Formosat-5

Long name	Formosat-5
Short name	FMS5
Sensor type	Electro-optical
Platform	Formosat-5
Key file name (use to open dataset)	FS5_*.dim
Supported file name extensions	.tif, .rpb, .jpg
Sections	Data product name and description Distribution disk files Returned data for supported format References

Data product name and description

Formosat-5 is an Earth-observation satellite operated by the National Space Organization (NSPO) of Taiwan in a Sun-synchronous orbit (SSO) at a mean altitude of 720 kilometers. The satellite provides high-resolution 2-meter panchromatic (PAN) and 4-meter multispectral (MS) imagery with a swath width of 24 kilometers.

A follow-on mission of FormoSat-2, Formosat-5 is the first remote-sensing satellite developed indigenously by NSPO. An important objective for FormoSat-5 is to build up the domestic capability for the high-resolution, optical, remote-sensing instrument (RSI) by integrating NSPO with the Instrument Technology Research Center (ITRC) of the National Applied Research Laboratories (NARL). Both NSPO and ITRC belong to NARL, a nonprofit organization under the supervision of the National Science Council (NSC).

FORMOSAT-5 satellite includes the spacecraft bus, RSI, and advanced ionospheric probe (AIP). The spacecraft bus and RSI are self-reliantly developed by NSPO. The AIP, the scientific payload, is built by National Central University (NCU) in Taiwan.

The main characteristics of the instrument are as described in the following table.

Characteristic	Description
Registration	After ground processing
Pointing capability	± 45 degrees roll and pitch
Focal length	3600 millimeters
Pupil diameter	450 millimeters
Type	Cassegrain with refractive corrector
Complementary metal-oxide-semiconductor (CMOS) sensor	C468
Processing rate:	40 megapixels per second
Mass	138 kilograms
Power consumption	100 watts for orbit average
Image product	PAN-only, MS-only, PAN + MS
Acquisition mode	Recording (RECORD), direct data transmission (DDT)
Geo-accuracy of imagery：	#8226; With ground control points (GCP): 2 meter #8226; Without GCPs: 390 meter

Information specific to the PAN and MS imagery is as described in the following table.

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
PAN 450 - 700	2.0	2.0 x 2.0 (12-bit)	Integration time: 0.297 milliseconds Compression ratio: 1.0,1.5 Signal-to-noise ratio (SNR): ≥ 92
MS 450 - 520 (Blue) 520 - 600 (Green) 630 - 690 (Red) 760 - 900 (NIR)	4.0	4.0 x 4.0 (12-bit)	Integration time: 0.594 milliseconds Compression ratio: 3.75,7.5 Signal-to-noise ratio (SNR): ≥ 100

* Resolution is always nadir position unless noted otherwise.

Formosat-5 data is available in the following processing levels:

Level 1A (L1A)
Level 2 (L2TWD97) with TWD97 map-projection coordinate
Level 2 (L2UTM) with UTM map-projection coordinate
Level 2 (L2WGS84) with WGS84 coordinate
Level 4 (L4TWD97) with TWD97 map-projection coordinate
Level 4 (L4UTM) with UTM map-projection coordinate
Level 4 (L4WGS84) with WGS84 coordinate

Note: Only L1A and L4TWD97 are available and tested.

Processing level	Horizontal accuracy (m)	Description/notes
L1A	N/A	Only Data Strip is available. It includes ephemeris, attitudes, sensor configuration, calibration data, and so forth.
L4TWD97		This product does not have a rational functions math model.

Distribution disk files

A Formosat-5 data set is organized in a specific folder structure on disk. GDB uses this folder structure and the file names to identify the data product type.

Warning: To ensure the image data and auxiliary information are imported correctly, do not alter the folder structure or any file names prior to data ingestion.

You can open a Formosat-5 data set by selecting the FS2_*.dim file.

When opening a Formosat-5 data set, the files read by GDB are as described in the following table.

File name	Format	Required	Contents/details
FS5_*.dim	DIM	Yes	Key file name. Contains data-set metadata.
FS5_*.tif	GeoTIFF	Yes	Image data.
FS5_*.rpb	Text	Optional	Applicable only with L1A.
FS5_*cds.jpg	Joint Photographic Experts Group	Optional	Thumbnail file.
FS5_*qls.jpg	Joint Photographic Experts Group	Optional	Overview file.

File name convention

The file name convention of Formosat-5 data is as described in the following table, based on a sample file name of FS5_G031_MS_L1A_20171220_024019.tif.

File name segment	Description
FS5_G031	Grid index
MS	Spectrum type
L1A	Processing level
20171220_024019	Date of acquisition (YYYYMMDD_HHMMSS)

Returned data for supported format

Formosat-5 data can be opened directly in its raw vendor format or imported into a PCIDSK (*.pix) file using the key file name FS5_*.dim). 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
L1A (PAN)	1 x [16U] Raster channel 1 x [BIN] Rational functions model 1 x [TEX] Product annotation 1 x [ORB] Orbit segment	N/A
L1A (MS)	4 x [16U] Raster channels 1 x [BIN] Rational functions model 1 x [TEX] Product annotation 1 x [ORB] Orbit segment	N/A
L4TWD97 (PAN)	1 x [16U] Raster channel 1 x [TEX] Product annotation 1 x [ORB] Orbit segment	N/A
L4TWD97 (MS)	4 x [16U] Raster channels 1 x [TEX] Product annotation 1 x [ORB] Orbit segment	N/A

References

For more information, visit: nspo.org