Common High Bandwidth Data Link - Surface Terminal (CHBDL-ST)
The Common High Bandwidth Data Link - Surface Terminal (CHBDL-ST) will support the
Navy's efforts by providing a wideband, full duplex, digital data communications link
between the ship and the airborne sensor platform equipped with the Common Data Link
Airborne (CDL A/B) subsystem. The CHBDL-ST is not designed to counter any specific
threat, instead it is intended to operate in the threat environment.
CHBDL-ST is a communications terminal that provides full duplex data communications
(at line-of-sight ranges) between aircraft, equipped with a Common Data Link Airborne
(CDL A/B), and shipboard users’ signal processing equipment. The terminal receives
variable data rates with an encryption and decryption capability in accordance with the
interface specifications of the supported systems. The CHBDL-ST transmits user
commands to the CDL A/B for Battle Group Passive Horizon Extension System (BGPHES)
or JSIPS-N (ATARS) Prime Mission Equipment (PME) in the aircraft. CHBDL-ST receives
link status and user mission data in the downlink and provides this mission data to the
BGPHES-ST and JSIPS-N shipboard processors. The command uplink has Low Probability
of Intercept (LPI) characteristics based upon parabolic antenna directivity, signal
modulation format and transmitter power output control. The system is capable of
operating only one link at a time.
The CHBDL-ST is comprised of two major functional
subsystems, the Expandable Multi-Link Processor (EMLP) subsystem, and the
Antenna/Radio Frequency (ARF) subsystem. The EMLP Subsystem consists of EMLP
Group I, located in Radio or CIC spaces, and EMLP Group II located in the BGPHES-ST
and JSIPS-N equipment spaces. The EMLP subsystem performs data formatting,
modulation/demodulation, and Link Control (LC) operations which are divided
functionally between the Command and Control Processor (CCP), the Modem(s), and
the Link Switch (LS). These functional areas allow a system operator to input mission
requirements, select a link configuration, and allocate CHBDL-ST resources for link
operation.
The CHBDL-ST system operator uses the CCP to monitor link status and
perform on-line testing of the equipment. The LC functions consist of data formatting
and single link control. The ARF Subsystem consists of two equipment groups, the
Shipboard Antenna (SA) Group and the Shipboard Antenna Electronics (SAE) Group. The
SA Group, located above decks, is divided between two antenna systems. The
shadowing effects imposed by the ship’s superstructure dictate the use of two
independent antenna systems with handover coordination to provide 360 degrees of
azimuth tracking. The two SAE Groups will be located in sheltered spaces between the
EMLP Subsystem and each antenna. The EMLP and ARF are connected within the ship
by an internal Fiber Optic Interface (FOI). External interfaces with CHBDL-ST exist
between the EMLP subsystem, and the BGPHES-ST and JSIPS-N systems, where user
commands originate and the PME sensor data is processed within the ship.
Sources and Methods
http://www.fas.org/irp/program/disseminate/chbdl-st.htm
Created by John Pike
Maintained by Steven Aftergood
Updated Friday, February 11, 2000 12:31:18 PM
