Low-Cost Collaborative Positioning for Autonomous Agents Using Carrier Phase DGNSS

This paper presents a DGNSS-based collaborative positioning approach for multiple agents where one of the agents is equipped with highly precise GNSS equipment and the other agents are equipped with low-cost sensors. Sensors for low-cost navigation modules were selected and a panel of circuit boards was designed. To evaluate the proposed approach, the designed low-cost navigation modules and a high-end receiver were set up on geodetic pillars with precisely known coordinates. Carrier phase DGNSS was used to compute the baselines between the receivers. By comparing the estimated baselines to the true baselines, the horizontal and vertical positioning errors were analysed. The results show that when the ambiguities are successfully fixed, sub-dm accuracy can be achieved even for the low-cost boards. Moreover, it was investigated whether barometric height differences could be used to improve the height estimation. However, the results showed that the barometric height differences between agents are not accurate enough to support an already cm-accurate height estimation, even after calibration. When all GNSS baselines are jointly used to estimate the positions of the receivers, mean horizontal errors of less than 3 cm and mean vertical errors of less than 10 cm can be achieved.