Beijing-3

Long name	Beijing-3
Short name	BJ3
Sensor type	Electro-optical
Platform	Beijing-3
Key file name (use to open dataset)	BJ3A1_.xml, BJ3B1_.xml
Supported file name extensions	.xml, .tif, .txt, jpg
Sections	Data product name and description Distribution disk files Returned data for supported format References

Data product name and description

Beijing-3 is an AI-enabled agile remote sensing optical satellite of Twenty First Century Aerospace Technology Co., Ltd., developed by DFH Satellite Co., Ltd., which could pick its flight path on its own, monitoring up to 500 points of interest across the world with roughly 100 trips every day. It can provide high-resolution remote sensing data and information products for the global market.

Beijing-3 uses two cameras to complete 24 kilometers swath high-resolution satellite image. The focal plane of each camera uses a five spectrum in one device to obtain 2-meter resolution blue, green, red, near-infrared multispectral images and 0.5-meter resolution panchromatic images.

Currently GDB supports L1 Data Product which identified as BJ3A1 or BJ3B1. The satellites take the single camera standard scene as the basic unit to provide L1 level sensor correction products to users all over the world.

The satellite ground preprocessing system obtains the original code stream data received by the ground station. Image data separation, attitude and orbit parameter analysis, system radiation correction, sensor geometry correction, band registration, MTF restoration, product packaging and other steps are used to output L1 sensor products.

Note: The information provided herein is based on the data distributor's documentation cited under References.

Spectral bands: Spectral range (nm)	Spatial resolution (m)* (spectral resolution)	Maximum image dimensions (Across track x along track, km)	Notes
B1 (Blue): 450 - 520 B2 (Green): 520 - 590 B3 (Red): 630 - 690 B4 (NIR): 770 - 890 PAN (Panchromatic): 450 - 700	PAN: 0.5 (Panchromatic) MS: 2.0 (multispectral) At nadir 20 degrees – 0.57 At nadir 30 degrees – 0.67	Single Pass Maximum Collection Geometry Mono: 70 x 170 (7 strip wide) Stereo: 23.5 x 70 (3 pairs wide)	• Altitude: 500 km • Dynamic Range: 12-bits • Footprint Width: 23.5 km (at nadir) • Georeferenced Horizontal Accuracy: < 10m CE90 (global average, dependent on terrain)

* Resolution is always nadir position unless noted otherwise.

The supported product types for standard scene are as follows:

Processing level	Product Name	Description/notes
L1A/L1B	L1 sensor correction product: The relative radiation normalization and absolute radiation correction are completed for each band image, which eliminates the geometric distortion of the camera optical system and the geometric error of the attitude orbit parameter system, and provides the geometric positioning information of the image through auxiliary parameters.	The RPC coefficient file that comes with the commonly used data product provides the geometric positioning information of the image.

Distribution disk files

Warning: Data sets for this sensor are organized in a specific folder structure on disk. GDB uses this structure and the file names to identify the data product type. Do not alter the folder structure or any file names prior to data ingestion to ensure the image data and auxiliary information are imported correctly.

You can open a Beijing-3 data set by selecting the BJ3A1(or B1)_MS*.xml file or BJ3A1(or B1)_PAN*.xml file.

The naming regulations of its standard data products are as follows:

Satellite name + camera name + imaging time + product level + imaging task number + imaging mode + scene number

An example of L1 product naming is as follows:

BJ3A1_PMS1_20210801040512_L1_100258_SC_001

BJ3A1: the satellite name
PMS1: the camera identification (PMS1 is camera A and PMS2 is camera B)
20210801040512: the imaging time (UTC) of the central point of the scene
L1: the product level
100258: imaging task number
SC: the imaging mode (SC: Scene, ST: Stereo, TR: Tri-Stereo)
001: the scene number (where the first character 0 represents the number of stripe images in the imaging mode, and the second and third characters 01 represent the starting scene number of the stripe image).

When opening a Beijing-3 data set, the files read by GDB are as described in the following table.

File name	Format	Required	Contents/details
BJ3A1(or B1)_MS.xml BJ3A1(or B1)_PAN.xml	Extensible Markup Language	Yes	Key file name, Contains data set metadata.
BJ3A1(or B1)_MS.tif BJ3A1(or B1)_PAN.tif	GeoTIFF	Yes	Image data file
BJ3A1(or B1)_MS_rpc.txt BJ3A1(or B1)_PAN_rpc.txt	Text	Yes	Text file of Rational Polynomial Coefficients
BJ3A1(or B1)_MS_browser.jpg BJ3A1(or B1)_MS_browser.png BJ3A1(or B1)_MS_browser.tif BJ3A1(or B1)_MS_thumb.jpg BJ3A1(or B1)_PAN_browser.jpg BJ3A1(or B1)_PAN_browser.png BJ3A1(or B1)_PAN_browser.tif BJ3A1(or B1)_APN_thumb.jpg	TIFF	Optional	Browser and thumbnail files

Returned data for supported format

Beijing-3 data can be opened directly in its raw vendor format or imported into a PCIDSK (*.pix) file using the key file name (BJ3A1_MS*.xml or BJ3A1_PAN*.xml). For optimal processing, use the PCIDSK format.

The following table describes the data structure after it is opened by GDB.

Data product	Data returned	Details
MS (Multispectral)	4 x [16U] raster channels 1 x [ORB] Orbit segment 1 x [BIN] Rational function model	4-band multispectral Image (Blue, Green, Red, NIR)
PAN (Panchromatic)	1 x [16U] raster channels 1 x [ORB] Orbit segment 1 x [BIN] Rational function model	1-band Panchromatic Image

References

For more information, visit:

BJ3_L1_Product Manual.pdf August 24, 2021

BJ3A1_satellite_specs.v2.pdf