The Standard Operating Procedures for Public Surveys were partially amended in March 2013. By this amendment, applications of GNSS observations with GLONASS are extended and using QZSS as complementing GPS is permitted.
The Geospatial Information Authority of Japan (GSI) has operated the GPS Earth Observation Network system (GEONET) since 1996, as an indispensable national infrastructure for GPS surveying, crustal deformation monitoring and precise Location Based Services. With the advent of multi GNSS environment, advanced users require GNSS data other than GPS, such as GLONASS, Quasi Zenith Satellite System (QZSS), Galileo, and so on. In response to these demands, GSI updated all receivers and antennas of about 1,300 GEONET stations, and started to provide QZSS and GLONASS data from May 10, 2013, yielding a network-based RTK-GNSS positioning service for all over Japan by the private sector. GEONET is now literally a GNSS Earth Observation Network system.
Survey using GPS has been spreading in the world including Japan. Japanese government launched QZS (Quasi-Zenith Satellite) which is the first satellite of QZSS (Quasi-Zenith Satellite System) for the purpose to improve of GPS weak point. It can stay over Japan for 8 hours and keep the high zenith angle. Moreover, it is possible to obtain location information of high accuracy by support signal transmitted from QZS which is LEX signal. The purpose of the research is to conduct the demonstrated experiment which uses the LEX signal from QZS in Hokuriku area of Japan, and it was compared with accuracy for absolute positioning between VRS-GPS and QZSS.
This study was conducted to examine the possibility of monitoring growth and yield estimation of rice utilizing high resolution SAR satellite data (X-band, dual-polarized). We considered a quantitative understanding of the relationship between changes in the backscattering coefficient and changes in growth and yield of rice. Results indicated that with 11 day repeat pass of TerraSAR-X satellite data, it was possible to observe the time series changes of the backscattering coefficient of rice growth. The polarized TerraSAR-X data indicated the possibility to estimate growth conditions of the stems and plant height due to high correlation between TerraSAR-X data and the stems, the rate of vegetation cover during phonological stage. In addition, there was a correlation between the HH polarization and grains, ripening rate of the crop growth period from heading stage to pre-maturing stage. The yield was correlated with the HH polarization of 49° angle of incidence at the heading stage and VV polarization or HH×VV dB of 49° angle of incidence before maturation stage. Utilizing the SAR data (X-band, dual-polarized) of the time series was highly effective for monitoring the plant growth and yield estimation. In the future work, based on the relationship between the crop growth, yield and obtaining the backscattering coefficients during multiple years, considerations of climatic changes, it would be significant to develop a comprehensive crop growth model derived from the regression equations to estimate the SAR backscattering coefficients. Additionally, we intend to expand the growth models for yield predictions.