Yasutoshi Hyakusoku

Dual-frequency precipitation radar (DPR) development on theglobal precipitation measurement (GPM) core observatory

The Dual-frequency Precipitation Radar (DPR) on the Global Precipitation Measurement (GPM) core observatory is developed by Japan Aerospace Exploration Agency (JAXA) and National Institute of Information and Communications Technology (NICT). GPM objective is to observe global precipitation more frequently and accurately. GPM contributes to climate and water cycle change studies, flood prediction and numerical weather forecast. GPM consists of GPM core observatory and constellation satellites carrying microwave radiometers (MWRs) and/or sounders (MWSs). The frequent measurement will be achieved by constellation satellites, and the accurate measurement will be achieved by DPR with high sensitivity and dual frequency capability. GPM core observatory is jointly developed by National Aeronautics and Space Administration (NASA) and JAXA. NASA is developing the satellite bus and GPM microwave radiometer (GMI), and JAXA is developing DPR. GPM algorithms for data processing are developed jointly. The DPR consists of Ku-band (13.6 GHz) radar suitable for heavy rainfall in the tropical region, and Ka-band (35.55 GHz) radar suitable for light rainfall in higher latitude region. Drop size distribution information will be derived which contributes to the improvement of rainfall estimate accuracy. DPR will also play a key role to improve rainfall estimation accuracy of constellation satellites. DPR proto-flight test at JAXA Tsukuba space center is finished and it is delivered to NASA for integration to the GPM observatory. In this paper, DPR PFT test result at Tsukuba space center, DPR status in the GPM observatory environmental test, and DPR on-orbit calibration plan will be presented.

Satellite system test status of The Dual-Frequency Precipitation Radar on the global precipitation measurement core spacecraft

The Dual-frequency Precipitation Radar (DPR) installed on the Global Precipitation Measurement (GPM) core satellite is being developed by JAXA and NICT. This paper describes mission objectives, technical performance, resource allocation, critical design, proto-flight test (PFT) of the DPR instrument and satellite system test status. The DPR system PFT has completed in February 2012. DPR has handed over to NASA and integration of the DPR to the GPM core spacecraft have completed in May 2012. GPM core spacecraft satellite system test has started at NASA Goddard Space Flight Center. After completion of all satellite system tests, the GPM core spacecraft will be sent to JAXA Tanegashima Space Center and launched by H-IIA launch vehicle.

Status of proto-flight model of the dual-frequency precipitation radar for the global precipitation measurement

The Dual-frequency Precipitation Radar (DPR) on the Global Precipitation Measurement (GPM) core spacecraft is being developed by Japan Aerospace Exploration Agency (JAXA) and National Institute of Information and Communications Technology (NICT). The GPM is a follow-on mission of the Tropical Rainfall Measuring Mission (TRMM). The objectives of the GPM mission are to observe global precipitation more frequently and accurately than TRMM. The frequent precipitation measurement about every three hours will be achieved by some constellation satellites with microwave radiometers (MWRs) or microwave sounders (MWSs), which will be developed by various countries. The accurate measurement of precipitation in mid-high latitudes will be achieved by the DPR. The GPM core satellite is a joint product of National Aeronautics and Space Administration (NASA), JAXA and NICT. NASA is developing the satellite bus and the GPM microwave radiometer (GMI), and JAXA and NICT are developing the DPR. JAXA and NICT are developing the DPR through procurement. The contractor for DPR is NEC TOSHIBA Space Systems, Ltd. The configuration of precipitation measurement using an active radar and a passive radiometer is similar to TRMM. The major difference is that DPR is used in GPM instead of the precipitation radar (PR) in TRMM. The inclination of the core spacecraft is 65 degrees, and the flight altitude is about 407 km. The non-sun-synchronous circular orbit is necessary for measuring the diurnal change of rainfall similarly to TRMM. The DPR consists of two radars, which are Ku-band (13.6 GHz) precipitation radar (KuPR) and Ka-band (35.55 GHz) precipitation radar (KaPR). According to the different detectable dynamic ranges, The KaPR will detect snow and light rain, and the KuPR will detect heavy rain. In an effective dynamic range in both KuPR and KaPR, drop size distribution information and more accurate rainfall estimates will be provided by a dual-frequency algorithm. The proto-flight test for DPR have finished in February 2012 and DPR integration on GPM core spacecraft was successfully completed in May 2012. The status of proto-flight model of DPR will be presented.

Preliminary design of the spaceborne dual-frequency precipitation radar for the global precipitation measurement

The dual-frequency precipitation radar (DPR) installed on the Global Precipitation Measurement (GPM) core satellite is being developed by JAXA and NICT. This paper describes the results of preliminary design of the DPR instrument.

Orbital checkout result of the dual-frequency precipitation radar on the global precipitation measurement core spacecraft

The Dual-frequency Precipitation Radar (DPR) on the Global Precipitation Measurement (GPM) core satellite was developed by Japan Aerospace Exploration Agency (JAXA) and National Institute of Information and Communications Technology (NICT). The GPM is a follow-on mission of the Tropical Rainfall Measuring Mission (TRMM). The objectives of the GPM mission are to observe global precipitation more frequently and accurately than TRMM. The frequent precipitation measurement about every three hours will be achieved by some constellation satellites with microwave radiometers (MWRs) or microwave sounders (MWSs), which will be developed by various countries. The accurate measurement of precipitation in mid-high latitudes will be achieved by the DPR. The GPM core satellite is a joint product of National Aeronautics and Space Administration (NASA), JAXA and NICT. NASA developed the satellite bus and the GPM Microwave Imager (GMI), and JAXA and NICT developed the DPR. JAXA and NICT developed the DPR through procurement. The contract for DPR was awarded to NEC TOSHIBA Space Systems, Ltd. The configuration of precipitation measurement using active radar and a passive radiometer is similar to TRMM. The major difference is that DPR is used in GPM instead of the precipitation radar (PR) in TRMM. The inclination of the core satellite is 65 degrees, and the flight altitude is about 407 km. The non-sun-synchronous circular orbit is necessary for measuring the diurnal change of rainfall similarly to TRMM. The DPR consists of two radars, which are Ku-band (13.6 GHz) precipitation radar (KuPR) and Ka-band (35.5 GHz) precipitation radar (KaPR). Both KuPR and KaPR have almost the same design as TRMM PR. The DPR system design and performance were verified through the development test and the proto flight test. DPR had handed over to NASA and integration of the DPR to the GPM core spacecraft had completed in May 2012. GPM core spacecraft satellite system test had completed in November 2013. The result of the satellite system test concerning to the DPR satisfied system requirements. GPM core observatory was shipped to Tanegashima Space Center, JAPAN and Launch Site Operations had started on November 2013 and GPM core observatory was launched at 18:37:00 (UT) on February 27, 2014 successfully. DPR orbital check out was completed in May 2014. The orbital check out and the initial calibration and validation operation result of DPR is reported.

Proto-flight test of the Dual-frequency Precipitation Radar for the Global Precipitation Measurement

The Dual-frequency Precipitation Radar (DPR) installed on the Global Precipitation Measurement (GPM) core satellite is being developed by JAXA and NICT. This paper describes objectives, technical performance, resource allocation, preliminary design, development model test, critical design and proto-flight test (PFT) of the DPR instrument. The DPR system PFT will be completed in 2011. After completion of all PFT, the DPR instrument will be verified as a space borne radar.

Onboard calibration of the dual-frequency precipitation radar (DPR) installed on the global precipitation measurement (GPM) core observatory

Onboard calibration method of the Dual-frequency Precipitation Radar (DPR) installed on the Global Precipitation Measurement (GPM) core observatory, launched in February 2014, is described. The orbital check out status of DPR will be reported.

Status of development of the GPM Dual-frequency Precipitation Radar (DPR), algorithm development, and ground validation activities

In July 2009, NASA and JAXA signed implementation phase Memorandum of Understanding to be the central body for creating the Global Precipitation Measurement (GPM) partnership. The Global Precipitation Measurement (GPM) started as an international project and a follow-on mission of the Tropical Rainfall Measuring Mission (TRMM) project to achieve more accurate and frequent precipitation observations than it. A Dual-frequency Precipitation Radar (DPR) on board the GPM core satellite is being developed steadily by JAXA and NICT, and consists of Ku-band (13.6GHz) and Ka-band (35.5GHz) precipitation radars to measure light rainfall and snowfall as well as moderate-to-heavy rainfall. The GPM core observatory scheduled to be launched by Japanese H-IIA rocket in summer of 2013. In January 2010, JAXA has selected the principal investigators by the 6th Precipitation Measuring Mission (PMM) Research Announcement, especially focusing on the GPM algorithm development and pre-launch validation. The GPM standard algorithm will be developed by U.S.-Japan Joint GPM Algorithm Team, and Japanese members will play central role in developing DPR and DPR/GMI combined algorithms. Pre-launch validation aims to contribute to the development and improvement of algorithms, through validating parameter errors, which are involved in satellite-based precipitation retrieval algorithms, such as attenuation by precipitation particles, raindrop size distribution, and drop velocity and density of snowfall. JAXA will put two new field-portable Ka-band Ground Validation radars in 2009-2010 to achieve this target. The new science team will be organized in April 2010, and team members expected to make effective interactions between algorithm development and pre-launch validation activities.