Abstract: Precision breeding and a local position system (LPS) substitute GPS for field local positioning was proposed in this paper. The system mainly consisted of an omnidirectional vision sensor, artificial landmarks, PC and PC software operating vehicle. The artificial landmarks adopted a primary landmark and three subsidiary landmarks. The algorithm mainly included landmark color pixels beyond threshold which were extracted and divided as a small area based on the Euclid geometrical distance. The center of gravity of the extracted small area was calculated and represented as a position of one landmark. Omnidirectional vision sensor position was estimated according with circumferential theorem and geometric transformation formula based on the direction angles. Experiments were conducted on a level lawn under the sun in a 30 m×30 m rectangular area. Results showed that the distance RMS error between estimated position and test position was about 15 cm. The system is feasible for precision breeding such as field positioning, precision fertilizing and spaying and production mapping.