Link 1


Link 1 is a computer network standard developed by NATO to provide information exchange for air defence.

General description

Link 1 is a point-to-point, duplex, non-encrypted, digital NATO Tactical Data Link Standard for the automatic exchange of Track and Strobe data, combined with link and data management messages between ground based ASACS-elements / e.g. :de:Control and Reporting Centre|CRC and CAOC, specific units and data link buffers.
In everyday language, the different meaning of the wording Link 1 TDL Standard and Link 1 information content to be transmitted on this particular TDL Standard is mixed up in many cases.
Remark:
Link 1 is a NATO first Generation's TDL Standard. It was developed in the 1950s as pure Air Surveillance data link format in order to exchange radar track date between defined Areas of Responsibility – AOR or Track Continuity Areas .

Data links first generation

NATO first generation's TDL Standards were developed in line with the appropriate Standardization Agreement in the mid 1960s. These proprietary types of data formats do not support direct data and information exchange between different military IT architectures without specific conversion of data.
NATO TDL Standards are being developed by the Data Link Working Group of the ''Information Systems Sub-Committee.

Utilisation

Today the Link 1 TDL Standard is not only used by NATO nations but also in Partnership for Peace countries. Air Force internal it supports NATO Air Defence Ground Environment and is used by the TACC Service, in CRC, CAOC and Air Defence.

Types of tracks

The following tracks are exchanged by Link 1 between different users of the Recognized Air Picture.
tracks, which have received their last position-update by a ground site. These are either local ore remote.
Tracks, which have received their last position-update by an AEW-platforms. These are always remote.
These Tracks are used as "Track Pairs" for registration purposes and are update by both the ground site and AEW.
The Tracks of an active E-3A, usually correlated with the received P-1 Message on IJMS.

Messages

The following link messages are supported by Link 1 in the NATO Air Defense Ground Environment :
The NATO Link 1 TDL Standard is characterised by the specification as:
Link 1SpecificationTerm
ReferenceSTANAG 5501 Jan 2007
NCGX-101-IS
Standardization levelNATO Data Link StandardS-series-messages
Configuration's
controlling 		- ADSC
- ADSIA
Services concerned
and TACC Systems 		Air Force, Army
NADGE, national weapon management systems
Messages
transmitted 		1. surveillance
2. ECM-strobe-tell
3. Info-management
Message-
format 		2 messages/frame
- 128 bits/frame
- 49 infobits/message		fixed message format
Message Series S-series
Number of Messages 6
Speed
of transmission 		1200 bit/sec
600 or 2400 bit/sec
Communication FSK, point-to-pointFOC, Wire, Radio relay
IT-Security ECM
Encryption		NO
NO
Releasable to: - NATO
- PfP nations
- Internet		Yes
Yes
Yes

Conclusion

Link 1, as a NATO 1st generation TDL Standard, is out of date and no longer meets operational requirements. Moreover, there is no IT security of information transmitted, as the result of no Electronic countermeasure resistance and insufficient encryption. Although Link 1 became obsolete, it is still in operation.