Fruit tree canopy volume is an important factor for precision management in fruit orchards such as pesticide variable spraying,precision fertilizing and yield estimation.In order to overcome the problems of uneven hilly environment and irregular planting on fruit tree canopy volume,a platform for measuring fruit tree canopy volume by laser was set up.Based on AHRS and DGPS sensors,3-D data of laser scanned point of fruit tree canopy in geodetic coordinate system was deduced through spatial coordinates transforming.The area and line information of point cloud of fruit tree canopy were extracted by using slicing technology,and the canopy volume was calculated with an accumulation method.The test showed that the shape of fruit tree canopy could be represented by the canopy point cloud of litchi fruit tree in the geodetic coordinate system.Taking three artificial pruning cylindrical hedgerow trees as experimental object,the relative measuring errors between artificial measurement and laser measurement was about 5%.

Inertial sensor is important for navigation applications.In this paper,the integrated inertial sensor of ADI's ADIS16355 was studied experimentally with a three-axis turntable SGT320E.After a brief introduction of its application in navigation and basic IO operations about data reading and processing,procedures were presented to test ADIS16355 in terms of sensor bias,scale factor,scale factor linearity and long-term stability performances,which led to establishing of its output model.The experiment data with the three-axis turntable was analyzed using Matlab and it was shown that the ADIS16355 XYZ axis static gyro drift and scale factors were in agreement with its datasheet.

MEMS inertial sensors are widely used in navigation,so it is necessary to establish an accurate output model for parameter test.The three-axis turntable test platform is introduced,which is followed by experimental test of the sensor including single axis gyroscope static test,rate transfer test,and three-axis accelerometer six-position test.A MATLAB program is finished for reading data,real-time plotting,and data processing.Test results show the main parameters are in good agreement with the datasheet,and based on the experimental results a simple model is developed for both the built-in gyroscope and accelerometer respectively of the sensor.

The characteristics of MEMS inertial sensor ADIS16209(produced by Analog Device) is introduced.The principle and method to measure the inclination with ADIS16209 are elaborated.An inclination measuring system was designed by using LM3S8962 ARM7 microprocessor and ADIS16209.The measuring system can accurately measure inclination through comparing the results gained by this system with AHRS of Crossbow Technology Company.