Measurement of the LOFAR-HBA beam patterns using an unmanned aerial vehicle in the near field

Virone, G.; Paonessa, Fabio; Ciorba, Lorenzo; Matteoli, Stefania; Bolli, Pietro; Wijnholds, Stefan J.; Addamo, Giuseppe

doi:10.1117/1.jatis.8.1.011005

Cited by 6 publications

(7 citation statements)

References 24 publications

(30 reference statements)

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“…In the next step, the IESS computes the far-field of the equivalent sources in Fig. 23 Ref max (8) is defined as the difference between the far-field magnitudes of the UAV-based result UAV ( , ) and the reference UAV ( , ). Both are normalized to the maximum magnitude UAV max and Ref max , respectively, of the considered far-field cut.…”

Section: B Measurement Results For 18 Ghzmentioning

confidence: 99%

“…This is of major interest when the environment of the antenna influences the radiated field as it might occur for broadcast [3], [4], aircraft navigation [5] or mobile communication [6] systems. On-site testing is also inevitable when the antenna is immobile or simply too large for any indoor measurement facility as is the case for the lowfrequency antenna array (LOFAR) radio telescope [7], [8] and the square kilometer array (SKA) [9]. Small hovering platforms are also suitable for field distribution measurements due to their minimal scattering behavior compared to conventional probe positioning systems.…”

Section: Introductionmentioning

confidence: 99%

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A Cost-Effective Tethered-UAV-Based Coherent Near-Field Antenna Measurement System

Mauermayer¹,

Kornprobst

2022

IEEE Open J. Antennas Propag.

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For antenna measurements, the device under test (DUT) is usually transported to an anechoic chamber equipped with a scanner system. To measure on-site, unmanned aerial vehicles (UAVs) are a flexible solution as they can precisely maneuver a probe antenna over a surface in the DUT's nearfield region. In this work, the designed multi-rotor UAV enables electromagnetically optimal placement of the probe antenna and effective gravity center re-balacing by payload position adjustment. The onboard software-defined radio (SDR) serves as a dual-channel receiver for the dual-polarized probe and as a signal source. For phase-coherent measurements, the source signal is transmitted to the DUT via an optical fiber tethering the UAV to the ground control station. Power supply cables allow unlimited flight times. A laser-based tracking system originating from virtual reality (VR) applications measures the probe position and orientation. The developed operator software guides the UAV along a trajectory and records the irregularly distributed near-field samples. An inverse equivalent sources solver (IESS) with full probe correction computes equivalent sources for antenna diagnostics and the DUT far field. The deployed components make the system very cost-effective. Still, verification measurements demonstrate its usability and the accuracy of the results for frequencies up to several GHz.INDEX TERMS near-field antenna measurement, unmanned aerial vehicle (UAV), software-defined radio (SDR), radio-frequency over fiber (RFoF), near-field to far-field transformation (NFFFT), inverse equivalent sources solver (IESS)

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Section: B Measurement Results For 18 Ghzmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

A Cost-Effective Tethered-UAV-Based Coherent Near-Field Antenna Measurement System

Mauermayer¹,

Kornprobst

2022

IEEE Open J. Antennas Propag.

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show abstract

“…Moreover, the differential GNSS position accuracy of few centimeters translates to a negligible angular error of about 0.03 degrees. Magnitude and phase of the FF EEPs have been extracted from this measurement as in [47], [48]. In particular, the reference antenna has been used also in this FF case for the computation of each EEP measured phase.…”

Section: Embedded Element Patterns (Eeps)mentioning

confidence: 99%

“…The agreement between the 2D patterns is quite satisfactory, i.e., main lobe size and first sidelobe locations and levels are in agreement. The 2D FF measured pattern is not available due to its prohibitive time duration (only a few FF cuts can be scanned by the UAV in a single flight [47]). For example, a complete FF pattern measurement within the ± 29 • angular range with a resolution of 1 • will require a flight duration larger than 120 minutes.…”

Section: Array Patternmentioning

confidence: 99%

Large Horizontal Near-Field Scanner Based on a Non-Tethered Unmanned Aerial Vehicle

Ciorba

Virone

Paonessa

et al. 2022

IEEE Open J. Antennas Propag.

Self Cite

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A horizontal planar scanner with an approximate size of 40 m × 40 m has been implemented using the Unmanned Aerial Vehicle (UAV) technology. The UAV is not wired to the ground to maintain the flexibility and short setup time of a non-tethered flight. In this configuration, the UAV-mounted continuous-wave source is not phase-locked to the on-the-ground receiver. A dual-polarized reference antenna placed on the ground is hence used to retrieve the relevant phase information. The presented approach has been applied on the Pre -Aperture Array Verification System (Pre -AAVS1) of the Square Kilometre Array, which is a digital beamformed array with 16 active elements. An inverse source technique has been applied on measured Near-Field (NF) data acquired on two different sets of points (one for each electric field component) from all the receiver channels. In this way, Embedded Element Patterns (EEPs), array calibration coefficients and pattern have been determined from NF data only. The achieved results have been validated using a complementary set of Far-Field (FF) measurements and simulations.INDEX TERMS Antenna measurements, near-field measurements, unmanned aerial vehicle, digital beamforming array, phased-array radio telescopes, array calibration.

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“…This is of major interest when the environment of the antenna influences the radiated field as it might occur for broadcast [3], [4], aircraft navigation [5] or mobile communication [6] systems. On-site testing is also inevitable when the antenna is immobile or simply too large for any indoor measurement facility as is the case for the low-frequency antenna array (LOFAR) radio telescope [7], [8] and the square kilometer array (SKA) [9]. Small hovering platforms are also suitable for field distribution measurements due to their minimal scattering behavior compared to conventional probe positioning systems.…”

Section: Introductionmentioning

confidence: 99%

A Cost-Effective Tethered-UAV-Based Coherent Near-Field Antenna Measurement System

Mauermayer¹,

Kornprobst²

2022

Preprint

View full text Add to dashboard Cite

<p>For antenna measurements, the device under test (DUT) is usually transported to an anechoic chamber equipped with a scanner system. To measure on-site, unmanned aerial vehicles (UAVs) are a flexible solution as they can precisely maneuver a probe antenna over a surface in the DUT’s near-field region. In this work, the designed multi-rotor UAV enables electromagnetically optimal placement of the probe antenna and effective gravity center re-balacing by payload position adjustment. The on-board software-defined radio (SDR) serves as a dual-channel receiver for the dual-polarized probe and as a signal source. For phase-coherent measurements, the source signal is transmitted to the DUT via an optical fiber tethering the UAV to the ground control station. Power supply cables allow unlimited flight times. A laser-based tracking system originating from virtual reality (VR) applications measures the probe position and orientation. The developed operator software guides the UAV along a trajectory and records the irregularly distributed near-field samples. An inverse equivalent sources solver (IESS) with full probe correction computes equivalent sources for antenna diagnostics and the DUT far field. The deployed components make the system very cost-effective. Still, verification measurements demonstrate its usability and the accuracy of the results for frequencies up to several GHz.</p>

show abstract

Measurement of the LOFAR-HBA beam patterns using an unmanned aerial vehicle in the near field

Cited by 6 publications

References 24 publications

A Cost-Effective Tethered-UAV-Based Coherent Near-Field Antenna Measurement System

A Cost-Effective Tethered-UAV-Based Coherent Near-Field Antenna Measurement System

Large Horizontal Near-Field Scanner Based on a Non-Tethered Unmanned Aerial Vehicle

A Cost-Effective Tethered-UAV-Based Coherent Near-Field Antenna Measurement System

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