Paddy field hard bottom layer contour sensing and digital modeling method

The invention relates to a paddy field hard bottom layer contour sensing and digital modeling method. The paddy field hard bottom layer contour sensing method comprises the following steps: S1, acquiring position and attitude data of a wheeled agricultural machine during running by adopting a GNSS and an AHRS; s2, according to the relative positions of the installed GNSS and AHRS and the rear wheel of the agricultural machine, coordinate transformation is carried out to obtain the coordinate value of the contact point of the wheel bottom and the hard bottom layer in the point set of the coordinate system; the paddy field hard bottom layer contour digital modeling method comprises the following steps: S3, uniformly diluting a point set, and performing triangulation to construct a bottom layer three-dimensional contour; and S4, based on a ray method and a point-surface intersection principle, extracting a specific triangle containing an estimated point, and estimating the elevation of any point in the whole dom