Acronyms

The metadata of Sentinel-2 is full of acronyms and a description is most of the times missing. A list by ESA is also given [here](https://sentinels.copernicus.eu/web/sentinel/technical-guides/sentinel-2-msi/appendices), but more terms are used in the metadata description. For sake of readability here is an attempt to list them:

abbreviation	written out fully
AOCS	attitude and orbit control system
ATBD	algorithm theoretical basis document
AUX	auxiliary
BOA	bottom of atmosphere
BOL	beginning of life
CAMS	copernicus atmosphere monitoring service
CDS	copernicus data service
CRS	coordinate reference system
CMOS	silicon complementary metal oxide semiconductor, Si
CoG	center of gravity
CoM	center of mass
CopDEM	copernicus digital elevation model
COSPAR	committee on space research international designator
DEM	digital elevation model
DGED	defence gridded elevation data
DS	datastrip
DTED	digital terrain elevation data
EPSG	european petroleum survey group (a coordinate refenence database)
ESA	european space agency
ESOC	european space operations centre
FEE	front end electronic
FPA	focal plane assembly
GCP	ground control point
GDOP	geometric dilution of precision
GMES	global monitoring for environment and security
GIPP	ground image processing parameters
GML	geographic markup language
GNSS	global navigation satellite system
GPS	global positioning system
GRI	global reference image
IERS	international Earth rotation & reference systems service
IMG	imagery
IMT	instrument measurement time
IMU	inertial measurement unit
L1B	level-1 processing step B, imagery with top of atmosphere radiances in sensor geometry
L1C	level-1 processing step C, imagery with top of atmosphere radiances in cartographic geometry
L2A	level-2 processing step A, imagery with bottom of atmosphere reflectances in cartographic geometry
MAC	magnetotorquers to generate magnetic moment
MCT	mercury cadmium telluride, HgCdTe
MGRS	US military grid reference system
MTD	metadata
MSI	multi spectral instrument
NAPEOS	navigation package for earth orbiting satellites
NOF SV	number of space vehicles
NORAD	north american aerospace defense satellite catalog number
NSM	navigation solution method
PCO	phase center offset of the satellite navigation antenna
PCV	phase center variation of the satellite navigation antenna
PDI	product data item
PDOP	position dilution of precision
POD	precise orbit determination
QI	quality information
RW	reaction wheels
SADM	solar array drive mechanism
SAFE	standard archive format for Europe
SAS	sun acquisition sensors
SIA	Sagnac interferometer assembly
STR	star tracker
STD	digital Earth sensors for roll and pitch
SSD	sun sensors for yaw
SWIR	short wave infra-red
S2	sentinel-2
TCI	true colour image
TCS	thermal control sub-system
TDI	time delay and integration
TDOP	time dilution of precision
TL	tile
TLE	two line element
TMA	trim mirror anastigmat
TOA	top of atmosphere
UTC	coordinated universal time
UTM	universal transverse mercator projection
VLORF	viewing local orbital reference frame
VNIR	very near infra-red
WKT	well known text
WGS	world geodetic system
XFDU	xml formatted data unit
XML	extensible markup language
XSD	xml schema definition

still unknown term(s) in the metadata: CSM