1. Wide Area Multilateration Demonstration System
Radar Research Group
Wide Area Multilateration Demonstration System
Rudolf Seller, Ádám Szüllő
Budapest University of Technology and Economics

2. WAMLAT Radar Research Group
Passive distributed radar system to improve ATC reliability
Wide-area coverage (>10km diameter)
Multiple receivers
Synchronization challenge
GPS based synchronization

3. WAMLAT System Radar Research Group GPS based synchronization
Data transfer via Ethernet
Server

4. Geometry of the Receivers
Radar Research Group
Geometry of the Receivers
Multilateration is nonlinear
Location dependent position estimation accuracy
Zone defined by the receivers

5. Synchronization Radar Research Group
GPS Disciplined Oscillator (GPSDO)
No physical clock distribution network
Tens of nanosecond accuracy
Long term time difference measurement between two GPSDOs:

6. Arrangement of the Receivers
Radar Research Group
Arrangement of the Receivers
Across and around the city of Budapest
Not optimal geometry

7. Results Radar Research Group Persistent displaying
Fligth information from

8. Results Radar Research Group
Mode A and Mode C based multilateration has high false detection rate

9. Radar Research Group
Results
Only Mode S based multilateration

10. Radar Research Group
Results
„Invisible” aircraft

11. Location dependent accuracy
Radar Research Group
Location dependent accuracy
Multilateration is nonlinear

12. Accuracy of the system Radar Research Group
Multilateration compared to ADS-B
ADS-B accuracy is questionable (eg. systematic error because of delay)
Accuracy estimation based on longterm dataset
Median error is 128 meters
Estimated accuracy is 150 meters

13. Future work Develope tracking algorithm Expand the system nation-wide
Radar Research Group
Future work
Develope tracking algorithm
Expand the system nation-wide

14. Radar Research Group
Thank You!