SAE J 3088-2017 Active Safety System Sensors.pdf

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4、0 (outside USA) Fax: 724-776-0790 Email: CustomerServicesae.org SAE WEB ADDRESS: http:/www.sae.org SAE values your input. To provide feedback on this Technical Report, please visit http:/standards.sae.org/J3088_201711 SURFACE VEHICLE INFORMATION REPORT J3088 NOV2017 Issued 2017-11 Active Safety Syst

5、em Sensors RATIONALE This SAE Surface Vehicle Information Report is intended to provide comprehensive reference and background information pertaining to sensors used by automotive active safety systems. TABLE OF CONTENTS 1. SCOPE . 6 2. REFERENCES . 6 3. ACTIVE SAFETY SYSTEM SENSORS BASIC DEFINITION

6、S . 6 4. ACTIVE SAFETY SYSTEM PERCEPTION LAYERS . 6 4.1 JDL Data Fusion Model for Automotive . 7 5. COMMON RANGE SENSOR EVALUATION PARAMETERS AND CONSIDERATIONS 8 5.1 Angular Resolution . 8 5.2 Distance Precision . 8 5.3 Range . 9 5.4 Angle of View . 9 5.5 Object Material . 10 5.6 Weather and Exteri

7、or Testing Conditions 10 6. RADAR . 10 6.1 Types of Automotive Radar Systems . 11 6.1.1 Pulsed Radar . 11 6.1.2 Continuous-Wave Radar 11 6.1.3 Frequency-Modulated Continuous-Wave (FMCW) Radar . 11 6.1.4 Radar Sensor Architectures . 11 6.2 Radar Frequency . 12 6.3 Regulation 12 6.4 Radar Limitations/

8、Characteristics 13 6.4.1 Angular Resolution . 13 6.4.2 Distance Resolution . 13 6.4.3 Doppler Resolution . 13 6.4.4 Obscuration 13 6.5 Classification/Feature Extraction . 13 6.6 Radar Applications . 14 SAE INTERNATIONAL J3088 NOV2017 Page 2 of 53 7. VISION SENSORS 14 7.1 Types of Vision Sensors 14 7

9、.1.1 Charge Coupled Devices . 15 7.1.2 CMOS Devices . 15 7.2 Configurations 15 7.2.1 Mono versus Stereo Cameras . 15 7.3 Vision Limitations/Characteristics 16 7.4 Feature Extraction 17 7.5 Communications Protocols 17 7.6 Vision Applications . 17 8. LIDAR . 18 8.1 Types of Automotive LiDAR Sensor Tec

10、hnologies 19 8.1.1 Pulsed LiDAR . 19 8.1.2 Coherent Energy Detection 20 8.2 LiDAR Sensor Architectures 20 8.2.1 Light Source . 20 8.2.2 Wavelength 21 8.2.3 Photodetector Type 22 8.3 Scanned versus Flash LiDAR 22 8.4 Eye Safety 23 8.5 LiDAR Limitations/Characteristics 24 8.5.1 Angular Resolution . 24

11、 8.5.2 Distance Resolution . 25 8.5.3 Obscuration 25 8.5.4 Field of View . 25 8.5.5 Mounting Location 25 8.6 Classification/Feature Extraction . 25 8.7 LiDAR Applications 26 9. ULTRASONIC SENSORS . 26 9.1 Types of Automotive Ultrasonic Sensor Technologies 27 9.2 Ultrasonic Sensor Architecture 27 9.2

12、.1 Transducer Type 28 9.2.2 Detection Processor . 28 9.2.3 Frequency and Wavelength . 29 9.2.4 Beam Pattern . 30 9.2.5 Single Echo, Multiple Echo 31 9.2.6 Measurement Cycle . 31 9.2.7 Triangulation 33 9.3 Ultrasonic Sensor Limitations/Characteristics 33 9.3.1 Range . 33 9.3.2 Temperature . 33 9.3.3

13、Corner Reflections . 34 9.3.4 Noise Sensitivity . 34 9.4 Ultrasonic Sensor Applications 34 10. GLOBAL NAVIGATION SATELLITE SYSTEMS (GNSS) 34 10.1 Global Positioning System (GPS) Description . 34 10.1.1 GPS Background . 34 10.1.2 GPS Satellites 35 10.1.3 GPS Receivers . 36 10.2 GPS Types . 36 10.3 GP

14、S Architecture . 36 10.4 GPS Limitations/Characteristics 36 10.5 GPS Applications . 37 SAE INTERNATIONAL J3088 NOV2017 Page 3 of 53 11. COMPASSES 37 11.1 Types of Compasses . 37 11.2 Configurations 37 11.3 Compass Characteristics . 38 11.3.1 Heading Precision 38 11.3.2 2 Axis versus 3 Axis . 38 11.3

15、.3 Temperature Stability . 38 11.3.4 Bandwidth 38 11.3.5 Heading Compensation 38 11.4 Magnetic Sensitivity . 39 11.5 Calibration 39 11.6 Applications 39 12. LINEAR ACCELERATION (ACCELEROMETERS) . 40 12.1 Types of Accelerometers . 40 12.1.1 Piezoresistive Micro-Electrical-Mechanical-Systems (MEMS) 40

16、 12.1.2 Capacitive MEMS . 40 12.1.3 Heat Transfer MEMS . 40 12.1.4 Resonant-Beam MEMS . 40 12.2 Configurations 40 12.3 Accelerometer Characteristics . 40 12.3.1 Acceleration Range 40 12.3.2 Sensitivity (On and Off-Axis) 40 12.3.3 Zero-g Bias Level . 40 12.3.4 Linearity 40 12.3.5 Shock Limit . 40 12.

17、3.6 Frequency Response . 41 12.3.7 Temperature Range . 41 12.4 Communication 41 12.5 Applications 41 13. ANGULAR RATE SENSOR (GYROSCOPE) 41 13.1 Types of Angular Rate Sensors . 41 13.2 Configurations 41 13.3 Angular Rate Sensor Characteristics . 41 13.3.1 Angular Rate Range . 41 13.3.2 Sensitivity .

18、 42 13.3.3 Bias, Bias Drift, Bias Instability 42 13.3.4 Linearity 42 13.3.5 Shock Limit . 42 13.3.6 Bandwidth 42 13.3.7 Temperature Range . 42 13.4 Communication 42 13.5 Applications 42 14. WHEEL SPEED SENSORS 43 14.1 Types of Automotive Wheel Speed Sensors . 43 14.1.1 Passive Sensors 43 14.1.2 Acti

19、ve Sensors . 43 14.2 Wheel Speed Sensor Limitations/Characteristics 43 14.2.1 Speed Resolution . 43 14.2.2 Speed Accuracy/Noise . 43 14.3 Wheel Speed Sensor Applications . 43 15. BRAKE SENSORS 43 15.1 Types of Automotive Brake Sensors 43 15.1.1 Brake Pedal Switches 43 15.1.2 Brake Pedal Position Sen

20、sors . 44 15.1.3 Master Cylinder Switches/Position Sensors 44 SAE INTERNATIONAL J3088 NOV2017 Page 4 of 53 15.1.4 Master Cylinder Pressure Sensors 44 15.2 Brake Sensor Limitations/Characteristics 44 15.3 Brake Sensor Applications . 44 16. ACCELERATOR POSITION SENSOR 44 16.1 Accelerator Position Sens

21、or Description 44 16.2 Accelerator Position Sensor Types 44 16.2.1 Potentiometric Sensor 44 16.2.2 Hall Effect Sensor 45 16.3 Accelerator Position Sensor Architecture 46 16.4 Accelerator Position Sensor Limitations/Characteristics . 46 16.5 Accelerator Position Sensor Applications 46 17. CLUTCH PEDA

22、L ACTIVATION SENSOR . 46 17.1 Clutch Pedal Activation Sensor Description. 46 17.2 Clutch Pedal Activation Sensor Types . 46 17.2.1 Mechanical Switches 46 17.2.2 Reed Switches . 47 17.2.3 Potentiometric Sensors 48 17.2.4 Hall Effect Sensors . 48 17.3 Clutch Pedal Activation Sensor Architecture . 48 1

23、7.4 Clutch Pedal Activation Sensor Limitations/Characteristics 48 17.5 Clutch Pedal Activation Sensor Applications . 48 18. GEAR SHIFT POSITION SENSOR . 48 18.1 Gear Shift Position Sensor Description 48 18.2 Gear Shift Position Sensor Types 48 18.2.1 Mechanical Switches 48 18.2.2 Reed Switches . 49

24、18.2.3 Potentiometric Sensors 49 18.2.4 Hall Effect Sensors . 49 18.3 Gear Shift Position Sensor Architecture 49 18.4 Gear Shift Position Sensor Limitations/Characteristics . 49 18.5 Gear Shift Position Sensor Applications 50 19. TURN SIGNAL POSITION SENSOR 50 19.1 Turn Signal Position Sensor Descri

25、ption . 50 19.2 Turn Signal Position Sensor Types 50 19.2.1 Mechanical Switches 50 19.2.2 Reed Switches . 50 19.2.3 Potentiometric Sensors 50 19.2.4 Hall Effect Sensors . 50 19.3 Turn Signal Position Sensor Architecture 50 19.4 Turn Signal Position Sensor Limitations/Characteristics . 51 19.5 Turn S

26、ignal Position Sensor Applications 51 20. STEERING ANGLE SENSOR . 51 20.1 Steering Angle Sensor Description 51 20.2 Steering Angle Sensor Types 51 20.2.1 Analog Sensors 51 20.2.2 Hall Effect . 51 20.2.3 Giant Magneto Resistance . 51 20.2.4 Optical Sensors 52 20.3 Steering Angle Sensor Architecture .

27、 52 20.4 Steering Angle Sensor Limitations/Characteristics 52 20.4.1 Angular Resolution . 52 20.4.2 Wear . 52 20.4.3 Contaminants . 52 20.4.4 Stand-By Current . 52 20.5 Steering Angle Sensor Applications . 53 SAE INTERNATIONAL J3088 NOV2017 Page 5 of 53 21. NOTES . 53 21.1 Revision Indicator . 53 Fi

28、gure 1 Active safety system perception layers 7 Figure 2 Angular resolution 8 Figure 3 Range vs Angle of view measurement (sample) . 10 Figure 4 Possible applications of a radar sensor . 14 Figure 5 Possible applications of a vision sensor 18 Figure 6 EM spectrum 21 Figure 7 MPEs as energy density v

29、ersus wavelength for various exposure times (pulse durations) 24 Figure 8 Possible applications of LiDAR sensors 26 Figure 9 Ultrasonic transducer bandwidth impact on performance 28 Figure 10 Attenuation characteristics of sound pressure by distance 29 Figure 11 A transducer with a circular radiatin

30、g surface whose diameter is large in comparison to a wavelength produces a narrow, conical beam pattern with multiple secondary lobes . 30 Figure 12 Difference in detection distance with varying frequency at the same size of vibrating surface . 31 Figure 13 Detail of measurement cycle 32 Figure 14 P

31、rinciple of triangulation . 33 Figure 15 Ultrasonic sensor applications . 34 Figure 16 GPS operating principle . 35 Figure 17 Magnetic declination 39 Figure 18 Angular rate sensor applications 42 Figure 19 Potentiometric sensor architecture 45 Figure 20 Hall effect sensor architecture . 45 Figure 21

32、 Clutch pedal - mechanical switch . 46 Figure 22 Reed switch 47 Figure 23 Reed switch in gear shift sensor 49 SAE INTERNATIONAL J3088 NOV2017 Page 6 of 53 1. SCOPE The current document is a part of an effort of the Active Safety Systems Committee, Active Safety Systems Sensors Task Force whose objec

33、tives are to: a. Identify the functionality and performance you could expect from active safety sensors b. Establish a basic understanding of how sensors work c. Establish a basic understanding of how sensors can be tested d. Describe an exemplar set of acceptable requirements and tests associated w

34、ith each technology e. Describe the key requirements/functionality for the test targets f. Describe the unique characteristics of the targets or tests This document will cover items (a) and (b). 2. REFERENCES Lytrivis, P. T. (2009). Sensor Data Fusion in Automotive Applications. Dans N. Milisavljevi

35、 (d.), I-Tech (pp. 123-140). Vienna, Austria: Sensor and Data Fusion, Ed. Milisavljevi, N. Richards, M. A. (2005). Fundamentals of Radar Signal Processing. NY: McGraw Hill. Steinberg, A. N. (March 1999). Revisions to the JDL Data Fusion Model. Proc. SPIE 3719, Sensor Fusion: Architectures, Algorithm

36、s, and Applications III, (p. 430). 3. ACTIVE SAFETY SYSTEM SENSORS BASIC DEFINITIONS Many Active Safety System sensors have some processing capability that goes beyond just the acquisition of a physical phenomenon. What we refer to generally as Active Safety System sensors are, in fact, sensing subs

37、ystems of variable complexity, designed to be integrated in an Active Safety System that manages one or more Active Safety System applications. Active Safety System architectures must have an understanding of the processing architecture at the sensor level in order to fully understand how the data p

38、rovided by sensors should be interpreted. 4. ACTIVE SAFETY SYSTEM PERCEPTION LAYERS In discussions comparing “sensors” or sensor “technologies”, one must be able to describe the identified perceived features of the technologies: Nature of the information provided Limitations Strengths Applicability

39、A better understanding will come from being able to identify how the information is provided by a specific sensor. The processing architecture can be described as processing “layers” of information starting with the initial acquisition of the surrounding physical environment up to the control or act

40、uator layer. SAE INTERNATIONAL J3088 NOV2017 Page 7 of 53 The division of tasks between each of the processing layers varies greatly with sensor system architectures. It is not, as the following proposed model implies, a clear-cut separation between layers, nor is that separation necessarily impleme

41、nted in different physical devices. The following discussion aims only at orienting the upcoming discussion on features of Active Safety System sensors. 4.1 JDL Data Fusion Model for Automotive The functional model maintained by the Data Fusion Group of the Joint Directors of Laboratories (JDL) has

42、been revised several times and eventually also for automotive purposes (Lytrivis, 2009) (Steinberg, March 1999). The standard model at different levels of revision generally has five levels in the data fusion domain that connects the data source to the human-computer interface. Level 0: source prepr

43、ocessing sensor measurement (pixel/signal) preprocessing Level 1: object refinement estimation/prediction of entity states based on inferences from observations Level 2: situation refinement estimation/prediction of entity states based on inferred relations Level 3: threat refinement estimation/pred

44、iction of effects on situations or estimated/predicted actions by participants Level 4: process refinement adaptive data acquisition and processing to support process refinement In applying the JDL model to automotive, the Level 4 is not considered to belong to the fusion domain and hence it is left

45、 out, while a Level 5 which is the HMI layer is brought in. The revised JDL model for automotive has three layers in it: Perception Layer includes Level 0 (Pre-processing) and Level 1 (Object Refinement) Decision Application Layer includes Level 2 (Situation Refinement) and Level 3 (Threat Refinemen

46、t) Action/HMI Layer Level 5 (Human Refinement) In support of this discussion, a special emphasis will be made on the “physical interface” to the exterior world, within the Perception Layer. Object refinementPre-processingSituation refinementThreat refinementProcess refinementActionPhysicalinterfaceP

47、erceptionDecisionActi on /HMIFigure 1 - Active safety system perception layers1 1Source: Phantom Intelligence Inc. SAE INTERNATIONAL J3088 NOV2017 Page 8 of 53 5. COMMON RANGE SENSOR EVALUATION PARAMETERS AND CONSIDERATIONS This section covers some of the sensor evaluation parameters that are common

48、 to most technologies and highlights some of the aspects that should be taken into consideration when evaluating technologies. 5.1 Angular Resolution In general2, sensors measure the exterior environment from a single vantage point with a limited field of view (see Figure 2) from that vantage point.

49、 Polar coordinate systems are often used to represent detection information from sensors, since the polar information (distance, vertical angle, and horizontal angle), relative to the sensor, is an adequate representation of the physical perception of devices. As a consequence of this “polar” nature of sensors, the “transversal” resolution of sensors decreases with distance. Figure 2 - Angular