Accuracy Verification of a Smartphone-Based PPK GNSS Surveying Technique and Earth Volume Determinations

Raw global navigation satellite system (GNSS) measurements from a smartphone are used for position determinations as they can be extracted from the Android operating systems together with Thailand Department of Lands (DOL) provide network real-time kinematic GNSS correction services; hence, enabling cheaper and more compact for high precision solutions.  This study applies the GNSS raw observations obtained from a smartphone in order to determine positions and later compute an Earth volume based on obtained positioning results as Thailand constructions are increasing in different scales and earthworks is one of the primary works.  The experimental area is 11,145 square meters with 21 ground markers.  GNSS signals are measured every 1 second at 1-hour observation period.  Computed observations from a smartphone provide relatively optimal horizontal and vertical positioning accuracies of 4 and 8 centimetres with the longest convergence time of 40 minutes.  Differences between the determined Earth volumes using the smartphone-based and traditional surveying technique do not exceed 10%.  The estimated manhour and equipment cost are efficient can lead to 90% reduction.  Performances are demonstrated and assessed on actual earthwork computations.  Future work may apply estimated smartphone-based network real-time kinematic (NRTK) and post-processed kinematic (PPK) positioning solutions as ground control points for other earthwork determinations through aerial photography