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UK Tactical Data Systems
Reference Guide
Tactical Data Links
Link
1
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Designed in the late 1950s, Link 1 has low capacity and is
usually insecure. It is used between ground-based Air Surveillance and
Control system (ASACS) units, but it may also be used by ground-based mobile
units to connect into a static C2 system. Link 1 units are allocated areas
of responsibility, termed Track Production Areas (TPA), whose boundaries are
overlapped by Track Continuity Areas (TCA). Tracks within the TCAs are
exchanged automatically between the adjacent units, but wider area data
exchange may also be carried out within operator-defined Area of Operational
Interest (AOI)s.
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Purpose
Exchange air tracks and EW strobes in near real-time.
Attributes
Simplex or duplex, Point to point
Not normally encrypted.
Data rate 600 or 1200 bps (but may be operated at any
multiple of 600 bps if agreed to by the participants).
Format
‘S’ series messages
128 bits (30 bits overhead, 2 x 49 bit paired data
messages).
Track
No
15 bit NATO Track Numbers (NTN) (2-letter alpha bi-graph,
3 digit octal number. The bi-graph indicates the originating unit and not the
current tracking unit).
Medium
Landline (cable, microwave, SATCOM) or multi-channel
radio. Synchronous Differential Frequency Shift Keying (DFSK) waveform.
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Strengths
Widely used throughout Europe.
ECM-resistant, as is inherent in a buried cable or
microwave link.
Limitations
No free text capability.
Track management is basic (e.g. change Identification (ID)).
No C2 capability (but target engagement and fighter
allocation status can be handled).
Slow - track telling is prioritised by category and tracks
with low priority (typically friendlies) can be minutes out of date.
Standards
STANAG 5501
STANAG 5601
SOPs
ADatP-31
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Link 14
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Link 14 is a nonreal-time radio teletype link that allows TDS equipped units to provide a broadcast to other units without TDSs. The HCI is either a
simple list on a teleprinter or a pictorial presentation on an Autoplot Visual
Display Unit (VDU). Link 14 was designed to pass track data, but the link is
very slow and so it is now used primarily to provide a (High Interest Track
Broadcast (HITB) to supplement real-time data links and voice reports.
Although it was discontinued as a NATO TDL from 2000, it is still likely to
remain in service for several years. Some UK platforms (E3D and T42/CVS) remain fitted but it does not form part of the current UK TDL operational TDL capability
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Purpose
Exchange of EW data, air, surface and subsurface tracks,
and points and free text.
Attributes
Broadcast.
Encrypted (BID 850).
Data Rate 75 bps.
Format
Man-readable character strings.
Track No
12 bit Data Link Reference Number (DLRN) (4 digit octal
number).
Medium
HF, UHF or SHF satellite Radio Teletype (RATT).
Uses Frequency Shift Keying (FSK) with a 2-tone Keyer.
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Strengths
The design of the Teletype transmission allows reception
over very long-ranges.
It is more resistant to jamming on HF than is Link 11.
Limitations
Although there is a standard NATO format for Link 14,
almost nobody uses it and numerous national formats have been developed, not
all of which are interoperable. Units must therefore agree on a version
before use.
The data rate is very slow and tracks may only be updated
approximately every 6 mins.
Standards
STANAG 5514
SOPs
ADatP-14
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Link 11 (TADIL A)
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Link 11, sometimes called Link 11A (Tactical Digital
Information Link A (TADIL A)) to differentiate it from Link 11B, is based on
1960’s technology and is a relatively slow link. It is secure, but not ECM-resistant,
and is used widely to exchange digital information among airborne,
land-based, and shipboard systems. It is normally operated in a roll call,
or netted polling, mode under the control of a Data Net Control Station (DNCS).
The DNCS initiates the roll call by addressing and transmitting an
interrogation message to a specific Participating Unit (PU), which then
responds by transmitting its data, while all other stations receive. The
DNCS then interrogates the next PU in the prescribed roll call. Link 11 can
also operate in a broadcast mode where one participant makes a single data
transmission, or a series of single transmissions. Each Link 11 platform has
a Data Terminal Set (DTS) that changes digital computer information into
audio tones for transmission by radio. Link 11 has two waveforms – Conventional
Link Eleven Waveform (CLEW) and Single tone Link Eleven Waveform (SLEW).
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Purpose
Real-time exchange of EW data, and air, surface, and
subsurface tracks and points, together with amplifying data. Transmission of
orders, alerts and commands.
Attributes
Simplex (but may be regarded as half-duplex).
Parallel, Netted with single NCS.
Broadcast.
Data Rate 1364 or 2250 bps.
Encryption. KG-40/40A.
Standards
STANAG 5511
MIL-STD-6011B
MIL-STD-188-203-1A
OPSPEC-411
UK DTDL-IRS (Part II) – Link 11
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Medium
HF or UHF
CLEW. DTS: AN/USQ-111, MX512P, AN/USQ-125 or
AN/USQ-120.
SLEW. DTS: AN/USQ-125 or AN/USQ-120.
MFL. DTS: AN/USQ-120.
DNL.
S-TADIL A. Full implementation of Link 11A using Satellite
Communication (SATCOM) in place of HF / UHF (different from Link 11B SATCOM).
Format
‘M’ series messages.
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CLEW
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Data is transmitted in two 30-bit frames, each consisting
of 24 information bits and six error detection and correction bits. The
information message is essentially a 48-bit word. A frame is transmitted in
parallel on 15 multiplexed tones. Diversity is available as required by
identical transmissions or independent side band. A 16th tone is reserved
for Doppler correction.
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SLEW
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Data is transmitted in a message format consisting of an
acquisition preamble followed by a header block, a number of data fields, and
End-Of-Message (EOM) field. The preamble resolves Automatic Gain Control (AGC), signal detection, synchronisation, Doppler requirements and equalisation. The header and
data fields use digital procedures for Error Detection And Correction (EDAC) to gain robustness.
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CLEW and SLEW are not compatible waveforms.
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Track No
12 bit Data Link Reference Number (DLRN) (4 digit octal
number, indicating the originating unit, not current tracking unit).
DLRNs correlate with, and may be, mapped onto L16 TNs (but
must be cross referenced to L1 NATO Track Numbers (NTN).
Strengths
Very widely fitted in NATO and beyond, and will remain
operational until at least 2015.
HF ground wave provides BLOS range out to 300nm, but often
unreliable beyond 150nm.
Sky-wave capability can provide reliable ranges in excess
of 600nm.
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SOPs
ADatP-11
ADatP-33
Limitations
The CLEW / SLEW waveforms are incompatible and all PUs
must use the same waveform to achieve connectivity.
Nodal nature makes it vulnerable to loss of DNCS.
Lack of ECM-resistance means it can be rendered inoperative
in a hostile jamming environment.
Cannot handle ground tracks.
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Link 11B (TADIL B)
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Link 11B, sometimes called Serial Link 11, is essentially
a point-to-point version of Link 11 (TADIL A), but its implementation differs
slightly in some areas. For instance, Link 11B includes a unique message to
monitor the status of its link and it does not implement some messages
concerned with ASW data. Link 11B is typically used to disseminate a track
picture between ground units in the same way as Link 1, but it is more
capable and secure.
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Purpose
Real-time exchange of EW data, and air, surface, and
subsurface tracks and points, together with amplifying data.
Transmission of orders, alerts and commands. Free text
available.
Attributes
Duplex.
Serial.
Point-to-point. Pairs of RUs operate on separate LINK 11B channels often referred to as B links.
Data Rate 600, 1200, 2400, 4800 and 9600bps.
Encryption. (KG-30, KG-84, KG-94A, KG-194A).
Format
‘M’ series messages.
72 bits per message (24 bits overhead and 48 bits of
information) arranged in eight 9-bit frames with:
1 start frame;
6 data frames, each with a mark bit;
1 end check frame with a mark bit.
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Medium
Single or multi-channel radio.
Landline.
Microwave.
SATCOM.
Track No
12 bit DLRN (4 digit octal number).
Standards
STANAG 5511
MIL-STD-6011
MIL-STD-188-212
UK DTDL-IRS (Part II) – Link 11B
SOPs
ADatP-11
ADatP-33
Strengths
ECM-resistant, as is inherent in a buried cable or
microwave link.
Limitations
Cannot handle ground tracks.
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JTIDS
IJMS
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Interim JTIDS Message Specification (IJMS) was developed
to provide an interim operational capability for JTIDS because the JTIDS
hardware was available before the Link 16 message standard. IJMS is based on
Link 11 messages, packaged to fit into the JTIDS architecture. Consequently,
it has the same functionality as Link 11, but with greater security, speed
and EPM. It also provides secure voice communications, but it is not
optimised for the JTIDS architecture and so it cannot use the enhanced JTIDS
features that increase data throughput. IJMS usually operates on a network
shared with Link 16, for which capacity is allocated by assigning time slots
to IJMS participants in the same way as for Link 16 units. IJMS is still
used by NATO but message standards are no longer maintained.
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Purpose
Exchange of EW data, points, air, surface and subsurface
tracks, with amplifying data. Free text and ECM Resistant Voice (ERV), reduced
C2 capability providing digital control and related command and exchange of
weapons status information.
Attributes
Netted Time Division Multiple Access (TDMA) architecture.
Frequency hopping through 51 discrete frequencies.
Spread spectrum.
Encrypted (KGV-8).
Keying Devices KYK-13 or AN/CZY-10.
Data Rate 26,000 bps.
Format
‘C,I, N, P, S, T’ series messages.
225 bits per message.
Track No
15 bit System Track Number (STN) (5 octal digits).
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Medium
Upper UHF (960-1215 MHz).
Terminals
JTIDS Class 1 – Hughes Improved Terminal (HIT) (also known as ECM Resistant Communication System (ERCS)). JTIDS Class 2 - bilingual models
(some Class 2 terminals only allow JU to synchronise with IJMS).
Standards
Now withdrawn or dormant.
Strengths
No critical nodes once network is established. Can be
used by Link 16 JUs for time synchronisation.
Limitations
JTIDS Class 1 terminals are not capable of operating on
Link 16.
Some (but not all) JTIDS Class 2 platforms can operate on
IJMS and Link 16 concurrently.
SOPs
ADatP-16 contain some IJMS procedures.
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MIDS
/ JTIDS Link 16 (TADIL J)
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MIDS describes NATO need for a secure, high capacity,
ECM-resistant communications link designed for all environments (space, air,
surface and land) and all platform types (including both C2 and non-C2 units).
Based on 1970s technology, the requirement was originally fulfilled by
hardware called JTIDS, but newer terminals called MIDS Low Volume Terminal (LVT)
also exist. Utilising time division architecture, Link 16 JUs have
pre-assigned sets of multiple time slots in which to transmit their data and
to receive data from other units. The time slots of a net can be parcelled
out to one or more Network Participation Group (NPG), which are defined by
operational function and by the types of messages that will be transmitted in
it. Link 16 is one of two message standards that may be carried on MIDS /
JTIDS, the other being IJMS.
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Purpose
Exchange of EW data, points, lines, areas, air, space,
surface, subsurface and land tracks, with amplifying data, in real-time.
Navigation and identification data, free text, ERV,
transmission of orders, alerts, commands and status data. Digital ac control.
Attributes
Netted TDMA architecture.
Frequency hopping through 51 discrete frequencies.
Spread spectrum.
Encrypted (KGV-8, CDH).
Keying Devices KYK-13 or AN/CZY-10.
Nodeless multi-netting support for up to 127 nets (but
practical limit is stated to be 20).
Medium
Upper UHF (960-1215 MHz).
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Terminals
JTIDS Class 2/2H .
AN/URC-138.
MIDS LVT 1 (standard terminal).
MIDS LVT 2 (US Army version).
MIDS LVT 3 (F15 FDL).
MIDS LVT 4 – 10 (LVT 1 platform variants - see ADatP-33).
Packing
Standard Double Pulse. Three words, preceded by
EPM jitter, time synchronisation and refinement and message header, 500nm
propagation available.
Packed 2 Single Pulse. Six words, with EPM jitter
500nm propagation available.
Packed 2 Double Pulse. Six words, no EPM jitter
300nm propagation only.
Packed 4 Single Pulse. Twelve words, no EPM jitter,
300nm propagation only.
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Format
‘J’ series messages.
Messages
Made up of one or more of three types
of 75-bit words (all starting with 2-bit word format label and ending with
5-bit parity check, the remainder being the fields described below):
Initial Word
5-bit label, 3-bit sub-label, 3-bit message length
indicator, 57-bit data.
Extension Word
One to four words, 68-bit data.
Continuation Word
One to 31 words, 5-bit continuation label, 63-bit data.
Strengths
Large and comprehensive message catalogue.
No critical nodes once network is established.
Relay, with up to five dedicated hops, may be designed
into the system to achieve BLOS performance, but facility uses data capacity.
Message Packing increases data capacity, but at expense of
EPM.
Precise Participant Location & Identification (PPLI)
messages provide crypto-secure positive identification.
Two modes of establishing grid position available:
Relative grid when relative navigation is provided by measuring Time Of Arrival
(TOA) of signals from each terminal; JUs update their geodetic position using
data from the position of a terminal acting as
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Navigation
Controller. For Geodetic Grid terminals use geodetic position derived from GPS. TOA data is still calculated but a navigation controller is not active. GPS is the more accurate and preferred method.
Track No
19 bit STN (Two character alpha numeric – 5-bits each, 0-7
or A-Z, but not I and O – and 3 octal digits, 3-bits each).
Standards
STANAGs 5516 and 4175.
MIL-STD-6016C.
UK DTDL-IRS (Part II) – Link 16.
SOPs
ADatP-16
ADatP-33
Limitations
High capacity requirement constrains link to a UHF
solution, range limited to direct LOS (300nm normal mode or 500nm extended).
All participants synchronise on Network Time Reference
(NTR) on network entry, but once synchronised, network can operate for only a
few hours without NTR.
System shares frequency band of some flight navigation
systems (notably DME / TACAN) - permission required from civilian ATC
authorities to operate.
MIDS / JTIDS network design is a complex activity and
configuration details must be disseminated to all participants before
operations can commence.
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Clearance to operate MIDS / JTIDS within the UK Flight
Information Region (FIR) is administered by the JDLMO Data Link Management Cell
(DLMC), UK CAOC, RAF High Wycombe; Monitoring of the UK Frequency Clearance
Agreement with the CAA is undertaken by the JDLMO.
MIDS / JTIDS networks operating in the UK are planned, designed and disseminated by the JDLMO Network Design Cell (NDC) using the TDL
Network Design System (TNDS).
MIDS / JTIDS Network Participation Groups
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NPG‑1 Network Entry
NPG‑2 RTT-A
NPG‑3 RTT-B
NPG‑4 Network Management
NPG‑5 PPLI A
NPG‑6 PPLI B
NPG‑7 Surveillance
NPG‑8 Mission Management / Weapons Coordination
NPG‑9 Control
NPG‑10 Electronic Warfare
NPG‑11 Not used by US platforms
NPG‑12 Voice A
NPG‑13 Voice B
NPG‑14 Reserved joint use (USN Indirect
PPLI Interim Use Only)
NPG‑15 Reserved joint use (THAAD Interim
Use Only)
NPG‑16 Reserved joint use (THAAD (Interim
Use Only)
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NPG‑17 Not used by US platforms
NPG‑18 Reserved joint use (USN
Interim Use Only)
NPG‑19 Fighter-to-Fighter A
NPG‑20 Fighter-to-Fighter B
NPG‑21 Engagement
NPG-22 Composite A
NPG‑23 Composite B
NPG‑24 Not used by US platforms
NPG‑25 Reserved joint use (THAAD
Interim Use Only)
NPG‑26 Not used by US platforms
NPG‑27 Joint Net PPLI
NPG‑28 Distributed Network
Management
NPG‑29 Residual Messages
NPG‑30 IJMS P Message, Position
NPG‑31 IJMS T Message, Track Report
NPG‑32 to 511 USA Need Lines
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NB: An ‘Interim Use
Only’ NPG is not approved for joint use.
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Qt / Qp Table
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Time Accuracy
nanoseconds
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Quality
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Position Accuracy
feet
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<50 (NTR)
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15
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<50
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<71
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14
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<71
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<100
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13
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<100
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<141
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12
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<141
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<200
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11
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<200
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<282
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10
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<282
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<400
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9
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<400
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<565
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8
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<565
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<800
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7
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<800
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<1130
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6
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<1130
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<1600
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5
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<1600
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<2260
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4
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<2260
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<4520
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3
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<4520
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<9040
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2
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<9040
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<18080
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1
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<18080
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>18080
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0
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>18080
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CPD Table
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Leap Year CPD Prediction Tables
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2008
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2004
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Month
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Day
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Month
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Day
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Odd
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Even
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Odd
|
Even
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January
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0
|
1
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January
|
1
|
0
|
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February
|
1
|
0
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February
|
0
|
1
|
|
March
|
0
|
1
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March
|
1
|
0
|
|
April
|
1
|
0
|
April
|
0
|
1
|
|
May
|
1
|
0
|
May
|
0
|
1
|
|
June
|
0
|
1
|
June
|
1
|
0
|
|
July
|
0
|
1
|
July
|
1
|
0
|
|
August
|
1
|
0
|
August
|
0
|
1
|
|
September
|
0
|
1
|
September
|
1
|
0
|
|
October
|
0
|
1
|
October
|
1
|
0
|
|
November
|
1
|
0
|
November
|
0
|
1
|
|
December
|
1
|
0
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December
|
0
|
1
|
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Non Leap Year CPD Prediction Tables
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2006, 2009
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2005, 2007, 2010
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|
Month
|
Day
|
Month
|
Day
|
|
|
Odd
|
Even
|
|
Odd
|
Even
|
|
January
|
0
|
1
|
January
|
1
|
0
|
|
February
|
1
|
0
|
February
|
0
|
1
|
|
March
|
1
|
0
|
March
|
0
|
1
|
|
April
|
0
|
1
|
April
|
1
|
0
|
|
May
|
0
|
1
|
May
|
1
|
0
|
|
June
|
1
|
0
|
June
|
0
|
1
|
|
July
|
1
|
0
|
July
|
0
|
1
|
|
August
|
0
|
1
|
August
|
1
|
0
|
|
September
|
1
|
0
|
September
|
0
|
1
|
|
October
|
1
|
0
|
October
|
0
|
1
|
|
November
|
0
|
1
|
November
|
1
|
0
|
|
December
|
0
|
1
|
December
|
1
|
0
|
Link 22
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Originally called NATO Improved Link Eleven (NILE) and
predominantly designed for maritime forces, Link 22 is planned as a secure,
ECM-resistant, medium speed replacement for Link 11 that will work in harmony
with Link 16. It has similar message capabilities to Link 16, but with
extended BLOS capability (which is achieved at the expense of data
throughput). Tactical data may be exchanged selectively among NUs within
communities of interest, which are defined by functional requirements. All
NUs will be capable of single network operation, but some will be able to
communicate on up to four Mission Area Sub Networks (MASN) simultaneously,
either using the same or a combination of media. A set of interconnected
networks is known as a Super Network.
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Purpose
Exchange of EW data, air, space, land, surface &
subsurface tracks and points, with amplifying data in real-time.
Transmission of orders, commands and alerts between C2
systems.
Attributes
TDMA or dynamic TDMA.
Spread spectrum.
Frequency hopping.
NILE Link Level Crypto (LLC).
Data Rate better than Link 11, but less than Link 16.
Format
‘F’ and ‘F/J’ series messages (‘F/J’ messages are ‘J’
messages with 2 additional bits of overhead).
72 bits per message.
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Track No
19 bit STN (Two character alpha numeric – 5-bits each, 0-7
or A-Z, but not I and O – and 3 octal digits, 3-bits each).
Medium
HF (2 - 30 MHz) and UHF (225 - 400 MHz), simultaneously on
different networks using either fixed or frequency agile waveforms.
Standards
STANAG 5522
SOPS
ADatP-22
ADatP 33
Strengths
Gapless coverage > 300nm range on HF. Relay may
increase geographic coverage of HF > 1000 nm and UHF > 300nm.
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VMF
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VMF has its origins in a 1970s US Army requirement for a
variable message extension to Link 16 and is primarily aimed at ground
operations fire support. Although it will also support many other
operations, it is not intended as a surveillance picture compilation link. Sometimes
erroneously called Joint VMF, VMF messages are designed as a common means of
exchanging digital data between combat units at various organisational
levels. With the flexibility to accommodate varying needs for volume and
detail, VMF messages may be applied to a broad range of tactical
communication systems. VMF is bearer-independent, although most current
users employ a Combat Net Radio (CNR) compatible system.
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Purpose
Real-time data exchange for Fire Support, and Close Air
Support (CAS). No real-time Situational Awareness (SA) but has Blue Force
tracking capability. Many other army based functions.
Attributes
Can be transmitted in either secure or non-secure mode. Effective
throughput varies with medium in use: typically 2,400 bps, 4,800 bps or 9,600
bps using different generation VHF radios, or 16,000 bps using landline.
Format
‘K’ series messages.
VMF is bit-oriented but can use character-oriented
elements. Message lengths may vary.
Medium
Network functions independent of textual portion of
message thus VMF is media independent and can operate over any digital
point-to-point or network architecture broadcast capable radio system.
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Messages
Uses predefined fixed length fields and employs a header
extension and internal syntax to specify the presence, absence and recurrence
of fields, as selected by user.
Header Information
Originator Address Group.
Recipient Address Group.
Information Address Group.
Message Handling Group.
Originator Date/Time/Group.
Perishability Date/Time/Group.
Acknowledgement Request Group.
Response Data Group.
Version Number.
Compression Type.
Message ID Address Group.
Reference Message Group.
Date Time Group Extensions.
User Data
Data Field Indicator.
Data Use Indicator.
Data Item.
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Strengths
Achieves higher effective data flow
by more efficient use of message space than other types of TDL.
Provides user with flexibility to send specific
information only, on demand, and is thus suitable for use in bandwidth
constrained environments.
Standards
MIL-STD-6017 (K-series messages).
MIL‑STD‑188‑220 (CNR protocols).
MIL‑STD‑2045‑47001 (Message header).
MIL‑STD‑2045‑14502 Ch1/6.
Reference Documents:
US VMF IOP
Part of the JMTOP. Provides guidance on how VMF systems
should be used in the US.
UK VMF Users Guide (VUG)
This UK Unclassified comprehensive guide has been
developed for the novice and the systems implementer alike. The guide covers:
the communications bearer, messages and their headers, network management,
data forwarding and hardware and equipment issues.
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UK Single
Link Interface Requirement Specification (SLIRS)
SLIRS describes in a user friendly manner, the way that the
K-series messages and the MIL-STD-2045-47001 message header are to be
implemented by UK platforms. It also describes related issues such as the
Tactical Internet interoperability, and network planning and management.
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