Gnss antenna system for receiving multi-band gnss signals

Patent metadata

Field	Value
Publication number	US-2025183521-A1
Application number	US-202519049559-A
Country	US
Kind code	A1
Filing date	Feb 10, 2025
Priority date	Sep 3, 2021
Publication date	Jun 5, 2025
Grant date	—

Abstract

A GNSS antenna system for receiving GNSS signals in the L1 and L2/L5 frequency band, and to an unmanned aerial vehicle (UAV) comprising the GNSS antenna system.

First claim

1 . An unmanned aerial vehicle (UAV) for flying in a physical environment, comprising:
a body extending along an axis from a front end to a back end having a housing, a first mounting structure attached to the body and extending away from the body in a direction to a left side of the axis, a second mounting structure attached to the body and extending away from the body in a direction to a right side of the axis being an opposite direction to the direction to the left side, four propulsion units, in particular rotor assemblies, two of which are mounted to the first mounting structure and two of which are mounted to the second mounting structure, a directional distance measuring module including: a measuring field of view with a main view direction, within which measuring field of view directions and distances to surfaces in the physical environment are measurable by directionally emitting distance measurement radiation into the field of view, a detector unit for detecting distance measurement radiation reflected from a surface, and a distance measurement radiation source, and a GNSS antenna system for receiving GNSS signals, wherein a part of the housing of the UAV is embodied as carbon fiber housing, wherein on the upper side of the UAV the carbon fiber housing surrounds a part of the housing embodied as fiber glass housing, wherein the GNSS antenna system is arranged below the fiber glass housing.

2 . The unmanned aerial vehicle (UAV) according to claim 1 , wherein the UAV comprises a curved surface made of plastic, and the GNSS antenna system comprises at least one inverted F-antenna which comprises an antenna, which antenna is arranged on the curved surface, which curved surface is physically separate from the fiber glass housing and arranged below the fiber glass housing.

3 . The unmanned aerial vehicle (UAV) according to claim 2 , wherein the fiber glass housing and the curved surface are shaped in a substantially similar manner, wherein the fiber glass housing tightly follows the curved surface, in particular with only a small gap between the curved surface and the fiber glass housing.

4 . The unmanned aerial vehicle (UAV) according to claim 2 , wherein the GNSS antenna system comprises eight inverted F-antennas, and the UAV comprises a first quadrifilar 4-phased antenna feeder, a second quadrifilar 4-phased antenna feeder and a printed circuit board, wherein the eight antennas of the eight inverted F-antennas are arranged on the curved surface, and on which curved surface the first quadrifilar 4-phased antenna feeder is mounted, and wherein the eight inverted F-antennas comprise a common ground plane below the curved surface, which common ground plane is arranged on the printed circuit board, wherein the second quadrifilar 4-phased antenna feeder is mounted on the printed circuit board.

5 . The unmanned aerial vehicle (UAV) according to claim 3 , wherein the GNSS antenna system comprises eight inverted F-antennas, and the UAV comprises a first quadrifilar 4-phased antenna feeder, a second quadrifilar 4-phased antenna feeder and a printed circuit board, wherein the eight antennas of the eight inverted F-antennas are arranged on the curved surface, and on which curved surface the first quadrifilar 4-phased antenna feeder is mounted, and wherein the eight inverted F-antennas comprise a common ground plane below the curved surface, which common ground plane is arranged on the printed circuit board, wherein the second quadrifilar 4-phased antenna feeder is mounted on the printed circuit board.

6 . The unmanned aerial vehicle (UAV) according to claim 1 , wherein the GNSS antenna system for receiving GNSS signals comprises
at least one inverted F-antenna configured to receive GNSS signals in the L1 frequency band (L1-antenna), and at least one inverted F-antenna configured to receive GNSS signals in the L2/L5 frequency band (L2/L5-antenna), wherein each inverted F-antenna comprises an antenna having an antenna end point and a grounded end, a ground plane and a feed, wherein the feed is connected at an intermediate point to the antenna and wherein the antenna is connected at the grounded end to the ground plane, each inverted F-antenna having a direction defined between the grounded end and the antenna end point, wherein the GNSS antenna system comprises four L1-antennas and four L2/L5-antennas, wherein:
a first L1-antenna of the four L1-antennas is oriented in a first direction,
a second L1-antenna of the four L1-antennas is oriented in a second direction substantially orthogonal to the first direction,
a third L1-antenna of the four L1-antennas is oriented in a third direction substantially orthogonal to the second direction and substantially antiparallel to the first direction, and
a fourth antenna of the four L1-antennas is oriented in a fourth direction substantially orthogonal to the third direction and substantially antiparallel to the second direction,
wherein each L2/L5-antenna of the four L2/L5-antennas has a corresponding L1-antenna and wherein the direction of each L2/L5-antenna substantially corresponds to the direction of the corresponding L1-antenna.

7 . The unmanned aerial vehicle (UAV) according to claim 6 , wherein at least one of the four L1-antennas and/or at least one of the four L2/L5-antennas comprises an antenna which is bent.

8 . The unmanned aerial vehicle (UAV) according to claim 6 , wherein the four L1-antennas and the four L2/L5-antennas share a common ground plane.

9 . The unmanned aerial vehicle (UAV) according to claim 6 , wherein:
the antennas of the four L1-antennas are configured to be fed by a first quadrifilar 4-phased antenna feeder (L1-feeder) using the respective feed, and the antennas of the four L2/L5-antennas are configured to be fed by a second quadrifilar 4-phased antenna feeder (L2/L5-feeder) using the respective feed, wherein a phase of a feed signal provided by the respective feed differs by 90 degrees between consecutive L1-antennas and by 90 degrees between consecutive L2/L5-antennas.

10 . The unmanned aerial vehicle (UAV) according to claim 9 , wherein the first quadrifilar 4-phased antenna feeder and/or the second quadrifilar 4-phased antenna feeder are configured to enable right-handed circular polarization (RHCP) or left-handed circular polarization (LHCP) of the four L1-antennas and/or the four L2/L5-antennas respectively.

11 . The unmanned aerial vehicle (UAV) according to claim 6 , wherein each antenna of the four L1-antennas has an average distance to its respective ground plane, the average distance in particular being between the intermediate point and the ground plane or being an actual average in distance between antenna and ground plane along the antenna, and wherein the respective ground plane is in particular embodied as the common ground plane, wherein the average distance of at least one of the four L1-antennas differs from the average distance of the remaining L1-antennas, and in that at least one of the four L1-antennas is:
tuned, in particular by adjusting a distance between the intermediate point and the grounded end of the at least one tuned L1-antenna and/or by adjusting the length of the antenna of the tuned L1-antenna, and/or phased in addition to the phase provided to the tuned L1-antenna by the first quadrifilar 4-phased antenna feeder, wherein the additional phasing is in particular provided by a delay line, wherein tuning and additional phasing is done in such a way as to compensate influences on radiation properties of the GNSS antenna system in the L1 frequency band due to the at least one bent L1-antenna and due to the difference in average distance between at least one of the four L1-ant

Assignees

• Hexagon Geosystems Services Ag
• Leica Geosystems Ag

Inventors

• Diem Fabio
• Bruneau Garance
• Gohl Pascal
• Haarakangas Tuomo
• Heikura Ilkka

Classifications

• H01Q9/0414

  in a stacked or folded configuration · CPC title

• H01Q1/246

  specially adapted for base stations · CPC title

• H01Q1/286

  substantially flush mounted with the skin of the craft · CPC title

• H01Q9/42

  with folded element, the folded parts being spaced apart a small fraction of the operating wavelength · CPC title

• H01Q5/42

  using two or more imbricated arrays (H01Q5/49 takes precedence) · CPC title