GNSS ANTENNA SYSTEM FOR RECEIVING MULTI-BAND GNSS SIGNALS

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.

Claims

1. A GNSS antenna system for receiving GNSS signals, comprising: 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.

2. The GNSS antenna system according to claim 1, 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.

3. The GNSS antenna system according to claim 1, wherein the four L1-antennas and the four L2/L5-antennas share a common ground plane.

4. The GNSS antenna system according to claim 1, 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.

5. The GNSS antenna system according to claim 4, 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.

6. The GNSS antenna system according to claim 1, 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-antennas and the remaining L1-antennas.

7. The GNSS antenna system according to claim 1, wherein each antenna of the four L2/L5-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 L2/L5-antennas differs from the average distance of the remaining L2/L5-antennas, and in that at least one of the four L2/L5-antennas is: tuned, in particular by adjusting a distance between the intermediate point and the grounded end of the at least one tuned L2/L5-antenna and/or by adjusting the length of the antenna of the tuned L2/L5-antenna, and/or phased in addition to the phase provided to the tuned L2/L5-antenna by the second 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 L2/L5 frequency band due to the at least one bent L2/L5-antenna and due to the difference in average distance between at least one of the four L2/L5-antennas and the remaining L2/L5-antennas.

8. The GNSS antenna system according to claim 1, wherein the feed signals fed to the four L1-antennas each have a same first power, and/or the feed signals fed to the four L2/L5-antennas each have a same second power.

9. A GNSS antenna system for receiving GNSS signals, comprising: at least one inverted F-antenna configured to receive GNSS signals in at least one GNSS frequency band, wherein each inverted F-antenna comprises an antenna, 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 a grounded end to the ground plane, each antenna having an average distance to its ground plane, the average distance in particular being between the intermediate point and the ground plane, wherein the GNSS antenna system comprises four inverted F-antennas, wherein the four inverted F-antennas have a common ground plane, and wherein at least one of the four inverted F-antennas has an average distance to the common ground plane which differs from the average distances to the common ground plane of the remaining inverted F-antennas, and wherein at least one of the four inverted F-antennas has an antenna which is bent, and wherein at least one of the four inverted F-antennas is tuned and phased to compensate influences on radiation properties of the GNSS antenna system in the at least one GNSS frequency band due to the at least one bent antenna and due to the difference in average distance between at least one of the four inverted F-antennas and the remaining inverted F-antennas.

10. 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.

11. The unmanned aerial vehicle (UAV) according to claim 10, 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.

12. The unmanned aerial vehicle (UAV) according to claim 11, 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.

13. The unmanned aerial vehicle (UAV) according to claim 11, 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.

14. The unmanned aerial vehicle (UAV) according to claim 12, 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.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Aspects are described below in more detail purely by way of example with the aid of concrete exemplary embodiments illustrated schematically in the drawings, further advantages also being examined Identical elements are labelled with the same reference numerals in the figures. In detail:

[0048] FIG. 1 shows an illustrative depiction of an embodiment of a GNSS antenna system;

[0049] FIG. 2 shows another illustrative depiction of an embodiment of a GNSS antenna system from a different perspective;

[0050] FIG. 3 shows a further illustrative depiction of an embodiment of a GNSS antenna system from another perspective;

[0051] FIG. 4 shows an illustrative depiction of parts of the inside of an embodiment of a GNSS antenna system;

[0052] FIG. 5 shows an illustrative depiction of an embodiment of a GNSS antenna system with a transparent curved surface for visualization purposes; and

[0053] FIG. 6 shows an illustrative depiction of an embodiment of an unmanned aerial vehicle (UAV).

DETAILED DESCRIPTION

[0054] FIG. 1 shows an illustrative depiction of an embodiment of a GNSS antenna system 1. The GNSS antenna system 1 comprises inverted F-antennas for capturing GNSS signals in the L1 and in the L2/L5 frequency band. The inverted F-antennas are arranged on a curved surface 8. In the embodiment of FIG. 1, eight inverted F-antennas are present (only five of the eight inverted F-antennas are at least partly visible in FIG. 1), wherein four inverted F-antennas are configured to receive GNSS signals in the L1 frequency band and four inverted F-antennas are configured to receive GNSS signals in the L2/L5 frequency band. The eight inverted F-antennas jointly share a common ground plane 4. Each antenna 2 configured for receiving signals in the L1 frequency band has a grounded end 6 at which it is connected to the common ground plane 4, an intermediate point 5 at which a feed signal is provided, and an antenna end point 7 at which the antenna 2 ends. Equivalently, each antenna 3 configured for receiving signals in the L2/L5 frequency band also has a grounded end 6 at which it is connected to the common ground plane 4, an intermediate point 5 at which a feed signal is provided, and an antenna end point 7 at which the antenna 3 ends. The antennas in FIG. 1 are bent as they are arranged on a curved surface 8.

[0055] Each of the inverted F-antennas in FIG. 1 has a direction defined between its grounded end 6 and its antenna end point 7. The four antennas 3 on the curved surface 8 (only three are visible in FIG. 1) configured to receive L2/L5 GNSS signals are direction wise arranged as follows: a first L2/L5 antenna points in a first direction, a second L2/L5 antenna has a second direction which is roughly orthogonal to the first direction, a third L2/L5 antenna has a third direction which is roughly orthogonal to the second direction and roughly antiparallel to the first direction, and a fourth L2/L5 antenna has a fourth direction which is roughly orthogonal to the third direction and roughly antiparallel to the second direction. Each of the four antennas 2 configured to receive L1 GNSS signals has a corresponding L2/L5 antenna, wherein the direction of each of the four antennas 2 configured to receive L1 GNSS signals roughly corresponds to the direction of the corresponding L2/L5 antenna.

[0056] The curved surface 8 has a mounting structure 9 in which a quadrifilar 4-phased antenna feeder can be mounted, which quadrifilar 4-phased antenna feeder is configured to provide phasing to the four inverted F-antennas in the L2/L5 frequency band.

[0057] FIG. 2 shows an illustrative depiction of an embodiment of a GNSS antenna system 1, which embodiment of FIG. 2 corresponds to the embodiment of FIG. 1 shown from a different perspective, specifically from behind. In the perspective of FIG. 2, further antennas 2,3 are visible which are not visible in the perspective of FIG. 1.

[0058] FIG. 3 shows an illustrative depiction of an embodiment of a GNSS antenna system 1, which embodiment of FIG. 3 corresponds to the embodiment of FIGS. 1 and 2, wherein the embodiment is shown from above in FIG. 3.

[0059] FIG. 4 shows an illustrative depiction of a part of the inside of an embodiment of a GNSS antenna system 1. FIG. 4 depicts parts of the curved surface 8 of FIGS. 1 to 3 from within the GNSS antenna system 1, showing the mounting structure 9 embedded in the curved surface 8. One antenna 2 configured to receive L1 GNSS signals is arranged on the inside of the GNSS antenna system 1, i.e. on a different side of the curved surface 8 compared to the other antennas 2,3.

[0060] FIG. 5 shows an illustrative depiction of an embodiment of a GNSS antenna system 1, wherein the embodiment of FIG. 5 corresponds to the embodiments of FIGS. 1 to 4. For visualization purposes, the cover surface 8 in FIG. 5 is made transparent. The antenna 2 arranged on the inside of the GNSS antenna system 1 is therefore visible in FIG. 5.

[0061] FIG. 6 shows an illustrative depiction of an unmanned aerial vehicle (UAV) 10. The UAV comprises a body 11 extending along an axis from a front end to a back end having a housing, a first mounting structure 12 attached to the body and extending away from the body in a direction to a left side of the axis and a second mounting structure 13 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, which are not shown in FIG. 6 may be mounted to the body 11, two of which may be mounted to the first mounting structure 12 and two of which may be mounted to the second mounting structure 13.

[0062] A part of the housing of the UAV 10 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 14, wherein the GNSS antenna system is arranged below the fiber glass housing 14. The numbers shown in FIG. 6 in the area of the fiber glass housing indicate a rough location of eight antennas for receiving GNSS signals in the L1 and L2/L5 frequency band.

[0063] 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, and a detector unit for detecting distance measurement radiation reflected from a surface, and a distance measurement radiation source are part of the UAV 10. These components may be arranged in the front of the UAV 10.

[0064] Although aspects are illustrated above, partly with reference to some preferred embodiments, it must be understood that numerous modifications and combinations of different features of the embodiments can be made. All of these modifications lie within the scope of the appended claims.