International Conference on Electromagnetics in Advanced Applications September 7-11, 2015 Torino – Italy Antenna Pattern Calibration of Radio Telescopes using an UAV-based device A. Martínez Picar, C. Marqué, M. Anciaux, H. Lamy, and S. Ranvier Solar-Terrestrial Belgian Institute for Royal Observatory Centre of Excellence Space Aeronomy of Belgium
The Humain Radio-Astronomy Station
The Humain Radio-Astronomy Station LPDA (e-Callisto) 45 – 400 MHz 6m Parabolic Reflector 300 – 800 MHz BRAMS Yagi Array ~ 50 MHz
Antenna Pattern Characterization Humain Antenna Systems LPDA Proper Gain Real 6m-dish Characterization Flux Density BRAMS Array
Antenna Pattern Characterization Humain Antenna Systems LPDA Proper Gain Real 6m-dish Characterization Flux Density BRAMS Array Measurements using 𝑔𝑔 ≥ 2𝑀 2 Well-Known Test 𝐸 𝜇 Signal (source) located at
Antenna Pattern Characterization Humain Antenna Systems 3 ~ 27 m LPDA Proper Gain Real 75 ~ 195 m 6m-dish Characterization Flux Density BRAMS Array Measurements ~ 3 m using 𝑔𝑔 ≥ 2𝑀 2 Well-Known Test 𝐸 𝜇 Signal (source) located at
Measurements using a test signal RF Unit H AUT Spectrum Analyzer
Measurements using an UAV Flight Path UAV RF Unit H AUT Spectrum Analyzer
RAMON System Radio Flight Path UAV Antenna Measurement ONsite RF Unit H AUT θ φ Avionics & Spectrum Sync Flight Log PC Analyzer Clock
Unmanned Aerial Vehicle (UAV) OktoXL – Mikrokopter • Payload: 2.6 kg (max) • Range: 500 m • GPS-aided navigation • Barometric altimeter • ~ 15 min autonomy
Unmanned Aerial Vehicle (UAV) • Predefined waypoints-based autonomous flight path • Position and hold mode with heading control (3º) • 5 satellites (min): ~3 m accuracy OktoXL – Mikrokopter • Payload: 2.6 kg (max) • Range: 500 m • GPS-aided navigation • Barometric altimeter • ~ 15 min autonomy
Unmanned Aerial Vehicle (UAV) • Predefined waypoints-based autonomous flight path • Position and hold mode with heading control (3º) • 5 satellites (min): ~3 m accuracy OktoXL – Mikrokopter • Payload: 2.6 kg (max) • Range: 500 m • GPS-aided navigation • Barometric altimeter • ~ 15 min autonomy
RF Unit Short Monopole Antenna SBC (Raspberry Pi) Battery Bank Metallic Mesh RF signal generator
RF Unit Z = 50 Ω Short Monopole Antenna Freq Control SBC (Raspberry Pi) +6h autonomy Battery Bank Metallic Mesh EM isolation RF signal generator -6 dBm (max)
Receiver / Data Logger AUT Spectrum Analyzer • Python script (GUI) • SCPI commands over FTP • Max Hold mode • Output: received power & timestamps Ethernet
Measurement Strategy “Static” Waypoints every 10º in azimuth + Circular paths around AUT, separated 10º in elevation Avionics & Flight Received Logging PC Spectrum Signal Analyzer
Measurement Strategy “Static” Waypoints every 10º in azimuth + Circular paths around AUT, separated 10º in elevation Avionics & Flight Received Ethernet Logging PC Spectrum Signal Analyzer
Measurement Strategy “Static” Waypoints every 10º in azimuth + Circular paths around AUT, separated 10º in elevation Avionics & Flight Received Ethernet Logging PC Spectrum Signal Analyzer
Data Processing t 1 : p 1 [ f 1 ], p 1 [ f 2 ], p 1 [ f 3 ], …, p 1 [ f m ] t 2 : p 2 [ f 1 ], p 2 [f 2 ], p 2 [ f 3 ], …, p 2 [ f m ] t 3 : p 3 [ f 1 ], p 3 [f 2 ], p 3 [ f 3 ], …, p 3 [ f m ] … t x : p x [ f 1 ], p x [f 2 ], p x [ f 3 ], …, p x [ f m ] … … t y : p y [ f 1 ], p y [f 2 ], p y [ f 3 ], …, p y [ f m ] t n-1 : p n-1 [ f 1 ], p n-1 [f 2 ], …, p n-1 [ f m ] t n : p n [ f 1 ], p n [f 2 ], p n [ f 3 ], …, p n [ f m ] Flight Track Received Power Log
Data Processing t 1 : p 1 [ f 1 ], p 1 [ f 2 ], p 1 [ f 3 ], …, p 1 [ f m ] t 2 : p 2 [ f 1 ], p 2 [f 2 ], p 2 [ f 3 ], …, p 2 [ f m ] t 3 : p 3 [ f 1 ], p 3 [f 2 ], p 3 [ f 3 ], …, p 3 [ f m ] … t A : lon A , lat A , alt A , speed A t x : p x [ f 1 ], p x [f 2 ], p x [ f 3 ], …, p x [ f m ] … … t y : p y [ f 1 ], p y [f 2 ], p y [ f 3 ], …, p y [ f m ] t n-1 : p n-1 [ f 1 ], p n-1 [f 2 ], …, p n-1 [ f m ] t n : p n [ f 1 ], p n [f 2 ], p n [ f 3 ], …, p n [ f m ] Flight Track Received Power Log
Data Processing Quasi-Static Waypoints Group I t 1 : p 1 [ f 1 ], p 1 [ f 2 ], p 1 [ f 3 ], …, p 1 [ f m ] t 2 : p 2 [ f 1 ], p 2 [f 2 ], p 2 [ f 3 ], …, p 2 [ f m ] t 3 : p 3 [ f 1 ], p 3 [f 2 ], p 3 [ f 3 ], …, p 3 [ f m ] Group II … t A : lon A , lat A , alt A , speed A t x : p x [ f 1 ], p x [f 2 ], p x [ f 3 ], …, p x [ f m ] Group III … … t y : p y [ f 1 ], p y [f 2 ], p y [ f 3 ], …, p y [ f m ] t n-1 : p n-1 [ f 1 ], p n-1 [f 2 ], …, p n-1 [ f m ] t n : p n [ f 1 ], p n [f 2 ], p n [ f 3 ], …, p n [ f m ] Flight Track Received Power Log
Data Processing Quasi-Static Waypoints Group I t 1 : p 1 [ f 1 ], p 1 [ f 2 ], p 1 [ f 3 ], …, p 1 [ f m ] t 2 : p 2 [ f 1 ], p 2 [f 2 ], p 2 [ f 3 ], …, p 2 [ f m ] t 3 : p 3 [ f 1 ], p 3 [f 2 ], p 3 [ f 3 ], …, p 3 [ f m ] Group II … t A : lon A , lat A , alt A , speed A t x : p x [ f 1 ], p x [f 2 ], p x [ f 3 ], …, p x [ f m ] Group III … … t y : p y [ f 1 ], p y [f 2 ], p y [ f 3 ], …, p y [ f m ] t n-1 : p n-1 [ f 1 ], p n-1 [f 2 ], …, p n-1 [ f m ] t n : p n [ f 1 ], p n [f 2 ], p n [ f 3 ], …, p n [ f m ] Flight Track Received Power Log
Data Processing Quasi-Static Waypoints Group I t 1 : p 1 [ f 1 ], p 1 [ f 2 ], p 1 [ f 3 ], …, p 1 [ f m ] t 2 : p 2 [ f 1 ], p 2 [f 2 ], p 2 [ f 3 ], …, p 2 [ f m ] t 3 : p 3 [ f 1 ], p 3 [f 2 ], p 3 [ f 3 ], …, p 3 [ f m ] Group II … t A : lon A , lat A , alt A , speed A t x : p x [ f 1 ], p x [f 2 ], p x [ f 3 ], …, p x [ f m ] Group III … … t y : p y [ f 1 ], p y [f 2 ], p y [ f 3 ], …, p y [ f m ] t n-1 : p n-1 [ f 1 ], p n-1 [f 2 ], …, p n-1 [ f m ] t n : p n [ f 1 ], p n [f 2 ], p n [ f 3 ], …, p n [ f m ] Flight Track Received Power Log
Data Processing Group I t 1 : p 1 [ f 1 ], p 1 [ f 2 ], p 1 [ f 3 ], …, p 1 [ f m ] t 2 : p 2 [ f 1 ], p 2 [f 2 ], p 2 [ f 3 ], …, p 2 [ f m ] t 3 : p 3 [ f 1 ], p 3 [f 2 ], p 3 [ f 3 ], …, p 3 [ f m ] Group II … t A : lon A , lat A , alt A , speed A t x : p x [ f 1 ], p x [f 2 ], p x [ f 3 ], …, p x [ f m ] Group III … … t y : p y [ f 1 ], p y [f 2 ], p y [ f 3 ], …, p y [ f m ] t n-1 : p n-1 [ f 1 ], p n-1 [f 2 ], …, p n-1 [ f m ] t n : p n [ f 1 ], p n [f 2 ], p n [ f 3 ], …, p n [ f m ] Flight Track Received Power Log
Data Processing median(lon I ; lat I ; alt I ) t 1 : p 1 [ f 1 ], p 1 [ f 2 ], p 1 [ f 3 ], …, p 1 [ f m ] median ( p 1 ; p 2 ) for each f t 2 : p 2 [ f 1 ], p 2 [f 2 ], p 2 [ f 3 ], …, p 2 [ f m ] t 3 : p 3 [ f 1 ], p 3 [f 2 ], p 3 [ f 3 ], …, p 3 [ f m ] median(lon II ; lat II ; alt II ) … median ( p x ; p x+1 ; …) for each f t x : p x [ f 1 ], p x [f 2 ], p x [ f 3 ], …, p x [ f m ] median(lon III ; lat III ; alt III ) … … t y : p y [ f 1 ], p y [f 2 ], p y [ f 3 ], …, p y [ f m ] median(lon N ; lat N ; alt N ) t n-1 : p n-1 [ f 1 ], p n-1 [f 2 ], …, p n-1 [ f m ] median (…; p n-1 ; p n ) for each f t n : p n [ f 1 ], p n [f 2 ], p n [ f 3 ], …, p n [ f m ] Flight Track Received Power Log
First Task Pattern of the Test Signal Source • The UAV will be always oriented towards the AUT • Measured with a calibrated antenna 𝑄 𝑆 = 𝑄 𝑈 − 𝑀 + 𝐻 𝑈 + 𝐻 𝑆
First Task Pattern of the Test Signal Source • The UAV will be always oriented towards the AUT • Measured with a calibrated antenna 𝑄 𝑆 = 𝑄 𝑈 − 𝑀 + 𝐻 𝑈 + 𝐻 𝑆
Proof of Concept • AUT: 6m-dish antenna • f = 328.5 MHz • Flights @ different distances • 1 day mission 𝑄 𝑆 = 𝑄 𝑈 − 𝑀 + 𝐻 𝑈 + 𝐻 𝑆
Numerical Simulation
Measurements
Discussion • Statistical approach (more points are needed) • Differentiate measurements under dry and humid conditions • Variability of points location is less sensitive flying far away • Authorization (BELGOCONTROL) – permission for flying up to 120 m agl
International Conference on Electromagnetics in Advanced Applications September 7-11, 2015 Torino – Italy Thank you! Antonio Martínez Picar antonio.martinez@observatory.be Solar-Terrestrial Belgian Institute for Royal Observatory Centre of Excellence Space Aeronomy of Belgium
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