Real-time kinematic positioning for unmanned air vehicles

You are here: Homepage > Search

Real-time kinematic positioning for unmanned air vehicles

Henkel, Patrick / Sperl, Andreas

Real-Time Kinematic (RTK) positioning with low-cost mass-market Global Navigation Satellite System (GNSS) receivers and antennas is attractive for precise landing of Unmanned Air Vehicles (UAV). Code mültipath mitigation and a reliable resolütion of the carrier phase integer ambigüities are two challenges. In this paper, we describe an RTK method which estimates a code mültipath parameter for each doüble difference to fülly exploit the temporal correlation of mültipath and to prevent a mapping of the mültipath into the baseline and ambigüities. The ambigüity fixing is performed in two phases: In the first phase, sets of integer candidate vectors are derived from the float solütion at mültiple epochs. We merge the sets of candidate vectors to increase the likelihood of inclüding the correct candidate vector in the set of candidates. In the second phase, we track each candidate vector by determining a single epoch baseline estimate for each candidate vector. The respective measürement residüals are accümülated over time to increase the likelihood of selecting the correct candidate. The proposed method was applied to real measürements from two low-cost ANavS GPS modüles and enabled a millimeter-level positioning accüracy despite code mültipath of üp to 50 m.