Optical system and method for space surveillance

Abstract

Disclosed is an optical system (110) including a front lens unit (112) including one or more lenses (112a, 112b, 112c), such that at least one lens of the one or more lenses (112a, 112b, 112c) is configured to move along a radial direction. The optical system (110) further includes a middle lens unit (114) including one or more lenses (114a, 114b, 114c), such that at least one lens of the one or more lenses (114a, 114b, 114c) is configured to move along one of, the radial direction, an axial direction, or a combination thereof. The optical system (110) further includes a rear lens unit (116) including one or more lenses (116a, 116b, 116c), such that at least one lens of the one or more lenses (116a, 116b, 116c) is configured to move along the axial direction.

Description

[0001] OPTICAL SYSTEM AND METHOD FOR SPACE SURVEILLANCE FIELD OF DISCLOSURE

[0002] The present disclosure relates to optical systems, and more particularly to an optical system and method for space surveillance.

[0003] BACKGROUND

[0004] Optical systems for surveillance and space monitoring have become increasingly important in recent years. These systems play a crucial role in various applications, including tracking satellites, detecting space debris, multi-pixel imaging of space debris, rendezvous and proximity operations (RPO) missions and monitoring celestial objects. The ability to accurately observe and analyze objects in space is essential for maintaining space situational awareness and ensuring the safety of space-based assets.

[0005] Conventional optical systems for space surveillance often face challenges in achieving high performance across a wide field of view while maintaining compact dimensions. Many existing systems struggle to provide diffraction-limited performance, especially when dealing with off-axis imaging. Additionally, these systems frequently encounter difficulties in maintaining optimal focus and alignment across a broad range of operating temperatures, which is critical for space-based applications where environmental conditions can vary significantly. Another common limitation of current optical systems is their inability to effectively compensate for mechanical tolerances and thermal expansion, leading to degraded image quality and reduced reliability. Furthermore, many existing designs lack the flexibility to adapt to different observation scenarios, such as focusing on objects at varying distances or adjusting for atmospheric disturbances. Therefore, there exists a need for a technical solution that solves the aforementioned problems of conventional systems and methods for optical space surveillance.

[0006] SUMMARYThis summary is provided to introduce a selection of concepts in a simplified form that are further described below in the detailed description. This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter.

[0007] In an aspect of the present disclosure, an optical system is disclosed. The optical system includes a front lens unit including one or more lenses. At least one lens of the one or more lenses of the front lens unit is configured to move along a radial direction. The optical system further includes a middle lens unit including one or more lenses. At least one lens of the one or more lenses of the middle lens unit is configured to move along one of, the radial direction, an axial direction, or a combination thereof. The optical system further includes a rear lens unit including one or more lenses. At least one lens of the one or more lenses of the rear lens unit is configured to move along the axial direction.

[0008] In some aspects of the present disclosure, a lens adjustment assembly is coupled to the optical system. The lens adjustment assembly includes at least one lens holding ring configured to secure the at least one lens of one of, the one or more lenses of the front lens unit, the one or more lenses of the middle lens unit, or the one or more lenses of the rear lens unit. The lens adjustment assembly further includes one or more grub screws disposed on the at least one lens holding ring and configured to adjust a radial position of the at least one lens of one of, the one or more lenses of the front lens unit or the one or more lenses of the middle lens unit. The lens adjustment assembly further includes at least one inner ring coupled to the at least one lens holding ring. The lens adjustment assembly further includes one or more constrainers disposed on the at least one inner ring and configured to constrain radial movement of the at least one lens holding ring while permitting axial movement of the at least one lens holding ring. The lens adjustment assembly further includes at least one outer ring threadedly coupled to the at least one inner ring. The lens adjustment assembly further includes one or more rotators disposed on the at least one outer ring and configured to rotate the outer ring to cause axial movement of the inner ring through force transfer along the axial direction bythreads between the outer ring and the inner ring to adjust an axial position of the at least one lens of one of, the one or more lenses of the middle lens unit or the one or more lenses of the rear lens unit.

[0009] In some aspects of the present disclosure, the one or more lenses of the front lens unit, the one or more lenses of the middle lens unit, and the one or more lenses of the rear lens unit are arranged along an optical axis such that the optical system has a focal length range between 65-75 mm.

[0010] In some aspects of the present disclosure, a modulation transfer function of the optical system ranges between 65%-70% on-axis and 50%-55% off-axis, at a spatial frequency of 157 cycles / mm. A field of view of the optical system ranges between 25-30 degrees. A track length of the optical system ranges between 130-145 mm. In some aspects of the present disclosure, the optical system is configured to provide diffraction-limited performance across a field of view with a spot diameter at 80% encircled energy of 2.4-3.2 pm on-axis and 3.2-4.2 pm off-axis.

[0011] In some aspects of the present disclosure, the optical system is disposed in a housing. The radial direction movement of one of, the at least one lens of the one or more lenses of the front lens unit or the at least one lens of the one or more lenses of the middle lens unit, compensates the effect of tilt and decenter with respect to the housing of one of, the one or more lenses of the front lens unit, the one or more lenses of the middle lens unit, the one or more lenses of the rear lens unit, or a combination thereof. The axial direction movement of one of, the at least one lens of the one or more lenses of the middle lens unit, the at least one lens of the one or more lenses of the rear lens unit, or a combination thereof, provides athermalization of the optical system within a temperature range of -40°C to +60°C.

[0012] In some aspects of the present disclosure, the housing includes a baffle configured to reduce stray light from entering the optical system. The housing further includes a barrel configured to enclose the optical system. The housing further includes the lens adjustment assembly.In some aspects of the present disclosure, the housing further includes at least one protection window disposed in front of the optical system and configured to provide radiation resistance.

[0013] In an aspect of the present disclosure, a method of operating an optical system is disclosed. The method includes moving at least one lens of one or more lenses of a front lens unit along a radial direction. The method further includes moving at least one lens of one or more lenses of a middle lens unit along one of, the radial direction, an axial direction, or a combination thereof. The method further includes moving at least one lens of one or more lenses of a rear lens unit along the axial direction.

[0014] In some aspects of the present disclosure, the method further includes securing the at least one lens of one of, the one or more lenses of the front lens unit, the one or more lenses of the middle lens unit, or the one or more lenses of the rear lens unit, by way of at least one lens holding ring of a lens adjustment assembly coupled to the optical system. The method further includes adjusting a radial position of the at least one lens of one of, the one or more lenses of the front lens unit or the one or more lenses of the middle lens unit, by way of one or more grub screws disposed on the at least one lens holding ring. The method further includes constraining radial movement of the at least one lens holding ring while permitting axial movement of the at least one lens holding ring, by way of one or more constrainers disposed on at least one inner ring coupled to the at least one lens holding ring. The method further includes rotating the outer ring to cause axial movement of the inner ring through force transfer along the axial direction by threads between the outer ring and the inner ring to adjust an axial position of the at least one lens of one of, the one or more lenses of the middle lens unit or the one or more lenses of the rear lens unit, by way of one or more rotators disposed on at least one outer ring threadedly coupled to the at least one inner ring.

[0015] The foregoing general description of the illustrative aspects and the following detailed description thereof are merely exemplary aspects of the teachings of this disclosure and are not restrictive.BRIEF DESCRIPTION OF FIGURES

[0016] The following detailed description of the preferred aspects of the present disclosure will be better understood when read in conjunction with the appended drawings. The present disclosure is illustrated by way of example, and not limited by the accompanying figures, in which like references indicate similar elements.

[0017] FIG. 1 A illustrates an isometric view of a housing for an optical system, according to aspects of the present disclosure.

[0018] FIG. IB illustrates a cross-sectional view of the housing of FIG. 1 A containing the optical system, according to aspects of the present disclosure.

[0019] FIG. 1C illustrates a cross-sectional view of the optical system of FIG. IB showing lens units and ray tracing paths, according to aspects of the present disclosure. FIG. ID illustrates a top view of a lens adjustment assembly of the housing of FIG.

[0020] 1 A, according to aspects of the present disclosure.

[0021] FIG. 2 illustrates a flowchart for a method of operating the optical system, according to aspects of the present disclosure.

[0022] FIG. 3 illustrates a flowchart for a method of adjusting lens position using the lens adjustment assembly, according to aspects of the present disclosure.

[0023] FIG. 4 illustrates a flowchart for a method of operating the optical system, according to aspects of the present disclosure.

[0024] FIG. 5 illustrates a flowchart for a method of operating the lens adjustment assembly, according to aspects of the present disclosure.

[0025] DETAILED DESCRIPTION

[0026] The following description sets forth exemplary aspects of the present disclosure. It should be recognized, however, that such description is not intended as a limitation on the scope of the present disclosure. Rather, the description also encompasses combinations and modifications to those exemplary aspects described herein. The present disclosure provides an optical system designed for space surveillance including but not limited to, tracking satellites, detecting space debris, multi -pixelimaging of space debris, rendezvous and proximity operations (RPO) missions and monitoring celestial objects.

[0027] As used herein, the term "housing" refers to a structural enclosure configured to contain, protect, and support optical components and associated mechanical elements within an optical system.

[0028] As used herein, the term "space surveillance" refers to the observation, detection, tracking, and monitoring of objects in space, including satellites, space debris, and celestial bodies.

[0029] FIG. 1A illustrates an isometric view of a housing 100 for an optical system for space surveillance, according to aspects of the present disclosure.

[0030] The housing 100 may comprise a baffle 102, a barrel 104, and a lens adjustment assembly 106. The baffle 102 may be coupled to the barrel 104. The barrel 104 may be configured to enclose an optical system 110. The lens adjustment assembly 106 may be disposed on the barrel 104.

[0031] The baffle 102 may be positioned at a front end of the housing 100. The baffle may be adapted to avoid stray light coming from outside of the field of view. Specifically, the baffle 102 may be adapted to reduce stray light from entering the optical system 110. The baffle 102 may extend outward from a main body of the housing 100 and may include multiple annular ridges along an interior surface of the baffle 102.

[0032] As used herein, the term "baffle" refers to a mechanical structure comprising one or more light-blocking elements configured to prevent unwanted light rays from reaching an optical sensor or image plane.

[0033] As used herein, the term "stray light" refers to undesired light that enters an optical system from outside a designated field of view or through unintended optical paths, which may degrade image quality.

[0034] Examples of the baffle 102 may include, but are not limited to, a conical baffle, a cylindrical baffle, a vane-type baffle, a honeycomb baffle, or the like. Aspects of the present disclosure are intended to include and / or otherwise cover any type ofthe baffle 102 known to a person having ordinary skill in the art, without deviating from the scope of the present disclosure.

[0035] The baffle 102 may provide an advantage of preventing stray light from outside the field of view from entering the optical system 110, thereby enhancing image quality and contrast. The output of the baffle 102 may be filtered light that is directed toward the optical system 110 without interference from unwanted light sources. The barrel 104 may form a main cylindrical body of the housing 100 and may provide structural support for internal optical components. As used herein, the term "barrel" refers to a cylindrical or tubular mechanical structure configured to house and align optical elements along an optical axis.

[0036] The barrel 104 may be made up of materials that may be chosen for their high strength-to-weight ratio, resistance to corrosion, and thermal stability, making them suitable for use in the harsh conditions of space.

[0037] In some aspects of the present disclosure, the barrel 104 may be made of spacegrade aluminum alloy, titanium or the like.

[0038] Examples of the barrel 104 may include, but are not limited to, a cylindrical barrel, a stepped barrel, a tapered barrel, a segmented barrel, or the like. Aspects of the present disclosure are intended to include and / or otherwise cover any type of the barrel 104 known to a person having ordinary skill in the art, without deviating from the scope of the present disclosure.

[0039] The barrel 104 may provide an advantage of maintaining precise alignment of optical elements while providing structural integrity and protection from physical damage. The output of the barrel 104 may be a stable and aligned optical path for light transmission through the optical system 110.

[0040] The lens adjustment assembly 106 may be disposed on the barrel 104 and may include mechanisms for adjusting a position of the optical components such as lenses supported within the barrel 104. The lens adjustment assembly 106 may feature external adjustment elements that allow for radial and axial positioning of the optical components.As used herein, the term "lens adjustment assembly" refers to a mechanical system comprising one or more components configured to enable precise positioning of optical lens elements along radial and axial directions.

[0041] The optical elements may be adjusted using the lens adjustment assembly 106. In some aspects of the present disclosure, the adjustment of the optical elements by the lens adjustment assembly 106 may be automated using actuators.

[0042] The lens adjustment assembly 106 may provide positioning resolution of 0.5 micrometers, enabling precise alignment of the optical elements.

[0043] Examples of the lens adjustment assembly 106 may include, but are not limited to, a screw-based adjustment mechanism, an actuator-based adjustment mechanism, a piezoelectric adjustment mechanism, a motorized adjustment mechanism, or the like. Aspects of the present disclosure are intended to include and / or otherwise cover any type of the lens adjustment assembly 106 known to a person having ordinary skill in the art, without deviating from the scope of the present disclosure. The lens adjustment assembly 106 may provide an advantage of enabling compensation for manufacturing tolerances, thermal effects, and focus adjustment with high precision. The output of the lens adjustment assembly 106 may be precisely positioned optical elements (i.e., lenses) that achieve optimal optical performance.

[0044] A rear portion of the housing 100 may include a mounting flange with multiple attachment points for securing an electronic system unit (not shown) for image acquisition. The housing 100 may provide a compact enclosure that integrates optical components and adjustment mechanisms into a unified assembly suitable for space surveillance applications.

[0045] In some aspects of the present disclosure, the housing 100 may be designed with a compact form factor, making the housing 100 suitable for space-based applications where size and weight are critical considerations.

[0046] In operation, the housing 100 may receive incoming light through the baffle 102, which may filter stray light from outside the field of view, and may direct the filtered light through the barrel 104 enclosing the optical elements, where the lensadjustment assembly 106 may enable precise positioning of lens elements to achieve optimal optical performance for space surveillance applications.

[0047] FIG. IB illustrates a cross-sectional view of the housing 100 of FIG. 1 A containing the optical system 110, according to aspects of the present disclosure.

[0048] Referring to FIG. IB, the housing 100 may further include an optical system 110 and a protection window 108. The protection window 108 may be disposed in front of the optical system 110. The optical system 110 may be enclosed within the barrel 104 of the housing 100.

[0049] The protection window 108 may be configured to shield internal optical components from environmental factors.

[0050] As used herein, the term "protection window" refers to a transparent optical element configured to shield internal optical components from environmental factors while permitting transmission of light within a specified wavelength range.

[0051] The protection window 108 may be made of fused silica and may be at least 5mm thick thereby providing high radiation resistance to absorb most of the space radiation, prevent transmission loss, maintain performance, and provide longer lifetime to the optical elements. Fused silica as used herein may be a type of glass that is highly transparent to visible and near infrared light, making it an ideal material for the protection window.

[0052] In some other aspects of the present disclosure, the protection window 108 may be made of any other suitable material having properties similar to the fused silica, without deviating from the scope of the present disclosure. Examples of the protection window 108 may include, but are not limited to, a fused silica window, a sapphire window, a borosilicate glass window, a quartz window, or the like. Aspects of the present disclosure are intended to include and / or otherwise cover any type of the protection window 108 known to a person having ordinary skill in the art, without deviating from the scope of the present disclosure.

[0053] The protection window may serve to shield lens units of the optical system 110 from the harsh space environment, including exposure to high-energy particles and extreme temperatures.The protection window 108 may provide an advantage of providing radiation resistance and protecting internal optical elements from harsh space environment conditions while maintaining high optical transmission. The output of the protection window 108 may be transmitted light with minimal loss that enters the optical system 110.

[0054] The optical system 110 may comprise multiple lens elements arranged in sequence along an optical axis, with lenses positioned within the barrel 104 of the housing 100.

[0055] As used herein, the term "optical system" refers to an assembly of optical elements configured to receive, manipulate, and focus light to form an image at a designated focal plane.

[0056] As used herein, the term "optical axis" refers to an imaginary line passing through centers of curvature of optical elements in an optical system, along which light propagates with minimal aberration.

[0057] The lens elements within the optical system 110 may include various lens shapes and configurations, with some lenses having convex surfaces and others having concave surfaces, arranged to manipulate incoming light rays. The housing 100 may provide structural support and alignment for the optical system 110, with internal features that secure lens elements in designated positions.

[0058] Examples of the optical system 110 may include, but are not limited to, a refractive optical system, a catadioptric optical system, a multi-element lens system, an aspheric lens system, or the like. Aspects of the present disclosure are intended to include and / or otherwise cover any type of the optical system 110 known to a person having ordinary skill in the art, without deviating from the scope of the present disclosure.

[0059] The optical system 110 may provide an advantage of achieving diffraction -limited performance across a wide field of view while maintaining compact dimensions. The output of the optical system 110 may be focused light that forms a high-resolution image at a focal plane.In operation, the housing 100 may receive light through the protection window 108, which may shield internal optical components from environmental factors while transmitting light to the optical system 110, such that the optical system 110 may manipulate and focus the light to form an image suitable for space surveillance applications.

[0060] FIG. 1C illustrates a cross-sectional view of the optical system 110 of FIG. IB showing lens units and ray tracing paths, according to aspects of the present disclosure.

[0061] Referring to FIG. 1C, the optical system 110 may comprise a front lens unit 112, a middle lens unit 114, and a rear lens unit 116. In some aspects, the optical system 110 may have dimensions including diameters of 52 mm and length of 145 mm including a protection window. In some aspects of the present disclosure, the barrel 104 may be configured to enclose the optical system 110. The barrel 104 may serve to hold the lens units 102, 104, and 106 in place and protect them from physical damage. The front lens unit 112 may be coupled to the middle lens unit 114. The middle lens unit 114 may be coupled to the rear lens unit 116. The front lens unit 112, the middle lens unit 114, and the rear lens unit 116 may be arranged sequentially along an optical axis.

[0062] As used herein, the term "lens unit" refers to a group of one or more optical lens elements configured to perform a specific optical function within an optical system. As used herein, the term "ray tracing" refers to a method of analyzing optical systems by calculating paths of light rays as the light rays pass through optical elements.

[0063] The front lens unit 112 may be positioned at a left side of the optical system 110. The front lens unit 112 may comprise one or more lenses 112a, 112b, 112c. Specifically, the front lens unit 112 may include a first lens 112a, a second lens 112b, and a third lens 112c. The first lens 112a, the second lens 112b, and the third lens 112c may be arranged in sequence along an optical path, with light rays entering from a left side and passing through each element.In some aspects of the present disclosure, the first lens 112a, the second lens 112b, and the third lens 112c may be of varying shapes. In some aspects, the front lens unit 102 may include at least one lens from the one or more lenses i.e., the first lens 112a, the second lens 112b, and the third lens 112c such that the at least one lens is configured to move along a radial direction. Specifically, the second lens 112b from the first lens 112a, the second lens 112b, and the third lens 112c of the front lens unit 102 may be configured to move along the radial direction. The movement may compensate for the effect of tilt and decenter of all the lenses of the optical system 110 with respect to the housing 100 (specifically, the barrel 104) during assembly of lenses in the front, the middle and the rear lens unit.

[0064] As used herein, the term "radial direction" refers to a direction perpendicular to an optical axis, extending outward from or toward the optical axis.

[0065] As used herein, the term "tilt" refers to an angular deviation of an optical element from a nominal orientation perpendicular to an optical axis.

[0066] As used herein, the term "decenter" refers to a lateral displacement of an optical element from a nominal position on an optical axis.

[0067] Although FIG. 1C illustrates that the front lens unit 112 may include three lenses (i.e., the first lens 112a, the second lens 112b, and the third lens 112c), a person skilled in the art will appreciate that the scope of the present disclosure is not limited to three lenses. In various other aspects, the front lens unit 112 may include more than three lenses or fewer than three lenses without deviating from the scope of the present disclosure. In such a scenario, each lens may be configured to perform one or more optical functions in a manner similar to the operations of the first lens 112a, the second lens 112b, and the third lens 112c as described herein.

[0068] Examples of the front lens unit 112 may include, but are not limited to, a singlet lens configuration, a doublet lens configuration, a triplet lens configuration, an aspheric lens configuration, or the like. Aspects of the present disclosure are intended to include and / or otherwise cover any type of the front lens unit 112 known to a person having ordinary skill in the art, without deviating from the scope of the present disclosure.The front lens unit 112 may provide an advantage of receiving and initially shaping incoming light rays while enabling compensation of the effect of tilt and decenter of the lenses through radial movement of at least one lens. The output of the front lens unit 112 may be partially manipulated light that is directed toward the middle lens unit 114.

[0069] The middle lens unit 114 may be situated between the front lens unit 112 and the rear lens unit 116. The middle lens unit 114 may comprise one or more lenses 114a, 114b, 114c. Specifically, the middle lens unit 114 may include a fourth lens 114a, a fifth lens 114b, and a sixth lens 114c. In some aspects of the present disclosure, the fourth lens 114a and the fifth lens 114b may have larger diameters compared to other lenses in the optical system 110, with the fifth lens 114b exhibiting a biconvex configuration. The sixth lens 114c may be positioned at a transition between the middle lens unit 114 and the rear lens unit 116.

[0070] The middle lens unit 104 may include at least one lens of the one or more lenses i.e., the fourth lens 114a, the fifth lens 114b, and the sixth lens 114c, that may be configured to move along the radial direction for compensating the effect of tilt and decenter of the optical system 110 with respect to the housing 100 (specifically the barrel 104). Specifically, the sixth lens 114c of the the fourth lens 114a, the fifth lens 114b, and the sixth lens 114c may be configured to move along the radial direction. Additionally, at least one lens of the one or more lenses i.e., the fourth lens 114a, the fifth lens 114b, and the sixth lens 114c of the middle lens unit 104 may be configured to move along an axial direction for athermalization within a temperature range of -40°C to +60°C. Specifically, the sixth lens 114c of the the fourth lens 114a, the fifth lens 114b, and the sixth lens 114c of the middle lens unit 104 may be configured to move along the axial direction.

[0071] As used herein, the term "axial direction" refers to a direction parallel to an optical axis, along which light propagates through an optical system.

[0072] As used herein, the term "athermalization" refers to a design approach or mechanism that compensates for changes in optical performance caused by temperature variations.The axial movement may allow the optical system 110 to maintain its performance across a wide range of operating temperatures, making it suitable for use in harsh environments such as space.

[0073] Although FIG. 1C illustrates that the middle lens unit 114 may include three lenses (i.e., the fourth lens 114a, the fifth lens 114b, and the sixth lens 114c), a person skilled in the art will appreciate that the scope of the present disclosure is not limited to the three lenses. In various other aspects, the middle lens unit 114 may include more than three lenses or fewer than three lenses without deviating from the scope of the present disclosure. In such a scenario, each lens may be configured to perform one or more optical functions in a manner similar to the operations of the fourth lens 114a, the fifth lens 114b, and the sixth lens 114c as described herein. Examples of the middle lens unit 114 may include, but are not limited to, a singlet lens configuration, a doublet lens configuration, a triplet lens configuration, an aspheric lens configuration, or the like. Aspects of the present disclosure are intended to include and / or otherwise cover any type of the middle lens unit 114 known to a person having ordinary skill in the art, without deviating from the scope of the present disclosure.

[0074] The middle lens unit 114 may provide an advantage of enabling both tilt / decenter compensation through radial movement and athermalization through axial movement, thereby maintaining optical performance across a wide temperature range. The output of the middle lens unit 114 may be further manipulated light that is directed toward the rear lens unit 116.

[0075] The rear lens unit 116 may be located at a right side of the optical system 110. The rear lens unit 116 may comprise one or more lenses 116a, 116b, 116c. Specifically, the rear lens unit 116 may include a seventh lens 116a, an eighth lens 116b, and a ninth lens 116c. In some aspects of the present disclosure, the lens elements in the rear lens unit 116 may progressively decrease in diameter toward an image plane, with the ninth lens 116c being a smallest element in the optical system 110.

[0076] The rear lens unit 106 may include at least one lens of the one or more lenses i.e., the seventh lens 116a, the eighth lens 116b, and the ninth lens 116c, that may beconfigured to move along the axial direction. Specifically, the eighth lens 116b from the seventh lens 116a, the eighth lens 116b, and the ninth lens 116c of the rear lens unit 106 may be adjusted axially. The feature may allow the optical system 110 to focus on objects at varying distances, making it versatile for wide field of view surveillance applications.

[0077] In some aspects, the axial adjustments may be done by way of the independent axial movement or combination of axial movement of the eighth lens 116c from the rear lens unit 116 and the sixth lens 114c from the middle lens unit 114 to focus on objects at distances ranging from 10 meters to infinity.

[0078] Although FIG. 1C illustrates that the rear lens unit 116 may include three lenses (i.e., the seventh lens 116a, the eighth lens 116b, and the ninth lens 116c), a person skilled in the art will appreciate that the scope of the present disclosure is not limited to three lenses. In various other aspects, the rear lens unit 116 may include more than three lenses or fewer than three lenses without deviating from the scope of the present disclosure. In such a scenario, each lens may be configured to perform one or more optical functions in a manner similar to the operations of the seventh lens 116a, the eighth lens 116b, and the ninth lens 116c as described herein.

[0079] Examples of the rear lens unit 116 may include, but are not limited to, a singlet lens configuration, a doublet lens configuration, a triplet lens configuration, an aspheric lens configuration, or the like. Aspects of the present disclosure are intended to include and / or otherwise cover any type of the rear lens unit 116 known to a person having ordinary skill in the art, without deviating from the scope of the present disclosure.

[0080] The rear lens unit 116 may provide an advantage of enabling focus adjustment for objects at varying distances through axial movement while bringing light rays into final convergence at a focal plane. The output of the rear lens unit 116 may be focused light that forms an image at a focal plane where an image sensor is positioned.

[0081] Ray tracing paths illustrated throughout the optical system 110 may show multiple bundles of light rays originating from different field positions, demonstrating awide field of view capability of the optical system 110. The rays may converge and diverge as the rays pass through each lens element, with final convergence occurring after the ninth lens 116c where an image sensor may be positioned. In some aspects of the present disclosure, the optical system 110 may be designed to provide diffraction-limited performance across a wide field of view. The optical system 110 may have a focal length range between 65-75 mm, an optical aperture greater than 48 mm, and a wavelength range of 0.4-1.1 pm.

[0082] As used herein, the term "focal length" refers to a distance from a principal plane of an optical system to a focal point where parallel light rays converge.

[0083] As used herein, the term "optical aperture" refers to an opening through which light enters an optical system, typically defined by a diameter of a limiting element. In some aspects of the present disclosure, the optical system 110 may have a modulation transfer function (MTF) that ranges between 65%-70% on-axis and between 50%-55% off-axis at a spatial frequency of 157 cycles / mm. The MTF may be a measure of the optical system's ability to reproduce contrast in the object being imaged, with higher values indicating better resolution performance.

[0084] As used herein, the term "modulation transfer function" or "MTF" refers to a measure of an optical system's ability to transfer contrast from an obj ect to an image at various spatial frequencies.

[0085] In some aspects of the present disclosure, the optical system 110 may have a field of view that ranges between 25-30 degrees. A wide field of view may allow the optical system 110 to capture a large area in a single image, which may be beneficial for space surveillance as it allows for the monitoring of a large area of space. As used herein, the term "field of view" refers to an angular extent of an observable area that an optical system can capture at a given moment.

[0086] In some aspects of the present disclosure, the optical system 110 may have a track length ranging between 130-145 mm.

[0087] As used herein, the term "track length" refers to a total distance from a front surface of a first optical element to an image plane in an optical system.In some aspects of the present disclosure, the optical system 110 may provide diffraction-limited performance across a wide field of view. Diffraction-limited performance may refer to the ability of the optical system 110 to focus light to the smallest possible spot, limited only by the diffraction of light.

[0088] As used herein, the term "diffraction -limited performance" refers to optical performance wherein image quality is limited only by diffraction effects rather than aberrations or manufacturing imperfections.

[0089] In some aspects of the present disclosure, the optical system 110 may have a spot diameter at 80% encircled energy of 2.4-3.2 pm on-axis and 3.2-4.2 pm off-axis. In some aspects of the present disclosure, optical system 110 may have a root mean square (RMS) spot size of 3 pm at center and 3.2 pm at comer. In some aspects of the present disclosure, after including manufacturing tolerances of lens, performance of the optical system 110 may remain close to the diffraction limit. As used herein, the term "encircled energy" refers to a measure of optical performance indicating a percentage of total energy contained within a specified diameter at an image plane.

[0090] In some aspects of the present disclosure, the optical system 110 may have a transmission greater than 72%. The transmission of an optical system may refer to the percentage of incident light that passes through the system without being absorbed or reflected.

[0091] In some aspects of the present disclosure, the optical system 110 may have F number less than 1.75. The F number may refer to the ratio of focal length of a lens to aperture diameter of the lens. The small f-number here may indicate simultaneous optimal performance for wide field of view and higher sensitivity of the optical system which may be required for the space surveillance applications.

[0092] As used herein, the term "F number" refers to a ratio of a focal length of an optical system to a diameter of an entrance pupil.

[0093] In some aspects of the present disclosure, the optical system 110 may have a grid distortion less than 0.6% (barrel distortion). Grid distortion may refer to the deviation of the image formed by the optical system 110 from a perfect grid.Distortion may be within the 1% across the image sensor. This may show that the optical lens system provides absolute angular position of detected objects.

[0094] As used herein, the term "distortion" refers to an optical aberration that causes straight lines in an object to appear curved in an image.

[0095] In some aspects of the present disclosure, the optical system 110 may have a relative illumination greater than 89%. Relative illumination may refer to the variation in brightness across the image formed by the optical system 110. Relative illumination above 90% may show that the system has stable performance from center to the comer without degradation of light intensity.

[0096] As used herein, the term "relative illumination" refers to a ratio of illumination at a peripheral point of an image to illumination at a center of the image.

[0097] In some aspects of the present disclosure, the optical system 110 may have no vignetting. Vignetting may refer to a reduction in image brightness at the periphery compared to this center of the image.

[0098] As used herein, the term "vignetting" refers to a reduction in image brightness or saturation at a periphery of an image compared to a center of the image.

[0099] In some aspects of the present disclosure, the optical system 110 may have an anti-reflective coating with greater than 98% transmission in the visible and nearinfrared regime. The anti-reflective coating may serve to reduce reflections from the lens surfaces, allowing more light to pass through the lenses and reach the sensor. Specifically, the anti-reflective coating may minimize ghost images and prevent stray light from outside the field from reaching the focal plane.

[0100] As used herein, the term "anti -reflective coating" refers to an optical coating applied to lens surfaces to reduce reflection and increase transmission of light.

[0101] In some aspects of the present disclosure, the lenses within the front lens unit 102, middle lens unit 104, and rear lens unit 106 may be made from a variety of glass materials, including but not limited to CAF2, S-BSL7, S-PHM53, S-TIM2, S-NPH3, SNPH-5, and S-FPM2 or the like. In some other embodiment, the lenses within the front lens unit 102, middle lens unit 104, and rear lens unit 106 may bemade from a variety of glass materials, including but not limited to fused silica, BAF2, S-FPM2, S-NBH5, N-KZSF4, S-NPH3, S-LAL59, or the like.

[0102] These materials may be chosen for their optical properties, such as their refractive indices and Abbe numbers, which may affect the focusing power and chromatic aberration of the lenses.

[0103] In some aspects of the present disclosure, the optical system 110 may be designed for use with a variety of high resolution CMOS or CCD or the like sensor model. The optical system 100 may be compatible and may support smaller pixel pitch less than 4 micrometers and thereby may provide high resolution images in combination with a variety of high resolution pixel sensors.

[0104] In operation, the optical system 110 receives light through the front lens unit 112, which initially shapes incoming light rays and enables compensation for tilt and decenter through radial movement of at least one lens, passes the light through the middle lens unit 114, which further manipulates the light and enables both tilt / decenter compensation and athermalization through radial and axial movement, and focuses the light using the rear lens unit 116, which brings light rays into final convergence at a focal plane and enables focus adjustment for objects at varying distances through axial movement.

[0105] FIG. ID illustrates a top view of the lens adjustment assembly 106 of the housing 100 of FIG. 1 A, according to aspects of the present disclosure.

[0106] Referring to FIG. ID, the lens adjustment assembly 106 may include at least one lens holding ring 118 (hereinafter referred to and designated as "the lens holding ring 118"), one or more grub screws 120a, 120b, 120c, 120d, at least one inner ring 122 (hereinafter referred to and designated as "the inner ring 122"), at least one outer ring 124 (hereinafter referred to and designated as "the outer ring 124"), one or more constrainers 126a, 126b, and one or more rotators 128a, 128b.

[0107] The lens holding ring 118 may be positioned at a center of the lens adjustment assembly 106. The innerring 122 may surround the lens holding ring 118. Theouter ring 124 may encircle the inner ring 122. The one or more grub screws 120a, 120b, 120c, 120d may be disposed on the lens holding ring 118. The one or moreconstrainers 126a, 126b may be disposed on the inner ring 122. The one or more rotators 128a, 128b may be disposed on the outer ring 124.

[0108] The lens holding ring 118 may be configured to secure a lens element within the optical system 110. In some aspects of the present disclosure, the lens adjustment assembly 106 may include plurality of lens holding ring 118 such that each of the lenses present in the front lens unit 112, the middle lens unit 114, and the rear lens unit 116 may be held by a corresponding lens holding ring 118. The lens holding ring 118 may be fixedly attached to the inner wall of the barrel 104 of the housing 100.

[0109] As used herein, the term "lens holding ring" refers to a mechanical component configured to secure and position an optical lens element within an optical assembly.

[0110] Examples of the lens holding ring 118 may include, but are not limited to, a threaded lens ring, a snap-fit lens ring, a clamping lens ring, a retaining lens ring, or the like. Aspects of the present disclosure are intended to include and / or otherwise cover any type of the lens holding ring 118 known to a person having ordinary skill in the art, without deviating from the scope of the present disclosure.

[0111] The lens holding ring 118 may provide an advantage of securely holding lens elements while enabling precise positioning through associated adjustment mechanisms. The output of the lens holding ring 118 may be a securely mounted lens element that can be adjusted radially and axially.

[0112] The one or more grub screws 120a-120d may be arranged around the lens holding ring 118 at approximately 90-degree intervals. The one or more grub screws 120a-120d may include a first grub screw 120a positioned on a left side, a second grub screw 120b positioned at a top, a third grub screw 120c positioned on a right side, and a fourth grub screw 120d positioned at a bottom. The first grub screw 120a, the second grub screw 120b, the third grub screw 120c, and the fourth grub screw 120d may be configured to apply force on the lens holding ring 118 from four directions to adjust a radial position of a lens attached to the lens holding ring 118.As used herein, the term "grub screw" refers to a headless screw configured to apply force on an adjacent component for positioning or securing purposes.

[0113] To the lens that may be allowed to be moved radially (e.g., second lens 112b of the front lens unit 112) or radially as well as axially (e.g., the sixth lens 114c of the middle lens unit 114), a small air gap may be provided between the lens holding ring 118 and the inner wall of the barrel 104 such that the gap may allow the lens holding ring 118 to be moved radially outward or radially inward when force is applied on the one or more grub screws 120a-120d disposed on the lens holding ring 118 for adjusting the radial position of the lens that is attached with the lens holding ring 118.

[0114] In some aspects of the present disclosure, the one or more grub screws 120a-120d may be attached to the lens holding ring 118 only when the the lens holding ring 118 is associated with the lenses that may be either allowed to be moved radially or both radially and axially. The one or more grub screws 120a-120d may facilitate in holding the lens holding ring 118 inside the barrel 104 such that the small air gap exists between the inner wall of the barrel 104 and the lens holding ring 118. In some aspects of the present disclosure, the one or more grub screws 120a-120d may pass through one or more holes disposed on the barrel 104 such that once lens attached with the lens holding ring 118 is adjusted with the help of the one or more grub screws 120a-120d, the one or more grub screws 120a-120d passing through the corresponding holes present in the barrels may be locked therein (e.g., using space-graded glue).

[0115] Although FIG. ID illustrates that the lens adjustment assembly 106 may include four grub screws (i.e., the first grub screw 120a, the second grub screw 120b, the third grub screw 120c, and the fourth grub screw 120d), a person skilled in the art will appreciate that the scope of the present disclosure is not limited to four grub screws. In various other aspects, the lens adjustment assembly 106 may include more than four grub screws or fewer than four grub screws without deviating from the scope of the present disclosure. In such a scenario, each grub screw may be configured to perform one or more adjustment functions in a manner similar to theoperations of the first grub screw 120a, the second grub screw 120b, the third grub screw 120c, and the fourth grub screw 120d as described herein.

[0116] Examples of the grub screws 120a, 120b, 120c, 120d may include, but are not limited to, a set screw, an Allen screw, a socket head screw, a hex socket screw, or the like. Aspects of the present disclosure are intended to include and / or otherwise cover any type of the grub screws 120a, 120b, 120c, 120d known to a person having ordinary skill in the art, without deviating from the scope of the present disclosure. The grub screws 120a, 120b, 120c, 120d may provide an advantage of enabling precise radial positioning of lens elements from multiple directions to compensate the effect of tilt and decenter of the lenses of the optical system 110. The output of the grub screws 120a, 120b, 120c, 120d may be a radially adjusted lens position that compensates for manufacturing tolerances and alignment errors.

[0117] The inner ring 122 may be coupled to the lens holding ring 118. The inner ring 122 may include a first constrainer 126a and a second constrainer 126b. The first constrainer 126a may be positioned in a lower region of the inner ring 122, and the second constrainer 126b may be positioned in an upper region of the inner ring 122. As used herein, the term "inner ring" refers to a mechanical component configured to couple a lens holding ring to an outer ring while enabling controlled axial movement.

[0118] To the lens that may be allowed to be moved axially or radially, as well as axially (e.g., the sixth lens which is the part of the middle lens unit and the eighth lens of the rear lens unit), the lens holding ring 118 may be fixedly attached with the inner ring 122 such that the inner ring 122 may be configured to constrain the radial movement of the lens holding unit 118 by way of one or more constrainers 126a, 126b thereby causing the lens holding unit 118 to be free to move axially and not radially.

[0119] Examples of the inner ring 122 may include, but are not limited to, a threaded inner ring, a keyed inner ring, a splined inner ring, a guided inner ring, or the like. Aspects of the present disclosure are intended to include and / or otherwise cover any type ofthe inner ring 122 known to a person having ordinary skill in the art, without deviating from the scope of the present disclosure.

[0120] The inner ring 122 may provide an advantage of enabling controlled axial movement of the lens holding ring 118 while constraining radial movement through the constrainers 126a, 126b. The output of the inner ring 122 may be axial translation of the lens holding ring 118 in response to rotation of the outer ring 124. The first constrainer 126a and the second constrainer 126b may be configured to constrain radial movement of the lens holding ring 118 while permitting axial movement.

[0121] As used herein, the term "constrainer" refers to a mechanical element configured to restrict movement in one or more directions while permitting movement in other directions.

[0122] The Inner ring 122 may be holding the lens holding ring 118 free to move only in axial direction by constraining its radial motion using constrainers.

[0123] Although FIG. ID illustrates that the inner ring 122 may include two constrainers (i.e., the first constrainer 126a and the second constrainer 126b), a person skilled in the art will appreciate that the scope of the present disclosure is not limited to two constrainers. In various other aspects, the inner ring 122 may include more than two constrainers or fewer than two constrainers without deviating from the scope of the present disclosure. In such a scenario, each constrainer may be configured to perform one or more constraining functions in a manner similar to the operations of the first constrainer 126a and the second constrainer 126b as described herein. Examples of the constrainers 126a, 126b may include, but are not limited to, a guide pin, a key, a spline, a linear bearing, or the like. Aspects of the present disclosure are intended to include and / or otherwise cover any type of the constrainers 126a, 126b known to a person having ordinary skill in the art, without deviating from the scope of the present disclosure.

[0124] The constrainers 126a, 126b may provide an advantage of ensuring that axial adjustment does not introduce unintended radial displacement of the lens element.The output of the constrainers 126a, 126b may be constrained radial movement of the lens holding ring 118 while permitting axial movement.

[0125] The outer ring 124 may be threadedly coupled to the inner ring 122. The outer ring 124 may encircle the inner ring 122 and may be configured to rotate to facilitate axial movement of the lens holding ring 118.

[0126] As used herein, the term "outer ring" refers to a mechanical component configured to rotate and transfer force to an inner ring through a threaded interface to cause axial movement.

[0127] Further, the inner ring 122 may be coupled to the outer ring 124 using threads such that the outer ring 124 may be disposed in such a way that its position is fixed w.r.t the barrel 104 and the outer ring 124 may only rotate using the rotators. Upon rotation of the outer ring using the one or more rotators 128a, 128b, the inner ring 122 may move only axially due to force transfer along the axial direction by the threads thereby adjusting the axial position of the lenses.

[0128] The outer ring 122 may be allowed to rotate from outside such that the position of the outer ring 122 may be fixed w.r.t the barrel 104 for movement into the axial direction. Since the outer ring 122 and the inner ring 124 may be coupled to each other by way of threads, therefore when the outer ring is rotated, the inner ring may move only in the axial direction due to the force transfer along the axial direction by the threads.

[0129] Examples of the outer ring 124 may include, but are not limited to, a threaded outer ring, a gear-driven outer ring, a cam-driven outer ring, a motorized outer ring, or the like. Aspects of the present disclosure are intended to include and / or otherwise cover any type of the outer ring 124 known to a person having ordinary skill in the art, without deviating from the scope of the present disclosure.

[0130] The outer ring 124 may provide an advantage of converting rotational motion into precise axial translation of the inner ring 122 through the threaded interface. The output of the outer ring 124 may be rotational motion that is converted to axial movement of the inner ring 122.The outer ring 124 may be equipped with a first rotator 128a positioned in an upper region and a second rotator 128b positioned in a lower region. The first rotator 128a and the second rotator 128b may extend outward from the outer ring 124 and may be configured to facilitate rotation of the outer ring 124. When the outer ring 124 is rotated using the first rotator 128a and the second rotator 128b, a threaded interface between the outer ring 124 and the inner ring 122 may cause the inner ring 122 to move axially, thereby adjusting an axial position of a lens attached to the lens holding ring 118.

[0131] As used herein, the term "rotator" refers to a mechanical element configured to facilitate rotation of an associated component.

[0132] Although FIG. ID illustrates that the outer ring 124 may include two rotators (i.e., the first rotator 128a and the second rotator 128b), a person skilled in the art will appreciate that the scope of the present disclosure is not limited to two rotators. In various other aspects, the outer ring 124 may include more than two rotators or fewer than two rotators without deviating from the scope of the present disclosure. In such a scenario, each rotator may be configured to perform one or more rotation functions in a manner similar to the operations of the first rotator 128a and the second rotator 128b as described herein.

[0133] Examples of the rotators 128a, 128b may include, but are not limited to, a manual rotator, a motorized rotator, an actuator-driven rotator, a gear-driven rotator, or the like. Aspects of the present disclosure are intended to include and / or otherwise cover any type of the rotators 128a, 128b known to a person having ordinary skill in the art, without deviating from the scope of the present disclosure.

[0134] The rotators 128a, 128b may provide an advantage of enabling external access for adjusting axial position of lens elements without disassembling the optical system. The output of the rotators 128a, 128b may be rotation of the outer ring 124 that causes axial movement of the inner ring 122.

[0135] Finally, after alignment is achieved, the entire mechanisms may be permanently locked by potting with the space-grade glue in the threaded regions.In operation, the lens adjustment assembly 106 secures a lens element using the lens holding ring 118, adjusts a radial position of the lens element using the grub screws 120a, 120b, 120c, 120d, constrains radial movement while permitting axial movement using the constrainers 126a, 126b disposed on the inner ring 122, and adjusts an axial position of the lens element by rotating the outer ring 124 using the rotators 128a, 128b, such that the threaded interface between the outer ring 124 and the inner ring 122 converts rotational motion into axial translation.

[0136] FIG. 2 illustrates a flowchart for a method 200 of operating the optical system 110, according to aspects of the present disclosure.

[0137] Referring to FIG. 2, the method 200 may comprise a step 202, a step 204, and a step 206. The method 200 may provide a structured approach for adjusting lens positions within the optical system 110 through radial and axial movements of respective lens units.

[0138] At step 202, the optical system 110 may move at least one lens of the one or more lenses 112a, 112b, 112c of the front lens unit 112 along a radial direction. The step 202 may enable radial positioning adjustment of lens elements within the front lens unit 112. The method 200 may involve moving at least one lens in the front lens unit 102 along a radial direction to compensate for tilt and decenter of all elements with respect to a mechanical housing. In some aspects, the at least one lens in the front lens unit 112 may be the second lens 112b.

[0139] At step 204, the optical system 110 may move at least one lens of one or more lenses 114a, 114b, 114c of the middle lens unit 114 along a radial direction, an axial direction, or a combination thereof. The step 204 may provide flexibility in adjusting lens elements within the middle lens unit 114 through multiple directional movements. At least one lens in the middle lens unit 104 may be moved along a radial direction. In some aspects of the present disclosure, the at least one lens in the middle lens unit 104 may be the sixth lens 114c that may be moved along the radial direction. The movement may be designed to compensate for tilt and decenter with respect to the mechanical housing. The at least one lens in the middle lens unit 104 may be moved axially using various mechanisms, such as mechanical actuatorsor piezoelectric devices, which may precisely control the position and orientation of the lens. The step 204 may further include moving the at least one lens in the middle lens unit 104 along an axial direction for athermalization within a temperature range of -40°C to +60°C. In some aspects of the present disclosure, the at least one lens in the middle lens unit 104 may be the sixth lens 114c that may be moved along the axial direction.

[0140] At step 206, the optical system 110 may move at least one lens of one or more lenses 116a, 116b, 116c of the rear lens unit 116 along an axial direction. The step 206 may enable axial positioning adjustment of lens elements within the rear lens unit 116. The method 200 may involve moving at least one lens in the rear lens unit 106 along an axial direction to focus on objects at distances from 10 meters to infinity. In some aspects, the at least one lens in the rear lens unit 116 may be the eighth lens 116b.

[0141] FIG. 3 illustrates a flowchart for a method 300 of adjusting lens position using the lens adjustment assembly 106, according to aspects of the present disclosure. Referring to FIG. 3, the method 300 may comprise a step 302, a step 304, a step 306, and a step 308. The method 300 may provide a structured approach for positioning lenses within the optical system 110 using the lens adjustment assembly 106.

[0142] At step 302, the lens adjustment assembly 106 may secure at least one lens of the one or more lenses of the front lens unit 112, the middle lens unit 114, and the rear lens unit 116 by way of the lens holding ring 118. Each of the lenses present in the first, second and third lens units may be held by a corresponding lens holding ring 118 such that each of the lens holding rings 118 may be fixedly attached to the inner wall of the barrel 104 of the housing 100.

[0143] At step 304, the lens adjustment assembly 106 may adjust a radial position of at least one lens of the one or more lenses of the front lens unit 112, the middle lens unit 114, and the rear lens unit 116 by way of the grub screws 120a, 120b, 120c, 120d disposed on the lens holding ring 118. A small air gap may be provided between the lens holding ring 118 and the inner wall of the barrel 104 such that thegap may allow the lens holding ring 118 to be moved radially outward or radially inward when force is applied on one or more grub screws 120a, 120b, 120c, 120d attached to the lens holding ring 118 for adjusting the radial position of the lens that is attached with the lens holding ring 118.

[0144] At step 306, the constrainers 126a, 126b disposed on the inner ring 122 may constrain radial movement of the lens holding ring 118 while permitting axial movement. The lens holding ring 118 may be fixedly attached with the inner ring 122 such that the inner ring 122 may constrain the radial movement of the lens holding ring 118 by way of one or more constrainers 126a, 126b thereby causing the lens holding unit to be free to move axially and not radially.

[0145] At step 308, the rotators 128a, 128b may rotate the outer ring 124 to cause axial movement of the inner ring 122 through force transfer by threads to adjust an axial position of a lens coupled to the lens holding ring 118 that is fixedly attached to the inner ring 122. Upon rotation of the outer ring 124 using the rotators 128a, 128b, the inner ring 122 may move only axially due to force transfer along the axial direction by the threads thereby adjusting the axial position of the lens.

[0146] FIG. 4 illustrates a flowchart for a method 400 of operating the optical system 110, according to aspects of the present disclosure.

[0147] Referring to FIG. 4, the method 400 may comprise a step 402, a step 404, a step 406, a step 408, a step 410, a step 412, and a step 414. The method 400 may demonstrate a combination of light transmission through three lens units followed by adjustment movements that may compensate for mechanical tolerances, thermal variations, and focus requirements.

[0148] At step 402, the optical system 110 may receive light through the front lens unit 112. Light may be received through the front lens unit 102. In the step, the front lens unit 102, which may include at least three lens elements of varying shapes, may capture incoming light from the surveillance scene. The light may come from a variety of sources, such as stars, planets, or man-made objects in space. In some aspects, the front lens unit 102 may be designed to capture light over a wide fieldof view, allowing the optical system 110 to monitor a large area of space in a single image.

[0149] At step 404, the optical system 110 may pass light through the middle lens unit 114. The light may pass through the middle lens unit 104. The middle lens unit 104, situated between the front lens unit 102 and the rear lens unit 106, may manipulate the incoming light rays to correct for various optical aberrations. The manipulation may involve changing the direction of the light rays, altering their speed, or modifying their phase, depending on the specific design and arrangement of the lens elements within the middle lens unit 104.

[0150] At step 406, the optical system 110 may focus light using the rear lens unit 116. The light may be focused using the rear lens unit 106. The rear lens unit 106, located at the rightmost side of the optical system 110, may further manipulate the light rays to bring them into focus at a specific point. The rear lens unit 106 may thus be involved in adjusting the path of the light rays so that they converge at the desired focal point, which may be at varying distances from the optical system 110 depending on the surveillance requirements.

[0151] At step 408, the optical system 110 may move a lens in the front lens unit 112 radially to compensate for tilt and decenter. The method 200 may involve moving at least one lens in the front lens unit 102 along a radial direction to compensate for tilt and decenter of all elements with respect to a mechanical housing.

[0152] At step 410, the optical system 110 may move a lens in the middle lens unit 114 radially for tilt and decenter compensation. At least one lens in the middle lens unit 104 may be moved along a radial direction. The movement may be designed to compensate for tilt and decenter with respect to the mechanical housing. By adjusting the position of the at least one lens, the optical system 110 may correct for any misalignments or deviations in the optical path, ensuring that the light rays are accurately directed towards the desired focal point. The feature may enhance the performance of the optical system 110 by ensuring that the image formed by the system is sharp and clear, even when the alignment of the optical elements is disturbed due to factors such as mechanical vibrations or thermal expansion.At step 412, the optical system 110 may move a lens in the middle lens unit 114 axially for athermalization within a temperature range of -40°C to +60°C. The method 200 may involve moving the at least one lens in the middle lens unit 104 along an axial direction for athermalization within a temperature range of -40°C to +60°C. The axial movement may allow the optical system 110 to maintain its performance across a wide range of operating temperatures, making it suitable for use in harsh environments such as space. In some aspects of the present disclosure, the axial movement of the at least one lens in the middle lens unit 104 may be controlled using temperature sensors and feedback control systems to adjust the position of the lens in response to changes in temperature.

[0153] At step 414, the optical system 110 may move a lens in the rear lens unit 116 axially to focus on objects at distances from 10 meters to infinity. The method 200 may involve moving at least one lens in the rear lens unit 106 along an axial direction to focus on objects at distances from 10 meters to infinity. The feature may allow the optical system 110 to focus on objects at varying distances, making the optical system 110 versatile for different surveillance applications. In some aspects of the present disclosure, the axial movement of the at least one lens in the rear lens unit 106 may be controlled using a focus control system, which may adjust the position of the lens based on the distance to the object being observed.

[0154] The radial movements in steps 408 and 410 may address alignment compensation, while the axial movements in steps 412 and 414 may provide thermal stability and focus adjustment capabilities for the optical system 110.

[0155] FIG. 5 illustrates a flowchart for a method 500 of operating the lens adjustment assembly 106, according to aspects of the present disclosure.

[0156] Referring to FIG. 5, the method 500 may comprise a step 502, a step 504, a step 506, a step 508, a step 510, and a step 512. The method 500 may provide a structured approach for performing radial and axial adjustments of lenses within the optical system 110, with decision points that may allow for selective adjustment based on requirements of the optical system 110.At step 502, the lens adjustment assembly 106 may secure each of the lenses in the lens holding ring 118 such that the lens holding ring 118 is attached to inner wall of the barrel 104. Each of the lenses present in the first, second and third lens units may be held by a corresponding lens holding ring 118 wherein the lens holding rings may be fixedly attached to the inner wall of the barrel 104 of the housing 100. At step 504, the method 500 may determine whether radial adjustment is required. The step 504 may be a decision point that determines whether radial adjustment is required.

[0157] At step 506, when radial adjustment is required (Yes branch from step 504), the lens adjustment assembly 106 may apply force on grub screws to move the lens holding ring 118 radially using an air gap between the lens holding ring 118 and the barrel 104. A small air gap may be provided between the lens holding ring 118 and the inner wall of the barrel 104 such that the gap may allow the lens holding ring 118 to be moved radially outward or radially inward when force is applied on one or more grub screws 120a-120d attached to the lens holding ring 118 for adjusting the radial position of the lens that is attached with the lens holding ring 118.

[0158] At step 508, the method 500 may determine whether axial adjustment is required. The step 508 may be another decision point that determines whether axial adjustment is required. The method 500 may proceed to step 508 following step 506, or when radial adjustment is not required (No branch from step 504).

[0159] At step 510, when axial adjustment is required (Yes branch from step 508), the lens adjustment assembly 106 may rotate the outer ring 124 using the rotators 128a, 128b to transfer force axially through threads to the inner ring 122. Upon rotation of the outer ring 124 using the rotators 128a, 128b, the inner ring 122 may move only axially due to force transfer along the axial direction by the threads thereby adjusting the axial position of the lenses.

[0160] At step 512, the lens adjustment assembly 106 may lock adjustment mechanisms using space-grade glue. The method 500 may proceed to step 512 following step 510, or when axial adjustment is not required (No branch from step 508). Finally,after alignment is achieved, the entire mechanisms may be permanently locked by potting with the space-grade glue in the threaded regions.

[0161] The movements of the lenses in the front, middle, and rear lens units 102, 104, and 106 may be coordinated to optimize the performance of the optical system 110. For example, the movements of the lenses may be synchronized to compensate for tilt, decenter, and thermal effects while maintaining focus on the object being observed. This coordinated movement of the lenses may allow the optical system 110 to provide high-quality images under a wide range of conditions, making it a versatile and reliable solution for space surveillance applications.

[0162] The optical system 110 and the methods 200-500 may provide several significant technical advantages. The system 110 may offer diffraction-limited performance across a wide field of view, enabling high-resolution imaging crucial for space surveillance applications. Its compact design, with dimensions of 52 mm x 52 mm x 145 mm, may allow for easy integration into various space-based platforms. The system's ability to operate within a temperature range of -40°C to +60°C through athermalization may ensure reliable performance in extreme space environments. The movable lenses in each unit may provide precise compensation for tilt, decenter, and focus, enhancing image quality and system flexibility. Additionally, the optical system's high modulation transfer function (MTF) and large aperture may contribute to superior image clarity and light -gathering capability, critical for detecting and tracking small or distant objects in space.

[0163] The optical system's design may allow for flexible integration and assembly, making it a cost-effective solution for space surveillance. The optical system 110 may overcome the challenges faced by conventional optical systems, such as achieving high performance across a wide field of view while maintaining compact dimensions, and effectively compensating for mechanical tolerances and thermal expansion.

[0164] Aspects of the present disclosure are discussed here with reference to flowchart illustrations and block diagrams that depict methods, systems, and apparatus in accordance with various aspects of the present disclosure. Each block within theseflowcharts and diagrams, as well as combinations of these blocks, can be executed by computer-readable program instructions. The various logical blocks, modules, circuits, and algorithm steps described in connection with the disclosed aspects may be implemented through electronic hardware, software, or a combination of both. To emphasize the interchangeability of hardware and software, the various components, blocks, modules, circuits, and steps are described generally in terms of their functionality. The decision to implement such functionality in hardware or software is dependent on the specific application and design constraints imposed on the overall system. Person having ordinary skill in the art can implement the described functionality in different ways depending on the particular application, without deviating from the scope of the present disclosure.

[0165] The flowcharts and block diagrams presented in the figures depict the architecture, functionality, and operation of potential implementations of systems, methods, and apparatus according to different aspects of the present disclosure. Each block in the flowcharts or diagrams may represent an engine, segment, or portion of instructions comprising one or more executable instructions to perform the specified logical function(s). In some alternative implementations, the order of functions within the blocks may differ from what is depicted. For instance, two blocks shown in sequence may be executed concurrently or in reverse order, depending on the required functionality. Each block, and combinations of blocks, can also be implemented using special-purpose hardware-based systems that perform the specified functions or tasks, or through a combination of specialized hardware and software instructions.

[0166] Although the preferred aspects have been detailed here, it should be apparent to those skilled in the relevant field that various modifications, additions, and substitutions can be made without departing from the scope of the disclosure. These variations are thus considered to be within the scope of the disclosure as defined in the following claims.

[0167] Features or functionalities described in certain example aspects may be combined and re-combined in or with other example aspects. Additionally, different aspectsand elements of the disclosed example aspects may be similarly combined and recombined. Further, some example aspects, individually or collectively, may form components of a larger system where other processes may take precedence or modify their application. Moreover, certain steps may be required before, after, or concurrently with the example aspects disclosed herein. It should be noted that any and all methods and processes disclosed herein can be performed in whole or in part by one or more entities or actors in any manner.

[0168] Although terms like "first," "second," etc., are used to describe various elements, components, regions, layers, and sections, these terms should not necessarily be interpreted as limiting. They are used solely to distinguish one element, component, region, layer, or section from another. For example, a "first" element discussed here could be referred to as a "second" element without departing from the teachings of the present disclosure.

[0169] The terminology used here is intended to describe specific example aspects and should not be considered as limiting the disclosure. The singular forms "a," "an," and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. The terms "comprises," "includes," "comprising," and "including," as used herein, indicate the presence of stated features, steps, elements, or components, but do not exclude the presence or addition of other features, steps, elements, or components.

[0170] As used herein, the term "or" is intended to be inclusive, meaning that "X employs A or B" would be satisfied by X employing A, B, or both A and B. Unless specified otherwise or clearly understood from the context, this inclusive meaning applies to the term "or."

[0171] Unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by one of ordinary skill in the relevant art. Terms should be interpreted consistently with their common usage in the context of the relevant art and should not be construed in an idealized or overly formal sense unless expressly defined here.The terms "about" and "substantially," as used herein, refer to a variation of plus or minus 10% from the nominal value. This variation is always included in any given measure.

[0172] In cases where other disclosures are incorporated by reference and there is a conflict with the present disclosure, the present disclosure takes precedence to the extent of the conflict, or to provide a broader disclosure or definition of terms. If two disclosures conflict, the later-dated disclosure will take precedence.

[0173] The use of examples or exemplary language (such as "for example") is intended to illustrate aspects of the invention and should not be seen as limiting the scope unless otherwise claimed. No language in the specification should be interpreted as implying that any non-claimed element is essential to the practice of the invention. While many alterations and modifications of the present invention will likely become apparent to those skilled in the art after reading this description, the specific aspects shown and described by way of illustration are not intended to be limiting in any way.

[0174] A number of implementations have been described. Nevertheless, it will be understood that various modifications may be made without departing from the scope of the disclosure. Accordingly, other implementations are within the scope of the following claims.

Claims

WE CLAIMS1. An optical system (110) comprising:a front lens unit (112) comprising one or more lenses (112a, 112b, 112c), wherein at least one lens of the one or more lenses (112a, 112b, 112c) is configured to move along a radial direction;a middle lens unit (114) comprising one or more lenses (114a, 114b, 114c), wherein at least one lens of the one or more lenses (114a, 114b, 114c) is configured to move along one of, the radial direction, an axial direction, or a combination thereof; anda rear lens unit (116) comprising one or more lenses (116a, 116b, 116c), wherein at least one lens of the one or more lenses (116a, 116b, 116c) is configured to move along the axial direction.

2. The optical system (110) as claimed in claim 1, wherein a lens adjustment assembly (106) is coupled to the optical system (110), the lens adjustment assembly (106) comprising:at least one lens holding ring (118) configured to secure the at least one lens of one of, the one or more lenses (112a, 112b, 112c) of the front lens unit (112), the one or more lenses (114a, 114b, 114c) of the middle lens unit (114), or the one or more lenses (116a, 116b, 116c) of the rear lens unit (116);one or more grub screws (120a, 120b, 120c, 120d) disposed on the at least one lens holding ring (118) and configured to adjust a radial position of the at least one lens of one of, the one or more lenses (112a, 112b, 112c) of the front lens unit (112) or the one or more lenses (114a, 114b, 114c) of the middle lens unit (114);at least one inner ring (122) coupled to the at least one lens holding ring (118); one or more constrainers (126a, 126b) disposed on the at least one inner ring (122) and configured to constrain radial movement of the at least one lens holding ring (118) while permitting axial movement of the at least one lens holding ring (H8);at least one outer ring (124) threadedly coupled to the at least one inner ring (122); andone or more rotators (128a, 128b) disposed on the at least one outer ring (124) and configured to rotate the outer ring (124) to cause axial movement of the inner ring (122) through force transfer along the axial direction by threads between the outer ring (124) and the inner ring (122) to adjust an axial position of the at least one lens of one of, the one or more lenses (114a, 114b, 114c) of the middle lens unit (114) or the one or more lenses (116a, 116b, 116c) of the rear lens unit (116).

3. The optical system (110) as claimed in claim 1, wherein one or more lenses (112a, 112b, 112c) of the front lens unit (112), the one or more lenses (114a, 114b, 114c) of the middle lens unit (114), and the one or more lenses (116a, 116b, 116c) of the rear lens unit (116) are arranged along an optical axis such that the optical system (110) has a focal length range between 65-75 mm.

4. The optical system (110) as claimed in claim 1, wherein:a modulation transfer function of the optical system (110) ranges between 65%-70% on-axis and 50%-55% off-axis, at a spatial frequency of 157 cycles / mm;a field of view of the optical system (110) ranges between 25-30 degrees; and a track length of the optical system (110) ranges between 130-145 mm.

5. The optical system (110) as claimed in claim 1, wherein the optical system (110) is configured to provide diffraction-limited performance across a field of view with a spot diameter at 80% encircled energy of 2.4-3.2 pm on-axis and 3.2-4.2 pm off-axis.

6. The optical system (110) as claimed in claim 1, wherein the optical system (110) is disposed in a housing (100), wherein:the radial direction movement of one of, the at least one lens of the one or more lenses (112a, 112b, 112c) of the front lens unit (112) or the at least one lens of the one or more lenses (114a, 114b, 114c) of the middle lens unit (114),compensates the effect of tilt and decenter with respect to the housing (100) of one of, the one or more lenses (112a, 112b, 112c) of the front lens unit (112), the one or more lenses (114a, 114b, 114c) of the middle lens unit (114), the one or more lenses (116a, 116b, 116c) of the rear lens unit (116), or a combination thereof; andthe axial direction movement of one of, the at least one lens of the one or more lenses (114a, 114b, 114c) of the middle lens unit (114), the at least one lens of the one or more lenses (116a, 116b, 116c) of the rear lens unit (116), or a combination thereof, provides athermalization of the optical system (110) within a temperature range of -40°C to +60°C.

7. The optical system (110) as claimed in claim 6, wherein the housing (100) comprises:a baffle (102) configured to reduce stray light from entering the optical system (no);a barrel (104) that is configured to enclose the optical system (110); and the lens adjustment assembly (106).

8. The optical system (110) as claimed in claim 1, wherein the housing (100) further comprises at least one protection window (108) disposed in front of the optical system (110) and configured to provide radiation resistance.

9. A method (200) of operating an optical system (110), the method (200) comprising:moving at least one lens of one or more lenses (112a, 112b, 112c) of a front lens unit (112) along a radial direction;moving at least one lens of one or more lenses (114a, 114b, 114c) of a middle lens unit (114) along one of, the radial direction, an axial direction, or a combination thereof; andmoving at least one lens of one or more lenses (116a, 116b, 116c) of a rear lens unit (116) along the axial direction.

10. The method (200) as claimed in claim 7, wherein the method (200) further comprising:securing, by way of at least one lens holding ring (118) of a lens adjustment assembly (106) coupled to the optical system (110), the at least one lens of one of, the one or more lenses (112a, 112b, 112c) of the front lens unit (112), the one or more lenses (114a, 114b, 114c) of the middle lens unit (114), or the one or more lenses (116a, 116b, 116c) of the rear lens unit (116);adjusting, by way of one or more grub screws (120a, 120b, 120c, 120d) disposed on the at least one lens holding ring (118), a radial position of the at least one lens of one of, the one or more lenses (112a, 112b, 112c) of the front lens unit (112) or the one or more lenses (114a, 114b, 114c) of the middle lens unit (114);constraining, by way of one or more constrainers (126a, 126b) disposed on at least one inner ring (122) coupled to the at least one lens holding ring (118), radial movement of the at least one lens holding ring (118), wherein the one or more constrainers (126a, 126b) is configured to permit axial movement of the at least one lens holding ring (118); androtating, by way of one or more rotators (128a, 128b) disposed on at least one outer ring (124) threadedly coupled to the at least one inner ring (122), the outer ring (124) to cause axial movement of the inner ring (122) through force transfer along the axial direction by threads between the outer ring (124) and the inner ring (122) to adjust an axial position of the at least one lens of one of, the one or more lenses (114a, 114b, 114c) of the middle lens unit (114) or the one or more lenses (116a, 116b, 116c) of the rear lens unit (116).

Images