The Advanced Land Observing Satellite-2 (ALOS-2) was launched on May 24, 2014 by an H-2A launch vehicle. The designed mission life is five years as operational phase and the target is more than seven years since launch the satellite. While the satellite has reached almost its final stage of the operational phase, it is still operating well. The mission objectives of ALOS-2 are as follows;
1) Disaster monitoring of damage areas, both in considerable detail, and when these areas may be large,
2) continuous updating of data archives related to national land and infrastructure information,
3) effective monitoring of cultivated areas, and
4) global forest monitoring in support of carbon cycle science.
To achieve its mission, ALOS-2 carries the Phased Array type L-band Synthetic Aperture Radar-2 (PALSAR-2), which is an active microwave radar using the 1.2 GHz frequency band. Compared to the PALSAR instrument onboard its predecessor ALOS satellite, the PALSAR-2 instrument has several enhanced features (e.g. finer spatial resolution, spotlight mode, dual-polarisation ScanSAR).
JAXA’s Earth Observation Research Centre (EORC) is in charge of ALOS-2 research and analysis activities, comprising pre-launch study, instrument calibration, algorithm development for various applications, generation and distribution of research products, organisation of Research Announcement (RA) program etc. in collaboration with the JAXA ALOS-2 Project Team and external institutions and researchers. In this presentation, the ALOS-2 research activities are introduced with a summary of results obtained during the operational phase.
Regarding to response and monitor natural disasters, more than 400 times of the emergency observations have been conducted to identify damages caused by volcanic activities, earthquakes, flooding etc. both in Japan and worldwide. As examples of some typical results, fine-beam observations were used to identify small subsidence due to volcanic activity in Hakone, Japan on June 2015, and the ScanSAR mode was used to detect large surface deformation caused by an earthquake in Hawaii, US on May 2018. These examples illustrate how the precise platform orbit control and high PALSAR-2 interferometric coherence are two of strengths of ALOS-2.
For monitoring global and tropical forests, 25 m pixel spacing annual global mosaics (MOS) and corresponding forest / non-forest (FNF) maps were generated by JAXA for the years 2015, 2016, and 2017, complementing the similar mosaic products produced from ALOS PALSAR for the years 2007 to 2010, and from JERS-1 SAR for 1996, allowing the detection of temporal changes over more than 20 years. All 25 m global mosaic data are available for public download free of charge from JAXA EORC web site.
The Japan International Cooperation Agency (JICA) and JAXA initiated the “JICA-JAXA Forest Early Warning System in the Tropics” (JJ-FAST) project in November 2016 as their commitment under the Forest Governance Initiative, which was announced at UNFCCC COP 21 in Paris in 2015. JJ-FAST is a web-based system using ALOS-2 ScanSAR data to monitor tropical forests in 77 countries every 1.5 months to release deforestation alerts, even in the rainy season. Countries are encouraged to use JJ-FAST to support national forest management and early warning. These applications show the importance of the global wall-to-wall acquisition capability of ALOS-2 as well as all-weather observations by PALSAR-2.

“COSMO-SkyMed di Seconda Generazione” (CSG) programme has been funded by the Italian Space Agency (ASI) and the Italian Ministry of Defence; CSG system is the follow-on of COSMO-SkyMed (CSK). The launches of PFM and FM2 satellites, aimed at providing operational continuity to CSK with increased performance and flexibility, are foreseen in 2019 and 2020 respectively. An overview of CSG standard and non-standard acquisition modes and of the products characteristics has been reported in this paper.

With regard to the acquisition modes, a very original novelty will be the possibility to perform the spotlight Non-standard operational “Theatre” acquisitions with the satellite in a “squinted” (i.e. “pitched”) attitude and the new Non-Standard operational DI2S spotlight 2 multi-swath mode. Three civilian spotlight modes will be available and the users will be able to choose among a very high-resolution “2a” mode (with small swath), a CSK-like “2b” mode (same swath of CSK, but improved resolution) and a low power consumption “2c” mode. The CSK Scansar modes will be improved thanks to the possibility to acquire in dual polarization. The basic Stripmap product will be available in single or dual polarisation featuring the same CSK resolution and swath size. Furthermore, CSG will have a full Stripmap quad-polarisation mode, and, in continuity with CSK, a multi-polarisation Ping-Pong mode, which is a “burst polarimetric” mode.

SAR standard products will be generated starting from input data acquired by the above mentioned instrument modes. They are classified in five processing levels (from 0 up to 1d level). The paper highlights the basic features of each standard CSG product anc the expected image quality specifications. Also, an overview of CSG Non-Standard products has been provided.

International Cooperation in the space sector is one of the most powerful tool to achieve significant goals at a global level. In the Earth Observation (EO) field, multilateral efforts often dominate discussions, whereas bilateral partnerships co-exist to reach specific scientific, economic and political goals or critical issue such as prevention and risk and emergency management. In this framework, a significant cooperation is represented by the SIASGE (Italian-Argentine Satellite System for Emergency Management) program, one of the most ambitious space projects in the world.
SIASGE is a Space Earth Observation Asset for complementary utilization of the Italian COSMO-SkyMed Mission, based on a constellation of 4 X-Band SAR satellites, and the Argentine SAOCOM Mission, based on a constellation of 2 L-Band full polarimetric SAR satellites.
The Italian Space Agency (ASI) and the Comisión Nacional de Actividades Espaciales of Argentina (CONAE) have signed, in July 2005, a Memorandum of Understanding (MoU) to operationally integrate two national systems focusing on the general issue of Disaster Risk Reduction (DRR) and Management (DRM). This MoU has been subsequently extended in 2008 and 2010.
The 4 satellites of the COSMO-SkyMed constellation were launched in the time range 2007-2010 and they are currently still working and providing data with the required image quality. The launch of the first Argentina’s radar imaging satellite, SAOCOM 1A, that has been deployed in October 2018 from the Vandenberg Air Force Base with the SpaceX Falcon 9 rocket, represents the concretisation of a visionary idea conceived 20 years ago from these two Countries. This choice has proved to be even more relevant today than ever considering that Synthetic Aperture Radar is the technology that in geoinformation and space sector is growing faster than the others. Nowadays, the integration between the large investments in the space sector made from the Italian Government and from the Argentinian side offers a new scenario and a unique opportunity for integrated applications. The possibility of working in the two radio spectrums at the same time, which have very different features in terms of penetrating the Earth's surface illuminated by the radar, makes SIASGE an innovative and highly effective system for EO application.
One of the final goals of the program is the commercial exploitation of the data and services deriving from the two satellite constellations with the enlargement of the existing portfolio of products.

Access to data from Synthetic Aperture Radar (SAR) sensors continues to grow as a direct result of an increasing number of SAR missions and commitments to open data policies. In parallel, research efforts have led to promising outcomes which have encouraged end users to consider SAR missions as critical sources of data to map and monitor. To support this growing uptake of SAR, efforts are required to ensure delivery of well calibrated image (L1) data and well validated bio- and geophysical products (L2-L4). Coordination of effort is required to collect, collate and share the in situ data needed to facilitate cal/val activities for a range of SAR missions and higher level products.

One outcome of the International Coordination for Spaceborne Synthetic Aperture Radar Data Acquisition, Processing and Analysis for Earth Science and Applications Workshop (Pasadena, May 2018) was a recommendation to better coordinate and share data from common test sites to support calibration and validation of SAR image and derived bio- and geophysical products. Working Group 3 (WG3) was tasked with addressing this challenge.

As an initial action, WG3 is querying the international community to take stock of existing cal/val efforts. This includes documenting current individual sites as well as more coordinated efforts to collect in situ data for all levels of product cal/val. This effort will lead to improved understanding of ongoing activities and assist in facilitating greater collaboration among site leads. In addition, this WG will explore establishment of mutually agreed upon supersites for cal/val of current and planned SAR missions.

Sharing of SAR and in situ data from these supersites would also enable inter-mission comparisons and data fusion. Such efforts will require multi-agency participation. This WG is addressing one particular challenge - to bring SAR data providers together with those agencies whose mandate it is to exploit derived products to meet information and knowledge requirements in their respective sectors. Such linkages are needed to engage a wide community of end users.

This presentation will review the recommendation around cal/val coordination and provide a status report on the efforts of WG3 to address this recommendation.

The Argentine Microwave Observation Satellite SAOCOM 1A has been designed, produced, tested and operated by Argentinians within the framework of the National Space Plan. The mission will bring into space a complex Earth observation technology and is one of the most challenging technological projects ever developed in the country. SAOCOM (Satélite Argentino de Observación COn Microondas, Spanish for Argentine Microwaves Observation Satellite) is an Earth observation satellite constellation of Argentina's space agency CONAE. The first of two satellites has been launched on 8th October 2018, while the second one is planned to be launched in 2019.

The SAOCOM satellite carries on board a full polarimetric L-band Synthetic Aperture Radar instrument, with the goal to provide timely information in support of natural and anthropogenic disaster management (such as regional flooding, volcanic eruptions, Earth quakes, landslides, forest fires, etc.), and to conduct monitoring services for agriculture, mining and ocean applications - including monitoring surveys of Antarctica (study of continental glacier evolution, global change indicators, etc.).

The SAOCOM instruments will also work in synergy with Italian COSMO-SkyMed X-band SAR satellites in the framework of the Italian-Argentine System of Satellites for Emergency Management (SIASGE) program. The calibration activities performed during the Commissioning Phase of the SAOCOM mission are of the utmost importance to ensure that the synergy between L-band and X-band SAR data is fruitful.

In the framework of the SAOCOM development activities Aresys provided the SAOCOM SAR Processor (SSP), which is operationally used to ingest Level-0 data and process them into the official Level-1 products. Furthermore, during the SAOCOM Commissioning Phase, Aresys performs an independent assessment of the overall SAR system calibration. In particular the independent calibration activities will include:
• The determination of the sensor pointing along-track (through the Doppler Centroid estimates) and across-track (with the dedicated Elevation Notch acquisitions)
• The analysis of images with point targets to verify the Impulse Response Function and to assess the absolute calibration of the system
• The analysis of polarimetric images to estimate polarimetric co-registration offsets and channel imbalance and cross talks.
• The analysis of images acquired over the Rain Forest to assess the relative calibration of the images in terms of Elevation Antenna Pattern and beam-to-beam radiometric offsets.

The SAOCOM Commissioning Phase is planned to start in December 2018 and, with a planned duration of 8 months, will be fully on going during the LPS 2019. The paper will provide an overview of the main results of the independent calibration/validation activities performed during the first months of the Commissioning Phase. A particular focus will be dedicated to the analysis of the data quality in view of the start of the SIASGE constellation operations.

Sentinel-1 is the first space-borne SAR mission in the frame of the Copernicus program for Earth Observation directed by the European Commission in partnership with ESA. The main objective of the Sentinel-1 mission is to ensure the continuity of C-band SAR data acquisitions for global monitoring applications. The mission consists of two satellites (Sentinel-1A and Sentinel-1B) flying in near-polar sun-synchronous orbits and each operating a synthetic aperture radar (SAR) at C-band (5405 MHz). The first satellite of this constellation, Sentinel-1A, was launched on 3rd April 2014, the second one, Sentinel-1B, two years later on 25th April 2016. The calibration of both SAR instruments was performed by ESA and their partners during the commissioning phase. Additionally independent verifications of the SAR instrument calibration were carried out by the German Aerospace Center (DLR) on behalf of ESA for both Sentinel-1A and Sentinel-1B.
The current study continues the calibration and verification activities. The radiometric accuracy and long-term stability of both SAR instruments are analyzed over a period of two-years. For the continuous time series the Interferometric wide-swath (IW) mode with dual-polarization is used which is the main mode for Sentinel-1. The evaluation includes both: point targets and distributed targets with expected high backscatter stability over time. This allows verifying the radiometric accuracy of both SAR instruments for a broad radar reflectivity range, including
• high backscattering point targets (transponders and corner reflectors),
• medium reflectivity, e.g. found over the Amazon rainforest, and
• low reflectivity (near noise), e.g. available in calm water regions.
From point target evaluations a high radiometric accuracy is found for both SAR systems. We obtain a radiometric accuracy for the IW mode of 0.35 dB (1σ) for Sentinel-1A and 0.31 dB (1σ) for Sentinel-1B. The slightly higher standard deviation, derived for Sentinel-1A, is mainly due to a drift of the absolute calibration factor which has been observed until autumn 2017. The standard deviation of the calibration factor derived from targets seen under the same geometry (same beam, same elevation) is smaller (by about 40%) compared to the overall deviation. That means that a proper balanced elevation antenna pattern could reduce the bias, found for each elevation angle, and improve further the radiometric accuracy.
Comparing the radar reflectivity for both Sentinels over distributed targets, only small differences in the order of 0.1 dB are found in particular in regions with medium backscatter indicating how accurate both systems are matched to each other. In contrast to this, for regions with very low backscatter (near noise) differences of up to 1 dB are observed with lower values for Sentinel-1B compared to Sentinel-1A which is related to a higher signal-to-noise ratio for Sentinel-1B in general.