EEE381B Aerospace Systems - PowerPoint PPT Presentation

1 / 25
About This Presentation
Title:

EEE381B Aerospace Systems

Description:

Identification - 2. Outline. Introduction. Transponders. ATC. TCAS. IFF. Network-centric warfare ... an aircraft equipped with a modern, serviceable TCAS system. ... – PowerPoint PPT presentation

Number of Views:223
Avg rating:3.0/5.0
Slides: 26
Provided by: tarpi
Category:

less

Transcript and Presenter's Notes

Title: EEE381B Aerospace Systems


1
EEE381BAerospace Systems Avionics
  • Identification Systems
  • Ref Moir Seabridge, Chapter 7
  • Dr Ron Smith

2
Outline
  • Introduction
  • Transponders
  • ATC
  • TCAS
  • IFF
  • Network-centric warfare
  • In-class exercises

3
1. Introduction
  • Identification the classification and
    identification of a target before engagement as
    dictated by the rules of engagement.

4
1.1 Identification (transponder) systems
  • Military aircraft employ a number of different
    interrogators and transponders
  • Distance measurement equipment (DME)
  • Tactical air navigation (TACAN)
  • Air traffic control (ATC) mode S
  • Traffic collision avoidance system (TCAS)
  • Automatic dependent surveillance (ADS)
  • Identification friend or foe (IFF)

DME and TACAN will be described in the
Navigation section of the course.
5
1.2 RF Spectrum1
  • Identification equipment
  • Air traffic control (ATC)
  • Collision Avoidance (TCAS)
  • Identification friend or foe (IFF)

6
2. Transponders
  • A transponder is a receiver / transmitter device
    designed to transmit a response signal when
    legitimately interrogated. NATO definition
  • An automatic device that transmits a
    predetermined message in response to a predefined
    received signal. Wikipedia

7
2.1 Air traffic control (ATC)
  • A ground-based primary surveillance radar (PSR)
    detects the presence of an aircraft and indicates
    its bearing and distance.
  • At the same time a secondary surveillance radar
    (SSR), synchronized (on boresight) with the PSR,
    interrogates the aircraft using a series of
    pulses.
  • The aircraft transponder responds with a
    different series of pulses containing situational
    information, typically its aircraft identifier
    and altitude.
  • The information from the PSR and SSR is then
    integrated and presented on the ATC console.

8
2.1.1 Air traffic control (ATC)
9
2.1.2 Air traffic control (ATC)
  • This system is also known as identification
    friend or foe / secondary surveillance radar
    (IFF/SSR)
  • The onboard aircraft equipment consists of
  • an ATC transponder control unit for setting the
    modes of operation and the control codes,
  • a dedicated ATC transponder, and
  • antennas.

10
2.1.3 Air traffic control (ATC)
  • Mode A (simple system)
  • Aircraft identification (Call-sign)
  • Mode C (more advanced)
  • Mode A altitude
  • Mode S (more recently)
  • Mode C 24 bit address identifier (unambiguous)
  • Provides limited air-air and air-ground
    communications
  • Can also provides whereabouts of other aircraft
    in its vicinity
  • Uses digital error-correcting codes for improved
    reliability

11
2.2 Traffic Collision Avoidance System
TCAS
  • A type of collision and avoidance system that
    functions independently from the ground based ATC
    suite.
  • Used to detect possible aircraft conflicts
  • Requires that all possible conflict aircraft are
    equipped with an SSR transponder.
  • Mandated above 10,000 ft and within 30 miles of
    major airports.

12
2.2.1 TCAS architecture 1
13
2.2.2 TCAS operation
  • Altitude and identification is obtained from
    modes C or S of an airborne ATC transponder (only
    bearing from mode A).
  • Distance is obtained by calculating the response
    delay.
  • Directional antennas obtain the bearing of the
    responding aircraft.

14
2.2.3 TCAS operation
  • TCAS builds a three-dimensional map of the
    aircraft within vicinity and extrapolates their
    closing distance and altitudes to determine if
    there are any possible collisions.
  • Vicinity is typically defined as 15-40 nm
    forward, 5-15 nm aft and 10-20 nm on each side.
  • Remember that the system can only communicate
    with aircraft equipped with serviceable
    transponders.

15
2.2.4 TCAS types
  • TCAS I
  • Indicates distance and bearing
  • Issues traffic advisories (TA)
  • 'TRAFFIC, TRAFFIC
  • TCAS II
  • Negotiates and indicates deconfliction strategies
  • Issues resolution advisories (RA)
  • Climb Climb Climb,
  • Descend Descend Descend,
  • Maintain vertical speed , ...

16
2.3 Identification friend or foe (IFF)
  • Used in two ways
  • Provide 360 coverage to respond to
    interrogations and receive interrogation returns
    from friendly aircraft (very similar to the
    airborne operation of ATC mode S when used in
    combination with TCAS)

AN/APX-113(V) by BAE Systems
17
2.3.1 Identification friend or foe (IFF)
  • Used to specifically identify targets seen by the
    primary radar.

18
3. Network-centric operations 3
  • Based upon the hypothesis that
  • A robustly networked force improves information
    sharing
  • Information sharing enhances the quality of
    information and shared situational awareness
  • Shared situational awareness enables
    collaboration and self-synchronization, and
    enhances sustainability and speed of command and
  • These, in turn, dramatically increase mission
    effectiveness.

19
3.1 Network-centric operations
  • Employs
  • High speed, high bandwidth digital communications
  • Sophisticated signal processing
  • High speed internal (onboard) networks
  • Integrates
  • Command control structure (C2)
  • Ultra high resolution sensors
  • Sensor and weapons delivery platforms

20
3.2 Network-centric operations 1
21
3.3 NCO example 4
22
4. In-class exercises
23
4.1 Quick response exercise 1
  • You are flying (VFR) in an aircraft equipped with
    a modern, serviceable TCAS system.
  • You receive a traffic advisory (TA) that a
    potential conflict exists directly in your flight
    path range is closing and the bearing is
    straight ahead.
  • You perform the necessary visual check, but you
    do not see any other aircraft.
  • What is a likely explanation?

24
4.2 Quick response exercise 2
  • What problem do you see with having the IFF
    transponder oriented co-boresight with the
    primary radar?

25
References
  • Moir Seabridge, Military Avionics Systems,
    American Institute of Aeronautics Astronautics,
    2006. Sections 2.6 2.7
  • Wikipedia
  • Military Communication Systems, LFTSP course
    notes, ECE Dept, RMC, 2007
  • Air Power Australia, http//www.ausairpower.net/TE
    -NCW-JanFeb-05.html.
  • Georgia State University, hyperphsyics,
    http//hyperphysics.phy-astr.gsu.edu/hbase/audio/b
    cast.htmlc3
  • Mark A. Hicks, "Clip art licensed from the Clip
    Art Gallery on DiscoverySchool.com"
Write a Comment
User Comments (0)
About PowerShow.com