1. Prof. dr. sc. Ivan Markežić ivan.markezic@fpz.hr
Универзитет „Св. Климент Охридски“
Технички Факултет – БИТОЛА
МУЛТИРАТЕРАЦИЈА КАКО ТЕХНИКА НА КОНТРОЛА НА ВОЗДУШНИОТ СООБРАЌАЈ MULTILATERATION AS SURVEILLANCE CHOICE
Prof. dr. sc. Ivan Markežić
MULTILATERACIJA KAO TEHNIKA KONTROLE ZRAČNOG PROMETA

2. Air Traffic Surveillance – Techniques and Technologies
Content
Air Traffic Surveillance – Techniques and Technologies
Multilateration System Description
Multilateration in an ECAC Context
Conclusion
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3. ”In The Beginning”
atc6.AV
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4. Air Traffic Surveillance – Techniques and Technologies
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5. Air Traffic Surveillance – Techniques and Technologies
Principle of Multilateration
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6. Surveillance strategy:
Air Traffic Surveillance – Techniques and Technologies
Surveillance strategy:
- mutually interoperable and compatible technologies
MSSR/SSR Mode S
ADS-B
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Multilateration, WAM

7. MLT System Description
Principle of Multilateration
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multilat_princip.avi

8. MLT System Description
Principle of Multilateration
Co-operative Independent Surveillance
- a number of antennas receive a signal from an aircraft
- central processing unit calculates the aircraft’s position from the time difference of arrival (TDOA) of the signal at the different receivers
- the TDOA between two antennas corresponds with a hyperboloid, a 2D surface in a 3D space
- at least four antennas are required for a 3D position calculation
- if altitude is known already, three antennas are sufficient
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9. MLT System Description
Active and Passive WAM System
Passive WAM Systems
No transmitter means:
- No transmitter license
- No 1030 spectrum usage
- No increase to 1030/1090 SSR environment (FRUIT)
Aircraft detection requires:
- The aircraft is Mode S equipped or
- The aircraft is within existing MSSR coverage
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10. MLT System Description
Active and Passive WAM System
Active WAM Systems
Independent of existing infrastructure
- Improved detection of Mode A/C only aircraft
Simpler and cheaper than MSSR interrogator
- Fixed antenna
- Low power interrogation option
Suitable for Mode S Surveillance
Care must be taken not to generate excess 1030/1090MHz FRUIT
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11. MLT System Description
WAM performance
Multilateration and Wide Area Multilateration
Multilateration
- Independent cooperative surveillance
Surface Multilateration
- Tracks aircraft on the surface
- Uses 2D algorithms
Wide Area Multilateration
- Tracks aircraft in flight
- Uses 3D algorithms
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12. MLT System Description
WAM performance
(en route application)
MSSR
WAM
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A 5 receiver WAM system with a 60nm baseline gives:
- Higher accuracy than MSSR
- Reduced range due to horizon effect

13. MLT System Description
WAM performance
(en route application)
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A 9 receiver WAM system with a 60nm baseline gives:
- Higher accuracy than MSSR
- Similar range to MSSR
Horizon effect (WAM horizon is the horizon of multiple sites)

14. MLT System Description
WAM performance
(TMA application)
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Coverage at 3000ft :
- Larger baselines give better accuracy
Shorter baselines give better low level coverage

15. MLT System Description
Impact on existing ATM operations
There is no negative impact on existing ATM operations
- WAM systems can easily be integrated into current ATM architectures
- WAM systems can exceed the performance of existing surveillance sensors
- There need be no difference in the information presented to the controller
WAM systems could provide benefits to ATM operations in the future
- WAM systems are capable of higher accuracies than current sensors
- WAM systems are capable of higher update rates than current sensors
- WAM systems can measure geometric height in addition to receiving pressure altitude
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16. Multilateration in an ECAC Context
Eurocontrol is promoting WAM technology for ATC surveillance:
(relatively low cost and good performance)
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Ground based surveillance infrastructure for En-Route and TMA

17. Multilateration in an ECAC Context
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Surveillance Strategy at the Aerodrome
ADS-B/WAM Combination - future surveillance scenario (!?)

18. En-route WAM systems can also provide accurate height measurement
Conclusion
WAM systems are potentially capable of significantly higher accuracies than an equivalent radar service:
a five receiver WAM system has a higher accuracy than MSSR
(both an en-route and terminal )
The range is lower due to the horizon of multiple receivers
A comparable range can be achieved by adding in additional receivers
En-route WAM systems can also provide accurate height measurement
information
All current WAM systems are based on 1090 MHz technology because:
wide availability of the technology as part of the airborne infrastructure
The properties of these signals for use in a WAM system
(aircraft identification and accurate TDOA measurements)
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Provide ADS-B data in addition to independent position
Do not require additional avionics
Ref.: The ATM Surveillance Strategy for ECAC, 2.2, ed. date 07/04/2008.

19. ВИ БЛАГОДАРАМ НА ВНИМАНИЕТО
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