Preliminary analysis of the RTK positioning using Android GNSS Raw Measurements and Application Feasibility for the Trajectory mapping using UAV's

摘要

With the release of Android N, Google announced the availability of GNSS Raw data from the mobile phone. This opens up to the broader prospective for research, analysis and enhancement of the positioning quality in mobile phones. With increasing applications based upon augmented reality, e-banking, e-health, etc., there is a rapid increase in the demand for precise positioning using the existing architecture of mobile devices. But, the quality of carrier phase raw data is not adequate for the substantial RTK (precise positioning). Artifacts in smartphone GNSS antenna, environmental degradation and cycle slips are few of the major issues to be addressed for reliable carrier phase positioning in the smartphone. The code range residual for kinematic and static measurement setup are very noisy in comparison to carrier phase residual. This results in invalid positioning solution with wrong ambiguity fixing. Doppler smoothed code pseudorange (Kalman Filter) shows a considerable improvement in the positioning accuracy as comparted to standard SPP solution. The RTK positioning is feasible with the raw GNSS data from the smartphone, but only float solutions are reliable. The position error due to gyroscope bias in x and y axis is 0.0036 m and 0.0032 m respectively and thus, can be used for small cycle slips detection and corrections.