An easy-to-carry optical ground station

Abstract

An optical ground station (4) for optical satellite communications of the Lasercom or QKD type, transportable in a container, comprising: - a telescope (2) with a side surface (200) and an optical interface part (2'); - a holder (3); - a detector (6) and / or an optical signal source; - an optical bench (1) operatively connected to the detector (6) and / or the optical signal source and comprising an optical platform (10) having a structure (10') with an optical transit point (110) for the input of the optical beam coming from the optical interface part (2') of the telescope (2) or for the output of the optical signal directed thereto, the structure (10') having a connecting surface (12); wherein the connecting surface (12) is configured for a detachable connection to the holder (3); wherein the side surface (200) and the holder (3) each have a first and a second releasably connectable connecting means (301, 302); The telescope (2), the mount (3) and the optical bench (1) form separate units of the optical station (4), which can be coupled and separated from each other.

Description

Technical area

[0001] The present invention is generally applicable in the technical field of optical communication with satellites and, in particular, relates to an easily transportable optical ground station. Definitions

[0002] In this document, the term "optical bench" and derivatives refer to the assembly consisting of a support platform with optomechanical and electronic components, including an adaptive optics system and a logical component control unit. State of the art

[0003] In the field of optical communication with satellites, ground stations are known that consist of a telescope, an altazimuth mount and an optical bench that are coupled together.

[0004] Telecom C-band is the reference band, while in the quantum range the demonstrations carried out so far have been at a wavelength of 800 nm.

[0005] The telescope receives a beam of light from the satellite via laser or QKD communication, the wavefronts of which are distorted and altered by atmospheric disturbances.

[0006] This beam is transmitted to the optical bench to correct the distortions and thus obtain a light beam with a specific wavelength suitable for optimal focusing in a single- or multimode optical fiber to transmit it to a classical or QKD optical detector capable of converting the light beam into an electrical signal.

[0007] On the other hand, the ground station may include an optical signal source that is transmitted to the relevant satellites via the optical bench and the telescope.

[0008] It goes without saying that when evaluating the orbits of relevant satellites, it is often necessary to be able to move the optical ground station quickly.

[0009] However, commercially available optical ground stations are extremely bulky, making them difficult to port and requiring complex reconfiguration. Description of the invention

[0010] The aim of the present invention is to at least partially overcome the disadvantages outlined above by providing an easily transportable optical ground station.

[0011] Another object of the present invention is to provide a highly compact optical ground station.

[0012] Another object of the present invention is to provide an optical ground station that can be easily assembled and disassembled.

[0013] Another object of the present invention is to provide an optical ground station that meets the standards for transportability in a container.

[0014] These and other purposes, which will become more apparent later, are achieved by an optical ground station according to the provisions described, illustrated and / or claimed herein.

[0015] The dependent claims define advantageous embodiments of the invention. Short description of the drawings

[0016] Further features and advantages of the invention will become clearer from the detailed description of a preferred, but not exclusive, embodiment of the invention, illustrated by way of non-limiting example with the aid of the attached drawings. FIG. 1 is a schematic axonometric view of a station 4; FIG. 2 is a schematic axonometric view of a holder 3; FIG. 3 is an axonometric schematic view of an exploded view of the telescope 2; FIG. 4A is a schematic axonometric view of an assembled telescope 2; FIG. 4B is a schematic axonometric view of a partially disassembled telescope 2; FIG. 5A is a schematic axonometric view of an exploded view of an optical bench 1, of which Fig. 5B is an enlargement of a detail; FIG. 6 is a schematic axonometric view of an optical system 5 . Detailed description of some popular implementation examples

[0017] With reference to the attached figures, an optical ground station 4 for optical satellite communications of the Lasercom or QKD type, which is transportable by means of a container, is described.

[0018] Station 4 may comprise a telescope 2, a holder 3, a detector 6 and an optical bench 1.

[0019] The telescope 2, the mount 3 and the optical bench 1 can form different units that can be coupled to the optical station 4 and separated from each other.

[0020] Preferably, the telescope 2 may comprise a side surface 200 and an optical interface section 2'.

[0021] Advantageously, the mount 3 may comprise a fixed base 303, a central body 304 rotating around the azimuth axis, and two arms 305 for elevation.

[0022] Conveniently, the detector 6 may be a fiber-coupled single-mode detector, particularly when the optical link can transmit a data flow of more than 10 Gb / s.

[0023] In this configuration, the received signal can be focused onto an extremely small surface and with a reduced acceptance angle.

[0024] On the other hand, for data streams below 10 Gb / s, 6 detectors can be used in free space or coupled in multimode fibers.

[0025] This versatility allows Station 4 to handle different transmission capacities, thus improving communication efficiency.

[0026] Advantageously, the optical bench 1 can be operatively connected to the detector 6 and / or the optical signal source.

[0027] The bench 1 may comprise an optical platform 10 with a structure 10' having an optical passage point 110 for the input of the optical beam coming from the optical interface section 2' of the telescope 2 or for the output of the optical signal directed to the latter.

[0028] The structure 10' may include a connecting surface 12 configured for a detachable connection to the holder 3.

[0029] On the other hand, the side surfaces 200 of the telescope 2 and the mount 3 may each comprise first and second releasably connectable connecting means 301 and 302.

[0030] For example, the means 301 and 302 may have the form of plates with mutually coupling elements of complementary shape.

[0031] Of course, it is also possible to tighten identical or similar screws together, which are known in themselves. 4 a modular character, which allows for easier transport.

[0032] This configuration therefore facilitates rapid reconfiguration, maintenance and upgrade of Station 4 modules and supports operational flexibility in different operating scenarios.

[0033] This makes it possible to quickly move Station 4 to a specific location depending on the orbit of the transmitting satellite or to continuously adapt the network depending on atmospheric conditions.

[0034] Advantageously, the station 4 may comprise an optical system 5, which may comprise the optical bench 1 described above and connecting means 40 between the connecting surface 12 of the optical platform 10 of the optical bench 1 and the holder 3.

[0035] The connecting means 40 may comprise at least one interface body 41 having a first portion 41' configured to mate with the surface 12 of the optical platform 10 and a second portion 41" configured to mate with the holder 3.

[0036] The connecting means 40 can ensure a precise and stable mechanical coupling between the optical bench 1 and the holder 3 in order to maintain the optical alignment and to ensure the signal quality, particularly in the presence of vibrations or variable environmental conditions, with resulting high reliability.

[0037] In addition, this measure makes the optical alignment between optical bench 1 and telescope 2 repeatable each time station 4 is installed. laser communication and QKD communication, where even minimal misalignments can affect the quality or feasibility of the connection.

[0038] Advantageously, the structure 10' of the optical bench 1 may comprise several successive layers 16, including two final layers 161 and 162 with a respective thickness s1 and s1', and at least one intermediate layer 17.

[0039] The latter may have a predetermined thickness s2, which is for example greater than the thicknesses s1, s1', and may have a side wall 170 and a reinforcing structure 171 integral therewith.

[0040] The side wall 170 and the structure 171 may together define a plurality of through openings 1710 to substantially reduce the weight of the structure 10'.

[0041] Preferably, the intermediate layer 17 may comprise at least one insert 172, preferably one that is inserted into the openings 1710.

[0042] Such a layer structure with different thicknesses gives the optical bench 1 exceptional mechanical robustness and high torsional rigidity.

[0043] In fact, it will be possible to minimize structural deformations due to mechanical stresses, for example during transport, and thermal variations, thus ensuring the stability and precision of the alignment of the mounted optical elements.

[0044] In addition, the presence of the insert 172 and the openings 1710 helps to optimize the weight distribution and improve the vibration damping properties.

[0045] Advantageously, the insert 172 can be shaped in a counter-mold to the reinforcement structure 171 such that there is a mold coupling between the two and the insert 172 comes into mutual contact with the end layers 161 and 162 on opposite sides.

[0046] The positive engagement of the insert 172 with the reinforcement structure 171 and the direct contact with the end layers 161 and 162 ensure maximum structural stability without the need for complex adhesives or fasteners.

[0047] This mounting method improves resistance to mechanical stress and avoids potential weak points or play that can occur with other fastening systems.

[0048] The precision of this coupling can therefore contribute significantly to the accuracy and repeatability of optical alignment, which is crucial for laser communication and QKD applications.

[0049] Suitably, the optical bench 1 may comprise coupling means 18 between the reinforcement structure 171 and the end layers 161 and 162.

[0050] In this way, the insert 172 can be held in place by interposing it between the latter without the need for adhesives.

[0051] In this way, it will be possible to This is a significant advantage in terms of the longevity and stability of the optical bench 1 in terms of intrinsic mechanical and thermal stability, thus reducing the need for maintenance and extending the useful life of the bench 1 itself.

[0052] In addition, production and assembly processes can be significantly simplified. 16 consecutive layers made entirely of aluminum.

[0053] This maximizes the thermal conductivity in the plane of the platform 10, which facilitates the connection to the numerous optical components, which typically have an aluminum alloy structure, without the need for intermediate flexors.

[0054] The use of aluminum for the entire structure of Optical Bench 1 provides an excellent balance between lightness, rigidity and thermal stability.

[0055] Aluminum is indeed a well-known material for its good processability and its ability to dissipate heat efficiently, helping to maintain a stable operating temperature for sensitive optical elements.

[0056] Its lightness facilitates the transportability of the entire station 4 , while its rigidity ensures that the optical configuration remains unchanged even under load.

[0057] Suitably, the telescope 2 may comprise a section 2001 comprising a primary mirror 201 and a primary mirror support body 205 comprising the side surface 200 described above.

[0058] The telescope 2 may comprise a section 2002 comprising a secondary mirror 202 and a connecting structure 204 between it and the support body 205.

[0059] The connecting structure 204 may include a plurality of beams 204' made of carbon and a cover 204" surrounding the arrangement of the plurality of beams 204' and made of aluminum to filter solar radiation.

[0060] On the other hand, the carrier body 205 can be made of aluminum. 204-foot-long carbon beams in Telescope 2's interconnection structure provide thermal and mechanical stability to maintain targeting accuracy and image quality.

[0061] In addition, the special 204-inch solar radiation filter cover further protects the optical system from excessive heating and thermal deformation caused by the sun, thus ensuring consistent performance and longer component life.

[0062] Suitably, the primary mirror 201 and the secondary mirror 202 may each have a reflective optical surface 201' and 202', respectively.

[0063] The latter are coated with an appropriately selected optical coating to impart the desired optical properties and durability to the primary mirrors 201 and secondary mirrors 202 under different environmental conditions.

[0064] In particular, they can ensure high reflection in the near infrared and residual reflection in the visible range.

[0065] The presence of a modern protective coating on mirrors 201 and 202 ensures a long service life and increases the reliability of optical performance.

[0066] In fact, these coatings can protect the delicate reflective surfaces 201' and 202' from weathering, abrasion, and contamination that could otherwise degrade optical performance over time.

[0067] The increased durability reduces the need for frequent maintenance and ensures that the mirrors maintain high reflectivity and image quality under a wide range of operating conditions, which is critical for long-duration missions.

[0068] Advantageously, station 4 may also comprise a control system 203 for telescope 2, configured to command the latter to point to the satellite in question. 203- Control system can be based on an architecture that integrates technologies from the automation field.

[0069] This ensures a reliable hardware implementation that meets international standards.

[0070] The control system 203 is responsible for the precise alignment of the telescope 2 to celestial targets.

[0071] To ensure accurate alignment, the control system 203 may implement the alignment model equations and calibrate the actual position of the telescope 2 relative to the desired position.

[0072] the EtherCAT fieldbus, the conversion of the trajectory into commands for the drives, the management of the movement limits of the trajectory and the definition of the movement range of both axes. The 203 control system will also be capable of implementing functional safety, including emergency shutdown of the axes via an emergency switch, emergency shutdown for correcting fault conditions, and system monitoring. This ensures responsiveness and movement accuracy along the entire signal reception / transmission path, which is critical for LEO satellites with extremely high relative velocities. 203 automatic pointing control system could be crucial for the efficiency and precision of satellite communications, as it would enable Telescope 2 to track moving satellites with high accuracy, compensating for their speed and complex orbits.

[0073] This could result in a more stable and robust optical link, maximizing connection time and the amount of data that can be transmitted. Automatic target acquisition could reduce human intervention and thus increase the operational autonomy of Station 4.

[0074] Conveniently, the station 4 may also comprise at least one uplink transmitter module 400, for example two, positioned on the side surface 200 of the telescope 2.

[0075] This module 400 will be able to implement the corresponding functions for optical communication links.

[0076] By integrating the Uplink 400 transmitter module directly into Telescope 2, the signal path transmitted to the satellite is optimized.

[0077] This configuration can therefore reduce signal losses due to long fiber optic paths or complex coupling systems, thus improving the efficiency of the uplink connection.

[0078] In addition, it could contribute to a more compact and integrated design of Station 4, further simplifying assembly and deployment and reducing the overall footprint.

[0079] The present invention may comprise various similar or identical parts and / or elements. Unless otherwise stated, similar or identical parts and / or elements are designated by a single reference numeral. The described technical features apply to all similar or identical parts and / or elements.

[0080] The invention is capable of numerous modifications and may fall within the scope of the appended claims. All details may be replaced by other technically equivalent elements, and the materials may be varied as needed, without departing from the scope of the invention as defined in the appended claims.

Claims

[1] An optical ground station (4) for optical satellite communications of the Lasercom or QKD type, transportable in a container, comprising: - a telescope (2) with a side surface (200) and an optical interface part (2'); - a holder (3); - a detector (6) and / or an optical signal source; - an optical bench (1) operatively connected to the detector (6) and / or the optical signal source and comprising an optical platform (10) having a structure (10') with an optical transit point (110) for the input of the optical beam coming from the optical interface part (2') of the telescope (2) or for the output of the optical signal directed thereto, the structure (10') having a connecting surface (12); wherein the connecting surface (12) is configured for a detachable connection to the holder (3); wherein the side surface (200) and the holder (3) each have a first and a second releasably connectable connecting means (301, 302); The telescope (2), the mount (3) and the optical bench (1) form separate units of the optical station (4), which can be coupled and separated from each other. [2] Station according to the preceding claim, comprising an optical system (5) with the optical bench (1) and connecting means (40) between the connecting surface (12) of the optical platform (10) of the optical bench (1) and the support (3), wherein the connecting means (40) comprise at least one interface body (41) with a first portion (41') for coupling to the second surface (12) of the optical platform (10) and a second portion (41") for coupling to the support (3). [3] Station according to one of the preceding claims, wherein the structure (10') of the optical bench (1) comprises a plurality of successive layers (16) comprising a first and a second final layer (161, 162) with a first predetermined thickness (s1, s1') and at least one intermediate layer (17) with a second predetermined thickness (s2) comprising a side wall (170) and a reinforcing structure (171) integral therewith, defining a plurality of through openings (1710), the at least one intermediate layer (17) comprising at least one insert (172) inserted therein, the second predetermined thickness (s2) being greater than the first predetermined thickness (s1, s1'). [4] Station according to the preceding claim, wherein the at least one insert (172) is shaped with respect to the reinforcing structure (171) so that there is a mold coupling between them, the at least one insert (172) coming into mutual contact with the first and second end layers (161, 162) on opposite sides. [5] Station according to the preceding claim, wherein the optical bench (1) comprises connecting means (18) between the reinforcing structure (171) and the first and second end layers (161, 162), the at least one insert (172) being held in place by interposition between the latter, without the need for adhesives. [6] Station according to claim 3 or 4 or 5, wherein the plurality of successive layers (16) consist entirely of aluminum. [7] Station according to one of the preceding claims, wherein the telescope (2) comprises a first section (2001) with a primary mirror (201) and a support body (205) of the primary mirror with the side surface (200), and a second section (2002) with a secondary mirror (202) and a connecting structure (204) between it and the support body (205), wherein the connecting structure (204) comprises a plurality of beams (204') made of carbon and a cover (204") made of aluminum surrounding the arrangement of the plurality of beams (204') for filtering the solar radiation, wherein the support body (205) is made of aluminum. [8] Station according to the preceding claim, wherein the primary mirror (201) and the secondary mirror (202) each have a reflective optical surface (201', 202'), the latter being covered with an optical coating selected to impart the desired optical properties and durability under different environmental conditions to the primary mirror (201) and the secondary mirror (202). [9] Station according to one of the preceding claims, further comprising a control system (203) of the telescope (2) configured to command it to point at the desired satellite. [10] Station according to one of the preceding claims, further comprising at least one uplink transmitter module (400) positioned on the side surface (200) of the telescope (2).

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