Week 3 Flashcards by Zac Allin

What is SAR?

Synthetic Aperture radar

Coherent airborne side-looking radar which utilises the flight path of the platform to simulate an extremely large antenna or aperture electronically and generates high resolution imagery

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What is a Swath?

Aircraft flies at a constant velocity and transmits pulses 90 degrees to the flight line

Each pulse sent out at a different location on the flight line defines one element of a synthetic array

Known as a Swath

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What is a strip?

Multiple swaths create a strip

The total array

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What is Spot formation?

Using electronic steering to illuminate a designated area for longer than usual.

Spotlight mode - beam is held on a given region so it can be mapped repeatedly

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What is an advantage of Spot formation?

Gives better cross range resolution

Reduces radar shadow

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What are constraints to SAR?

Requires a lot of processing

Target motion can cause blurring

SAR maps have shadow regions due to mountains etc

Cross range resolution, PRF and velocity of a platform are all related and can’t be selected independently

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What is CCD? And for what purposes can it be used?

Coherent Change detection

Collect and compare SAR images from the same geometry collected at two different times

CCD algorithm will detect changes invisible to naked eye

Good for looking for IED placement or BDA

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What is ISAR and How does it differ to SAR?

Inverse synthetic Aperture radar

While SAR processing relies on motion of the imaging aircraft to collect radar returns for imaging ISAR are technology relies on target motion

A small Doppler change from a target movement in ISAR mode is equal to a large array movement in SAR mode

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What are the worst types of clutter for MTI?

Bird flocks
Wave and swell action
Rain in windy conditions
Trees in windy conditions

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What is GMTI?

Ground MTI

Can detect, locate and track moving vehicles (and low flying AC)

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Name some SAR platforms

P8
Sentinel
Reaper

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What should a TDL (tactical data link) provide to give a tactical advantage?

Speed
Security
Accuracy
Clear, unambiguous and easily assimilated information

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What is the definition of a digital data link

An automatic means of passing data in an agreed format and speed over a common medium

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Definition of tactical data link?

A digital data link carries sufficient data close enough to real time to be useful in a tactical situation

20 seconds or less

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What will a TDL report?

Tracks (Hostile, friendly and unknown)

Position
Speed
Heading
Altitude

Tactical orders

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What is commonality?

For forces to operate TDL they must have certain common attributes

Same frequency
Same format
Same parameters
Realtime

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What is the basic TDL architecture?

Sensor
Data handling and display system
Cryptographic system
Comms system (transmitter/reciever)

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What are the three fundamental types of TDL system?

Point to point
Broadcast
Netted

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What is point to point system?

Simplex
Duplex
Semi duplex

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What is a broadcast system?

Designed to transfer surveillance information from units capable of processing tactical data information to those not.

Simplex

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What is a netted system?

For exchanging digital information among airborne,
Land based and ship borne tactical data systems

Duplex

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What are the three TDL modes of operation?

Simplex -one way

Duplex - two way simultaneously

Semi- duplex - two way one at a time

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What are STANAGS?

Standardized NATO agreements

Technical specifications of TDLs and procedures for their operations

5511 for link 11
5516 for link 16

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Current platforms with TDL?

RJ
P8
E3D sentry

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Brevity codeword for link 11

Alligator

Brevity codeword for link 16

Timber

Brevity codeword for link 22

Elfin

What type of system is Link 11?

Semi duplex | Netted

What frequencies does link 11 use?

UHF (line of sight) | HF (beyond LOS)

What is the configuration of Link 11?

``` Tactical data system computer Encryption Data terminal set Radio Coupler Antenna ```

What does the Tactical Data system computer and encryption do?

Tactical Data system computer collects information and converts it into specific message format (M series for link 11) Hold in buffer before passing one word at a time to encrypt it

What does the data terminal set do?

Takes the digital encrypted data and converts it to analogue

What does the radio and coupler do?

Modulates a radio frequency carrier Sent through the coupler to antenna

What are the concepts of operation of link 11?

Requires network control station (NCS) and participating units (PU) A data link reference point is established (fixed point where positional information is derived) Network control station calls all participating units (roll call) - all PU reply with their data, then NCS transmits

Link 11 limitations

Operates on single Frequency More participants slow the net If you lose the NCS you lose the whole data link. All members recieve all data

Advantages of link 16

Multi frequency Nodeless (doesn't matter if you lose any aircraft, you still maintain Data link) Increased data rate Reduced terminal size

What message formats do link 11 and 16 use?

11 - M series | 16 - J series

What system does a link 16 operate?

Semi duplex - broadcast system

Explain Time division multiple access (TDMA)

Units are allocated time slots One transmit, the rest receive Some units have more information to pass so more time slots allocated Every minute of every day broken down into cyclic windows Epochs> Frames> timeslots (7.81miliseconds) 1 frame = 12 seconds

What does JTIDS stand for?

Joint tactical information distribution system

What are the 2 catagories for JTIDS units?

Command and control - more information to transmit so more time slots - AWACS, major naval units etc Non command and control - fighter AC - less information to transmit

What does AIS stand for?

Automatic identification system

What is the main purpose of AIS?

An automatic tracking system used on ships for identifying and locating vessels by electronically sharing data with other nearby ships, AIS base stations and satellites

What information will AIS include?

``` IMO number Type of vessel Position, course and speed Where it's from and going Gross tonnage ```

Who must have AIS fitted?

International voyaging ships over 300 tons Non international voyaging ships over 500 tons All passenger ships regardless of size

What does AIS utilise to transmit information?

SOTDMA Self organized time division multiple access

What is the advantage of self organized time division multiple access?

You didn't need a central station to assign slots or time synchronisation

What are airborne uses for AIS?

Fishing fleet monitoring and control Maritime security Search and rescue Fleet and cargo tracking

What is IBS?

Integrated Broadcast service

What is IBS-I?

Integrated Broadcast service interactive Reports unevaluated intelligence

IBS- S?

Integrated Broadcast service Simplex Time critical evaluated intelligence

What is SSSB?

Ship shore ship buffer Acts as a relay between CRC link 1 to link 11 naval vessels (and airborne assets) Transferring data between CRC (control reporting centre

Limitations of SSSB

Not all link 11 data can be transferred to link 1 Further coordination may be required through voice

What is an ELNOT?

ELINT notation A123Y

What does the first letter of an ELNOT do?

Platform and originating block

What does the last character of an ELNOT do?

Indicates family relationships

What are the Red first letter codes?

A-H ``` A - airborne B- Ground C - Ship borne F- Ground/Ship T- temporary notation ```

What are the blue first letter codes?

M-P ``` M- airborne N- ground O - ship borne P- ground/ship W- temporary notation ```

What letter range is given to commercial emissions for first letter ELNOTS?

I-K

What is L first letter ELNOTS?

Unknown

What is K first letter ELNOTS?

Comnav

What is G first letter ELNOTS?

Data link

What is J first letter ELNOTS?

ATC

What is I first letter ELNOTS?

COMAIR

What are the last character ELNOT?

Z - unique emission, no family members or one of a kind A-W - 1st-23rd family members X - unknown position Y- ambiguous emitter

What may a joining message contain?

``` Callsign Weapon loadout Serviceability ETA Latest SPINs changes ```

What may a handover message contain?

``` Current tasking Estimated time off task Threats in area Weather in area Other callsigns in area ```

Name 3 functions of TDL within a C2 environment

Surveillance Reconnaissance Operational intelligence

3 main characteristics of TDMA?

Epoch frame timeslots (7.81s) Units assigned which timeslots through timeslots assignment Automatic and transparent to operator

What are the moan operating differences between link 11 and link 16

Link 11 uses roll call (NCS roll calls all PU which reply with data then NCS transmits own) Link 16 uses TDMA

What AIS architecture is there?

AIS tranciever on ships SOTDMA Display