July 24, 2026

The NASA-ISRO Synthetic Aperture Radar (NISAR) mission is a groundbreaking Earth observation initiative providing unprecedented insights into our planet's dynamic surfaces. As the world's first spaceborne radar mission to employ dual-frequency (L-band and S-band) instrumentation, NISAR utilizes an advanced 12-meter reflector and innovative SweepSAR acquisition technology. This architecture allows the observatory to achieve an exceptional combination of wide-swath (~240 km) and high-resolution imaging without traditional coverage trade-offs. Operating in a 747 km Sun-synchronous orbit, NISAR provides persistent, all-weather global coverage with a rapid 12-day repeat cycle, generating a dense time-series of data essential for monitoring rapid environmental changes, geohazards, and resource management.

The mission is currently in science operations phase, acquiring data across global observation tracks as per the Reference Observation Plan, with S-band SAR data being acquired through ISRO ground stations and subsequent data processing, archival, and dissemination being carried out at the Integrated Multi-Mission Ground Segment for Earth Observation Satellites (IMGEOS), Shadnagar, NRSC.

Calibration and Validation (Cal/Val) activities are systematically performed using the PAN India Corner Reflector (CR) network, homogeneous distributed targets, and selected science targets to establish and maintain baseline radiometric, geometric, and polarimetric consistency across all acquisition geometries.

ISRO has released the NISAR S-Band SAR daily processed data products through Bhoonidhi, ISRO’S EO data dissemination hub (https://bhoonidhi.nrsc.gov.in). This data comprises of S band SAR collections over Indian land mass along with global locations spanning across diverse NISAR science themes.

• Onward Processing Release (Cycle 25 Onwards): Starting with Cycle 25 (commenced July 8, 2026), all acquired S-Band SAR products are systematically generated from the operational production environment and made directly available for user download.
• Historical Dataset Reprocessing: Datasets acquired prior to Cycle 25 will undergo systematic reprocessing in phased manner and will be added to archives.
• Product Version Baseline: Current released datasets are with Product Baseline version (Baseline v1.4.0 CRID P00500)

Following S-band SAR data products are being released

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• L1-RSLC: Range-Doppler Single Look Complex
• L2-GSLC: Geocoded SLC
• L2-GCOV: Geocoded Polarimetric Covariance Matrix

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• L1-RIFG: Nearest-Time Interferogram
• L1-RUNW: Nearest-Time Unwrapped Interferogram
• L2-GUNW: Geocoded Nearest-Time Unwrapped Interferogram

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• L1-ROFF: Range-Doppler Pixel Offsets
• L2-GOFF: Geocoded Pixel Offset Produc

NISAR data products are disseminated through Bhoonidhi, ISRO’s Earth Observation data dissemination hub (https://bhoonidhi.nrsc.gov.in). Registered users can access the Browse&Order interface to search, visualize, and download available NISAR products by specifying the area of interest, acquisition period, product type and NISAR data specify advanced filters. Level-1 and Level-2 products are available for access for data covering diverse NISAR science themes in accordance with the ISRO observation plan. Programmatic access is also supported through the Bhoonidhi API for authorized users. The portal serves as the primary distribution platform for NISAR S-band data products and a dedicated NISAR information page is made available containing associated documentation, product specifications, calibration status, and release updates for users (https://bhoonidhi.nrsc.gov.in/NISAR).

The current data product release incorporates the latest radiometric, geometric, and polarimetric calibrations derived from in-flight Cal/Val activities. Calibration parameters and algorithm enhancements will continue to evolve over the operational lifetime of the mission, with updates notified to the user community as processing baselines advance.

Users may observe residual radiometric banding in low signal-to-noise ratio (SNR) regions such as oceans, deserts, and other homogeneous surfaces in this version of products. Although, RFI mitigation has been applied to all scenes, residual RFI artifacts may still be present in certain areas, for which improvements are planned in future releases.

To facilitate seamless data handling and scientific analysis without extensive local processing overheads, Bhoonidhi provides an integrated suite of user utilities:

• HDF to GTiff Tool: Utility providing format conversion of NISAR HDF5 datasets into GeoTIFF and Cloud-Optimized GeoTIFF (COG) formats, with option for spatial sub-setting by point coordinates or user-defined shapefiles.
• SARPOL TOOL: A QGIS-integrated processing suite supporting NISAR format conversions along with Hybrid and Full Polarimetric decomposition techniques for SAR data analysis.