# SAR-C (EOS-04)
*sensor . products*

C-band synthetic aperture radar payload flown on EOS-04 / RISAT-1A.

## Specifications
- **product status**: operational
- **deployment context**: orbital
- **manufacturer**: isro
- **sensor**: {"instrument_family":"sar","measurement_principle":"active","frequency_band":"C","centre_frequency_mhz":5350,"notes":"WMO OSCAR lists SAR-C at 5.35 GHz on EOS-04; detailed public mode metadata remains in NRSC handbook sources.","spec_disclosure":"disclosed"}
- **entity type**: sensor
- **last verified date**: 2026-06-16
- **verified by**: agency-doc
- **claim status**: agency-sourced
- **provider**: isro
- **attributes**: {"kind":"sensor","product_status":"operational","deployment_context":"orbital","manufacturer":"isro","description":"C-band synthetic aperture radar payload flown on EOS-04 / RISAT-1A.","sensor":"{\"instrument_family\":\"sar\",\"measurement_principle\":\"active\",\"frequency_band\":\"C\",\"centre_frequency_mhz\":5350,\"notes\":\"WMO OSCAR lists SAR-C at 5.35 GHz on EOS-04; detailed public mode metadata remains in NRSC handbook sources.\",\"spec_disclosure\":\"disclosed\"}"}
- **relevance**: in-scope

## Editorial
SAR-C (EOS-04) is the C-band synthetic aperture radar payload flown on EOS-04 / RISAT-1A, using active microwave imaging for orbital SAR collection.[^nrsc-eos04-handbook][^isro-pslv-c52][^wmo-eos-04] Its working centre frequency is 5.350 GHz, while NRSC EOS-04 material also gives 5.4 GHz for the C-band payload, so buyers should treat frequency matching as a 5.35-5.4 GHz C-band context rather than a separate sensor variant.[^wmo-eos-04][^nrsc-eos04-handbook] The instrument has multiple C-band operation modes, including Stripmap and ScanSAR hybrid-polarimetric data.[^nrsc-eos04-handbook][^esa-polinsar-eos04-calval] SAR backscatter, SAR backscatter change detection and polarimetric SAR decomposition are demonstrated through EOS-04.[^nrsc-eos04-handbook][^esa-polinsar-eos04-calval] EOS-04 launched in February 2022 and is recorded as an operational RISAT-programme satellite.[^isro-pslv-c52][^wmo-eos-04]

## Compositional position
- eos-04 (missions) --[mission_payloads]--> SAR-C (EOS-04)

## Sources
- [nrsc-eos04-handbook] | EOS-04 (RISAT-1A) Handbook, NRSC | https://bhoonidhi.nrsc.gov.in/bhoonidhi_resources/help/docs/EOS-04_Handbook.pdf | tier=agency-doc | accessed=2026-06-16
- [isro-pslv-c52] | PSLV-C52/EOS-04 Mission, ISRO | https://www.isro.gov.in/mission_PSLV_C52.html | tier=agency-doc | accessed=2026-06-16
- [wmo-eos-04] | EOS-04 satellite record, WMO OSCAR | https://space.oscar.wmo.int/satellites/view/eos_04 | tier=third-party | accessed=2026-06-16
- [esa-polinsar-eos04-calval] | Calibration and Validation of EOS-04 Hybrid Polarimetric ScanSAR Data | https://polinsar-biomass2023.esa.int/iframe-agenda/files/126-PV-Jayasri-EOS-04-AbstractID-126-PolInSAR.pdf | tier=agency-doc | accessed=2026-06-16

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Source: https://eo-atlas.org/products/sensor/sar-c-eos-04
Maintainer: SpectraWorks B.V. (CC-BY 4.0)