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.....|