精确农业-全球定位系统GPS--2

1、精确农业概论Fundamentals of Precision Agriculture,2 GNSS及其应用,GNSS在精确农业中的应用 具体公司产品介绍 GNSS的实际应用 GNSS数据格式 GNSS定位信息由大地坐标转换为平面导航坐标,GNSS在精确农业中的应用,农情信息的收集 作业 播种 除草 喷药 施肥 收获,Precise plowing, seeding, watering, spraying Localized identification and treatment of distressed crops reduces chemical use Precise levelin

2、g of fields prevents fluid runoff Machinery, asset, and personnel management Automated Guidance自动导航,播种,除草,精确农业中的GNSS定位精度要求,变量施肥 Swath control 产量图 变量除草剂应用 喷药重叠控制 行播种 形成种床,30 m 1 m 10 m 1 m 10 cm 10 cm 5 cm,精确农业中的GNSS定位精度要求,占最大市场份额的GNSS应用 Guidance Systems,Automatically (or through visual cues) steers

3、a tractor through a series of GPS points or down an A-B Line. Reduces driver fatigue. Allows for straighter rows.,Reduces overlap and skips. Can skip a wet spot in field during planting/cultivating, work other side of field, then go back and plant or cultivate area that was skipped.,GNSS导航应用,农业车辆自动转

4、向和导航系统 John Deere iTEC Pro 农机具引导 Trimble GPS on Implement down to 1 inch. AutoFarm AFTracker,农业车辆GNSS导航系统,驾驶辅助系统 自动转向系统 完全自主（无人）驾驶系统,生产产家： John Deere CASEIH Trimble TOPCON Ag Leader Technology AgJunction .,驾驶辅助系统,定义：在有人驾驶的农用车辆进行作业时，将当时的车辆位置和作业轨迹、推荐的作业路线等在显示器上表示出来，帮助驾驶员进行判断和操作的系统。 Lightbar guidance s

5、ystem 显示控制器,What is a lightbar?,Uses lights to indicate what the operator should do to maintain the desired path,L160 Lightbar,Lightbar guidance system,GPS-based steering assistance: (a) lightbar system; (b) GUI screen,自动转向系统：两种,1,2,自动转向系统,农机自动导航,导航传感器 位置、航向 车轮转角,农机运动模型 运动学模型 动力学模型,导航规划 直线跟踪 曲线跟踪,转向

6、角 转向控制 PID控制 智能控制,农机 状态,运动 状态,农机 状态,运动 状态,农机状态,GNSS自动转向系统硬件,GNSS接收机 终端 自动转向ECU 前轮转角传感器 电动方向盘和电液阀组,Wheel angle sensors,(a) Linear potentiometer.,(b) Optical encoder.,Flow Meters（流量计）, Encoders（编码器）, and Potentiometers（电位计） for Front Wheel Steering Position,前轮转角传感器,Steering angle sensor measuring cyli

7、nder extension in a combine.,T2 TERRAIN COMPENSATION TECHNOLOGY,$3,495.00,EZ-Steer Assisted Steering System,Trimble Autopilot automated steering system,EZ-Pilot Assisted Steering System,(T3 Enhanced Terrain Compensation,Autopilot Automated Steering System,AES-25 Electric Steering System,System 350,O

8、nTrac3 Assisted Steering System,GeoSteer Automated Steering,John Deere卫星自动导航系统,IN-SEASON REPEATABILTY UNIQUE ACCURACY AND REPEATABILITY: RTK,John Deere卫星自动导航系统,ALL-TERRAIN ACCURACY: PARALLEL TRACKING AUTOMATIC GUIDANCE: INTEGRATED AUTOTRAC MULTI-BRAND COMPATIBILITY: AUTOTRAC CONTROLLER MULTI-BRAND C

9、OMPATIBILITY: ATU 200 STEERING KIT,The AutoTrac Universal 200 is approved for over 600 models from John Deere as well as other brands.,Resume switch, power supply, and microprocessor are built into the unit,iTEC Pro,1. As you approach your headland, iTEC Pro works with AutoTrac guidance through your

10、 GreenStar 3 display to automatically,2. Raise the implement and turn the tractor,3. And reengage the implement, all hands-free.,Case IH AFS ElectriSteer Affordable _ Effective Autoguidance,Case IH AFS AccuTurn- Hands Free End-of-Row Turning,GNSS语句格式及其解析 坐标转换 路径规划 自动转向控制器算法,GNSS导航系统软件,GNSS语句格式及其解析,A

11、SCII和二进制 NMEA-0183为专用GPS数据输出拟定的标准格式。几乎所有的GPS接收机均采用了这一标准，并可以输出多种数据格式。如GGA、ZDA、GLL、GSA、GSV、VTG等。,NMEA0183标准语句,$GPGGA,M,M,*hh,UTC时间，hhmmss（时分秒）格式 纬度ddmm.mmmm（度分）格式（前面的0也将被传输） 纬度半球N（北半球）或S（南半球） 经度dddmm.mmmm（度分）格式（前面的0也将被传输） 经度半球E（东经）或W（西经） GPS状态：0=未定位，1=非差分定位，2=差分定位，6=正在估算 正在使用解算位置的卫星数量（0012）（前面的0也将被传输）

12、,HDOP水平精度因子（0.599.9） 海拔高度（-9999.999999.9） 地球椭球面相对大地水准面的高度 差分时间（从最近一次接收到差分信号开始的秒数，如果不是差分定位将为空） 差分站ID号00001023（前面的0也将被传输，如果不是差分定位将为空）,GNSS定位信息由大地坐标转换为平面导航坐标,通过GPS测量获得的是WGS-84坐标系下的三维经纬度和海拔高度信息 而实际动态轨迹测量工作中，经常需要将信息在起始点为原点的平面直角坐标系中表达，因此需要进行数据转换。 此转换的目的在于将GPS接收器获得的物体在世界大地坐标系上的位置信息转换成便于对物体运行轨迹作评估分析的导航系统参照的

13、局部相切平面坐标数据。 两个步骤：首先，将数据从世界大地坐标系转换为地心地固坐标系；然后，将数据从地心地固坐标系转换到导航系统参照的局部相切平面坐标。,GNSS定位信息由大地坐标转换为平面导航坐标,GPS定位信息由大地坐标转换为平面导航坐标,在进行转换之前，首先要选择椭圆体作为参照来模拟地球形状。,GNSS定位信息由大地坐标转换为平面导航坐标,从大地坐标系转换为地心地固坐标系，公式如下：,GNSS定位信息由大地坐标转换为平面导航坐标,在转换过程中，局部相切平面坐标原点必须给予确定。通常将起点的转换坐标最终定义为（X0，Y0，Z0），作为相切平面坐标原点。将数据从地心地固坐标系转换到导航系统参照

14、的局部相切平面坐标的转换公式为：,软件：路径规划（ Path planning）,Path planning is a generic term used to describe the set of algorithms that determine where the vehicle should be guided. Most modern automatic guidance systems support a variety of guidance patterns to match planting practices.,Point Guidance,Target point se

15、lected on map screen. Cursor location indicates present position, target position highlighted. Cursor provides guidance to target.,Swath Guidance,Anchor points established to create base line on map screen. Parallel lines generated at desired swath spacing. Can be used for straight or contour swaths

16、 Light bar or similar device used to provide guidance along line. Automatic steering possible.,农业作业流程分析,Line A B is base line called Track 0 Guidance provided between points A and B,Example of the different guidance patterns offered by a modern guidance system,if a parallel track system has generate

17、d a series of waypoints parallel to the user-defined reference line (the A-B line), the navigation engine of the vehicle will compare its current position with the location of the subsequent point of the trajectory, and deduce the best steering command required to reach the targeted waypoint.,软件：路径跟

18、踪（ Path Tracking）,Offset and Heading,A list of requirements for automatic row guidance of agricultural vehicles could be as follows: 1. capable of following contour and straight rows; 2. can adapt to “guess row” conditions; 3. works at forward speeds of 0.512 km/h; 4. can be guided within standing a

19、nd lodged crops; 5. immune to weeds or other potential disturbances; 6. not affected by the sizes and positions of implements; 7. smooth transition to higher signal accuracy or alternative guidance systems.,软件：路径跟踪（ Path Tracking）,When the guidance lines are defined, given a vehicle position, the pa

20、th-planning algorithms can calculate the closest swath and corresponding cross-track error. Some algorithms also calculate the heading error, which is the angle between the current vehicle heading and the heading of the swath.,One limitation on control performance is imposed by the steering actuatio

21、n. A poorly designed or poorly tuned controller will have difficulty moving the vehicle smoothly to the A-B line. The minimum safe turn radius for any given speed must also be handled properly.,软件：路径跟踪（ Path Tracking）,软件：路径跟踪（ Path Tracking）,软件：路径跟踪（ Path Tracking）,Control algorithms use the cross-t

22、rack error and heading error calculated by the path-planning algorithms to calculate the steering corrections that the vehicle must then apply in order to minimize cross-track error and heading error. Tuning-Based Control Algorithms：PID Model-Based Control Algorithms,ECU程序：自动转向控制算法,Tuning-Based Cont

23、rol Algorithms：PID,ECU程序：自动转向控制算法,Model-Based Control Algorithms,ECU程序：自动转向控制算法,为了得到更高精度需增加相应传感器,Tilt sensor probably the best sensor you can add on IMU (Inertial Mass Unit): Next best sensor Helps short term loss of GPS signal.,地形补偿技术,Roll_offset_dist = height Tan(roll_angle),GNSS+INS,Inertial Navi

24、gation System (INS) Inertial Measurement Unit (IMU) 航位推算 Dead reckoning Helps short term loss of GPS signal 为了得到更高精度，需增加相应传感器，如Tilt sensor，FOG (Fiber optic gyroscope)，GDS (Geomagnetic direction sensor)。,GNSS+INS,惯性测量单元用于测量三个方位角: yaw（偏向）、Pitch（俯仰）、 roll（翻滚）,Innalabs Attitude and Heading Reference Sys

25、tem (AHRS),GNSS+INS,惯性测量单元用于测量三个方位角: yaw（偏向）、Pitch（俯仰）、 roll（翻滚）,NovAtel PwrPak7,GNSS+INS functionality,无人驾驶（完全自主）技术,多传感器融合：多传感器信息融合技术就是指通过一定的算法“合并”来自多个信息源的信息，以产生比单个传感器所得到数据更可靠、更准确的信息，并根据这些信息做出最可靠的决策。 RAdio Detection and Ranging (RADAR) ultrasonic sensors microwave sensors 机器人拖拉机,农机具GNSS引导,GPS引导 视觉引

26、导 超声波引导 机械触杆,GPS and Side-shift Controlled Inter-row Hoeing,RTK GPSAntenna Hoe,RTK GPSAntenna Tractor,Tractor Controller for speed, steering,engine rpm,Implement Controller Side shift,Conventional hoewith hydraulic side-shift,Automatic tractor,Trimble TrueGuide & TrueTracker,Orthmans Tracker IV system,GPS antenna senses implement position relative to path and sends corrective steering information from controller Tracker steers blades according to signal from controlle