Display:

Results

Viewing 1 to 30 of 12260
2017-10-08
Technical Paper
2017-01-2301
Hongli Gao, Fujun Zhang, Wenwen Zeng, Tianpu Dong, Zhengkai Wang
Abstract The electronic control of direct injection fuel system, which could improve engine fuel efficiency, dynamics and engine emission performance through good atomization, precise control of fuel injection time and improvement of fuel-gas mixture, is the key technology to achieve the stratified combustion and lean combustion. In this paper, a direct injection injector that based on voice coil motor was designed aiming at the technical characteristics of one 800cc two-stroke cam-less engine. Prior to a one - dimensional simulation model of injector was established by AMEsim and the maximal fuel injection demand was met via the optimization of the main parameters of the injector, the structure of the voice coil motor was optimized by magnetic equivalent circuit method. After that, the maximal flow rate of the injector was verified by the injector bench test while the atomization characteristic of the injector was verified by using a high-speed camera.
2017-10-08
Technical Paper
2017-01-2283
Anand Prabu Kalaivanan, Gnanasekaran Sakthivel
Abstract Electronic Fuel Injection Systems have revolutionised Fuel Delivery and Ignition timing in the past two decades and have reduced the Fuel Consumption and Exhaust Emissions, ultimately enhancing the Economy and Ecological awareness of the engines. But the ignition/injection timing that commands the combustion is mapped to a fixed predefined table which is best suited during the stock test conditions. However continuous real time adjustments by monitoring the combustion characteristics prove to be highly efficient and be immune to varying fuel quality, lack of transient performance and wear related compression losses. For developing countries, Automotive Manufacturers have been Tuning the Ignition/Injection timing Map assuming the worst possible fuel quality. Conventional knock control system focus on engine protection only and doesn't contribute much in improving thermal efficiency.
2017-10-08
Technical Paper
2017-01-2286
A S Ramadhas, Punit Kumar Singh, Reji Mathai, Ajay Kumar Sehgal
Abstract Ambient temperature conditions, engine design, fuel, lubricant and fuel injection strategies influence the cold start performance of gasoline engines. Despite the cold start period is only a very small portion in the legislative emission driving cycle, but it accounts for a major portion of the overall driving cycle emissions. The start ability tests were carried out in the weather controlled transient dynamometer - engine test cell at different ambient conditions for investigating the cold start behavior of a modern generation multi-point fuel injection system spark ignition engine. The combustion data were analyzed for the first 200 cycles and the engine performance and emissions were analyzed for 300 s from key-on. It is observed that cumulative fuel consumption of the engine during the first 60 s of engine cold starting at 10 °C was 60% higher than at 25 °C and resulted in 8% increase in the value of peak speed of the engine.
2017-10-08
Technical Paper
2017-01-2302
Tobias Knorsch, Dmitrii Mamaikin, Philippe Leick, Philipp Rogler, Jin Wang, Zhilong Li, Michael Wensing
Abstract The fuel spray behavior in the near nozzle region of a gasoline injector is challenging to predict due to existing pressure gradients and turbulences of the internal flow and in-nozzle cavitation. Therefore, statistical parameters for spray characterization through experiments must be considered. The characterization of spray velocity fields in the near-nozzle region is of particular importance as the velocity information is crucial in understanding the hydrodynamic processes which take place further downstream during fuel atomization and mixture formation. This knowledge is needed in order to optimize injector nozzles for future requirements. In this study, the results of three experimental approaches for determination of spray velocity in the near-nozzle region are presented. Two different injector nozzle types were measured through high-speed shadowgraph imaging, Laser Doppler Anemometry (LDA) and X-ray imaging.
2017-10-08
Technical Paper
2017-01-2314
Genmiao Guo, Zhixia He, Qian Wang, Shenxin Sun, Zhou Chen
Abstract Study of the spray formation in vicinity of the nozzle is essential to better understand and predict the physical processes involved in the diesel atomization. The initial spray patterns were found to be different from one injection to another during our visualization experiments, which was carried out based on a long distance microscope with a high speed camera in this work. It was found that the initial spray might contain a clear single mushroom, tail region and intact liquid column, or have a tail in front of the mushroom without changing its direction. Occasionally, it presented as a double-mushroom shape, or did not include a clear mushroom. Our visualization results showed that the various spray structures were observed at different injection pressures and different injection cycles under the same injection pressure.
2017-10-08
Technical Paper
2017-01-2307
Yijie Wei, Tie Li, Bin Wang, Weiquan Shi
Lift-off length is defined as the distance from injector hole to the location where flame stabilized on a high injection pressure direct injection (DI) diesel spray. In this paper we used the high-speed (40 kHz) Schlieren and time-averaged OH chemiluminescence imaging technique to simultaneously measure the flame lift-off locations on a DI diesel spray in an optically accessible and constant-volume combustion vessel. The time-resolved development of the diesel spray acquired from the high-speed Schlieren imaging system enabled us to observe the instantaneous spray structure details of the spray flames. The OH chemiluminescence image obtained from a gated, intensified CCD video camera with different delay and width settings was used to determine the quiescent lift-off length. Experiments were conducted under various ambient temperatures, ambient gas densities, injection pressures and oxygen concentrations.
2017-10-08
Technical Paper
2017-01-2425
Ramit Verma, Ramdas R Ugale
Abstract On two wheelers, magneto/alternator generates either single/three phase AC power and Regulator Rectifier Unit (RRU) does regulated rectification to charge the battery. In order to face the requirements of 2-wheeler engine with respect to upcoming stringent regulations like electronic fuel injection (EFI), anti-lock braking system (ABS), automatic headlamp on (AHO) in emerging markets like India; vehicles demand more electrical power from batteries. This demands higher power from alternator and consequently from RRU. Requirement of higher output power presents challenges on regulator rectifier unit in terms of size, power dissipation management and reliability. In this paper, improved performance of MOSFET based RRU is discussed in comparison to Silicon Controlled Rectifier (SCR) based RRU. The motivation/benefits of MOSFET based design is described along with the thermal behavior and temperature coefficient performance of RRU with test results.
2017-10-08
Technical Paper
2017-01-2412
Dojoong Kim, Dong Hyeong Lee, Jong Wung Park, Soo Hyun Hwang, Wan Jae Jeon
Abstract This paper introduces a two-step variable valve actuation (VVA) mechanism equipped with an electronic switching system, which can be applied to OHC valve trains with end pivot rocker arms. The electronic switching system is driven by a dedicated solenoid and is not affected by the temperature or pressure of the engine oil. Therefore, not only can the dynamic stability be secured at the time of mode switching but the operation delay time can also be kept short enough. Several models of two-step VVA mechanisms were fabricated and the operability of the mechanism and switching system was experimentally confirmed. The two-step VVA mechanism developed in this study can also be used as a cylinder deactivation (CDA) system by assigning the lift of the low-speed cam to be zero. By attaching a roller to the portion of the rocker arm that is in contact with the base cam, the problem of pad wear, which is often present in CDA mechanism, is also fundamentally solved.
2017-10-08
Technical Paper
2017-01-2367
Ganesan Mahadevan, Sendilvelan Subramanian
Abstract Control of harmful emissions during cold start of the engine has become a challenging task over the years due to the ever increasing stringent emission norms. Positioning the catalytic converter closer to the exhaust manifold is an efficient way of achieving rapid light-off temperature. On the other hand, the resulting higher thermal loading under high-load engine operation may substantially cause thermal degradation and accelerate catalyst ageing. The objective of the present work is to reduce the light-off time of the catalyst and at the same time reduce the thermal degradation and ageing of the catalyst to the minimum possible extent by adopting an approach with Dynamic Catalytic Converter System (DCCS). The emission tests were conducted at the cold start of a 4 cylinder spark ignition engine with DCCS at different positions of the catalyst at no load conditions.
2017-10-08
Technical Paper
2017-01-2198
Zhihong Li, Guoxiu Li, Lan Wang, Hongmeng Li, Jie Wang, Haizhou Guo, Shuangyi He
Abstract The electromagnetic valve driving mechanism is the significant equipment, which plays a vital role in the unit pump injection system; therefore, the performance of the electromagnetic valve directly influences the function of the control system. Based on the operation conditions of the unit pump injection system, a steady electromagnetic valve model was modified to study the influence factors of electromagnetic force and the best combination to get the maximum electromagnetic force. The validation model was verified by experiment. The effects of some crucial parameters upon the electromagnetic force were investigated in the present paper, (including working airspace, magnetic pole’s cross-sectional area, coil position, coil turn, the armature thickness). The results show that the electromagnetic force of the solenoid valve enhanced with the increase of driving current and with the decrease of working airspace.
2017-10-08
Technical Paper
2017-01-2452
Kingsley Joel Berry, Abdrahamane Traore, Aravind Krishna, Pavankumar Gangadhar, Allan Taylor
This paper documents the electrical infrastructure design of a Hybrid Go Kart competition vehicle which includes a dual Fuel Cell power system, Ultra Capacitors for energy storage, and a dual AC induction motor capable of independent drive. The Kart was built primarily to compete in the 2009 Formula Zero international event. This paper emphasized the vehicle model and control strategy as a result of three (3) graduate student research projects. The vehicle was fabricated and tested but did not participate in the race competition since the race organization folded. The vehicle model was developed in Simulink to determine whether the fuel cell and ultra-capacitor combination will be sufficient for peak transient power requirement of 14 kW. The vehicle’s functional description and performance specifications are documented including the integration of the fuel cell power modules, energy storage system, power converters, and AC motor and motor controllers.
2017-10-08
Journal Article
2017-01-2459
Liu Xiaojun, Yu Jinpeng, Yang Xia, Wu Daoming, Jie Zhu
Abstract In the case of electric vehicles, due to the charging current limitation of lithium battery at low temperatures (below -20°C), it has been proposed to heat the battery pack up to a suitable temperature range before charging through a liquid-heating plate with PTC. However, at a low state of charge (SOC), there is a question which one could take the place of battery pack to supply power for PTC when heating. So that off-board charger (OFC) has been considered to supply power for PTC in this paper. In order to control the current charging into the battery pack as less as possible at low temperatures, three control schemes of battery management system (BMS) are proposed and compared. Scheme 1: BMS controls the value of charging current request close to the working current of PTC. Scheme 2: BMS controls the value of charging voltage request to reach a state of relative balance. Scheme 3: BMS disconnects the pack from the charger and keeps the connection between PTC and charger.
2017-10-08
Technical Paper
2017-01-2221
Peixuan Zeng, Penghao Zhang, Binyu Mei, Shiping Huang, Gangfeng Tan
Abstract It’s not easy to start the engine in winter, especially in frigid highlands, because the low temperature increases the fuel’s viscosity, decreasing the lubricating oil flow ability and the storage performance of battery. Current electrical heating method can improve the engine starting performance in low temperature condition, but this method adds an external power to the engine, leading to the engine cannot maintain an efficient energy utilization. A warming device using the solar energy is designed to conserve the energy during the daytime, and directly warm up the engine at the time when the engine turns off for a long time, especially during the night. A solar collector installed on the top of the vehicle is used to convert the solar energy to the thermal energy, which is then transferred to the heat accumulator that contain the phase-change medium which can increase the heat storage performance.
2017-09-23
Technical Paper
2017-01-1951
Lingfei Wu, Hongshan Zha, Caijing Xiu, Qiaojun He
Abstract Local path planning for obstacle avoidance is one of the core topics of intelligent vehicle. A novel method based on dubins curve and tentacle algorithm is proposed in this article, with the consideration of obstacle avoidance and vehicle motion constraints. First, the preview distance of the vehicle is given according to the current speed, so that the preview point can be found with the information of global path. Then dubins curve is adopted to find a path with appropriate turning radius, between the current position and preview point, satisfying the constraints of current direction and target direction, considering handling and ride comfort of the vehicle. In order to avoid obstacle, tentacle algorithm is adopted. 20 tentacle points are given by moving the original preview point, and then 21 local paths can be given by using dubins curve. Cost function is used to find out the best option of the 21 paths.
2017-09-23
Technical Paper
2017-01-1953
Manfei Bai, Lu Xiong, Zhiqiang Fu, Renxie Zhang
Abstract In this paper, a speed tracking controller is designed for the All-terrain vehicles. The method of feedforward with state variable feedback based on conditional integrators is adopted by the proposed control algorithm. The feedforward is designed considering the influence of the road slope on the longitudinal dynamics, which makes the All-terrain vehicles satisfy the acceleration demand of the upper controller when it tracks the desired speed on the road with slope varying greatly. The road slope is estimated based on a combined kinematic and dynamic model. This method solves the problem that road slope estimation requires an accurate vehicle dynamic model and are susceptible to acceleration sensor bias. Based on the vehicle dynamic model and the nonlinear tire model, the method of conditional integration is used in the state variable feedback, which considers the saturation constraint of the actuator with the intention of preventing the divergent integral operation.
2017-09-23
Technical Paper
2017-01-1952
ChengJun Ma, Fang Li, Chenglin Liao, Lifang Wang
Abstract With the load of urban traffic system becomes more serious, the Automatic Parking System (APS) plays an important role in alleviating the burden of drivers and improving vehicle safety. The APS is consisted of environmental perception, path planning and path following. The path following controls the lateral movement of vehicle during the parking process, and requires the trajectory tracking error to be as small as possible. At present, some control algorithms are used including PID control, pure pursuit control, etc. However, these algorithms relying heavily on parameters and environment, have some problems such as slow response and low precision. To solve this problem, a path following control method based on Model Predictive Control (MPC) algorithm is proposed in this paper. Firstly, Kinematic vehicle model and path tracker based on MPC algorithm are built. Secondly, a test bench that composed of CANoe hardware in the loop (HIL) system and steering wheel system is built.
2017-09-23
Technical Paper
2017-01-1955
Yandong Ruan, Hui Chen, Jiancong Li
Abstract An integrated automatic driving system consists of perception, planning and control. As one of the key components of an autonomous driving system, the longitudinal planning module guides the vehicle to accelerate or decelerate automatically on the roads. A complete longitudinal planning module is supposed to consider the flexibility to various scenarios and multi-objective optimization including safety, comfort and efficiency. However, most of the current longitudinal planning methods can not meet all the requirements above. In order to satisfy the demands mentioned above, a new Potential Field (PF) based longitudinal planning method is presented in this paper. Firstly, a PF model is constructed to depict the potential risk of surrounding traffic entities, including obstacles and roads. The shape of each potential field is closely related to the property of the corresponding traffic entity.
2017-09-23
Technical Paper
2017-01-1954
Peng Hang, Xinbo Chen, Fengmei Luo
Abstract Path tracking is the rudimentary capability and primary task for autonomous ground vehicles (AGVs). In this paper, a novel four-wheel-independent-steering (4WIS) and four-wheel-independent-drive (4WID) electric vehicle (EV) is proposed which is equipped with steer-by-wire (SBW) system. For path-tracking controller design, the nonlinear vehicle model with 2 degrees of freedom (DOF) is built utilizing the nonlinear Dugoff tire model. The nonlinear dynamic model of SBW system is conducted as well considering the external disturbances. As to the path-tracking controller design, an integrated four-wheel steering (4WS) and direct yaw-moment control (DYC) system is designed based on the model predictive control (MPC) algorithm to track the target path described by desired yaw angle and lateral displacement. Then, the fast terminal sliding mode controller (FTSMC) is proposed for the SBW system to suppress disturbances.
2017-09-23
Technical Paper
2017-01-1963
Yuande Jiang, Weiwen Deng, Rui He, Shun Yang, Shanshan Wang, Ning Bian
Abstract Adaptive cruise control (ACC), as one of the advanced driver assistance systems (ADAS), has become increasingly popular in improving both driving safety and comfort. Since the objectives of ACC can be multi-dimensional, and often conflict with each other, it is a challenging task in its control design. The research presented in this paper takes ACC control design as a constrained optimization problem with multiple objectives. A hierarchical framework for ACC control is introduced, aimed to achieve optimal performance on driving safety and comfort, speed and/or distance tracking, and fuel economy whenever possible. Under the hierarchical framework, the operational mode is determined in the upper layer, in which a model predictive control (MPC) based spacing controller is employed to deal with the multiple control objectives. On the other hand, the lower layer is for actuator control, such as braking and driving control for vehicle longitudinal dynamics.
2017-09-23
Journal Article
2017-01-1966
Min Ke, Bing Zhu, Jian Zhao, Weiwen Deng
Abstract Knowledge of intelligent vehicle absolute position is a vital premise for the implementation of decision programming, kinematic and dynamics control. In order to achieve high accuracy positioning and reduce running cost as much as possible under all operating conditions, this paper proposed an integrated positioning method based on GPS and Ultra Wide Band(UWB) for intelligent vehicle’s navigation and position system. In this method, GPS and UWB are alternately active according to the confidence level of GPS signal. When the vehicle is traveling in a wide-open area and GPS signal is well received, the positioning results of Dead Reckoning system are corrected by the low frequency positioning output from GPS. During the correcting process, in order to realize the better fusion of measurement data, a simplified federal Kalman filter was designed by using indirect method.
2017-09-23
Journal Article
2017-01-1969
Yuanxin Zhong, Sijia Wang, Shichao Xie, Zhong Cao, Kun Jiang, Diange Yang
Abstract Real-time reconstruction of 3D environment attributed with semantic information is significant for a variety of applications, such as obstacle detection, traffic scene comprehension and autonomous navigation. The current approaches to achieve it are mainly using stereo vision, Structure from Motion (SfM) or mobile LiDAR sensors. Each of these approaches has its own limitation, stereo vision has high computational cost, SfM needs accurate calibration between a sequences of images, and the onboard LiDAR sensor can only provide sparse points without color information. This paper describes a novel method for traffic scene semantic segmentation by combining sparse LiDAR point cloud (e.g. from Velodyne scans), with monocular color image. The key novelty of the method is the semantic coupling of stereoscopic point cloud with color lattice from camera image labelled through a Convolutional Neural Network (CNN).
2017-09-23
Technical Paper
2017-01-1967
Wei Liu, Huan Tian, Jun Hu, Shuai Cheng, Huai Yuan
Abstract Image segmentation is critical in autonomous driving field. It can reveal essential clues such as objects’ shape or boundary information. The information, moreover, can be leveraged as input information of other tasks: vehicle detection, for example, or vehicle trajectory prediction. SegNet, one deep learning based segmentation model proposed by Cambridge, has been a public baseline for scene perception tasks. It, however, suffers an accuracy deficiency in objects marginal area. Segmentation of this area is very challenging with current models. To alleviate the problem, in this paper, we propose one edge enhanced deep learning based model. Specifically, we first introduced one simple, yet effective Artificial Interfering Mechanism (AIM) which feeds segmentation model manual extracted key features. We argue this mechanism possesses the ability to enhance essential features extraction and hence, ameliorate the model performance.
2017-09-23
Journal Article
2017-01-1972
Sen Li, Xin Bi, Libo Huang, Bin Tan
Abstract In Advanced Driver Assistant System (ADAS), the automotive radar is used to detect targets or obstacles around the vehicle. The procedure of Constant False Alarm Rate (CFAR) plays an important role in adaptive targets detection in noise or clutter environment. But in practical applications, the noise or clutter power is absolutely unknown and varies over the change of range, time and angle. The well-known cell averaging (CA) CFAR detector has a good detection performance in homogeneous environment but suffers from masking effect in multi-target environment. The ordered statistic (OS) CFAR is more robust in multi-target environment but needs a high computation power. Therefore, in this paper, a new two-dimension CFAR procedure based on a combination of Generalized Order Statistic (GOS) and CA CFAR named GOS-CA CFAR is proposed. Besides, the Linear Frequency Modulation Continuous Wave (LFMCW) radar simulation system is built to produce a series of rapid chirp signals.
2017-09-23
Journal Article
2017-01-1970
Guizhen Yu, Zhangyu Wang, Xinkai Wu, Yalong Ma, Yunpeng Wang
Abstract: In this paper, an efficient lane detection using deep feature extraction method is proposed to achieve real-time lane detection in diverse road environment. The method contains three main stages: 1) pre-processing, 2) deep lane feature extraction and 3) lane fitting. In pre-processing stage, the inverse perspective mapping (IPM) is used to obtain a bird's eye view of the road image, and then an edge image is generated using the canny operator. In deep lane feature extraction stage, an advanced lane extraction method is proposed. Firstly, line segment detector (LSD) is applied to achieve the fast line segment detection in the IPM image. After that, a proposed adaptive lane clustering algorithm is employed to gather the adjacent line segments generated by the LSD method. Finally, a proposed local gray value maximum cascaded spatial correlation filter (GMSF) algorithm is used to extract the target lane lines among the multiple lines.
2017-09-23
Technical Paper
2017-01-1973
Yang Yin, Xin Bi, Libo Huang, Shitao Yan
Abstract Millimeter wave (MMW) automotive radar plays an important role in the advanced driving assistance system (ADAS), which detects vehicles, pedestrians and other obstacles. In the adaptive cruise control (ACC) and the automatic emergency brake (AEB) system, the target needs to be oriented. One of the automotive radar’s task is to get the direction information which includes the range, speed, azimuth and height of the target by high intermediate frequency (IF) signal sampling rate. In order to solve the problem of high sampling rate for the MMW radar caused by the traditional Nyquist sampling theorem when the target is located, a new method based on the compressed sensing (CS) for the target location is proposed in this paper. This paper presents the linear frequency modulated continuous wave (LFMCW) model and simulates the sampling and reconstruction of the radar’s IF signal via CS technique by using MATLAB.
2017-09-23
Technical Paper
2017-01-1971
Sihan Chen, Libo Huang, Xin Bi, Jie Bai
Abstract For sensing system, the trustworthiness of the variant sensors is the crucial point when dealing with advanced driving assistant system application. In this paper, an approach to a hybrid camera-radar application of vehicle tracking is presented, able to meet the requirement of such demand. Most of the time, different types of commercial sensors available nowadays specialize in different situations, such as the ability of offering a wealth of detailed information about the scene for the camera or the powerful resistance to the severe weather for the millimeter-wave (MMW) radar. The detection and tracking in different sensors are usually independent. Thus, the work here that combines the variant information provided by different sensors is indispensable and worthwhile. For the real-time requirement of merging the measurement of automotive MMW radar in high speed, this paper first proposes a fast vehicle tracking algorithm based on image perceptual hash encoding.
2017-09-23
Technical Paper
2017-01-1977
Xin Bi, Bin Tan, Zhijun Xu, Libo Huang
Abstract Vehicle and pedestrian detection technology is the most important part of advanced driving assistance system (ADAS) and automatic driving. The fusion of millimeter wave radar and camera is an important trend to enhance the environmental perception performance. In this paper, we propose a method of vehicle and pedestrian detection based on millimeter wave radar and camera. Moreover, the proposed method complete the detection of vehicle and pedestrian based on dynamic region generated by the radar data and sliding window. First, the radar target information is mapped to the image by means of coordinate transformation. Then by analyzing the scene, we obtain the sliding windows. Next, the sliding windows are detected by HOG features and SVM classifier in a rough detect. Then using the match function to confirm the target. Finally detecting the windows in a precision detection and merging the detecting windows.
2017-09-23
Technical Paper
2017-01-1978
Yuxiang Feng, Simon Pickering, Edward Chappell, Pejman iravani PhD, Chris Brace
Abstract The major contribution of this paper is to propose a low-cost accurate distance estimation approach. It can potentially be used in driver modelling, accident avoidance and autonomous driving. Based on MATLAB and Python, sensory data from a Continental radar and a monocular dashcam were fused using a Kalman filter. Both sensors were mounted on a Volkswagen Sharan, performing repeated driving on a same route. The established system consists of three components, radar data processing, camera data processing and data fusion using Kalman filter. For radar data processing, raw radar measurements were directly collected from a data logger and analyzed using a Python program. Valid data were extracted and time stamped for further use. Meanwhile, a Nextbase monocular dashcam was used to record corresponding traffic scenarios. In order to measure headway distance from these videos, object depicting the leading vehicle was first located in each frame.
2017-09-23
Technical Paper
2017-01-1975
Wenhui Li, Wenlan Li, Jialun Liu, Yuhao Chen
Abstract Vehicle detection has been a fundamental problem in the research of Intelligent Traffic System (ITS), especially in urban driving environment. Over the past decades, vision-based vehicle detection has got a considerable attention. In addition to the rich appearance information, the stereo vision method also provides depth information, which could achieve higher accuracy and precision. In this paper, a hybrid method for stereo vision-based real-time vehicle detection in urban environment is proposed. Firstly, we extract vehicle features and generate the Region of Interest (ROI). Semi-global Matching (SGM) algorithm is then utilized on the ROIs to generate disparity maps and get the depth information, which could be used to compute the width of each ROI. The noise regions, always with obvious depth variation in the disparity maps are excluded by the clustering approach.
2017-09-23
Technical Paper
2017-01-1974
Tao Chen, Jie Bai, Fang Wang, Libo Huang
Abstract In the last years, in order to fit the requirements of automotive radar application under the multi-target conditions, several proposals about Continuous Waveform (CW)have been developed. The transmit signal with Multiple Frequency Shift Keying (MFSK) technology was developed to analyze the target information in range domain and Doppler frequency domain simultaneously, but the MFSK waveform has lower estimation accuracy in phase measuring. A higher accuracy signal type is the chirp sequence waveform of monopulse radar, which is based on two-dimension independent frequency measuring. It can also get the range and velocity information, but might lead to ambiguities in Doppler domain. To avoid the Doppler ambiguity, a method is proposed in this paper, which uses the modified chirp sequence waveform. The carrier frequencies of the modified chirp sequence are different, which causes the Doppler frequency offset.
Viewing 1 to 30 of 12260