Tactical Data Links - Common Data Links
Key words and phrases: tactical data links, common data link, CDL, tactical common data link, TCDL, high integrity data link, HIDL
Tactical Data Links - Common Data Link (CDL)
Tactical Common Data Link (TCDL)
High Integrity Data Link (HIDL)
Common Data Link (CDL)
The US DoD designated the Common Data Link (CDL) as its standard for use in imagery and signals intelligence in 1991. This link consists of a secure, jam resistant uplink operating at 200kbps and a down link that can operate at 10.71 Mbps, 137 Mbps or 274 Mbps (currently only the first of these downlink rates is secure).
There are five classes of link in the CDL family to achieve both line-of-sight (LOS) and, using relay, beyond-line-of-sight (BLOS):
- Class I
Ground-based applications with airborne platforms operating at speeds < Mach 2.3 at altitude up to 80,000 ft. - Class II
Speeds up to Mach 5 and Altitudes up to 150,000 ft. - Class III
Speeds up to Mach 5 and Altitudes up to 500,000 ft. - Class IV
Terminals in satellites orbiting at 750nm. - Class V
Terminals in relay satellites operating at greater altitudes
Current Class I Terminals:
- Land-based
MIST (Modular Interoperable Surface Terminal) - Sea-based
Common High Bandwidth Data Link Surface Terminal (CHBDL-ST)
The latter supports the Advanced Tactical Airborne Reconnaissance System (ATARS) and the Battle Group Passive Horizon Extension System (BGPHES).
CDL permits the remote operation and exploitation of sensors carried by CDL fitted platforms from BLOS locations via satellite. There are two satellite CDL systems in use; Senior Span and Senior Spur. Senior Span makes use of a Span Airborne Data Link system operating in the I-band via Defence Satellite Communication System II/III spacecraft. Senior Spur meanwhile operates in the Ku-band in order to gain bandwidth.
In August and November 1999 the USN demonstrated a phased array antenna that can handle both satcoms and CDL operation. Frequencies utilised were in the EF/S band (2.2-2.3 GHz) and I/X band (7.25-8.4 GHz) both for military satcom, plus I/X band (9.7-10.5 GHz) and Ku-band (14.5-15.35 GHz) for CDL and Ku-band (10.95-14.5 GHz) for commercial satcom.
The USAF's UAV Global Hawk participated in the exercise Linked Seas 00 demonstrating down-linking of radar imagery to both the US Army’s Tactical Exploitation System and to the USS George Washington, and subsequently to the Joint Analysis Centre at Molesworth in the UK. In the following Joint Task Force Exercise 00-02 CDL was utilised to pass retasking requests to Global Hawk from ship and land-based terminals.
Previously the USN sponsored a demonstration of Synthetic Radar Imagery downlinking direct from the UAV via CDL into the Joint Services Imagery Processor – Navy, passed through the Common Imagery Processor to the Precision Targeting Workstation (PWT) for analysis. Imagery was then provided to an airborne F/A-18.
Tactical Common Data Link (TCDL)
The US Defence Advanced Research Projects Agency (DARPA) - Defence Information Systems Agency (DISA) originally acting for the, former now disbanded, Defence Airborne Reconnaissance Office (DARO) is in the second phase of the procurement programme for the CDL compliant Tactical Common Data Link (TCDL). The TCDL programme is to provide a family of interoperable, secure, digital data links for use with both manned and unmanned airborne reconnaissance platforms.
It is planned to undergo trials on the Predator UAV. Possible fits include other UAVs as well as P-3 Orion. It will transmit radar, imagery, video and other sensor information at rates from 1.544Mbps to at least 10.7 Mbps over ranges of 200km. It is also intended that TCDL will soon support the required higher CDL rates of 45, 137 and 274 Mbps.
The USN and USMC are to acquire 12 and 11 respectively Vertical Take-Off and landing (VTOL) UAV (VTUAV) system; each system comprising 3 air vehicles capable of operation from a ship or unprepared shore site. This system replaces Pioneer and utilised TCDL. The USN version of TCDL incorporates asynchronous transfer mode protocols for data messaging and is due to be installed on surface combatant warships between 2002 and 2006. USS Kearsage will conduct operational evaluation of the VTUAV and production of the vehicle is due to commence 2003 with IOC due with the USMC by the end of that year. Deployment to cruisers and destroyers will occur from 2005.
Possible users of TDCL: apart from the US include:
- Denmark
Tactical UAVs - UK
Tactical UAVs (see HIDL below)
High Integrity Data Link (HIDL)
UK is evaluating a High Integrity Data Link (HIDL) for UAVs sponsored by the NATO Naval Armaments Group's Projects Group 35. This link will consist of airborne and surface-based terminals with a full-duplex narrow-band jam-resistant data link operating in broadcast mode to control at least two UAVs simultaneously to ranges of 200 km. It is a requirement that this link must be able to operate with the wideband TCDL. It will operate at 225-400MHz (UHF) and 100 kbps bandwidth.
Data Link descriptions: Tactical Data Links | Link 16 | Link 11 | Link 22 | IJMS | Link 1 | Link 14 | Link 4 | Other protocols | CDL, TCDL & HIDL | Satellite Link 16 | Variable Message Format - VMF
Further information is available from:
Email:
Tel: +44 (0)1252 732555
