PPP-RTK Service for Port Navigation using State Space Representation in DGNSS Medium Frequency Wave

Sul Gee Park，Won Seok Jang，Sang Hyun Park
[ Link to ion.org ]

Abstract – Recently, the precise positioning technique to meet PNT information requirement of positioning and navigation in maritime application is getting a lot of international attention. Especially, Horizontal positioning accuracy requirement in port navigation of International Maritime Organization (IMO) resolution A.915 (22) presented maritime policy and requirement for a future GNSS is 1m. Automatic docking, hydrograph survey, dredging, construction works and cargo handling applications are demanding precise positioning service. RTK technique. One of the precise positioning service solutions, is restricted in service coverage and two-way communication. On the contrary, PPP technique use one way communication for satellite orbit and clock correction and have the merit of wide coverage and absolute positioning. However, precise point positioning based on RTK networks (PPP-RTK) overcome these RTK and PPP limitations and gives centimeter-accuracy and short convergence time. PPP-RTK using state-space date estimate and describes each individual GNSS errors of satellite orbit, satellite clocks, ionosphere, and troposphere. Update rate of State Space Representation (SSR) is different from each error factor. However, it is required within 30 seconds. In Gerhard Wubbena’s paper, another factor for bandwidth reduction is the possibility to optimize the necessary parameter ranges. For SSR the parameter ranges can be chosen with respect to the expected range for the individual physical error components. The bandwidth requirement of SSR for a service area of 1000 km x 1000 km is 1500bps. Currently, Differential GNSS service can cover very large area because it uses the medium frequency wave. In South Korea, 17 DGNSS reference station are installed and these DGNSS reference station’s services are covered all over the country and shore. Especially, that service uses the medium frequency wave and its transmission speed is 200bps. So, It can send a lot of information. The main task of DGNSS reference station provides the pseudorange correction information (PRC) of GNSS. Therefore, the PRC’s correction age is very important factor. When the PRC’s correction age is extent, the error of DGPS positioning will be increased. If SSR information is transferred with PRC information, it necessarily influences the PRC’s correction age. Therefore, this paper proposed extended Korea DGNSS application design to service SSR. To validate extended Korea DGNSS application, experiment had been carried out. For experiment, the directly connected MSK modulator and demodulator was used for avoid the noise of medium frequency wave. As the result, experiments verify the possibility of the SSR information transmission via medium frequency wave and effect of PRC correction age and have shown that the precise orbit data can transmit via medium frequency wave and maximum PRC correction age is not over the 30 seconds.