Day 1 Week 3 Flashcards
What is SAR?
Synthetic aperture radar
What are the parameters for fine and coarse resolution?
Fine = 4 inches Coarse = 3m
Define SAR
SAR is a coherent side looking radar system which utilises the flight path of the platform to simulate an extremely large antenna or aperture electronically
Advantages of SAR
Doesn’t have to overfly area being mapped
All weather
Day and night
How does a SAR work? 3 types
Swath
Spot
Inverse aperture
How does swath work?
Transmits pulses at 90 degrees to the flight line at a constantly velocity. Multiple swaths create a strip. Simulates a synthetic array.
Explain spot formation?
Uses beam steering to illuminate a designated area longer than normal. Gives better cross range resolution and reduces radar shadow you get with swath.
What are the system constraints of SAR?
Requires large computing power
Cross range resolution, PRF and velocity of platform are all related and cannot be selected independently.
Target motion causes blurring and positional errors
Shadow regions
What is CCD?
Coherent change detection
Comparison of coherent sar imagery ie passing same area at same speed and path and compares imagery to detect changes. e.g Sand moving IEDs Foliage movement BDA
What is ISAR?
Inverse synthetic aperture radar
Relies on moving targets whereas SAR relies on static targets
What is MTI?
Moving target indicator - removes background and stationary clutter
measures doppler shift
What is ground MTI?
Provides detection, location and tracking of moving vehicles and slow moving low flying aircraft.
Why do we use data links?
Rapid comms in a complex environment Accuracy Security Speed Clear, unambiguous, easily assimilated Provide tactical advantage
Difference between digital data link and tactical data link
Digital = agreed format and speed over a common medium Tactical = Sufficient data close enough to real time (20 seconds)
What will a TDL report?
Track
Position, heading, speed, alt
Tactical orders
Sent in defined format
What does a TDL provide support to?
Op intel Surveillance Recon Engagement and weapons status info Conduit for info exchange ID of friendly forces
Basic components of a TDL
Sensor
Data handling system
Cryptographic system
Communications system (Tx & Rx)
What mediums can TDL be propagated through?
Radio, SatCom, Landline and Microwave
What are the 3 fundamental types of a TDL system? Explain them simplex/duplex/semi duplex
Point to point - simplex, duplex or semi duplex
Broadcast - Simplex
Netted - Duplex
TDL modes of operation
Simplex - one way
Semi duplex - two way but not simultaneously
Duplex - two way simultaneously
What is the documentation for data links called?
Comms = STANAG 5000 series
Link 11 = Mil-std 6011 / STANAG 5511
Link 16 - Mil-std 6016 / STANAG 5516
What are the brevity codewords for link 11 and 16
Link 11 - Alligator
Link 16 - Timber
Explain link 11 properties
Semi duplex netted system
Secure radio link UHF - LOS or HF beyond LOS
Exchanges digital info between land, ship and airborne systems
What are the link 11 limitations?
Requires network control station & participating units (central hub ie ISTAR platform) Operates on a single frequency Not a continuous data transfer (ie slow) More PU = slower time All net members receive all data
What are the improvements of Link 16 to 11
Nodeless Jam resistant Built in encryption Increased data rate Reduced terminal size Secure voice capability Precise participant location and ID
What are the characterstics of link 16?
Operates in the aeronautical radio navigation frequency band:
UHF 969 - 1206 mhz
Frequency hopping psuedorandom across 50 frequencies
Semi duplex broadcast systems
What is J series?
Specially formatted messages designed for link 16
What is TDMA? and how is it broken up
Time division multiple access used in link 16
Epochs - Frames - Timeslots
Day = 24 hours 112.5 EPOCHS
EPOCHS = 64 frames = 12.8 mins = 98304 timeslots
1 Frame = 12 seconds = 1536 timeslots
1 Timeslot = 7.8ms
How does TDMA work?
Nodeless so no single unit is key to the operation of the network.
Units are allocated timeslots to transmit, receive or relay data.
The more data a platform may need to send/receive, the more time it will be allocated.
How are JTID units categorised?
Command and control C2 - more time slots assigned
Non C2 - Less time slots
Ping Pong? (Brevity Code word)
Exchange of Link 11 Information on the datanet
Suspect? (Brevity Code word)
A track which is potentially hostile because of its characteristics, behaviour, origin or nationality
Hostile? (Brevity Code word)
A track declared to belong to any opposing nation, party group or entity, which by virtue of its behaviour or information collected on it such as characteristics, origin or nationality contributes to threat to friendly forces
Bent? (Brevity Code word)
System indicated is inoperative
System is Bent
Beanstalk?
Datalink users should check equipment for spurious tracks
Prelude? (Brevity Code word)
The reference point from which track positions are reported within a force
Sweet? (Brevity Code word)
Opposite of sour - cancels sick or bent
Equipment is operationg efficiently
Sour? (Brevity Code word)
Opposite of sweet
Equipment indicated is not operating efficiently
Cyclops? (Brevity Code word)
Unmanned Aerial Vehicle
Assumed Friend? (Brevity Code word)
A track which is assumed to be a friend because of its characteristics, behaviour or origin
Friend? (Brevity Code word)
A track belonging to a declared friendly nation
Neutral? (Brevity Code word)
A track whose characteristics, behaviour, origin or nationality indicate that it is neither supporting nor opposing friendly forces
Bandit? (Brevity Code word)
An aircraft identified as enemy, in accordance with theatre ID criteria.
The term does not necessarily imply direction or authority to engage
Faker? (Brevity Code word)
A friendly track acting as a hostile for exercise purposes
Joker? (Brevity Code word)
A friendly track acting as a suspect for exercise purposes
What is the main difference between how Link 11 and Link 16 operate?
Link 11: Network Control Station calls all Participating Units (Roll Call)
All PUs reply with their Data
When all have replied, the NCS transmits it’s own Data
Link 16: Nodeless Employs Time Division Multiple Access (TDMA) architecture
Epochs > Frames > Time Slots (~8 milliseconds)
Units assigned which timeslot to use through Time Slot Assignment
Automatic and transparent to the operator
Describe Automatic Identification System (AIS) architecture
Is an automatic tracking system used on ships
identifies and locates vessels by electronically exchangng data with other nearby ships, AIS base stations and satellites
Must be present on:
international 300 gross tonnage or more
non-international 500 gross tonnage or more
What information does AIS provide?
Unique Identification Type of Vessel Position, course, speed Voyage details = ports and ETAs Gross Tonnage & Draught
What are the airborne uses for AIS?
Fishing Fleet Monitoring & Control
Maritime Security
Search and Rescue (SAR)
Fleet and cargo tracking
What is IBS?
Integrated Broadcast Service
Provides real time or near real time intelligence data
Delivered via UHF or Satcom
Provided in common format to all users
Types of IBS?
IBS-I = Interactive IBS-S = Simplex
Explain Ship-Shore-Ship Buffer (SSSB)
Real-time data link buffer system that supports data exchange between naval forces
Explain SSSB Operations
SSSB nominated sit will establish:
Link 1 Connectivity with Control Reporting Centre (CRC)
Link 11 Connectivity with airborne/naval units
What are the limitation of SSSB
Not all Link 11 data received can be forwarded on to Link 1
Further coordination may be required through voice
What is Ground MTI used for?
joint intelligence preparation of the environment.
indicators and warnings
Attack ops
