Content Air Traffic Surveillance Techniques and Technologies Multilateration

Content Air Traffic Surveillance – Techniques and Technologies Multilateration System Description Multilateration in an ECAC Context Conclusion 2

”In The Beginning” atc 6. AV 3

Air Traffic Surveillance – Techniques and Technologies 4

Air Traffic Surveillance – Techniques and Technologies Principle of Multilateration 5

Air Traffic Surveillance – Techniques and Technologies • Surveillance strategy: - mutually interoperable and compatible technologies MSSR/SSR Mode S ADS-B Multilateration, WAM 6

MLT System Description • Principle of Multilateration multilat_princip. avi 7

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 2 D surface in a 3 D space - at least four antennas are required for a 3 D position calculation - if altitude is known already, three antennas are sufficient 8

MLT System Description • Active and 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 9

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 1030/1090 MHz FRUIT 10

MLT System Description • WAM performance Multilateration and Wide Area Multilateration - Independent cooperative surveillance Surface Multilateration - Tracks aircraft on the surface - Uses 2 D algorithms Wide Area Multilateration - Tracks aircraft in flight - Uses 3 D algorithms 11

MLT System Description • WAM performance (en route application) MSSR WAM A 5 receiver WAM system with a 60 nm baseline gives: - Higher accuracy than MSSR - Reduced range due to horizon effect 12

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

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

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 15

Multilateration in an ECAC Context • Eurocontrol is promoting WAM technology for ATC surveillance: (relatively low cost and good performance) Ground based surveillance infrastructure for En-Route and TMA 16

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

Conclusion WAM systems are potentially capable of significantly higher accuracies than an equivalent radar service: v a five receiver WAM system has a higher accuracy than MSSR (both an en-route and terminal ) v The range is lower due to the horizon of multiple receivers v 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: v wide availability of the technology as part of the airborne infrastructure v The properties of these signals for use in a WAM system (aircraft identification and accurate TDOA measurements) 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. http: //www. eurocontrol. int/surveillance/gallery/content/public/documents/WAM_study_report_1_1. pdf 18

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