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FORMOSAT-7 Program Description Satellite Payloads International Cooperation Data Processing and Utilization


Program Description

The FORMOSAT-7/COSMIC-2 (simplified as FORMOSAT-7 in the following descriptions) is a major collaborative space program between Taiwan and the U.S. In this collaborative program, the designated representative for Taiwan is TASA (Taiwan Space Agency) and the designated representative for the U.S. is NOAA (National Oceanic and Atmospheric Administration). The FORMOSAT-7 program is a follow-on program to the successful FORMOSAT-3/COSMIC program with upgraded performance for spacecraft bus and mission payload. The United States is responsible for satellite launches, payloads, and deployment of global ground receiving stations; the US team includes NOAA, the United States Air Force, and UCAR (The University Corporation for Atmospheric Research). Taiwan is responsible for the design and integration of mission systems, development of 6 spacecrafts, and constellation mission operations; the Taiwan team includes TASA, Central Weather Bureau, National Central University, and National Cheng Kung University. Data processing and application technology development are developed by the two parties in cooperation.

The FORMOSAT-7 satellites was launched by SpaceX Falcon Heavy rocket on June 25, 2019, at Kennedy Space Center, Florida, USA. 

The mission architecture

All six satellites of FORMOSAT-7 constellation were launched into a 720-km circular orbit. These satellites will be gradually transferred to their 550-km mission orbits and deployed to six different orbital planes through the scheduled orbit transfer by 2021 Q1.

FORMOSAT-7 constellation: one satellite per orbital plane

The data distribution simulation for 24-hr coverage by FORMOSAT-7 constellation

FORMOSAT-7 is equipped with a GNSS-R, which can receive GPS signals from the United States and GLONASS signals from Russia. By measuring radio occultation signals, atmospheric parameters such as humidity and humidity, and the electron concentration of the ionosphere can be derived. 
After the deployment of the FORMOSAT-7 constellation with the altitude of 550 kilometers and the inclination angle of 24 degrees, all six satellites orbit the earth for about 97 minutes. They can provide about 4,000 data per day between 50 degrees north and south latitudes. The amount of data in the vicinity of Taiwan is about 3 to 4 times that of FORMOSAT-3, which greatly increases meteorological data in low-latitude regions including Taiwan. Observation data provided by CWB of Ministry of Communications can be incorporated in a numerical forecasting system to improve the accuracy of domestic weather forecasts and the forecast accuracy of severe weather (including typhoon paths and rainfall). FORMOSAT-7 can provide an average of 4,000 points of atmospheric data every day, which is of great help to weather forecast, climate observation, and space weather monitoring.



  • 2022

    April - Space Weather Data Release: TGRS high rate scintillation, IVM In-situ measurements, GNSS RFI (Radio Frequency Interference)

    February - Agreement to Continue the Application of Terms of the FORMOSAT-7/COSMIC-2 Agreement was signed

    January - Tahiti ground station operation, reduce the RO data latency.

  • 2021

    April - IVM density data release

    February - All six satellite deployment was completed

    January - GLONASS absolute Total electron content data release

  • 2020

    October - 5 satellites have been maneuvered to mission altitudes

    March - Space weather provisional data release

    March - Neutral atmosphere data release

  • 2019

    December - Neutral atmosphere provisional data release

    July - First Radio Occultation profile was successfully observed.

    June - Six FORMOSAT-7 satellites under STP-2 mission were launched by Falcon Heavy.

    January - Joint Program Pre-Shipment Review was completed.

  • 2017

    March - Taiwan Data Processing Center readiness review was completed.

  • 2016

    May - Integration and test of six satellites was completed.

    February - Joint Program Critical Design Review was completed.

  • 2013

    December - Joint Program Preliminary Design Review was completed.

    May - FORMOSAT-7/COSMIC-2 TECRO/AIT Implementing Arrangement #1 was signed.

  • 2011

    April - Joint Program System Requirement Review was completed.

  • 2010

    August - Joint Program Mission Definition Review was completed.


The 6 mission satellite buses of FORMOSAT-7 are built by Surrey Satellite Technology Limited(SSTL). TASA is responsible to integrate the bus and payload instruments. The satellite has the following characteristics :

shape cuboid unilateral load solar array
size 100 x 125 x 125 cm3
mass 300 kg (per satellite)
communications capabilities S band,upload speed 32kbps ,download speed 2 Mbps
partners SSTL (Surrey Satellite Technology Ltd.)
payload support data capacity 2Gbits ,load 39.4 kg,power supply 95W
mission orbit low-inclination angle (24 deg), 520~550 km circular orbit

Domestic Efforts

S-band antenna Pyras Technology Inc
Ground Antenna of Taiwan backup station Pyras Technology Inc
Mechanical Ground Support Equipment Aerospace Industrial Development Corporation
Satellite Operations System (XPSOC software) Taiwan Space Agency
Data Processing Validation System (TROPS software) Taiwan Space Agency, National Central University,
National Cheng-Kung University, Central Weather Bureau  
Insurance Service of Pre-Launch Taiwan Fire & Marine Insurance Company, Ltd.
Insurance Service of Launch Taiwan Fire & Marine Insurance Company, Ltd.



Each of the 6 satellites equips with three payloads:

  • Each FORMOSAT-7 satellite equipped with a Radio Occultation (RO) receiver, the TriGNSS Radio occultation System (TGRS), that receives the refracted signals from Global Navigation Satellite System (GNSS) satellites is entering or leaving the line-of-sight between a FORMOSAT-7 satellite and a GNSS satellite(s).
  • In addition to the TGRS, the Ion Velocity Meter (IVM) is another on board instrument that directly measures the temperature, velocity, and density of ions in the path of each FOTMOSAT-7 satellite.
  • The RF Beacon (RFB) is the third scientific payload on board the FORMOSAT-7 satellite. The RFB measures the irregularity of electron densities in the ionospheric layer that has a strong influence to the stability of RF signal transmission from communication satellites or other space vehicles to the ground.


Tri-GNSS Radio occultation System (TGRS)

Ion Velocity Meter (IVM)

Radio Frequency Beacon (RFB)


Payload photo

responsible unit


International Cooperation

TASA is responsible for satellite operations control center, launch and early orbit operations, orbit maneuver operations, and mission operations as defined in Implementing TECRO/AIT Arrangement#1. A satellite operation control system (Cross Platform Satellite Operation Control System, XPSOC), developed by TASA and domestic companies, will be applied to FORMOSAT-7 mission operations.


The data latency requirement is 30 minutes (median) so that distribution of the ground stations is as shown below. The U.S. Team is responsible for deployment of stations, include Guam, Darwin, Mauritius, Kuwait, Ghana, Cuiaba, Honduras and Hawaii.


Data Processing and Utilization

Data Processing

Both Taiwan and the United States have established data processing centers to support system monitoring, data management, and user services for the radio occultation meteorological satellite constellation. 

The Taiwan Data Processing Center (TDPC) is located at Central Weather Bureau (CWB). Users can obtain FORMOSAT-3 and FORMOSAT-7 data through TDPC. In order to develop localized occultation data processing technology, a set of data processing verification platform (Taiwan RO Processing System, TROPS) is jointly developed by combining the energy of CWB, National Central University (NCU), and National Cheng Kung University (NCKU) to strengthen the domestic occultation data processing and application. 


First Retrieved Profiles from FORMOSAT-7

Data Utilization

National Applied Research Laboratories (NARLabs) combines the research and development energy of NCU and CWB to establish a localized occultation data application system to enhance the efficiency of the application of occultation in the meteorological numerical model to improve the forecasting ability of severe weather and reduce the uncertainty of disaster warning. The ionospheric space weather forcast module developed by NCKU was incorporated into the Space Weather Forecast Center of CWB to carry out routine operations of space weather forcast with the same function as general weather forecast, reducing the loss in national defense and people's livelihood.