Bridge Method between RTK and PPP-RTK by the Medium of Augmentation Data

Abstract

RTK (Real Time Kinematic) has been used widely in areas of land survey and construction with cm class position accuracy. RTK normally needs the base station, or the physical reference point, and two-ways communication between the reference point and its single rover. PPP-RTK (Precise Point Positioning in Real Time Kinematic networks) [1] is a relatively new technology, which utilizes cm class augmentation data broadcasted from satellite or ground system, and services also cm class positioning accuracy. The augmentation data will become available at L6 band from QZSS (Quasi Zenith Satellite System) [2] in Japan as 24 hours continuous service from April, 2018. The augmentation data are generated by SSR (State Space Representation) server based on the national CORS (Continuously Operating Reference Stations) information, and one set of such data can enable any number of rovers located within about 60kmx60km area to enjoy the high accuracy point positioning. In the near future, this service would be expanded to Asia-Pacific area [3], and mass users in the area as well as Japan are expected to enjoy it. However, PPP-RTK and SSR augmentation technology seem still unfamiliar to non-professional people and business entities in those countries. This is thought to be one of the reasons why very few kinds of PPP-RTK receivers are available on the market. In order to let non-professional people understand and inspire them to use such technology, this paper summarizes the physical meaning of PPP-RTK as comparison with well-known RTK using simplified diagrams. Also to accelerate the receiver development, how to drive RTK processors using augmentation data is described. This attempt gave us a hint to develop “L6 adaptor concept” which receives L6 augmentation signal from QZSS and/or the cell phone network and drives existing RTK equipment from outside. The L6 adaptor concept is further enhanced to the near-future application on the smartphones with existing antenna, GNSS chips and modules embedded inside. Through various discussions and verification tests conducted, it is introduced that L6 adaptor application software with the SSR augmentation can easily develop a new service of smartphones with “decimeter” class point positioning accuracy.