ATM

The NERC ARSF ATM is a multispectral scanner with 11 bands covering visible, near, short and thermal infra-red wavelengths. The instrument has been retired since the end of the 2008 flying season.

Further technical information about the ATM is available from NEODC at ​http://www.neodc.rl.ac.uk/?option=displaypage&Itemid=52&op=page&SubMenu=-1
and from ARSF operations at ​http://arsf.nerc.ac.uk/instruments/atm.asp

Band wavelengths

ATM Band no	Lower wavelength limit (nm)	Upper wavelength limit (nm)
1	424	448
2	469	518
3	522	601
4	594	635
5	627	694
6	691	761
7	754	924
8	897	1027
9	1600	1785
10	2097	2391
11	8400	11500

Spectral response

The ATM spectral response for the first 10 bands is described by this spreadsheet.

Raw data format

ATM data comes as raw on the flight disks and is moved into files by a program called azed. Each data frame has a 16 bit header (holding the scan number?) then 11 unsigned ints of data. Note that there are two types of ATM file - ones containing navigation (normally az*000 but not always) and ones containing imagery.

There's an apparent byte pattern of "AZSYS001" at the start of the files, at least for 2007 ATM. I suspect if the data you're looking at is old (early 90s?) it will be different as there was a change to the ATM back then sometime.

This is infact a data frame header, but still identifies the file as being ATM. You can only tell a nav file by checking all the records - if they are all nav frames then it is a nav only file. ATM files have both nav and ATM frames.

Samples from 2007 - first 16 bytes of files:

azhba000.130    00000000  41 5a 53 59 53 30 30 31  6e 40 32 01 5f 19 01 00  |AZSYS001n@2._...|
azhba001.130    00000000  41 5a 53 59 53 30 30 31  6e 40 32 01 5f 19 01 00  |AZSYS001n@2._...|
azhba002.130    00000000  41 5a 53 59 53 30 30 31  6e 40 32 01 5f 19 01 00  |AZSYS001n@2._...|
azhba003.130    00000000  41 5a 53 59 53 30 30 31  6e 40 32 01 5f 19 01 00  |AZSYS001n@2._...|
azhba004.130    00000000  41 5a 53 59 53 30 30 31  6e 40 32 01 5f 19 01 00  |AZSYS001n@2._...|
azhba005.130    00000000  41 5a 53 59 53 30 30 31  6e 40 32 01 5f 19 01 00  |AZSYS001n@2._...|
azhda000.166    00000000  41 5a 53 59 53 30 30 31  d7 40 32 01 ed 47 01 00  |AZSYS001.@2..G..|
azhda001.166    00000000  41 5a 53 59 53 30 30 31  d7 40 32 01 ed 47 01 00  |AZSYS001.@2..G..|
azhda002.166    00000000  41 5a 53 59 53 30 30 31  d7 40 32 01 ed 47 01 00  |AZSYS001.@2..G..|
azhda003.166    00000000  41 5a 53 59 53 30 30 31  d7 40 32 01 ed 47 01 00  |AZSYS001.@2..G..|
azhda004.166    00000000  41 5a 53 59 53 30 30 31  d7 40 32 01 ed 47 01 00  |AZSYS001.@2..G..|
azhda005.166    00000000  41 5a 53 59 53 30 30 31  d7 40 32 01 ed 47 01 00  |AZSYS001.@2..G..|
azhaa000.254    00000000  41 5a 53 59 53 30 30 31  ff 41 32 01 ed 13 01 00  |AZSYS001.A2.....|
azhaa010.254    00000000  41 5a 53 59 53 30 30 31  ff 41 32 01 ed 13 01 00  |AZSYS001.A2.....|
azhaa011.254    00000000  41 5a 53 59 53 30 30 31  ff 41 32 01 ed 13 01 00  |AZSYS001.A2.....|
azhaa012.254    00000000  41 5a 53 59 53 30 30 31  ff 41 32 01 ed 13 01 00  |AZSYS001.A2.....|
azhaa013.254    00000000  41 5a 53 59 53 30 30 31  ff 41 32 01 ed 13 01 00  |AZSYS001.A2.....|
azhaa014.254    00000000  41 5a 53 59 53 30 30 31  ff 41 32 01 ed 13 01 00  |AZSYS001.A2.....|
azhaa015.254    00000000  41 5a 53 59 53 30 30 31  ff 41 32 01 ed 13 01 00  |AZSYS001.A2.....|