1. law, govt and politics
2. law enforcement
3. coast guard

Direction Finding Systems
Cobham Antenna Systems
The most important thing we build is trust
Naval AW101
sar AW101
Super Lynx
RAF Sea King
Photographs courtesy of Agusta Westland
Directions Finding (DF) Systems for all
Search & Rescue (SAR) Missions
Typical SAR operation involving US Coast Guard.
SAR Requirements
Combat SAR (CSAR)
The ability to locate personnel in distress in all
theatres needs to be quickly and accurately
executed to maximise rescue success whatever
the prevailing conditions.
The military customer also needs the capability
to rescue personnel in a combat situation with
the aid of a Combat SAR system. The Cobham
935 DF System combined with the latest
Personal Locator System (PLS) interrogator
provides a full CSAR capability. The system
has the capability to operate with Personnel
Survival Radios (PSR), such as the AN/PRC-112
and PRC-434 to provide range, bearing and ID
information. In addition, these systems can
provide the bearing co-ordinates from
an imbedded GPS in the URX3000 PSR.
Aircraft or ships transmitting on the emergency
distress frequencies depend upon Homing/
Direction Finding (DF) equipment onboard
aircraft to guide the Search & Rescue crews.
Traditionally Homing systems have been used
to steer the rescue vehicle to the distress
source when it is within 30-40NM.
With the advent of the COSPAS-SARSAT 406MHz
service the satellite monitored distress beacon
signal now identifies the craft position and type.
Once decoded by the SAR aircraft equipment,
the signal can be used to augment the beacon
transmission to direct the rescue craft.
The Cobham range of DF equipment utilises
the latest multi-receiver technology and is
designed for both military and civil use. This
single box solution is also fully COSPAS-SARSAT
compliant and compatible with the
requirements of the Global Maritime
Distress and Safety System (GMDSS).
Beacons
Emergency Beacons come in several forms,
Emergency Locator Transmitters (ELT), Personal
Locator Beacon (PLB), Emergency Position
Indicator Radio Beacon (EPIRB), Personal
Emergency Location System (PELS) and Auto
Emergency Locator Beacons (ADELT).
Cobham manufactures a complete range of
Emergency Beacons. All of these Beacons are
fully compatible with the new SAR Homing and
DF Systems.
The solution:
Cobham DF systems are tailored to suit various
Search and Rescue requirements including DF
antennas for use with existing radios and up to
fully integrated multi-receiver solutions.
1
2
1 935 DF plus 715-40 controller.
3
2 931/933 Series plus 7-26-39 controller.
3 7-23-30 DF plus 400-047992 remote
control and display unit.
935 Series
931/933 Series
System 7
The 935 Series of tactical Direction Finders
provide a range of integrated DF solutions
for bus-controlled and stand-alone direction
finding systems. 935 DFs include an integral
synthesised receiver covering the frequency
range 30-470MHz together with five Guard
receivers to monitor pre-defined distress
frequencies. Bearings may be taken on all six
receivers simultaneously. Data decoding is
provided for COSPAS-SARSAT messages and
for marine DSC messages on the associated
Guard receivers.
The 931 and 933 Series Direction Finding
antennas are configured to operate
with external radios. Cobham Antenna
Systems provide a range of small-profile
Guard receivers to monitor the standard
international distress frequencies. Bearing
display is accomplished via serial interfaces
including ARINC429, ARINC407 and RS422.
Control is accomplished via a bus controller
or via a dedicated Cobham Antenna System
controller such as the 7-26-39. The 933 Series
permit control via ARINC429.
The System 7 Direction Finder forms part of a
small-size, stand alone, direction finding solution
designed to provide a DF capability on the
VHF and UHF distress frequencies. With two
integrated receivers, two frequencies can be
monitored simultaneously obviating the need
for an external receiver. The System 7 only
requires a remote control and display unit to
provide a complete system supplying relative
bearing information and additionally provides
an ARINC429 output of bearing and associated
receiver frequency. The system is also COSPASSARSAT capable.
935 SAR Solution
935 CSAR Solution
Remote CDU (Optional)
(RHXXX)
Multi-Function
Display
(Optional)
Cobham Dedicated CDU
(CHXXX)
ARINC 429
715-40 Series
Display/
Controller
RS422
ARINC 407
935 Series DF
RMI
(Optional)
Cobham
ARNIC 407
(Optional)
935 Series DF
Coposite
Audio Out
Stand Alone System 7 DF Solution
RS422
Interrogator
Audio Out
ARNIC 429
Bearing Info
Interrogator
UHF Antenna
DME TxSync
Int. Sense
DF Power
Cubic
V12
Interrogator
V12 Power
Third Party Radio Integration
ARINC 407
Multi-Function ARINC 429
Display
(Optional)
Control and
Display
400-047992
DF Antenna
Type 7-23-30
Existing V/UHF
Recover
DF Antenna
931 Series
ARINC 429
Configuration Capability
Features
935
931
933
System 7
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Frequency Range Operation
30 - 88MHz
88 - 118MHz
118 - 243MHz
225 - 407MHz
400 - 470MHz
Integrated Receivers
30 - 407MHz
121.5MHz Guard
156.525MHz (CH70) Guard
156.800MHz (CH16) Guard
243MHz Guard
406MHz
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Specific Functions
CSAR
COSPAS -SARSAT Decoding
GMDSS VHF DSC Decoding
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Interface Options
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Antenna Overall Diameter
286mm
286mm
286mm
192mm
Antenna Height above Airframe
90mm
90mm
90mm
114mm
Antenna Penetration
75mm
75mm
75mm
75mm
Controller/Display Size
68 x147x182mm
36 x 82 x113mm
RS 422
ARINC 407
ARINC 429
MIL STD 1553B
Left/Right Output Options
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Installation Details
64 x 80 x115mm
For further information please contact:
Cobham Antenna Systems, North America
1955 Lakeway Drive
Suite 200
Lewisville
Texas, 75057
USA
Cobham Antenna Systems, Rest of the World
The Cobham Centre
Fourth Avenue
Marlow
Buckinghamshire, SL7 1TF
England
Tel: +1 972 221 1783
Fax: +1 972 436 2716
Tel: +44 (0)1438 768800
Fax: +44 (0)1438 768822
Issue 1
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