With a larger global population and fewer farmers, harvests will have to be larger and easier to manage. By high precision planting, each crop will have the same available area on the field, yielding an even size of the crops which means the whole field can be harvested at the same time. This thesis investigates the possibility for such precision planting in curves. Currently, Väderstads planter collection Tempo, can deliver precision in the centimeter range for speeds up to 20 km/h when driving straight, but not when turning. This thesis makes use of the available sensors on the planters, but also investigates possible improvements by including additional sensors. An Extended Kalman Filter is used to estimate the individual speeds of the planting row units and thus enabling high precision planting for an arbitrary motion. The filter is shown to yield a satisfactory result when using the internal measurement units, the radar speed sensor and the GPS already mounted on the planter. By implementing the filter, a higher precision is obtained compared to using the same global speed for all planting row units.