EP4782594A1

EP4782594A1 - Device for fixing a gnss antenna to a rail of a railway track

Info

Publication number: EP4782594A1
Application number: EP25425001.2A
Authority: EP
Inventors: Elio Origoni; Eugenio Realini; Stefano Barindelli
Original assignee: Geomatics Research & Development Srl
Current assignee: Geomatics Research & Development Srl
Priority date: 2025-01-24
Filing date: 2025-01-24
Publication date: 2026-07-29

Abstract

The invention relates to a device (100; 200) for fixing an antenna (1, 1') of a global navigation satellite system, GNSS, to a rail (2) of a railway track; such a rail comprises a head portion (21) adapted to come into contact with the wheels of a train and connected to an opposite base portion (22) including a base surface (22a) facing the ballast (MC) of the railway track. The fixing device comprises:
- a body (101; 201) made of a metal material comprising:
- a first body portion (102; 202) for fixing a GNSS antenna to the fixing device;
- a plate-shaped second body portion (103; 203), removably fixable to the base portion of the rail;
- a third body portion (104; 204) configured to connect the first and second body portions,
wherein the first and second body portions of the metal body are associated with a first plane (P1; P1') and a second plane (P2; P2') parallel to each other, respectively, and wherein the plate-shaped second body portion comprises a first face (103a; 203a) facing the first plane and an opposite second face (103b; 203b);
- metal means (10, 14, 15; 10, 14, 15, 208) to removably fix the plate-shaped second body portion to the base portion of the rail;
wherein, when the fixing device is fixed to the rail, the first face of the plate-shaped second body portion is in contact with the base surface of the base portion of the rail and the second face of the second body portion faces the ballast of the railway track.

Description

TECHNOLOGICAL BACKGROUND OF THE INVENTION

Field of application

The present invention generally relates to the field of systems for detecting movements of infrastructures and/or the ground, based on the reception of satellite signals. In particular, the invention relates to a device for fixing an antenna of a global navigation satellite system (GNSS) to a rail of a railway track.

Background art

The use of global navigation satellite systems or GNSS to monitor any movements of the ground and displacements of infrastructures designed to remain fixed is known. In such GNSS systems, special antennas, constrained to the ground or to the infrastructure to be monitored, are configured to receive satellite signals, from which very accurate point measurements (order of magnitude of millimeters) are obtained, which are indicative of the displacement of points of the ground or of the infrastructure from the respective reference positions thereof. A requirement for the correct operation of a GNSS satellite system for detecting movements is that the antennas with which the satellite signal is received are positioned so as to maximize the quality of the received signal, thus reducing as much as possible the disturbances given by the surrounding environment.
Known applications of such GNSS systems comprise the monitoring of infrastructures (e.g., bridges, dams, telecommunications towers, aqueducts, natural gas storage sites), buildings (e.g., historic buildings or buildings with unsafe parts), and the ground (e.g., in order to predict critical situations such as landslides or subsidence) .
Only recently, the idea of using a GNSS satellite system for detecting movements also to detect the millimetric displacements to which railway tracks could be subjected has been suggested, so as to monitor any anomalies caused, for example, by wear, thermal deformation, impacts or landslides. In fact, the use of such a detection system was considered ineffective by the international geodetic community, since it was believed that GNSS antennas positioned close to the ground, directly next to the rails of railway tracks, and overtopped by the passage of trains, could not ensure a sufficient signal reception to achieve the desired measurement performance. For such a reason, the use of GNSS systems adapted to monitor any millimetric movements of railway tracks is currently not widespread.
As far as the Applicant is aware, using a satellite system which involves constraining the GNSS antenna to some sleepers of the track is known for monitoring railway track movements.
Such a solution, although it ensures that the GNSS antenna is positioned close to the rail without requiring drilling the rail itself, as required by regulations, and although it ensures a good quality of the satellite signal received by the antenna, has some limitations and drawbacks.
In fact, from a functional point of view, such a system allows monitoring only the transverse movements of the track, i.e., movements in the direction of the sleepers to which the GNSS antenna is fixed, and the vertical movements, whereas the longitudinal sliding of the rails with respect to the sleepers themselves cannot be detected.
For such reasons, there is a need to identify a solution for firmly and stably fixing a GNSS antenna to a railway track, avoiding drilling the rails, which allows monitoring the transverse movements, the vertical movements, and the longitudinal sliding of the track, while ensuring a good reception of the GNSS satellite signal.

SUMMARY OF THE INVENTION

It is the object of the present invention to devise and provide a device (or bracket) for fixing an antenna of a global navigation satellite system, GNSS, or GNSS antenna, to a rail of a railway track, which allows, at least partially, overcoming the limitations and drawbacks of the known solution mentioned above.
Such an object is achieved by a device for fixing a GNSS antenna to a rail of a railway track in accordance with claim 1.
In fact, the fixing device suggested with the invention comprises a body made of a metal material which, in turn, comprises:

a first body portion configured to fix a GNSS antenna to the aforesaid fixing device, so that such a GNSS antenna can receive a good quality GNSS signal, without hindering the passage of trains,
a second body portion which is plate-shaped to be removably engaged with a base portion of the rail, and
a third body portion configured to connect the first and second body portions to each other.

Such a fixing device further comprises metal means to removably fix the second body portion of the fixing device to the base portion of the rail.
In particular, when the fixing device of the invention is fixed to the rail, a first face of the plate-shaped second body portion is in contact with a base surface of the base portion of the rail and a second face of the second body portion, opposite to the first face, faces the ballast of the railway track.
Furthermore, the fixing of the second body portion of the fixing device to the base portion of the rail, by means of the aforesaid metal means, avoids drilling the rail itself and allows carrying out quickly the installation and uninstallation of the GNSS antenna at the rail, in compliance with the timing dictated by train circulation.
Preferred embodiments of such a fixing device are described in the dependent claims.
The present invention also relates to an antenna assembly, in accordance with claim 15, comprising a GNSS antenna and the device for fixing such a GNSS antenna to a rail of a railway track, wherein such a GNSS antenna is fixed to the fixing device.

BRIEF DESCRIPTION OF THE DRAWINGS

Further features and advantages of the device for fixing a GNSS antenna to a rail of a railway track according to the invention will become apparent from the following description of preferred embodiments, given by way of non-limiting indication, with reference to the accompanying drawings, in which:

Figure 1A shows a three-dimensional perspective view of a first embodiment of a body of the device for fixing a GNSS antenna to a rail of a railway track of the invention;
Figure 1B shows a top view of the body of the fixing device in Figure 1A;
Figure 1C shows a side view, in longitudinal section, of the body of the fixing device in Figure 1A;
Figure 2A shows a top view of an arched element usable in the fixing device of the invention;
Figure 2B shows a side view, in longitudinal section, of the arched element in Figure 2A;
Figure 3A shows a side view, in longitudinal section, of a first embodiment of the fixing device of the invention, wherein a GNSS antenna of the cone type is fixed to a first body portion of the fixing device, and a second body portion is fixed to a base portion of a rail of a railway track;
Figure 3B shows a side view, in longitudinal section, of the first embodiment of the fixing device in Figure 3A, in which a GNSS antenna of the flat type is fixed to the first body portion of the fixing device;
Figure 4A shows a top view of a second embodiment of a body of the device for fixing a GNSS antenna to a rail of a railway track of the invention;
Figure 4B shows a side view, in longitudinal section, of the body of the fixing device in Figure 4A;
Figure 5A shows a side view, in longitudinal section, of a second embodiment of the fixing device of the invention, wherein a GNSS antenna of the cone type is fixed to a first body portion of the fixing device and a second body portion is fixed to a base portion of a rail of a railway track;
Figure 5B shows a side view, in longitudinal section, of the second embodiment of the fixing device in Figure 5A, in which a GNSS antenna of the flat type is fixed to the first body portion of the fixing device.

Similar or equivalent elements in the aforesaid figures are indicated by the same reference numerals.

DETAILED DESCRIPTION

In relation to the aforesaid Figures, reference numeral 100, 200 is used to indicate a device (or bracket) for fixing an antenna of a global navigation satellite system, GNSS, or GNSS antenna to a rail 2 of a railway track of the present invention as a whole, in two embodiments.
In the following description, the term rail 2 means one of the two rails which form a railway track. In particular, with reference to Figures 3A-3B, 5A-5B, such a rail 2 comprises a head portion or head 21, adapted to come into contact with the wheels of a train, connected to an opposite base portion or foot 22 which includes a base surface 22a facing the ballast MC of the railway track. In the Figures, such a ballast MC is diagrammatically indicated by means of a continuous line.
Such a fixing device 100, 200 comprises a body 101, 201 made of a metal material.
In particular, such a body 101, 201 is made of stainless steel. More specifically, such a body 101, 201 is made of AISI 304 steel.
Note that the use of such a material ensures that the body 101, 201 of the fixing device 100, 200 is substantially immune to deformation and is less subject to oxidation effects caused by a prolonged exposure of the device to atmospheric agents. Furthermore, the use of steel is preferred to mitigate galvanic corrosion issues.
The body 101, 201, made of a metal material, of the fixing device 100, 200 advantageously comprises:

a first body portion 102, 202 for fixing a GNSS antenna 1, 1' to the fixing device 100, 200;
a plate-shaped second body portion 103, 203 removably fixable to the base portion 22 of the rail 2;
a third body portion 104, 204 configured to connect the aforesaid first 102, 202 and second 103, 203 body portions.

In particular, the first 102, 202 and second 103, 203 body portions of the metal body are associated with a first P1, P1' and a second P2, P2' planes parallel to each other, respectively. In Figures 1C and 4B the aforesaid planes P1, P1' and P2, P2' are indicated by dashed lines.
Furthermore, as shown in Figures 1A, 1B and 4A, the plate-shaped second body portion 103, 203 of the metal body 101, 201 of the device comprises a first face 103a, 203a facing the aforesaid first plane P1, P1' and an opposite second face 103b, 203b.
The fixing device 100, 200 further comprises metal means 10, 14, 15, 208 for removably fixing the plate-shaped second body portion 103, 203 to the base portion 22 of the rail 2.
Note that, when the fixing device 100, 200 is fixed to the rail 2, the first face 103a, 203a of the plate-shaped second body portion 103, 203 is in contact with such a base surface 22a of the base portion 22 of the rail 2, and the second face 103b, 203b of the second body portion 103, 203 faces the ballast MC of the railway track.
In an embodiment, with reference to Figures 2A, 2B, 3A, 3B, 5A, 5B, the removable-fixing metal means comprise:

at least one stop element 10 comprising:
- an arched element 11, 12 provided with a through hole 13 and configured to abut against at least one of a first 22b and a second 22c inclined surface of the base portion 22 of the rail 2 opposite to said base surface 22a, when the fixing device is fixed to the rail, and
- a junction element 14, 15 configured to engage both such a through hole 13 of the arched element 11, 12 and at least a first through hole 107, 207 obtained in the plate-shaped second body portion 103, 203 of the fixing device.

Such a junction element 14, 15 is adapted, in particular, to be tightened to compress the aforesaid arched element 11, 12 of the at least one stop element 10 abutting against at least one of the first 22b and second 22c inclined surfaces of the base portion 22 of the rail 2.
Note that the aforesaid first 22b and second 22c inclined surfaces of the base portion 22 of the rail 2 are the surfaces of the base portion of the rail 2 facing the head portion 21.
In a particular embodiment, as shown in Figures 2A, 2B, the arched element 11, 12 of the fixing device 100, 200 comprises a first arch portion 11 and a second arch portion 12, connected to each other. Such a first arch portion 11 is configured to abut against at least one of the aforesaid first 22b and second 22c inclined surfaces of the base portion 22 of the rail 2, when the fixing device 100, 200 is fixed to the rail 2. The second arch portion 12 is configured to abut against the first face 103a, 203a of the plate-shaped second body portion 103, 203 of the fixing device 100, 200.
As shown in Figure 2B, such first 11 and second 12 arch portions are connected to each other at a respective intersection to form an intersection angle α. In particular, such an intersection angle α is an obtuse angle. For example, such an obtuse angle α is equal to 115°.
Furthermore, the first 11 and second 12 arch portions have a respective thickness d'. Such a thickness d' is between 5 and 15 mm. Preferably, such a thickness d' is equal to 10 mm. Such a thickness d' ensures, on the one hand, the resistance of the arched element 11, 12 when the fixing device 100, 200 is fixed to the rail 2. The choice of this thickness d' ensures, on the other hand, that the arched element 11, 12 is not too heavy and has low production costs.
In a particular embodiment, the junction element 14, 15 is formed by a screw 14 and at least one nut 15, in particular, two nuts in the examples of the Figures, so as to form, with the aforesaid screw 14, a bolt. Such a screw 14 is adapted to engage both the through hole 13 of the arched element 11, 12 and the at least a first through hole 107, 207 obtained in the plate-shaped second body portion 103, 203 of the device 100, 200. In addition, the through hole 13 of the arched element 11, 12 has a diameter sufficient to be engaged, during insertion, by a M10 screw.
In a first embodiment of the fixing device 100 of the invention, the aforesaid removable-fixing metal means comprise two stop elements 10 which are similar to each other. Each stop element 10 comprises an arched element 11, 12 provided with a through hole 13 and a junction element 14, 15 configured to engage both such a through hole 13 and one of two first through holes 107 aligned along a longitudinal direction Y of the plate-shaped second body portion 103 of the fixing device 100.
With reference to the examples in Figures 3A, 3B, such first through holes 107 are also equidistant from a reference portion PR of such a second body portion 103 associated with an axis of symmetry X of the rail 2 orthogonal to the plate-shaped second body portion 103. In other words, the reference portion PR materializes in a point through which the axis of symmetry X of the rail 2 ideally passes.
Note that the second body portion 103 of the body 101 of the device 100 comprises a first free end 103' and a second end 103'', opposite to the first end 103' and connected to the third connecting body portion 104. Furthermore, such a longitudinal direction Y substantially coincides with the longitudinal axis of symmetry of the second body portion 103.
In a second embodiment of the fixing device 200 of the invention, with reference to Figures 4B, 5A, 5B, the removable-fixing metal means also comprise a hook element 208 connected in one piece to a respective first free end 203' of the second body portion 203 of the fixing device 200 opposite to a second end 203" of the second body portion 203 which is connected to the third body portion 204. Such a hook element 208 is configured to engage one of such first 22b and second 22c inclined surfaces of the base portion 22 of the rail 2 when the fixing device 200 is fixed to the rail 2.
In such a second embodiment, the removable-fixing metal means comprise a single stop element 10, similar to those described above, which comprises an arched element 11, 12 provided with a through hole 13 and a junction element 14, 15 configured to engage both such a through hole 13 and a respective first through hole 207 arranged along a longitudinal direction Y of the plate-shaped second body portion 203 of the fixing device 200. Such a first through hole 207 of the second body portion 203 is obtained along the aforesaid longitudinal direction Y so that one of the inclined surfaces 22b or 22c of the base portion 22 of the rail 2 can be engaged by the hook element 208 while the other of such inclined surfaces is simultaneously engaged by the stop element 10.
Furthermore, in an embodiment, the first 102, 202 and third 104, 204 body portions of the body 101, 201 of the device are also plate-shaped.
In addition, the plate-shaped first 102, 202 and second 103, 203 body portions are parallel to each other, and the third body portion 104, 204 is orthogonal to the aforesaid first 102, 202 and second 103, 203 body portions.
In a further embodiment, when the fixing device 100, 200 is fixed to the rail 2, the first body portion 102, 202 of the metal body 101, 201 of the fixing device is at a distance from the ballast MC of the railway track which is greater than the distance between such a ballast MC and the second 103, 203 body portion.
Furthermore, the first 102, 202 and third 104, 204 body portions are plate-shaped, and such first 102, 202, second 103, 203, and third 104, 204 body portions have the same thickness d, d".
In particular, such a thickness d, d'' is between 5 and 15 mm. Preferably, such a thickness d, d'' is 10 mm. Note that such a thickness d, d'' ensures that the GNSS antenna 1, 1', when fixed to the fixing device 100, 200, is substantially immune to vibrations when trains pass and that the body 101, 201 of the device is more resistant to deformations. Such a thickness d, d'' also ensures that the body 101, 201 of the fixing device 100, 200 is not too heavy and is low-cost.
In an embodiment, with reference to the Figures, the first body portion 102, 202 of the metal body is plate-shaped and comprises a further first face 102a, 202a and an opposite further second face 102b, 202b facing the aforesaid second plane P2, P2'. The GNSS antenna 1, 1' is removably fixable to such a further first face 102a, 202a.
In addition, the first body portion 102, 202 has a first end 102', 202' connected in one piece to the third body portion 104, 204 of the metal body 101, 201 of the device and an opposite free second end 102", 202".
In a further embodiment, the first body portion 102, 202 comprises a second 105, 205 and at least a third 106, 206 through hole of different sizes.
As shown in the examples in Figures 1A, 1B, 1C, 4A, 4B, the first body portion 102, 202 comprises a second through hole 105, 205 and two third through holes 106, 206. Such third through holes 106, 206 have the same diameter which is smaller than the diameter of the second through hole 105, 205. Such second through hole 105, 205 and third through holes 106, 206 are configured to fix, alternatively, a first and a second type of GNSS antenna 1, 1', different from each other, to the fixing device 100, 200.
Preferred examples of a GNSS antenna which can be fixed to the first body portion 102, 202 include a GNSS antenna of the cone type and a GNSS antenna of the flat type.
For example, the second through hole 105, 205 has a diameter of 18 mm and is configured to fix a GNSS antenna of the cone type to the first body portion 102, 202 of the body 101, 201 of the device.
Furthermore, for example, the second through holes 106, 206 each have a diameter of 4.5 mm, and are configured to fix a GNSS antenna of the flat type to the first body portion 102, 202.
Furthermore, the through holes 105, 106 are aligned with respect to each other along a respective longitudinal direction Y' which coincides with a longitudinal axis of symmetry of such a first body portion 102, 202 and with the longitudinal direction Y of the second body portion 103, 203.
Note that the third body portion 104, 204, configured to connect the aforesaid first 102, 202 and second 103, 203 body portions, is associated with a third plane P3, P3'. Such a third body portion 104, 204 is configured to connect the first end 102', 202' of the first body portion 102, 202 and the second end 103'', 203'' of the second body portion 103, 203 by means of connectors 104', 204' and 104'', 204'', respectively. For example, said connectors 104' and 104'' have a connection radius of 20 mm.
Furthermore, the third plane P3, P3' associated with the third body portion 104, 204 is incident with respect to both the first plane P1, P1' and the second plane P2, P2'. The first 102, 202, second 103, 203, and third 104, 204 body portions of the body 101, 201 thus form intersection angles at the aforesaid connectors 104', 204' and 104", 204''.
Furthermore, the first 102, 202, second 103, 203, and third 104, 204 body portions are aligned along the same longitudinal direction Y, Y'.
Advantageously, such a shape of the body 101, 201 of the device of the invention is such as to ensure both that the fixing device 100, 200 does not interfere with the passage of trains, when the device 100, 200 is fixed to the rail 2, and that a GNSS antenna receives good quality GNSS signals, when the GNSS antenna is fixed to the fixing device 100, 200.
The present invention also relates to an antenna assembly comprising:

an antenna 1, 1' of a global navigation satellite system, GNSS;
a device 100, 200 for fixing such a GNSS antenna 1, 1' to a rail 2 of a railway track of the present invention described above.

In such an antenna assembly, the GNSS antenna 1, 1' is removably fixed to a first body portion 102, 202 of a body 101, 201 made of a metal material of the aforesaid device.
According to a first embodiment, the fixing of such an antenna assembly to the rail 2 of a railway track, when such an assembly comprises the fixing device 100, comprises the steps of:

inserting the plate-shaped second body portion 103 of the body 101 of the device 100 between the base portion 22 of the rail 2 and the ballast MC;
positioning the arched element 11,12 of each of the two stop elements 10 so that:
- for a first stop element 10, the first arch portion 11 abuts against the first inclined surface 22b of the base portion 22 of the rail 2 and the second arch portion 12 abuts against the first face 103a of the second body portion 103 of the device,
- for the second stop element 10, the first arch portion 11 abuts against the second inclined surface 22c of the base portion 22 of the rail 2 and the second arch portion 12 abuts against the first face 103a of the second body portion 103 of the device;
positioning the junction element 14,15 of each of the two stop elements 10 so that the screw 14 of each junction element 14, 15 engages both the through hole 13 of the respective stop element 10 and the corresponding first through hole 107 obtained in the plate-shaped second body portion 103 of the body 101 of the device;
tightening the junction element 14,15 of each of the two stop elements 10 so as to compress the first arch portion 11 of the arched element of each stop element 10 against the respective inclined surface 22b, 22c of the base portion 22 of the rail 2 and the second arch portion 12 against the first face 103a of the second body portion 103.

Furthermore, still in such an embodiment, to disassemble such an antenna assembly from the rail 2, the following steps are provided:

loosening the junction element 14,15 of each of the two stop elements 10 so as to release the first arch portion 11 of the arched element of each stop element 10 from being compressed against the respective inclined surface, first and second 22b, 22c, of the base portion 22 of the rail 2 and the second arch portion 12 from being compressed against the first face 103a of the plate-shaped second body portion 103 of the body 101 of the device;
disengaging the screw 14 of the junction element 14,15 of each of the two stop elements 10 by extracting it from both the through hole 13 of the respective stop element 10 and the corresponding first through hole 107 obtained in the second body portion 103;
removing the arched element 11,12 of each of the two stop elements 10;
sliding out the second body portion 103 of the body 101 of the device 100 from the gap between the base portion 22 of the rail 2 and the ballast MC.

In accordance with a second embodiment, the fixing of such an antenna assembly to the rail 2 of a railway track, when such an assembly comprises the fixing device 200, comprises the steps of:

inserting the plate-shaped second body portion 203 of the body 201 of the device 200 between the base portion 22 of the rail 2 and the ballast MC;
positioning the hook element 208 of the second body portion 203 so as to engage the first inclined surface 22b of the base portion 22 of the rail 2;
positioning the arched element 11,12 of the single stop element 10 so that the first arch portion 11 abuts against the second inclined surface 22c of the base portion 22 of the rail 2 and the second arch portion 12 abuts against the first face 203a of the second body portion 203 of the device;
positioning the junction element 14,15 of the stop element 10 so that the screw 14 of the junction element 14, 15 engages both the through hole 13 of the respective stop element 10 and the first through hole 207 obtained in the second body portion 203 of the body 201 of the device;
tightening the junction element 14,15 so as to compress the first arch portion 11 of the arched element against the second inclined surface 22c of the base portion 22 and the second arch portion 12 against the first face 203a of the second body portion 203.

Furthermore, in accordance with such an embodiment, the disassembly of such an antenna assembly from the rail 2 comprises the steps of:

loosening the junction element 14,15 of the stop element 10 so as to release the first arch portion 11 of the arched element from being compressed against the second inclined surface 22c of the base portion 22 of the rail 2 and the second arch portion 12 from being compressed against the first face 203a of the plate-shaped second body portion 203 of the body 201;
disengaging the screw 14 of the junction element 14,15 by extracting it from both the through hole 13 of the stop element 10 and the first through hole 207 obtained in the second body portion 203;
removing the arched element 11,12 of the stop element 10;
disengaging the hook element 208 from the first inclined surface 22b of the base portion 22 of the rail by disengaging the device from the rail 2;
sliding out the second body portion 203 of the body 201 of the device 200 from the gap between the base portion 22 of the rail 2 and the ballast MC.

The device 100, 200 for fixing an antenna 1, 1' of a global navigation satellite system, GNSS, to a rail 2 of a railway track of the present invention has several advantages and achieves the preset objects.
In fact, the mechanism of the fixing device 100, 200 for fixing to rail 2 described above allows firmly constraining such a device without requiring to drill the rail 2 and simultaneously allows the workers responsible for the installation of the antennas and/or the removal and subsequent replacement thereof to quickly carry out the fixing operation, so as to comply with the timing imposed by the circulation of the trains.
Furthermore, both a GNSS antenna 1 of the cone type and a flat antenna 1' can be removably fixed to the fixing device 100, 200, in particular, to a first face 102a, 202a of the first body portion 102, 202 so that such GNSS antennas 1, 1' always face the sky, so as to receive a good quality GNSS signal. With the device 100, 200 for fixing the GNSS antenna 1, 1' to the rail 2 described above, it is possible to monitor the transverse movements, the vertical movements, and the longitudinal slidings of the rail of a track.
Furthermore, the body 101, 201 of the fixing device 100, 200 of the invention has a particular S-shape so that, in operating conditions, the first body portion 102, 202 is at a distance from the ballast MC which is greater than the distance of the second body portion 103, 203 from such a ballast MC. In particular, the difference between such distances, indicated with h, h' in Figures 3A, 3B, 5A, 5B, ensures that a cable connecting the GNSS antenna 1, 1' to external apparatuses can be connected, in a simple manner, to a portion of the antenna itself protruding from the further second face 102b, 202b of the first body portion facing the second plane P2, P2'. Such a configuration of the fixing device 100, 200 ensures that the GNSS antenna 1, 1' can operate without hindering the passage of trains.
In order to meet contingent needs, those skilled in the art may make changes and adaptations to the embodiments of the device for fixing an antenna of a global navigation satellite system, GNSS, to a rail of a railway track described above, or may replace elements with others which are functionally equivalent, without departing from the scope of the following claims. Each of the features described above as belonging to a possible embodiment can be implemented irrespective of the other embodiments described.

Claims

A device (100; 200) for fixing an antenna (1, 1') of a global navigation satellite system, GNSS, to a rail (2) of a railway track, said rail (2) comprising a head portion (21) adapted to come into contact with the wheels of a train and connected to an opposite base portion (22) including a base surface (22a) facing the ballast (MC) of the railway track,
said fixing device (100; 200) being characterized in that it comprises:
- a body (101; 201) made of a metal material comprising:
- a first body portion (102; 202) for fixing a GNSS antenna (1, 1') to said fixing device (100; 200),

- a plate-shaped second body portion (103; 203), removably fixable to the base portion (22) of the rail (2),

- a third body portion (104; 204) configured to connect said first (102; 202) and second (103; 203) body portions,
wherein the first (102; 202) and second (103; 203) body portions of the metal body are associated with a first (P1; P1') and a second (P2; P2') planes parallel to each other, respectively, and wherein the plate-shaped second body portion (103; 203) comprises a first face (103a; 203a) facing said first plane (P1; P1') and an opposite second face (103b; 203b);

- metal means (10, 14, 15; 10, 14, 15, 208) to removably fix said plate-shaped second body portion (103; 203) to the base portion (22) of the rail (2);

wherein, when the fixing device (100; 200) is fixed to the rail (2), the first face (103a; 203a) of the plate-shaped second body portion (103; 203) is in contact with said base surface (22a) of the base portion (22) of the rail (2) and the second face (103b; 203b) of the second body portion (103; 203) faces the ballast (MC) of the railway track.
A fixing device (100; 200) according to claim 1, wherein said removable-fixing metal means comprise:
- at least one stop element (10) comprising:
- an arched element (11, 12) provided with a through hole (13) and configured to abut against at least one of a first (22b) and a second (22c) inclined surface of the base portion (22) of the rail (2) opposite to said base surface (22a), when the fixing device is fixed to the rail, anda junction element (14, 15) configured to engage both said through hole (13) of the arched element (11, 12) and at least a first through hole (107; 207) obtained in the plate-shaped second body portion (103; 203) of the device, said junction element (14, 15) being adapted to be tightened to compress said arched element (11, 12) of the at least one stop element (10) abutting against at least one of said first (22b) and second (22c) inclined surfaces of the base portion (22) of the rail (2).
A fixing device (100; 200) according to claim 2, wherein said arched element (11, 12) comprises a first arch portion (11) and a second arch portion (12), connected to each other, wherein said first arch portion (11) is configured to abut against at least one of said first (22b) and second (22c) inclined surfaces of the base portion (22) of the rail (2), when the fixing device is fixed to the rail (2), said second arch portion (12) is configured to abut against the first face (103a; 203a) of the plate-shaped second body portion (103; 203) of the fixing device (100; 200).
A fixing device (100; 200) according to claim 2, wherein said junction element (14, 15) consists of a screw (14) adapted to engage both the through hole (13) of the arched element (11, 12) and the at least a first through hole (107; 207) obtained in the plate-shaped second body portion (103; 203) of the device (100; 200), and at least one nut (15), such as to form, with said screw (14), a bolt.
A fixing device (100) according to any one of claims 2-4, wherein said removable-fixing metal means comprise two stop elements (10) similar to each other, each stop element comprising an arched element (11, 12) provided with a through hole (13) and with a junction element (14, 15) configured to engage both said through hole (13) and one of two first through holes (107) aligned along a longitudinal direction (Y) of the plate-shaped second body portion (103) of the fixing device and equidistant from a reference portion (PR) of such a second body portion (103) associated with an axis of symmetry (X) of the rail orthogonal to said plate-shaped second body portion.
A fixing device (200) according to claim 2, wherein said removable-fixing metal means further comprise a hook element (208) connected in one piece to a first end (203') of the second body portion (203) of the fixing device (200) opposite to a second end (203'') of said second body portion (203) connected to the third body portion (204), said hook element (208) being configured to engage one of said first (22b) and second (22c) inclined surfaces of the base portion (22) of the rail (2) when said fixing device (200) is fixed to the rail (2).
A fixing device (100; 200) according to any one of the preceding claims, wherein said first (102; 202) and third (104; 204) body portions are also plate-shaped, said plate-shaped first (102; 202) and second (103; 203) body portions are parallel to each other, and said third body portion (104; 204) is orthogonal to said first (102; 202) and second (103; 203) body portions.
A fixing device (100; 200) according to any one of the preceding claims, wherein, when said fixing device (100; 200) is fixed to the rail (2), the first body portion (102; 202) of the metal body of the fixing device is located at a distance from the ballast (MC) of the railway track which is greater than the distance between said ballast (MC) and the second body portion (103; 203).
A fixing device (100; 200) according to any one of the preceding claims, wherein said first (102; 202) and third (104; 204) body portions are also plate-shaped, and said first (102; 202), second (103; 203), and third (104; 204) body portions have the same thickness (d; d").
A fixing device (100; 200) according to claim 9, wherein said thickness (d; d'') is between 5 and 15 mm.
A fixing device (100; 200) according to claim 10, wherein said thickness (d; d") is 10 mm.
A fixing device (100; 200) according to any one of the preceding claims, wherein said body (101; 201) of the fixing device is made of steel.
A fixing device (100; 200) according to claim 1, wherein said first body portion (102; 202) of the metal body is plate-shaped and comprises a further first face (102a; 202a) and an opposite further second face (102b; 202b) facing said second plane (P2), said GNSS antenna (1, 1') being removably fixable to said further first face (102a; 202a).
A fixing device (100; 200) according to claim 13, wherein said first body portion (102; 202) comprises a second (105; 205) and at least a third (106; 206) through hole of different sizes to allow alternatively fixing a first and a second type of said GNSS antenna (1, 1'), different from each other, to the fixing device (100; 200).
An antenna assembly comprising:
- an antenna (1, 1') of a global navigation satellite system, GNSS;

- a device (100; 200) for fixing said GNSS antenna (1, 1') to a rail (2) of a railway track according to any one of claims 1-14,
wherein said GNSS antenna (1, 1') is removably fixed to a first body portion (102; 202) of a body (101; 201) made of a metal material of said device.