navigation techniques of mobile robots in greenhouses

With the continuous development of the industrialization process, the countries all over the world gradually appeared lack of agricultural labor force and aging phenomenon, which was especially prominent in developed countries. however the agricultural robot with high operating efficiency, high qualities of work will play an increasingly important role in future agricultural production. robot navigation is not only the key to automation and also the biggest obstacle constraining their development. this paper provides a review of relevant mobile robot positioning technologies. the paper defines seven categories for positioning systems: 1. odometry; 2. inertial navigation; 3. magnetic compasses; 4. active beacons; 5. global positioning systems; 6. landmark navigation; and 7. model matching. therefore, the research status of agricultural robot navigation was introduced in this paper. also, this paper discusses the problem of using navigation methods for agricultural mobile robots in greenhouses. nowadays, many agricultural tasks are dangerous and repetitive for human beings and could be improved employing robots. the autonomous navigation in greenhouses has been solved using both deliberative and pseudo-reactive techniques.