The Instrument or <Sensor_Name> is the name of the instrument used to acquire the data. There are 3 categories of instruments, with additional levels of hierarchical classifications (see the Writer's Guide for Ancillary Descriptions):

• Earth Remote Sensing Instruments
• In Situ/Laboratory Instruments
• Solar/Space Observing Instruments

When using the GCMD metadata authoring tools, <Sensor_Name> classifications are automatically populated by selecting the <Short_Name>. This field allows for the specification of keywords that are the names of the instrument(s) used to collect or measure the data.  These keywords are important for the search and retrieval of information from the GCMD.  The field <Sensor_Name> consists of the short name and the long name of the instrument.  There is a 1:1 correspondence between the short name and the long name.

• <Short_Name> is the abbreviated name of the instrument used to acquire the data.
• <Long_Name> is the full name of the instrument used to acquire the data.

<Sensor_Name>
   <Short_Name>Instrument short name keyword</Short_Name>
   <Long_Name>Instrument long name keyword</Long_Name>
</Sensor_Name>

• The <Sensor_Name> field is highly recommended and may be repeated as many times as necessary.
• <Short_Name> 1 to 80 characters from the UTF-8 character set, except “>”
• <Long_Name> 1 to 160 characters from the UTF-8 character set, except “>”
• <Short_Name> and <Long_Name> must be selected from the controlled set of Instrument keywords. However, new instrument identifiers may only be added if the instrument does not already appear in the Instrument keyword List.
• The <Short_Name> is usually a mnemonic or abbreviated version of the <Long_Name>.  When submitting a new <Short_Name>, always check the Instrument Keyword Lists to ensure mutual exclusivity among instrument short names.  No two instruments may have the same <Short_Name>.

<Sensor_Name>
   <Short_Name>ADCP</Short_Name>
   <Long_Name>Acoustic Doppler Current Profiler</Long_Name>
</Sensor_Name>