Integrity Determination of RTK solutions in Precision Farming Applications

  • Mr Jun Wang, Queensland University of Technology, Australia
  • Mr Yanming Feng, Queensland University of Technology, Australia
  • Integrity of Real Time Kinematic (RTK) positioning solutions relates to the confidential level that can be placed in the information provided by the RTK system. It includes the ability of the RTK system to provide timely valid warnings to users when the system must not be used for the intended operation. For instance, in the controlled traffic farming (CTF) system that controls traffic separates wheel beds and root beds, RTK positioning error causes overlap and increases the amount of soil compaction. The RTK system’s integrity capacity can inform users when the actual positional errors of the RTK solutions have exceeded Horizontal Protection Levels (HPL) within a certain Time-To-Alert (TTA) at a given Integrity Risk (IR). The later is defined as the probability that the system claims its normal operational status while actually being in an abnormal status, e.g., the ambiguities being incorrectly fixed and positional errors having exceeded the HPL. The paper studies the required positioning performance (RPP) of a CTF system according to a survey conducted among a number of farming companies. The HPL and IR are derived from these RPP parameters. A RTK-specific rover autonomous integrity monitoring (RAIM) algorithm is developed to determine the system integrity according to real time outputs, such as root means squares (RMS) and testing of the likelihood rates of variances, PDOP values and Ambiguity Resolution success rate. Two sets of GPS RTK data collected in fields will be analysed to demonstrate the concept of RTK integrity and assess the RTK solution continuity.