SNEAK (inStrumeNt sourcE pAcket toolKit) is a toolkit composed of multiple command line utilities to extract/manipulate the values of specific ISP fields in L0 RAW files:

  • ISP Extractor extracts specific ISP field(s) into a CSV text file

  • ISP Transform updates specific ISP field(s) according to a timeline

  • ISP Sequencer corrects the SSC of a multi-file ISP stream

  • ISP CRCFix corrects the CRC of a multi-file ISP stream

  • ISP Tree Maker lists the fields of the ISP(s) stored in a file

  • ISP Multiplexer selects/reorders/combines the ISPs from multi-file ISP streams

  • ISP Annotate prepends a annotation field to each ISP in a ISP Stream

SNEAK is freely available at the EOP System Support Division website as pre-compiled installation package available for Linux, MacOS and Windows (64bit).

All SNEAK tools are developed in C++, and use the capabilities of DFDL4S to access the binary data in the ISP files. SNEAK uses the same Mission Schema Files used for S2G Data Viewer, but these schemas need to be extracted from the Jar files in order to be used by SNEAK tools.


SNEAK is available for Linux, MacOS and Windows (64bit), and has the following system requirements:

  • 25 MB disk space

  • 8 GB RAM

  • Java 11, consider using OpenJDK 11 (LTS) from AdoptOpenJDK


Make sure you have a Java JDK available and that the JAVA_HOME environment variable is properly set. For example

# On Linux
export JAVA_HOME=/path/to/jdk-11.0.18+10

# On macOS
export JAVA_HOME=/path/to/jdk-11.0.18+10/Contents/Home

# On Windows
# Add JAVA_HOME as C:\\path\\to\\jdk-11.0.18+10 in Environment Variables

Install SNEAK simply by extracting the downloaded package at the installation location. For example, to install SNEAK at /opt/sneak-X.Y.Z, execute the following:

# On Linux or macOS
tar zxvf sneak-X.Y.Z-linux64.tar.gz -C /opt

Consider adding the installation folder (i.e. /opt/sneak-X.Y.Z) to the PATH environment variable in order to be able to use the SNEAK tools regardless of the location.


After installing SNEAK, run the tool with the –version or –help options for a description of the command line options. For example

isp_extractor --version
isp_extractor --help

Via Parameters

All SNEAK tools take their parameters as CLI arguments, or via a file containing the key=value entries corresponding to the CLI arguments. For example, executing

isp_treemk --via arguments.txt

where the file arguments.txt contains


is the same as performing the following call

isp_treemk --schema MissionX-bandTMISP.xsd --isp mission.isp.bin --packet 1

Tools Reference