IDLS 2003
INTRODUCTION TO
JTIDS/MIDSLINK 16
IDLS 2003
TERMINOLOGY
JTIDSJoint Tactical Information Distribution
System
MIDSMultifunction
alInformation Distribution
SystemINFORMATION - sensors, navigation, status, commands, vectors, position
DISTRIBUTION - via Link-16
SYSTEM - Platforms joined in a tactical environment
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TERMINOLOGY
• JTIDS/MIDS refers to the communications equipment necessary to exchange Link 16 messages
• This includes:– Terminal hardware and software– RF equipment– Resulting waveform generated
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ENVIRONMENTS
• Air• Surface• Subsurface• Land• Space
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IJMS
• Interim JTIDS Message Standard• Bases on Link 11 M-Series messages• Adapted to utilise basic JTIDS architecture• Class 1 or Bilingual Terminals
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LINK 16• Message standard (STANAG 5516)• 256 combinations of label and sub-label• Link 16 messages support:
Surveillance Network Management Control EW Voice Free text messaging
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TECHNICAL CHARACTERISTICS
• L Band UHF
• 51 Frequencies
• 969 to 1206 Mhz @ 3 Mhz Intervals
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10301030 10901090960 1215
IFF FiltersIFF Filters
14 Frequencies 5 Freq’s 32 Frequencies
TACAN / DME Channels spaced every 1 MHz
Link-16 Frequencies spaced every 3 MHz (51 Frequencies)Link-16 Frequencies spaced every 3 MHz (51 Frequencies)
969 1206
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ARCHITECTURE
• JTIDS/MIDS Link-16 is a data link that is:– Real Time– Secure– ECM Resistant– High Capacity– Non-Nodal
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ARCHITECTURE
• Broadcast type system– each unit can receive directly from all
other assigned units
• No critical nodes– if one terminal goes down, the
network is not crippled
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ARCHITECTURE
• Time Division Multiple Access (TDMA)
• Time is divided into 128 time slots per second
• Each terminal can either transmit or receive
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DAY (24 Hours)
12.8 mins =EPOCH =
98304Timeslots
EPOCH = 64 FRAMES
1 FRAME =12 Seconds
1Timeslot =7.8125 ms
= 112.5 EPOCHS
FRAME = 1536 Timeslots
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ARCHITECTURE
• Each time slot is allocated to a specific user for transmission. All other users receive in that time slot.
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TIMESLOT
• Timeslot equates to 7.8125msec• 1536 timeslots in 12 seconds• Timeslot comprises several
components
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TIMESLOT
• Number of elements within a timeslot– Jitter– Synchronisation– Time refinement– Message header and data – Propagation
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TIME SLOT STRUCTURE
Jitter - variable time delay in the start of a transmission of a time slot; standard double pulse and packed-2 single pulse message packing structures
SYNCJITTER HEADER DATA PROPAGATION
7.8125 milliseconds
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TIME SLOT STRUCTURESynchronization - a pattern of pulses that
allows the receiving terminal to synchronize to the transmission
SYNCJITTER HEADER DATA PROPAGATION
7.8125 milliseconds
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TIME SLOT STRUCTURE
Time Refinement - used for Class 1 compatibility only
SYNCJITTER HEADER DATA PROPAGATION
7.8125 milliseconds
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TIME SLOT STRUCTURE
Header - 35 bit word providing information concerning the message(s) transmitted in the time slot
SYNCJITTER HEADER DATA PROPAGATION
7.8125 milliseconds
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TIME SLOT STRUCTURE
Data - message(s) transmitted in the time slot;3, 6, or 12 TADIL J words, depending on packing structure
SYNCJITTER HEADER DATA PROPAGATION
7.8125 milliseconds
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TIME SLOT STRUCTURE
Propagation - time period to allow the signal to propagate to 300 or 500 NM prior to start of next time slot
SYNCJITTER HEADER DATA PROPAGATION
7.8125 milliseconds
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• Header and Data– Link 16 message words taken in groups of:
• 3 words (Std)• 6 Words (P2)• 12 Words (P4)
– Header specifies:• Message Type• Coding• Packing |Structure• Source terminal
TIMESLOT
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STANDARD PACKING STRUCTURE
S TR H DATA
TIME SLOT
7.8125 MILLISECONDS
3.354 MILLISECONDS 4.4585 MILLISECONDS MINUS JITTER
JITTER
S = SYNCHRONISATIONTR = TIME REFINEMENTH = HEADER
PROPAGATION
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ACCESS METHODS• Dedicated
– Guaranteed reception– Inflexible
• Contention– Flexible– Reception uncertainty
• Time slot re-allocation– Shared Pool– Unit requests share
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ECM RESISTANCE
• Double Pulse• Jitter• Frequency Hopping• Crypto variable Encoding• Message Preparation
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SECURITY
• Message Security (MSEC)• Transmission Security (TSEC)
– Common Variable Mode– Partitioned variable mode
• Auto rollover
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MESSAGE PREPARATION
• Message Packets• Reed-Solomon encoding
– All J-Series Fixed Format words
• Interleaving• CCSK• Random Noise
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NETWORK ENTRY
• Network Time Reference (NTR)– First Platform in net
• Transmits Initial Entry Message (IEM) every 12 seconds
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• Platform other than NTR required to synchronise
NETWORK ENTRY
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NET ENTRY
Time Slots belonging to Net Entry Time Slot Block A-0-6
Coarse Synchronization will take place using this
time slot
Time error to within propagation
time (clock correction)
Estimate of current system time
Estimate of time of next entry time slot
Time uncertainty
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FINE SYNCHRONISATION
• Actively or passively– Passively utilising received PPLI’s
• Actively– RTT(A) or RTT(B)
•RTT (A) Dedicated•RTT (B) Contention
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MULTINETTING
• JTIDS provides the capability to operate simultaneously in up to 127 nets in the same network
• A terminal can operate (transmit or receive) in only one net in any one time slot but can operate in any net in any time slot as determined by assignment
• These nets use independent frequency hopping patterns with the net number a variable in determining the hopping pattern
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MULTINETTING
NET 127
NET ...
NET 2
NET 1
NET 0
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NETWORK PARTICIPATION GROUPS
• Previous links, data received and processed if applicable to a platforms role or not
• NPG’s allow for grouping of J-series messages into a functional role
• Aids network design
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• 13 VOICE GROUP B• 19 NON-C2 TO NON-C2
• 20 NON-C2 TO NON-C2
• 21 BMD • 22 COMPOSITE A• 23 COMPOSITE B• 27 JOINT NET PPLI• 29 RESIDUAL• 30 IJMS POSITION &
STATUS• 31 OTHER IJMS DATA
• 1 INITIAL ENTRY• 2 RTT-A• 3 RTT-B• 4 NETWORK MANAGEMENT• 5 PPLI & STATUS GROUP A• 6 PPLI & STATUS GROUP B• 7 SURVEILLANCE• 8 MISSION MANAGEMENT• 9 CONTROL• 10 ELECTRONIC WARFARE• 12 VOICE GROUP A
NPG’s
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RELAY
• UHF LOS Only• Paired Slot relay
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A0 B0 C0 A1 B1 C1 A2 B2 C2 A3 B3 C3 A4 B4 C4 A5
X
Originator Tx in T/S (X)
The relay terminal Rx in (X)
Y
The relay platform will re-Tx in the timeslot controlled by the relay delay (6-31). Y is the re-Tx slot, with a relay delay of 6 timeslots
X
Re-Tx for second Hop by additional relay platform
RELAY
Paired Slots Paired Slots
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RELAY
• Fixed Format and free text• Capable of relaying to different nets
• No limit to relay hops
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UK PLATFORMS• In Service
– E3D Tornado F3– Nimrod (R) VC10 &
Tristar– JAPNMS (NMGB) C130– JPC TJF– RN (CVS & T42) RN (JPC)– GRAP (RA & 16 AAB)
• Future– EFA Typhoon ASTOR– MRA (4) T45– GBAD
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OTHER NATIONS
• USA (USAF, USN, USMC, US Army)• France Germany• Italy Netherlands• Norway Belgium• Denmark Spain• Canada Australia• Switzerland Japan• and others
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ANY QUESTIONS