (FFT), and sums the amplitudes for each frequency to determine whether the objects are approaching or receding, using their locations. The algorithm is verified by simulations and experiments, which confirms that it successfully detects the approach or recede of two objects.

Occupancy estimation and occupant entry/exit detection can play a significant role in designing energy-efficient heating, ventilation, and air conditioning (HVAC) systems. Radar-based occupancy estimation is gaining attention as it is unobtrusive and does not give rise to privacy issues associated with video imaging. Most research is focused on estimating the number of occupants by employing frequency-modulated continuous wave (FMCW) radar using a micro-Doppler signature. Continuous wave (CW) radar has a simple architecture and fewer signal processing steps than FMCW radar and is mostly employed for sensing micro-Doppler signatures produced by human cardiopulmonary motion. This paper investigates the feasibility of using wavelet analysis to extract occupant entry and exit information from data produced by a single antenna 2.4 GHz CW radar occupancy sensor. Preliminary experimental results on a short scale demonstrated that maximum wavelet coefficient frequency (MWCF) and wavelet coefficient energy (WCE) vary significantly during the entry and exit event of occupants, and can provide a reliable indicator to estimate the number of occupants.

In order to solve the problem of the null detection point in the vital signs detection based on continuous wave(CW) Doppler radar, a novel dual-band hybrid down-conversion radar transceiver system is proposed. The proposed radar system operating frequency is 2.05 GHz and 1.64 GHz. Correlation between signals can improve the overall performance of the system. At λ/4 distance, the single-band single-channel detection has the problem of null detection point, and the proposed dual-band double-channel detection can solve the null detection point. On the other hand, at the non-λ/4 distance, the results of the dual-band detection double-channel can be mutually verified, ensuring the detection accuracy of the vital sign detection system. The simulation results prove the feasibility of the radar system. Regardless of whether the detected distance is at the λ/4 distance, the proposed vital sign detection system can always obtain the vital sign.

Using a continuous wave (CW) Doppler radar at 60 GHz, the radar cross sections of long metallic rods were measured. The results show linear increase with growing distance between radar and rods. A new expression for the radar cross section, which was also derived, demonstrates good agreement with the measured data.

Continuous-wave (CW) Doppler radar with a quadrature direct-conversion receiver (DCR) has critical issues about Direct-current (DC) offset to manage and measure it when remotely monitoring vital signs which are closely resemble DC values. The characterization process using Radio frequency (RF) single tone has been carried out to measure DC offset, but there is no known method for supporting multiple CW. This paper categorizes DC offset as one of a system DC offset and an environment DC offset, and proposes 1 to 5 experiments of a DC offset characterization process supporting multiple CW. The result experimentally shows that DC offsets have the tendency to follow experiment 4 of characterization when the RF-to-local oscillator (LO) isolation is achieved by using the absorber in front of the antenna.

Abstract. In this paper we describe the conversion of SESCAT (Sporadic-E SCATter experiment), a bistatic 50 MHz continuous wave (CW) Doppler radar located on the island of Crete, Greece, to a single (east-west) baseline interferometer. The first results show that SESCAT, which provides high quality Doppler spectra and excellent temporal resolution, has its measurement capabilities enhanced significantly when operated as an interferometer, as it can also study short-term dynamics of localized scattering regions within mid-latitude sporadic E-layers. The interferometric observations reveal that the aspect sensitive area viewed by the radar often contains a few zonally located backscatter regions, presumably blobs or patches of unstable metallic ion plasma, which drift across the radar field-of-view with the neutral wind. On average, these active regions of backscatter have mean zonal scales ranging from a few kilometers to several tens of kilometers and drift with westward speeds from ~ 20 m/s to 100 m/s, and occasionally up to 150 m/s. The cross-spectral analysis shows that mid-latitude type 1 echoes occur much more frequently than has been previously assumed and they originate in single and rather localized areas of elevated electric fields. On the other hand, typical bursts of type 2 echoes are often found to result from two adjacent regions in azimuth undergoing the same bulk motion westwards but producing scatter of opposite Doppler polarity, a fact that contradicts the notion of isotropic turbulence to which type 2 echoes are attributed. Finally, quasi-periodic (QP) echoes are observed simply to be due to sequential unstable plasma patches or blobs which traverse across the radar field-of-view, sometimes in a wave-like fashion.Key words. Ionosphere (ionospheric irregularities; mid-latitude ionosphere; plasma waves and instabilities)

Microwave Doppler radar has potential to provide a practical tool for noncontact detecting cardiopulmonary movement. In this paper, a noncontact sensor of vital signs was realized based on continuous wave Doppler radar, in addition, real-time signal processing was studied for single target noncontact cardiopulmonary monitoring, including short-time Fourier transform, Sinc interpolation and peak searching. These methods can improve the accuracy, response speed and shorten the latency of cardiopulmonary Doppler radar signal processing considerably, with relatively small amount of calculation.

Subject and Purpose. The paper is devoted to the microwave propagation over the sea in the nearshore region. Emphasis is on microwave attenuation measurements in the semi-shade and deep-shade areas with a view to study conditions of the microwave propagation on a beyond-the-horizon path in the nearshore area using a radar method. Methods and Methodology. A radar technique, developed and tested, provides measuring a microwave attenuation coefficient along a 60 km long beyond-the-horizon path in the tropospheric surface layer. High-grade radar and Doppler radar beacons (racons) are employed. Of interest are experimentally obtained temporal dependences of signals from racons situated at different heights and, also, spatial field distribution curves from a steadily moving racon running a height 1 to 27 m for 25 minutes. Results. A prototype of high-grade X-band coherent continuous-wave (Doppler) radar has been designed and fabricated. A radar technique has been developed and tested for the analysis of microwave beyond-the-horizon propagation conditions in the shadow region, which involves continuous-wave (Doppler) radar and Doppler racons with a radar cross section (RCS) of about 60 m2. Conclusions. The technique proposed enables reliable tracking of racon responses up to a double radiohorizon range on over-sea paths. This technique can be used for radar calibrations when dealing with various location problems in the nearshore area, including detection and tracking small-size and low-flying targets and their radar identification.

<div class="section abstract"><div class="htmlview paragraph">Honda has developed the 2018 model CLARITY PLUG-IN HYBRID. Honda’s new plug-in hybrid is a midsize sedan and shares a body platform with the CLARITY FUEL CELL and the CLARITY ELECTRIC. The vehicle’s electric powertrain boosts driving performance as an electric vehicle (EV) over Honda’s previous plug-in hybrid.</div><div class="htmlview paragraph">The CLARITY PLUG-IN HYBRID’s electric powertrain consists of a traction motor and generator built into the transmission, a Power Control Unit (PCU) positioned above the transmission, an Intelligent Power Unit (IPU) fitted under the floor, and an onboard charger fitted below the rear trunk.</div><div class="htmlview paragraph">The PCU integrates an inverter that drives the traction motor, an inverter that drives the generator, and a DC-DC converter to boost battery voltage (referred to as a “Voltage Control Unit (VCU)” below). The VCU employs an interleaved circuit configuration and a coupled inductor and realizes approximately three times the rated continuous power and approximately three times the power density of a standard unit employed in a hybrid vehicle.</div><div class="htmlview paragraph">The IPU contains 17 kWh high-capacity battery modules and a 12 V DC-DC converter. A coolant-cooling method has been adopted to respond to the increased power of the battery, boosting cooling performance. The battery modules are positioned below the front and rear seats, and the high-voltage wiring is positioned between the modules, in the center of the vehicle. This layout has made it possible to fit the IPU below the floor of the vehicle, helping to enable the realization of a spacious and comfortable cabin seating five passengers, as well as a useful amount of trunk space.</div><div class="htmlview paragraph">The use of a high-power VCU and a high-capacity IPU has made it possible to realize EV operation in the high-speed range with no need to start the engine, giving the vehicle an adequate all-electric range (AER) for everyday use. During hybrid operation, increasing both the VCU power and the battery power helps ensure quietness while also allowing the engine to be downsized from 2.0 to 1.5 liters. The developed electric powertrain realizes a long AER of 47 miles and extremely quiet hybrid operation with a high level of fuel economy at 42 mpg.</div></div>

The 24 GHz continuous-wave (CW) Doppler radar sensor (DRS) is widely used for measuring the instantaneous speed of moving objects by using a non-contact approach, and has begun to be used in train-borne movable speed measurements in recent years in China because of its advanced performance. The architecture and working principle of train-borne DRSs with different structures including single-channel DRSs used for freight train speed measurements in railway freight dedicated lines and dual-channel DRSs used for speed measurements of high-speed and urban rail trains in railway passenger dedicated lines, are first introduced. Then, the disadvantages of two traditional speed calibration methods for train-borne DRS are described, and a new speed calibration method based on the Doppler shift signal simulation by imposing a signal modulation on the incident CW microwave signal is proposed. A 24 GHz CW radar target simulation system for a train-borne DRS was specifically realized to verify the proposed speed calibration method for a train-borne DRS, and traceability and performance evaluation on simulated speed were taken into account. The simulated speed range of the simulation system was up to (5~500) km/h when the simulated incident angle range was within the range of (45 ± 8)°, and the maximum permissible error (MPE) of the simulated speed was ±0.05 km/h. Finally, the calibration and uncertainty evaluation results of two typical train-borne dual-channel DRS samples validated the effectiveness and feasibility of the proposed speed calibration approach for a train-borne DRS with full range in the laboratory as well as in the field.

Radio interference generated in a helicopter-borne continuous wave (CW) Doppler radar system due to the rotating blades is analyzed. This problem has been previously treated for the case of pulse Doppler radar systems with very narrow (near zero) beamwidth. In this case the strong interference component returning directly from the blades (with no ground reflection) need not be considered as it reaches the receiver when it is still blinded. In the case of a CW Doppler radar, however, this interference component must be included. Numerical calculations show that the total blade interference power level, dominated by the direct component, is higher than that of the direct ground clutter in the radar clutter region. It decreases approximately as (f - fo)-4 in the radar clear region. It stays, however, well above the thermal noise level which might cause false alarm and degrade the radar performance.

<div class="section abstract"><div class="htmlview paragraph">In order to reduce CO₂, Electric Vehicles (EV) and Hybrid Vehicles (HV) are effective. Those types of vehicles have powertrains from conventional vehicles. Those new powertrains drastically improve their efficiency from conventional vehicles keeping the same or superior power performance. On the other hand, those vehicles have an issue for thermal energy shortage during warming up process. The thermal energy is very large, and seriously affects the fuel economy for HV and the mileage for EV.</div><div class="htmlview paragraph">In this paper, we propose VHDL-AMS multi-domain simulation technique for the estimation of the vehicle performance at the concept planning stage. The VHDL-AMS is IEEE and IEC standardized language, which supports not only multi-domain (physics) but also encryption. The common modeling language and encryption standard is indispensable for full-vehicle simulation.</div><div class="htmlview paragraph">By the VHDL-AMS modeling, the fuel economy, the effect of heat energy recovery from the exhaust gas, and the power performance are discussed for HV. The fuel economy was estimated using LA#4 driving pattern and the base simulation model validation result was that simulation was 22.0 km/L and measurement was 21.7 km/L (error 1.4%). The energy management using an exhaust gas heat exchange system realized 10.3% fuel consumption improvement during warming up. As for the power performance, the simulated acceleration time of 0-100 km/h was 11.12 sec and the measured vehicle time was 11.27 sec. The error between simulation and actual measurement result was 1.4%.</div><div class="htmlview paragraph">We showed that the application of VHDL-AMS multi-domain HV simulation is effective for the vehicle concept planning. Since the HV model uses embedded real control software, the VHDL-AMS modeling can be used as SIL at system control development stage.</div></div>

<div class="section abstract"><div class="htmlview paragraph">Two modern light-duty passenger vehicles were selected for chassis dynamometer testing to evaluate differences in performance end efficiency resulting from CNG and gasoline combustion in a vehicle-based context. The vehicles were chosen to be as similar as possible apart from fuel type, sharing similar test weights and identical driveline configurations.</div><div class="htmlview paragraph">Both vehicles were tested over several chassis dynamometer driving cycles, where it was found that the CNG vehicle exhibited 3-9% lower fuel economy than the gasoline-fueled subject. Performance tests were also conducted, where the CNG vehicle's lower tractive effort capability and longer acceleration times were consistent with the lower rated torque and power of its engine as compared to the gasoline model.</div><div class="htmlview paragraph">The vehicles were also tested using quasi-steady-state chassis dynamometer techniques, wherein a series of engine operating points were studied. When the indicated thermal efficiency at each point was calculated, it was found that the CNG vehicle typically exhibited lower thermal efficiency.</div><div class="htmlview paragraph">Several operating points were chosen for further characterization of engine efficiency and combustion behavior, including an analysis of losses. Though the CNG engine had better theoretical efficiency potential, the losses suffered by this engine were repeatedly more significant than those suffered by the gasoline engine. As a result, the CNG engine was typically less efficient. There were a number of factors contributing to this phenomenon, including compression ratio, fuel properties, ignition and combustion timing and phasing, as well as EGR rates.</div></div>

<div class="htmlview paragraph">This paper describes an advanced vehicle radar system operating at a frequency of 60.5 GHz that has been jointly developed for the Japanese automobile and truck market by Eaton VORAD Technologies of San Diego, California, and Hitachi, Ltd. of Japan. The radar system is used for both collision warning system (CWS) applications and for adaptive cruise control (ACC) applications.</div> <div class="htmlview paragraph">The radar system employs monopulse radar technology to measure azimuth angle to each vehicle in the forward direction. The techniques used to reduce cost and complexity of monopulse radar for low cost use on commercial vehicles are described. These techniques combine Doppler radar technology with digitally derived monopulse processing.</div> <div class="htmlview paragraph">Japan is the only country that has selected the frequency band of 60 GHz for vehicle radar systems. The reasons for this selection are discussed and the advantages and disadvantages of this frequency band are presented. The Japanese Ministry of Post and Telecommunications (MPT) specifies radiation limitations differently than the United States and has unique testing and transmission requirements which are discussed.</div> <div class="htmlview paragraph">The radar system has completed the prototype phase and preproduction has commenced. The radar system will be co-produced by Eaton VORAD Technologies in the United States and by Hitachi, Ltd. in Japan. The paper also presents system specifications, component assemblies, block diagrams, and installation considerations</div>