BJ3N
30 cm multispectral, China's Beijing-3N — sub-meter with up to 45° off-nadir
When to use
- Sub-meter capture at lower cost than Vantor
- Stereo and tri-stereo for DSM/DTM
- Up to 45° off-nadir for difficult collection geometries
When it's the wrong fit
- Customers with regulatory restrictions on Chinese data
- SWIR analysis (no SWIR bands)
Processing levels
Five processing levels. Levels 1–3 are applied by default on every order; pansharpening (4) runs automatically when the sensor has a panchromatic band; mosaicking (5) runs automatically when the AOI spans multiple scenes. Specify any level explicitly if you need to override the default.
| L | Output | What's applied | Status |
|---|---|---|---|
| 0 | Raw | Digital numbers (sensor counts) with no calibration or geometric correction. Delivered as unprojected GeoTIFF with sensor metadata. | On request |
| 1 | Orthorectified | Geometric correction onto a DEM. Every pixel sits at its true ground position. Customer-supplied GCPs accepted at no extra cost. | Default |
| 2 | Surface reflectance | TOA radiometric correction plus atmospheric correction. Output is the actual fraction of light reflected by the ground, comparable across dates, sensors, and sun angles. | Default |
| 3 | Pansharpened | Gram-Schmidt fusion of panchromatic and multispectral bands. Spectral ratios preserved for downstream analytics. | Default |
| 4 | Mosaicked | Seamless multi-scene composite over the AOI with ML cloud/cirrus masking and custom seam-line path-finding. Applied automatically when the AOI spans more than one scene. | Default* |
*Mosaicking applies when the AOI spans more than one scene. Single-scene orders skip it.
Water masks, tree masks, glint handling, lidar-aligned reflectance, aquatic atmospheric correction, region-tuned models — anything your downstream pipeline requires. Quoted with the order.
DSM (digital surface model) and DTM (digital terrain model), priced per area. This sensor supports tri-stereo capture, required for elevation products.
Specifications
| General | |
| Provider | 21AT (Twenty-First Century Aerospace Technology) |
| Country | China |
| System type | Satellite |
| Product type | Multispectral |
| Availability | Tasking and catalog |
| Available since | 2022 |
| Sensor | |
| Resolution | Panchromatic: 30 cm · Pansharpened: 30 cm · Multispectral: 1.20 m |
| Bit depth | 8-bit, 16-bit |
| Swath width | 11.5 km |
| Off-nadir range | Up to 45° |
| Constellation | 1 satellite (Beijing-3N (BJ-3N)) |
| Orbit | Sun-synchronous, 610 km |
| Revisit | Every 5 days — in practice 5–10 days |
| Acquisition modes | Mono, Stereo, Tri-stereo (tasking) |
| Reference | |
| CRS | Geographic-WGS84 |
| Positional accuracy | < 10 m CE90 absolute |
| Processing levels | Primary/Georectified with TOA radiometric processing; Level 4 upon request |
| Tasking and catalog conditions | |
| Minimum AOI width | tasking 2 km wide · catalog 2 km wide |
| Minimum charge area | tasking 70 km² · archive 25 km² |
| Geographic restrictions | Chinese ground station coverage. Geographic restrictions in some areas. Some government and defence customers cannot use Chinese imagery for regulatory reasons. |
Live tracking
See all Geopera's satellites →BJ3N positions propagated from fresh TLEs in your browser. Satellites rendered at true orbital altitude, oriented nadir-pointing. The emerald rectangles on the ground are each sensor's current swath footprint.
Spectral bands
| Band | Designation and wavelength |
|---|---|
| Blue | 450-520 nm |
| Green | 520-590 nm |
| Red | 630-690 nm |
| NIR | 770-890 nm |
Delivery manifest
Each order delivers as a single archive containing the following files.
bj3n_[order_id].zip
├── data/ 4 band files, GeoTIFF, 8-bit
├── metadata.xml acquisition parameters, calibration coefficients
├── metadata.txt human-readable summary
├── masks/ cloud, transparency
├── thumbnails/ PNG previews
└── overviews/ JPEG quicklook
Compare with
Closest alternatives by resolution and product type.
| Spec | BJ3N | SuperView Neo | WorldView 4 | WorldView Legion |
|---|---|---|---|---|
| Resolution | 30 cm | 30 cm | 31 cm | 34 cm |
| Provider | 21AT (Twenty-First Century Aerospace Technology) | SPACEWILL (CASIC) | Vantor (formerly MAXAR) | Vantor (formerly MAXAR) |
| Country | China | China | United States | United States |
| Type | Multispectral | Multispectral | Multispectral | Multispectral |
| Availability | Tasking + catalog | Tasking + catalog | Archive only | Tasking + catalog |
Spectral indices
87 spectral indices are compatible with BJ3N. The most-used: NDVI,EVI,NDWI,SAVI,GNDVI,MSAVI. See the full spectral profile for the complete list and band mappings.
Ready to order BJ3N?
Browse the catalog, place a tasking order, or request a custom processing pipeline through the Geopera portal. We respond to quote requests within one business day.