government
Inmarsat L-TAC
Beyond Line of Sight
Communications
Using Existing Military Radios
Whitepaper: Inmarsat L-TAC™
Tactical Beyond Line of Sight (BLOS) communications for military users.
L-band TACSAT for existing tactical UHF radios through a combination of the Inmarsat L-band
satellite network with the Spectra SlingShot™ frequency converter and portable L-band antenna.
Introduction:
The military in general and troops in the land environment in
particular rely on robust, portable radio terminals to provide allinformed communications for command, control and coordination
of dispersed force elements. However, when operational distances
extend beyond line of sight, the normal workhorse VHF terminals
run out of range and are unable to meet the capability requirement
without the use of rebroadcast (or relay) stations. These lead to
additional force protection and force sustainment requirements
which, in turn, create logistic and combat tasks that potentially divert
assets from the main effort.
The alternative is Single Channel (SC) tactical satellite (TACSAT),
conventionally provided in the UHF band on military satellites. The
demand for these channels exceeds supply, meaning that nations
are often unable to lease or gain access to channels. Alternatively,
due to the limited availability of channels, they are forced to operate
user groups that are far larger than the optimal size. These large
groups result in the need for restrictions on the use of the channel.
If these are not strictly observed, net discipline can collapse quickly,
causing confusion and dragging down operational tempo.
Using Inmarsat Satellites to extend
UHF beyond the line of sight:
Inmarsat’s simple but innovative approach to making more
TACSAT channels available to the market exploits the ability of the
Inmarsat-4 (I-4) satellites to connect L-band transponders on the
spacecraft to provide the same single-hop relay capability in space
as is provided by military UHF.
Channels are engineered to offer a 25kHz channel for both Voice
and / or Low Speed Data (LSD), equal to that provided by UHF. The
25kHz channels can be divided into up to five 5kHz sub-channels
each providing Narrow Band Voice and/or LSD using ANDVT mode.
UHF Radio
SlingShot
Vehicle Omni Antenna
Man Pack
Antenna
SlingShot
UHF Radio
Man Pack
Antenna
SlingShot
UHF Radio
Coverage
ghout the global footprint of the I-4 constellation. Whilst individual regional and narrow
hout
thethe
global
of the
thesophisticated
I-4 constellation.
Whilst individual
regional
and narrow
nt
than
UHF footprint
equivalent,
capabilities
of the Inmarsat
network
allow
than the
UHF
equivalent,
the sophisticated
capabilities
of the
Inmarsat
networkwillallow
beam
when
required.
Customised
beams covering
the user’s
area
of operations
be
am whenbeing
required.
Customised
beams covering
the
user’s area
of operations
willuser’s
be
sources
available
on the constellation
when
ordered.
Recognising
that the
The
L-TAC
is available
throughout
the global
footprint
of the
I-4 constellation.
Whilst
ources
being
available
the
constellation
ordered.
Recognising
that
the
user’s
operations
may
notservice
beon
constant
during
thewhen
period
of
the
lease,
Inmarsat
willand
include
throughout
the
global
footprint
of
the
I-4 constellation.
Whilst
individual
regional
narrow
individual
regional
and
narrow
spot
beams
cover
a
smaller
footprint
than
the
UHF
equivalent,
perations
may
notperiod
be
constant
during
the period
of the lease,
will
include
notprint
duringthan
the
lease
(subject
to
agreed
conditions).
the
UHF
equivalent,
the
sophisticated
ofnets
theInmarsat
Inmarsat
network
the
sophisticated
capabilities
of the Inmarsatcapabilities
network allow
to
work across
more allow
than
during
the
lease
period
(subject
to
agreed
conditions).
one beam when
required.
Customised
beamsbeams
covering
the user’s
areaarea
of operations
one beam
when required.
Customised
covering
the user’s
of operationswill
willbe
he resources
available
onsubject
the constellation
when
ordered.
Recognising
that thewhen
user’s
bebeing
available
for lease,
to the resources
being
available
on the constellation
ordered.
Recognising
that the user’s
of operations
or theatre
of operations
may
tre of operations
may
not be constant
duringconcept
the period
of the lease,
Inmarsat
will include
not
belease
constant
during
the period
of the lease,
Inmarsat will include options to change the
ration during
the
period
(subject
to agreed
conditions).
nd
nd
d
ew
)
90°
90°
80°
70°
60°
50°
80°
70°
configuration during the lease period (subject to agreed conditions).
60°
50°
I-4 L-Band Coverage
90°
40°
80°
30°
lites,
20°
30°
25°E and
10°
20°
.geL-band
of
0°
d narrow
10°
of
meter) 0° 10°
40°
70°
The service is offered on the I-4 satellites,
which are currently located at 98°W, 25°E
and 143.5°E and provide global coverage.
L-band coverage is offered over the
standard narrow (1.4° diameter) and regional
(4.6° diameter) beams of the I-4 satellites.
60°
50°
40°
30°
20°
20°
10°
30°
does not
20°
e at the edge
of
40°
ns.
10°
50°
10°
60°
20°
0°
This map depicts Inmarsat’s expectations
of coverage, but does not represent a
guarantee of service. The availability of
service at the edge of coverage areas
fluctuates depending on various conditions.
30°
40°
50°
30°
70°
60°
40°
80°
70°
50°
90°
180°
80°
am
m
eam
60°160°
I-4 Americas
70°
90°
180°
140°
120°
160°
140°
100°
80°
60°
40°
20°
0°
20°
40°
60°
80°
100°
120°
140°
160°
180°
I-4 Asia-Pacific
I-4 EMEA
120°
100°
80°
60°
100°
80°
40°
20°
0°
20°
40°
60°
80°
100°
120°
140°
160°
180°
80°
I-4 Americas
90°
I-4 EMEA
180°
160°
I-4 Americas
I-4 Asia-Pacific
140°
I-4 EMEA
120°
60°
40°
20°
0°
20°
40°
60°
80°
100°
120°
140°
160°
180°
I-4 Asia-Pacific
Example Narrow Beam
Diameter circa 500 miles
Example Regional Beam
Diameter circa 2000 miles
Capabilities
The shorter wavelength of L-band compared to UHF allows users
to operate with much smaller, inexpensive antennas. This opens up
new opportunities for operational communications on the move that
have proved difficult to achieve cost effectively via UHF, both for
vehicles and for the soldier on foot.
The smaller antenna size also makes it easier to conceal a terminal
when a covert solution is required. L-band is no more susceptible
than UHF to rain fade or to attenuation by airborne particulates,
unlike services in the higher satellite bands.
However, L-band has not been commonly used for military tactical
BLOS communications in the past. To avoid the need for largescale capital investment in developing and buying new fleets of
tactical radios compatible with the L-TAC service, Inmarsat’s partner,
Spectra, has developed the SlingShot range of products for use on
the Inmarsat network.
Spectra’s compact [170 mm x 87 mm x 29 mm; 500g] vehicle unit
frequency converter (appliqué) is engineered and certified to military
standards for shock protection, EMC and ingress prevention. It is
powered from a separate intelligent power supply that draws power
from a 9V – 36V source and includes a self-diagnostic capability
display provided on four LEDs. The unit accepts an RF input between
281 MHz and 311 MHz from a host radio, which it converts to
L-band for transmission to the satellite and carries out the reverse
conversion for the returned signal, providing a half-duplex channel
equivalent to SC TACSAT. It is capable of supporting most military
TACSAT radio types.
Inmarsat L-TAC terminal
Ba
nd
TX
/R
X
SlingShot
UHF
L-
SlingShot Appliqué
L-Band
Antenna
UHF Radio
Power supply unit
The converter unit’s design allows it to be operated remotely e.g.
from inside a building, with the L-band antenna separated from the
appliqué by up to 2 metres and the appliqué by up to a further 10
metres from the UHF radio. The ability to site the antenna remotely
from the radio also allows the operator to achieve line of sight from
antenna to satellite while he himself remains concealed from view
and from fire.
The initial product release features omni-directional antennas for
Comms On The Move (COTM) applications. A directional antenna will
be available from 2014 and will allow a high quality link using lower
power when operating at the pause (COTP) or from static locations.
It will also allow the option of leasing full-channel (25 kHz) wideband
data in an I-4 regional beam.
The type of antenna to be used by a customer is designated when
taking out the lease but may be changed if co-ordinated with
Inmarsat. An omni-directional antenna will not function in a beam
sold for directional antennas, nor will a directional antenna operate
in a beam engineered for omni-directional use.
Technical specifications
Slingshot™ Appliqué
Antenna
Frequencies
Frequencies
Antenna Output
UHF Radio Input
Transmit
Receive
281 - 311MHz
240 - 270MHz
Power
RF Input
RF Output Manpack
RF Output Vehicle/Marine
Power Supply Unit
L-band
Power
2-4W
2W
400mW
Antenna power supply provided by SlingShot™
Appliqué
Power Output
Manpack
Vehicle/Marine
7.2VDC
9 to 36VDC
Electronic Protection
>5W overload - SlingShot shutdown
System Indicators (LED)
Synchronised
Green
Antenna OK
Green
Transmitting
Amber
Fault (power overload) Red
Protection
Electronic Protection against reverse connection,
transients over-heat, moisture ingress
Environmental
Temperature Range
(operating)
IP Rating
-26 to +58oC
Environmental
Temperature Range
-25 to +55°C
(operating)
Environmental
Temperature Range
(operating)
IP Rating
IP 67
-26 to +58oC
IP 67
Physical Characteristics
Physical Characteristics
Physical Characteristics
Size (mm)
Manpack
Vehicle/Marine
Weight (g)
Manpack
Vehicle/Marine
Mounting
Vehicle/Marine
Colour
Size (mm) * see note 1
Manpack Omni
Manpack Directional
Marine
Vehicle
Weight (g)
Manpack Omni
Directional
Vehicle
Marine
Mounting
Manpack
Vehicle
Marine
Colours
Manpack/Vehicle
Marine
Size (mm)
Vehicle/Marine
Weight (g)
Vehicle/Marine
Mounting
Vehicle/Marine
Colour
Manpack/Vehicle
170 x 75 x 29
170 x 87 x 29
495
500
M4 (4 off)
Matt Black
70 x 155
149 x 135
149 x 142
146 x 72
260
375
780
625
Screw Mount
Magnetic, Fixed
Screw Mount
Marine
120 x 90 x 60
400
M4 (4 off)
Matt Green
Matt Khaki
Matt Grey
Matt Black
Matt Green, Matt Khaki
Matt Grey, Matt Black
Connectors
Connectors
Connectors
Input
UHF Radio
Power
Output
Antenna
Input SMA
Output SMA
Input
Manpack * see note 2
Vehicle/Marine
2-pin Micro, Buccaneer
Output
Vehicle/Marine
8-pin Micro, Buccaneer
Approvals
Approvals
Approvals
CE, FCC, C Tick
MIL-STD-461 (EMC)
MIL-STD-810G (Mechanical Protection)
CE, FCC, IC, Canada.
CE, FCC, C Tick
MIL-STD-461 (EMC)
MIL-STD-810G (Mechanical Protection)
Note 1. Size is diameter and height at maximum points
Note 2. Manpack battery cables and connectors will be
supplied to match suitable in-service battery pack
TNC
LEMO
SMA
Network and terminals
Inmarsat I-4 Network
SlingShot™ - Spectra’s small, lightweight
external appliqué for military radios, allows
SlingShot™
low-latency
and data
regional
SlingShot™ voice
- Spectra’s
small,
lightweight
communications
with
the
additional
option
external
appliqué
for
military
radios,
allows
Spectra’s small, lightweight external
appliqué
of
connecting
toallows
an
out-of-theatre
rear
low-latency
voice
and
data regional
for
military radios,
low-latency
voice
based
command node
communications
with the additional
option
and
data regional communications
with the
of
connecting
out-of-theatre
rear
additional optionto
of an
connecting
to an outbased command
node
of-theatre
rear based
command node
Availability
Inmarsat
I-4 Network
Globally
in the I-4 footprint;
Narrow
Beam, Regional
Beam or Customised
Inmarsat
I-4 Network
Availability
Beam
Globally in the I-4 footprint;
*see
noteBeam,
3
Narrow
Regional Beam or Customised
Availability
Beam
Channel
Width
Globally in the I-4 footprint;
*see
note 3 channel lease is a 25kHz
A standard
Narrow Beam, Regional Beam or Customised
allocation,
which
may
Channel
Width
Beam *see
note
3 be used as a single
channel,
or channel
up to fivelease
5kHzissub
channels
A standard
a 25kHz
Channel
Width
allocation,
which
may be used as a single
Modes
of
Operation
channel,
or
up
to
five 5kHz
sub
A standard
channel
lease
is achannels
25kHz
Wideband
Mode
allocation,
which
may
be used
as a single
25kHz
at
the
centre
of
the
channel
Modes of Operation
channel, or
up to five 5kHz sub channels
Narrowband
Mode
Wideband Mode
Channels
are centre
engineered
offer a 25kHz
25kHz at the
of thetochannel
Modes
of
Operation
channel
for
both
voice
and/or
Low Speed
Narrowband Mode
Data
(LSD),
to that to
provided
Wideband
Mode
Channels
areequal
engineered
offer a by
25kHz
UHF.
Thefor
25kHz
channel
canchannel
beLow
divided
25kHz
at
the
centre
the
channel
both
voiceofand/or
Speed
up
to (LSD),
five times
with
channelsby
each
Narrowband
Mode
Data
equal
to5kHz
that provided
providing
Narrowband
voice
Channels
are engineered
toand/or
offdivided
er aLSD
25kHz
UHF.
The 25kHz
channel
can
be
channel
for
both
voice
and/or
Low
Speed
using
Advanced
Narrowband
Digital
Voice
up to five times with 5kHz channels each
Data (LSD),
equalmode
to that
by UHF.
Terminal
(ANDVT)
providing
Narrowband
voiceprovided
and/or LSD
The
25kHz
channel
can
be
divided
up
to fi
using Advanced
Narrowband
Digital Voice
Satellite
Figure
of Merit
ve times with
5kHz channels
each providing
Terminal
(ANDVT)
mode
Narrow
Beam
Narrowband
voice
and/or LSD>10dB/K
using
Regional
Beam
dB/K
Advanced
Narrowband
Digital>0
Voice
Terminal
Satellite
Figure
of Merit
(ANDVT)
mode
Narrow
Beam
>10dB/K
Waveform – Modulation Modes
Regional Beam
>0 dB/K
*see note 4
Satellite Figure of Merit
FM
Waveform – Modulation Modes
Narrow
Beam
>10dB/K
-*see
Voice
and/or
LSD
note
4 Beam
Regional
>0 dB/K
ANDVT
FM
-- Voice
and/or
LSD
Voice and/or LSD
– Modulation
A
listWaveform
of proprietary wave
forms available on
ANDVT
Modes
*see
note
4
-request
Voice and/or LSD
FM
Voice and/or LSD
A listANDVT
of proprietary
formsand/or
available
waveVoice
LSDon
*Note 3. Subject to availability satellite beam footprint
request
A list of proprietary wave forms available on
expansion is possible by using customised multiple beams.
This isrequest
a chargeable service.
*Note 3. Subject to availability satellite beam footprint
expansion
is3.possible
by
using
customised
multiple
beams.
Subject
to availability
satellite
beam purposes.
footprint
*Note*Note
4. Subject
to details.
Waveform
illustrative
is possible
by using customised multiple beams.
This isexpansion
a chargeable
service.
This is a chargeable service.
*Note 5. Manpack availability date may be subject to change
*Note
4. discretion
Subject
to details.
Waveform
illustrative
purposes.
*Note
4. Subject
to details.
Waveform
illustrative
purposes.
at
Inmarsat’s
*Note 5. Manpack availability date may be subject to
at Inmarsat’s
discretion
*Notechange
5. Manpack
availability
date may be subject to change
at Inmarsat’s discretion
T 1595 – 83 – Vehicle
Omni Antenna
(Active) COTM or COTP
T 1595 – 83 – Vehicle Omni
Antenna
(Active)
T 1595COTM
– 83or
–COTP
Vehicle Omni
Antenna
(Active) COTM or COTP
Manpack Omni Antenna
(Half Active) COTM or COTP
Manpack Omni Antenna
(Half Active) COTM or COTP
Available
Q4 2013
Available
Q4 2013
Manpack Omni Antenna
(Half Active) COTM or COTP
Why Inmarsat Government?
We are a trusted partner to U.S. government
since 1979
We provide both MSS and FSS in all environments
We are truly global
We dial in the right level of security
We take a unique end-to-end approach
We are platform and frequency band agnostic
We have built scalable infrastructure based on
MPLS backbone
We are tops in customer service
We provide a full situational awareness of your
network performance
We are experienced in designing, implementing
and managing large, complex networks
We are an ISO 9001:2008 company, dedicated
to your highest level of satisfaction
We bring you game-changing capabilities
About Inmarsat
Inmarsat Government provides secure, reliable and affordable mission-critical telecommunications
to U.S. military and civilian organizations. Equipped with the industry’s leading terrestrial and satellite
infrastructure and partners, it delivers custom, end-to-end networks and solutions that can sustain
communications anytime, anywhere. Inmarsat Government is headquartered in Herndon, VA, with
network assets and operations around the globe. To learn more, please visit inmarsatgov.com.
info@inmarsatgov.com
1-866-734-6842
Whilst the above information has been prepared by Inmarsat in good faith, and all reasonable efforts have been made to ensure its accuracy,
Inmarsat makes no warranty or representation as to the accuracy, completeness or fitness for purpose or use of the information. Inmarsat shall
not be liable for any loss or damage of any kind, including indirect or consequential loss, arising from use of the information and all warranties and
conditions, whether express or implied by statute, common law or otherwise, are hereby excluded to the extent permitted by English law. INMARSAT is
a trademark of the International Mobile Satellite Organisation, the Inmarsat LOGO is a trademark of Inmarsat (IP) Company Limited. Both trademarks
are licensed to Inmarsat Global Limited. © Inmarsat Global Limited 2014. All rights reserved. L-TAC White paper June 2014.