# Hyper-Spectral Imager - 2
*sensor . products*

VNIR hyperspectral imager carried by HJ-2A for land observation and detailed vegetation classification, with 128 channels from 450 to 950 nm, 48 m resolution, and 50 km swath.

## Specifications
- **product status**: operational
- **deployment context**: orbital
- **manufacturer**: cast
- **sensor**: {"instrument_family":"passive-optical","measurement_principle":"passive","spectral_range_nm":{"min":450,"max":950},"spectral_band_count":128,"gsd_m":{"native":48},"swath_km":50,"sampling_nm":4}
- **entity type**: sensor
- **last verified date**: 2026-06-16
- **verified by**: agency-doc
- **claim status**: agency-sourced
- **provider**: cast
- **attributes**: {"kind":"sensor","product_status":"operational","deployment_context":"orbital","manufacturer":"cast","description":"VNIR hyperspectral imager carried by HJ-2A for land observation and detailed vegetation classification, with 128 channels from 450 to 950 nm, 48 m resolution, and 50 km swath.","sensor":"{\"instrument_family\":\"passive-optical\",\"measurement_principle\":\"passive\",\"spectral_range_nm\":{\"min\":450,\"max\":950},\"spectral_band_count\":128,\"gsd_m\":{\"native\":48},\"swath_km\":50,\"sampling_nm\":4}"}
- **relevance**: in-scope

## Editorial
HSI-2 (Hyper-Spectral Imager 2) is a VNIR hyperspectral instrument manufactured by CAST and flown on HJ-2A for land observation and vegetation analysis.[^eoportal-hj2] It operates as a Large Aperture Static Imaging Spectrometer (LASIS) using a Sagnac lateral shearing interferometer, a Fourier-transform architecture that differs fundamentally from dispersive-grating pushbroom designs.[^mdpi-cross-cal-hsi2] The instrument covers 450 to 950 nm across 128 spectral channels with a nominal sampling interval of approximately 4 nm, though the interferometric acquisition produces a non-uniform wavenumber distribution in raw data that results in variable per-channel bandwidths across the range.[^mdpi-cross-cal-hsi2] Native ground sampling distance is cited as 48 m by Gunter's Space Page[^gunters-hj2ab] and the eoPortal HJ-2 mission overview[^eoportal-hj2]; the WMO OSCAR instrument record lists 100 m, which likely reflects a resampled delivered product.[^wmo-hsi2] Swath width is 50 km.[^wmo-hsi2] The spectral range and channel count suit detailed land-cover classification and vegetation index retrieval; cross-calibration with ZY1-02D/AHSI has been demonstrated to support multi-mission harmonisation of VNIR hyperspectral time series.[^mdpi-cross-cal-hsi2]

## Compositional position
- hj-2a (missions) --[mission_payloads]--> Hyper-Spectral Imager - 2
- hj-2b (missions) --[mission_payloads]--> Hyper-Spectral Imager - 2

## Sources
- [wmo-hsi2] | WMO OSCAR instrument record: HSI-2 | https://space.oscar.wmo.int/instruments/view/hsi_2 | tier=third-party | accessed=2026-06-16
- [eoportal-hj2] | HJ-2 (Huan Jing-2) mission page, eoPortal | https://www.eoportal.org/satellite-missions/hj-2 | tier=operator-engineering | accessed=2026-06-16
- [gunters-hj2ab] | HJ 2A/2B, Gunter's Space Page | https://space.skyrocket.de/doc_sdat/hj-2a.htm | tier=community | accessed=2026-06-16
- [mdpi-cross-cal-hsi2] | Dynamic Gaussian Modified Spectral Band Adjustment Factors for Radiometric Cross-Calibration of HJ-2A/HSI with ZY1-02D/AHSI, Remote Sensing 2025 | https://www.mdpi.com/2072-4292/17/24/3988 | tier=peer-reviewed | accessed=2026-06-16

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Source: https://eo-atlas.org/products/sensor/hsi-2
Maintainer: SpectraWorks B.V. (CC-BY 4.0)