Optical navigation system for spacecraft

Abstract

Systems and methods related to an optical navigation system for spacecraft are disclosed herein. The optical navigation system combines several types of sensors together into a compact optical sensor system, maintaining the functionality of each type of sensor. The optical navigation system uses optical sensors, artificial intelligence, auto dimming, and other features to perform navigation functions such as sun sensing, horizon sensing, and star tracking. Artificial intelligence may include deep neural networks that are trained to provide complex machine vision applications. The optical navigation system may be organized into modular slices to increase customizability. Types of slices may include optical slices, network switch slices, vision navigation slices, and inertial navigation system switch slices. Software packages for the navigation system are also customizable, reducing user cost and complexity to be only what is required for a given application.

Description

OPTICAL NAVIGATION SYSTEM FOR SPACECRAFTCROSS REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to U.S. Patent Application No. 18 / 735,146, filed on June 5, 2024, which claims the benefit of U.S. Provisional Patent Application No. 63 / 471,497, filed June 6, 2023, both of which are incorporated by reference herein in their entireties for all purposes.BACKGROUND

[0002] Space exploration promises huge advancements for human knowledge. For example, space exploration provides a unique perspective to study Earth and the solar system, generates innovative technologies, increases understanding of natural phenomena, and enhances our ability to prevent potential threats or disasters. Many tools, such as sun sensors, star trackers, vision navigation processors, navigation cameras, inertial measurement units (IMUs), precision clocks, and global navigation satellite systems, work separately and together to provide valuable data and meaningful functionality for spacecraft navigation and localization. For example, a sun sensor detects the position of the sun, a star tracker measures the positions of stars, and an IMU measures and reports the specific acceleration, angular rate, and orientation of the associated spacecraft. With each additional sensor or tool, a spacecraft has more capabilities, but is also heavier and more expensive. Beyond the cost of the additional physical features themselves, the added weight of each physical feature increases the cost to send the spacecraft into space. More sensors and tools make a spacecraft more functional, but also more expensive.SUMMARY

[0003] This disclosure relates to a navigation system for a spacecraft. Many tools such as optical image sensors, sun sensors, star trackers, vision navigation processors, navigation cameras, inertial measurement units (IMUs), precision clocks, and global navigation satellite systems, may be combined together to create an optical navigation system that is smaller than the sum of its parts, while still maintaining the functionality of each tool. Heavier spacecraft aremore expensive to send into space, thus methods to reduce the weight of a spacecraft (without sacrificing function) are desired.

[0004] By combining several sensors with artificial intelligence, the optical navigation system consolidates the sensors while maintaining the functionality of each. For example, depending on customer needs, the navigation system may provide sun sensing, horizon sensing, star tracking, target centroiding, target tracking, cis-lunar optical navigation, terrain relative navigation, hazard detection, customer-defined machine vision, and general-purpose computing applications with minimal additional hardware. Artificial intelligence may include deep neural networks that are trained, for example, to provide Terrain Relative Navigation (TRN) and Hazard Avoidance (HAZ) navigation data, among other complex machine vision applications. The spacecraft electro-optical navigation systems may be organized into modular slices to increase customizability. Types of slices include optical slices, network switch slices, vision navigation slices, and inertial navigation system switch slices as described herein. Software packages for the navigation system are also customizable, reducing user cost and complexity to be only what is required for a given application. Additionally, the navigational system may be small and light enough to be placed on very small spacecraft, booms, masts, solar arrays, antennas, robotic arms, crew space suits, rovers, air locks, mobile equipment, and science payloads.

[0005] Specific embodiments of the inventions described herein reduce cost, size, mass, power, and interface complexity of a spacecraft compared to conventional spacecraft, while also adding artificial intelligence capabilities and customizability. Compact, general-purpose systems may be upgraded in-flight via uploads of new application software.

[0006] In specific embodiments of the inventions described herein, an optical navigation system for a spacecraft is provided. The optical navigation system comprises: an array of optical image sensors to capture visible light data; and an artificial intelligence machine vision system on a chip communicatively coupled to the array of optical image sensors and storing at least one machine learning model to conduct optical navigation including sun sensing, horizon sensing, relative position, and star tracking using the optical image sensor data. In some examples, 4n steradian coverage is provided by the optical navigation system.

[0007] In specific embodiments of the inventions described herein, an optical navigation system for a spacecraft is provided. The optical navigation system comprises: a stack of modular casings, wherein each casing constitutes a slice of the stack; and an optical head having an integrated array of image sensors and forming a cap of the stack.

[0008] In specific embodiments of the inventions described herein, a method for configuring an optical navigation system for a spacecraft is provided. The method comprises: selecting at least one modular casing from a set of modular casings; placing the at least one modular casing in a stack, where each casing constitutes a slice of the stack; and forming a cap of the stack using an optical head, wherein an image sensor is part of the optical head.BRIEF DESCRIPTION OF THE DRAWINGS

[0009] The accompanying drawings illustrate various embodiments of systems, methods, and embodiments of various other aspects of the disclosure. A person with ordinary skills in the art will appreciate that the illustrated element boundaries (e.g., boxes, groups of boxes, or other shapes) in the figures represent one example of the boundaries. It may be that in some examples one element may be designed as multiple elements or that multiple elements may be designed as one element. In some examples, an element shown as an internal component of one element may be implemented as an external component in another, and vice versa. Furthermore, elements may not be drawn to scale. Non-limiting and non-exhaustive descriptions are described with reference to the following drawings. The components in the figures are not necessarily to scale, emphasis instead being placed upon illustrating principles.

[0010] Figures 1A and IB provide a system in accordance with specific embodiments of the inventions disclosed herein.

[0011] Figure 2 provides a system in accordance with specific embodiments of the inventions disclosed herein.

[0012] Figure 3 provides a block diagram in accordance with specific embodiments of the inventions disclosed herein.

[0013] Figure 4 provides a communications system in accordance with specific embodiments of the inventions disclosed herein.

[0014] Figure 5 provides a flow chart in accordance with specific embodiments of the inventions disclosed herein.DETAILED DESCRIPTION

[0015] Reference will now be made in detail to implementations and embodiments of various aspects and variations of systems and methods described herein. Although several exemplary variations of the systems and methods are described herein, other variations of the systems and methods may include aspects of the systems and methods described herein combined in any suitable manner having combinations of all or some of the aspects described.

[0016] Different systems and methods for optical navigation system for spacecraft in accordance with the summary above are described in detail in this disclosure. The methods and systems disclosed in this section are nonlimiting embodiments of the invention, are provided for explanatory purposes only, and should not be used to constrict the full scope of the invention. It is to be understood that the disclosed embodiments may or may not overlap with each other. Thus, part of one embodiment, or specific embodiments thereof, may or may not fall within the ambit of another, or specific embodiments thereof, and vice versa. Different embodiments from different aspects may be combined or practiced separately. Many different combinations and sub-combinations of the representative embodiments shown within the broad framework of this invention, that may be apparent to those skilled in the art but not explicitly shown or described, should not be construed as precluded.

[0017] Figs. 1A and IB provide system 100 in accordance with specific embodiments of the inventions disclosed herein. Fig. 1A provides a three-quarters view 101 of system 100. Fig. IB provides a top view 102 of system 100. System 100 may be suited for space applications and may be incorporated into a spacecraft. For example, system 100 may serve as a primary flight computer for a spacecraft or a network connected general purpose computer. System 100 includes a stack of slices such as optical slice 103-a (e.g., an upper optical slice) and optical slice 103-b (e.g., a lower optical slice), vision system slice 104-a (e.g., an upper vision system slice) and vision system slice 104-b (e.g., a lower vision system slice), a patch antenna 105, external connections 106, optical sensors 107, and slice connections 108 (e.g., examples of slice connections). Optical slice 103-a can serve as an optical head for the stack in that it forms a topof the stack and covers the slice below it. As illustrated, optical slice 103-a includes an integrated array of image sensors and forming a cap of the stack

[0018] Optical slice 103-a includes optical sensors 107-a and connects to vision system slice 104-a. Optical slice 103-b includes optical sensors 107-b and connects to vision system slice 104-b. Optical slice 103-b may include four optical sensors 107-b, similar to optical slice 103-a, although only two optical sensors 107-b are shown. Both optical slices 103-a and 103-b may be associated with respective patch antennas, although only patch antenna 105, associated with optical slice 103-a, is shown. One or more faces of optical slices 103 may be rounded and optical sensors 107 may be on rounded portions of the faces. For example, the top of optical slice 103-a may have a rounded dome-like portion and optical sensors 107-a may be attached to the dome-like portion. In specific embodiments, optical sensors 107 face outward from system 100 at an angle. Optical slices such as optical slice 103-a and 103-b may also be referred to as optical heads.

[0019] Slice connections 108 may be repeated around system 100, for example at the four corners of optical slices 103 and vision system slices 104. Slice connections 108 may connect the slices together in a stack. The subsystem of optical slice 103-a and vision system slice 104-a is shown with the respective slices connected together via slice connections 108. The slice connections may be screws inserted through threaded holes in the slices. The subsystem of optical slice 103-b and vision system slice 104-b is shown with the respective slices connected together via slice connections 108. Although shown apart, vision system slice 104-a and vision system slice 104-b may be further connected together via slice connections 108.

[0020] System 100 may be able to interface in a variety of ways. Vision system slice 104-a may include external connections 106-a and vision system slice 104-b may include external connections 106-b. External connections 106 may allow system 100 to connect to external hardware or peripheral devices (not shown). For example, external connections 106 may include RS-422 interfaces, USB interfaces, ethernet interfaces (e.g., gigabit ethernet), Wi-Fi access points, etc.

[0021] System 100 may incorporate an optical navigation system that includes a computer vision system for space applications. Optical slice 103-a and optical slice 103-b may, via opticalsensors 107-a and 107-b respectively, each capture 2n steradian coverage of a visual field. Together, optical slice 103-a and optical slice 103-b may capture a 4n steradian coverage. Optical sensors 107 may be evenly spaced on their respective optical slices 103. The optical sensors 107 may capture visible light, infrared light, or both. System 100 may be integrated with a machine vision computing navigation platform. System 100 may replace conventional sun sensors, star trackers, optical navigation cameras, vision navigation processors, inertial measurement units (IMUs), external precision clocks, global navigation satellite system (GNSS), and their associated power, data and thermal control harnessing, in a single compact package. In specific embodiments, the single compact package may be smaller than 1 rack unit (U), and weigh less than 0.8 kilograms (kg).

[0022] Optical sensors 107 may provide 4n steradian full sky coverage and may allow spherical machine vision coverage of all visible objects. In specific embodiments, this coverage may be obtained without spacecraft slews or attitude control mode changes. The 4n steradian coverage may be obtained for any class of mission operations including dynamic events such as in-space rendezvous, proximity operations, robotic manipulation, and planetary landing. Overlapping fields of view may be stitched into seamless Virtual Reality (VR) video and still images, which may be transmitted as compressed or uncompressed data sets for immersive VR experiences by Earth-based users. Sub-framing of the 4n steradian field may allow machine vision algorithms to focus on one or more specific fields of view of interest (e.g. location of the Sun, fields of stars, elements of the spacecraft itself that are within the field of view, resident space objects (RSOs) including satellites and on-orbit debris, the disc, limb, or horizon of a nearby planet, moon, asteroid, comet, etc.). In specific embodiments, multiple units of system 100 (with each system 100 including one or more optical sensors) may allow for higher resolution coverage and / or redundancy via field of view overlap in the 4n steradian field.

[0023] System 100 may incorporate artificial intelligence (Al). System 100 may use an Al- compatible system on a chip (SoC) on a system on a module (SoM). The SoC may be radiation tolerant (e.g., selected for its radiation tolerant characteristics). The Al may be able to use visible light data, infrared light data, or both. The visible light data, infrared light data, or both may be gathered via optical sensors 107. The Al may be a machine vision system on a chip thatis communicatively coupled to the optical sensors 107 and may store at least one machine learning model to conduct optical navigation including, sun sensing, horizon sensing, relative position, and star tracking using the visible light data from optical sensors 107. The Al may include a star tracking system, wherein the star tracking system determines a relative positioning of the optical navigation system based on image data from the array of optical image sensors. The star tracking system may determine the relative positioning of system 100 (e.g., the optical navigation system of system 100) without performing spectrum analysis and without locking onto guide stars.

[0024] The Al may include at least one encoding of an ephemeris. The Al may conduct optical navigation relative to large and small planetary objects (stars, planets, dwarf planets, moons, satellites, comets, asteroids, etc.) with known ephemeris. For example, optical navigation may include terrain relative navigation, feature tracking, hazard detection, and simultaneous localization and mapping (SLAM) using visible light data, infrared data, or both. The machine intelligence model may include an encoding of an ephemeris because it has been trained using images of direct or simulated observations of the star field, or other astronomical feature, which is the subject of the ephemeris. The training set may include labeled inputs with the inputs being a view of the astronomical feature and the label being a localized position relative to the astronomical feature from which the view was obtained. The simulated data may be generated from an existing ephemeris or using actual images taken of an astronomical feature while recording the location of the camera at the time the image was captured. As such, the machine intelligence model may encode the ephemeris because it has been trained using the data that is generally applied to the ephemeris and the data that is generally gleaned therefrom in response.

[0025] System 100 may include auto-dimming features, for example a dimming mechanism that reduces a quantity of light entering one or more optical sensors 107. Reducing the quantity of light entering the optical sensors 107 may be based on a quantity of light that reaches the optical sensors 107 satisfying a threshold (e.g., the quantity of light reaches a minimum quantity, for example a quantity of light associated with the sun being in view of the optical sensor 107). System 100 may include a 4n steradian optical field of view, with the sun always inview unless in eclipse or shadow. For some applications, a fixed inertial attitude may result in the sun remaining in the field of view of a sensor for long periods of time (e.g., months or years), with the potential for sensor damage or sun image burn-in. To avoid this, an autodimming function may automatically engage (e.g., when enabled) when the sun is in the field of view. Accordingly, a single optical sensor can be used for either sun tracking or for star tracking and substitute for a specialized shielded optical sensor for sun tracking and an optical sensor used for star tracking which is positioned in such a way that impending light is amplified before being applied to the sensor.

[0026] The auto-dimming feature may be implemented via electronic dimming circuitry, photochromatic lenses, or mechanical filters. For example, auto-dimming features may incorporate an auto iris, a shutter, or a solid-state solution. A solid-state solution may avoid moving parts and may, accordingly, increase reliability. The auto-dimming technology of system 100 may be similar to the auto-dimming used in welding helmets or may use photochromic lenses. For example, optical sensors 107 may include lenses that change tint in response to sunlight. Radiation resistant optical glasses (RROG) may be integrated into the lenses of system 100. The RROG may electronically control the auto-dimming feature of the lenses. In specific embodiments, 85% of sunlight may be blocked when entering a lens due to auto-dimming.

[0027] System 100 may be used for space situational awareness applications. In specific embodiments, system 100 may include built-in high-performance video, still imaging, and image processing capabilities, and bulk on-board data storage. For example, system 100 may be capable of video at 60 frames per second, high resolution full color still images, and on-board H.265 MPEG and JPG compression in hardware.

[0028] System 100 may allow for flight testing of various machine vision functions. For example, system 100 may allow for flight testing of sun sensing (e.g., <0.1° RMS), horizon sensing (e.g., <0.1° RMS), star tracking (e.g., <10 arcsec), target centroiding (e.g., bearing to <0.1° RMS and range to known targets with proportional error of <0.5%), and cis-lunar optical navigation (e.g., position and velocity in cis-lunar space based on centroiding and onboard ephemeris, error a function of integration time of Kalman filter).

[0029] Software for implementing Al machine vision capabilities of system 100 may be tightly integrated and optimized for a multicore advanced reduced instruction set computer machine (ARM) microprocessor, digital signal processor (DSP), and graphics processing unit (GPU). The ability to integrate advanced Al software capabilities are benefits of system 100. The ability to specify and procure space-qualified hardware, and to integrate current and future software capabilities into a turnkey hardware / software solution will result in a cost-effective product that can support the functionality of sun sensors, star trackers, vision navigation processors, and navigation cameras. Accordingly, system 100 may replace sun sensors and star cameras that many spacecraft rely on, at a net size, weight, power and cost (SWAP-C) savings. System 100 may also replace a separate conventional vision navigation computer and / or spacecraft primary flight computer and associated navigation cameras, situational awareness cameras, and even some science cameras.

[0030] System 100 reduces cost, mass, power, and interface complexity, while adding Artificial Intelligence capabilities for vision-based spacecraft and robotic system autonomy. System 100 may be incorporated into both large and small spacecraft. System 100 opens possibilities for small, low-cost systems to perform at high levels and expands functionality, performance, and productivity of spacecraft.

[0031] Fig. 2 provides system 200 in accordance with specific embodiments of the inventions disclosed herein. System 200 may incorporate elements of system 100. System 200 includes a stack 201 of slices. Slices may include optical head 202 (also called an optical slice), network switch slice 203, inertial navigation slice 204, and vision system slice 205. System 200 may include different combinations of the slices. System 200 may include multiple of a type of slice or may omit types of slices. For example, system 200 may include only optical head 202, a vision system slice 205, and an inertial navigation slice 204. In another example, system 200 may include only an optical head 202, a vision system slice 205, and a network switch slice 203. In another example, system 200 may include two optical heads 202, network switch slice 203, inertial navigation slice 204, and vision system slice 205. Each slice may be a modular casing. Optical head 202 may form a cap of the stack 201 and may include an array of optical sensors 207 (e.g., optical image sensors). Optical sensors 207 may be organized into an array or anintegrated array. Stack 201 may include an Al machine vision system on a chip contained in one or more of the slices. The slices (e.g., casings) may include hermetic seals around a center of the stack 201. The slices may communicate with each other (e.g., internally) via connections through the slices within the center of the stack 201 and may communicate with other systems (e.g., externally) via external connections 206 through the casings of the slices. Different types of slices may have different types of external connections 206 and may have different numbers of external connections 206.

[0032] Slices (e.g., optical head 202) in stack 201 of system 200 are easily reconfigured, modular, and replaceable. The organization of system 200 may allow standard and custom optical configurations. Optical head 202 may include any number of (e.g., four) optical sensors 207 (imagers, sensors, read out electronics, and optics) that may be configured with any combination of types of optical sensors 207. For example, optical sensors 207 may be visible range monochrome or color (e.g., Bayer filter), near infrared (NWIR), short wave infrared (SWIR) with integral thermoelectric cooler, long wave infrared (LWIR) (e.g. microbolometer array), time-of-flight (TOF), or neuromorphic sensor. Optical sensors 207 may be standard commercial M12 or C-Mount metal lenses ruggedized for flight, or custom optics tailored to the sensor and application, from fisheye to narrow field of view as appropriate to the imaging and / or machine vision application.

[0033] Many configurations of optical heads 202 are possible. For example, two identical, back- to-back, wide field of view (fisheye) sensors may be incorporated into system 200 for basic 4n steradian coverage. As another example, a standard configuration with four optical sensors 207 (e.g., evenly spaced) per optical head 202 and two optical heads 202 may be incorporated into system 200. This example may lead to the highest practical resolution 4n steradian optical field of view (FOV) coverage. In this case and other cases, system 200 may be mounted (e.g., on a mast or boom) to improve coverage. Optical navigation may be performed based on the image (e.g., 4n steradian image) of optical sensors 207. In specific embodiments, optical navigation may be performed without performing attitude changes or maneuvers to capture information other than information provided by the 4n steradian image.

[0034] System 200 may include dimming mechanisms to reduce a quantity of light reaching optical sensors 207. For example, once a quantity of light entering or reaching an optical lens of the optical sensors 207 satisfies a threshold, auto-dimming features may be enabled. Satisfying the threshold may include the quantity of light reaching a minimum threshold, with the minimum threshold being associated with a quantity of light output by the sun. In other words, auto-dimming features for an optical sensor 207 may be enabled once the sun is in view of optical sensor 207. Auto dimming features may include electronic dimming circuitry, photochromic lenses, mechanical filters, or a combination thereof.

[0035] Vision system slice 205 may include a central processing unit (CPU) (e.g., an 8 core CPU), a GPU, a digital signal processor (DSP), 1000T ethernet interfaces, USB3 interfaces, Wi-Fi interfaces, RS-422 interfaces, 5 - 36V input power with internal conversion / distribution, and a built-in closed loop heater. Vision system slice 205 may also be called an optical processing slice, a visional navigation system slice, or a visual processing slice.

[0036] Stack 201 may include network switch slice 203, which may provide high speed connectivity to other spacecraft systems, subsystems, and components. Network switch slice 203 may include any number (e.g., 12) of ports. Network switch slice 203 may include an integrated communication controller that supports standard managed ethernet, as well as rate- constrained and time-triggered ethernet traffic. The controller may be a radiation hardened application specific integrated circuit (ASIC) on a custom carrier card that includes the physical layer (PHY) magnetic transceivers, which may allow hot mate / demate and physical inflight separations without concern for electrical deadfacing. Network switch slice 203 may allow stack 201 to be a high-speed data hub for vision-based and high-performance computing applications where the primary flight software may be implemented on the system 200. Peripherals, components, subsystems, and other systems may be connected at up to gigabit speed, with very low latency. Network switch slice 203 may include 6 lanes of lOOOTand 6 lanes of 100T. The lanes may be configured as time triggered, rate constrained, or best effort by traffic class. Network switch slice 203 may also include 5 - 36V power switching on ports (e.g., on 6 ports) and a built in closed loop heater.

[0037] Inertial navigation slice 204 may include IMUs (e.g., dual range triple redundant IMUs, micro-electromechanical systems (MEMs)), a chip scale atomic clock (CSAC), a GNSS receiver, 5 - 36V input power with internal conversion, 1000T ethernet interfaces, USB2 interfaces, RS-422 interfaces, and a built-in closed loop heater. Inertial navigation slice 204 may be called an inertial navigation system (INS) switch slice or an INS slice. Slices may be hermetically sealed together. Slices may include a set of hermetic seals around a center of the stack 201. The stack may also include a venting feature that may be built into any slice to allow trapped air to vent into space in a way that maintains a Faraday Cage relative to potential radio frequency emissions or susceptibility.

[0038] System 200 may include additional hardware components that may increase the capabilities and functionality of the system. Some additional hardware components may be connected to system 200 via external connections 206, some additional hardware components may be built into the slices. The hardware components may include a new or evolved system on chip (SoC), system on module (SoM) board (e.g., custom, specified by space-ng), or new or evolved custom carrier board or electronics slice that includes key new chip scale functionality. The custom carrier board may include an internal high integrity IMU, a high precision clock (e.g. chip scale atomic clock (CSAC)), a GNSS receiver and antenna port, and auto-dimming capabilities (e.g., for long duration sun stare). Different SoCs may be used based on other features of the system 200 (e.g., intended capabilities of the system 200). For example, an SoC similar to an SoC targeted for level 3 self-driving cars may be incorporated into system 200. The SoC may include features such as boot image encryption, hardware crypto engine, hardware performance and interface monitors, built in self-tests, data integrity encoding, radiation mitigations using excess software performance, (e.g., sufficient to do memory scrubbing of large storage volumes), and a real time operating system (RTOS) certified for safety-critical and security-critical applications.

[0039] An electronic architecture of the SoC may be included in multiple slices or boards. One of the slices may include a system on a module (SoM) board. Another slice may include a SoM navigation board. The navigation slice may include one or more GNSS, IMU, microcontroller,internal closed-loop heater control, watchdog circuits, power conversion and distribution, over current / voltage protection, and a clock (e.g., CSAC).

[0040] Specific embodiments described herein may be configured to be cost effective and applicable to the majority of space flight systems. In specific embodiments, high end applications and missions requiring exquisite performance may be supplemented with additional external hardware. The external hardware and data paths may be connected to system 200 via wires (e.g., via RS-422, ethernet, and / or USB connections) or via a wireless network. Hardware components and associated capabilities may be added while maintaining low mass, cost and volume of the integrated system.

[0041] In specific embodiments, system 200 includes modular software modules that may be installed as software packages based on the customer's needs, including adding software defined functionality developed long after launch. The software packages may also include ground-based software, such as system application development, machine vision simulation, neural network training, and system testing (calibration testing, functional and performance testing, real-time hardware-in-the-loop testing, and faster than real time Monte Carlo style testing).

[0042] Software packages may be configured to different user's needs. Some users may only require attitude quaternions from sun sensing and star tracking. Other users might require horizon sensing. Others may require target tracking, marker recognition, QR code scanning, or terrain relative navigation and hazard identification for lunar landing. The modular software packages may work with the modular slices to customize system 200 for the user, reducing user cost by providing only the functionality needed by each customer.

[0043] Integrated, Al (e.g., Al-capable) vision systems within system 200 may replace conventional attitude knowledge hardware (sun sensors, star trackers, horizon sensors, situational awareness cameras) at lower size, weight, power, cost, and integration and operational complexity. The Al vision systems may be incorporated into a system on a chip, may be contained in one or more slices of stack 201, and may include at least one machine learning model. The Al vision systems may include a star tracking system that determines a relative orientation of the optical navigation system of system 200 based on image data from an arrayof optical sensors 207 (e.g., optical image sensors). The star tracking system may determine the relative orientation of the optical navigation system without performing spectrum analysis or locking onto guide stars. The Al vision systems, such as a machine learning model, may include an encoding of at least one ephemeris, and may conduct optical navigation relative to large and small planetary objects with known ephemeris, including terrain relative navigation, feature tracking, hazard detection, and simultaneous localization and mapping (SLAM) using the visible light data from the optical sensors 207.

[0044] Fig. 3 provides a block diagram of a system 300 in accordance with specific embodiments of the inventions disclosed herein. System 300 may incorporate aspects of system 100, system 200, or a combination thereof. System 300 may include image sensors and read out integrated circuits (ROICs). System 300 may use widely adopted interface standards and may allow a wide selection of sensors and sensor types. The sensors may have capabilities including color (e.g., via Bayer filter or similar), monochrome (e.g., black and white), short wave infrared (SWIR), rolling shutter, global shutter, time of flight (ToF), neuromorphic (e.g., active readout), video and still imaging, and resolutions up to very high resolution (e.g., >30 MPixel) per sensor.

[0045] System 300 may use an Al machine vision system on a chip (SoC) on a system on a module (SoM) (e.g., a space-ng-specified SoM). The SoC may be radiation tolerant (e.g., selected for its radiation tolerant characteristics). The SoC may include at least one multicore CPU, programmable digital signal processor (DSP), programmable neural net processing (NNP) engine, programmable graphics processing unit (GPU) engine, video compression engine (e.g., H.265 video compression engine), and peripheral component interconnect express (PCIe) bus. The SoC may also include support for high speed wired (e.g., GigE) and wireless (e.g., 802. Had Wi-Fi) network interfaces and support for utility serial interfaces including serial peripheral interface (SPI), inter-integrated circuit (I2C), and RS-422. System 300 may include physical layer (PHY) implementation of wired and wireless external data interfaces including transceivers for gigabit ethernet, Wi-Fi, USB, and RS-422.

[0046] The SoM of system 300 may provide direct support for space-flight-specific functionality. For example, system 300 may include hardware-controlled, software-settable,distributed, internal closed-loop heater circuits controlled by an internal closed-loop heater control. The closed-loop heater circuits may protect temperature sensitive (e.g., cold sensitive) components at the board level. The closed-loop heater circuits may be an array of small heaters installed directly on the circuit cards and may be adjacent to low temperature-sensitive electronic components including the image sensors.

[0047] Watchdog circuitry (e.g., watchdog circuits) may be implemented in system 300 (e.g., on the SoM) in addition to fault protection functionality on the SoC. Watchdog circuitry may monitor, reset, and power cycle the SoC as well as the field programmable gate arrays (FPGAs) and micro controllers on the SoM.

[0048] System 300 may include power conversion, distribution, and control circuitry. Power conversion, distribution, and control circuity may convert spacecraft power (e.g., 5±, 12±, or 28±V DC nominal) to secondary voltages. The SoC and other components may use the secondary voltages. Power conversion, distribution, and control circuity may switch power of individual internal elements of system 300 including the SoC, FPGAs, microcontrollers, and WiFi radio.

[0049] System 300 may incorporate a sleep mode. In the sleep mode, functions (e.g., all functions except closed-loop heater functions) may be turned off via an external command. The functions may be turned back on via another command (e.g., RS-422 command or via power cycling the system 300).

[0050] The mobile industry processor interface (Ml PI) camera high speed interfaces may support rolling shutter, global shutter, short wave infrared (SWIR), time of flight (ToF), or neuromorphic sensors as an option, enabling other classes of imaging and machine vision applications. MIPI to Gigabit Multimedia Serial Link (GMSL) converters may provide extended cable length for remotely mounted imagers (e.g., sensor arrays, ROICs, and optics). System 300 may provide full sky, 4n steradian coverage. In other words, imaging and machine vision functions may be performed without spacecraft maneuvers.

[0051] In specific embodiments, system 300 may be N+l scalable at the unit level. In other words, additional cooperative, network-connected units of system 300 may incrementally provide redundancy, increase fault tolerance, higher resolution imaging, higher accuracynavigation estimates, greater computing, greater data processing, greater data storage resources, and overlapping coverage from different perspectives, among other benefits. In specific embodiments, multiple units of system 300 (with each system 300 including multiple optical sensors or cameras) may allow for higher resolution coverage and / or redundancy via field of view overlap in the 4n steradian field.

[0052] In specific embodiments, two or more systems 300 may be able to logically connect. The logically connected systems 300 may share data and compute resources. For example, the systems 300 may share data and compute resources via gigabit ethernet. The gigabit ethernet may be connected through an external network switch, and from a data perspective, may only be limited by the number of available network switch ports. As another example, the systems 300 may share data and compute resources with each other via Wi-Fi. The Wi-Fi may be connected through antennas or through coaxial cables to external, passive attenuator units (e.g., radio frequency attenuator units) or coupler units. The Wi-Fi connection may be limited by the number of physical coaxial cable connections available. The Wi-Fi system on system 300 may be configured either as a client, or as an access point serving other Wi-Fi clients that may include other systems 300, or any other Wi-Fi compatible device. The systems may include network slices in order to facilitate the logical connection between two or more of these systems.

[0053] System 300 may perform machine vision tasks, as well as conventional video and still imaging tasks, as individual units or as part of a "hive mind." Hive mind functionality includes shared data, compute, and storage resources, allowing a range of configurations and behaviors. For example, full sky 4n steradian coverage may be higher and higher resolution as more systems 300 communicate with each other and the individual fields of view become proportionately narrower. Individual optical sensors (e.g., imagers) or an individual system 300 of the hive mind may be tasked with specific navigation, machine vision, or surveillance tasks (such as faint or distant object tracking). Multiple systems 300 may achieve higher levels of fault tolerance than an individual system 300. For example, redundant or overlapping machine vision or imaging coverage, block redundant hardware units, N+l redundant hardware units,and functional redundancy with other spacecraft computing, imaging, or data storage subsystems may increase fault tolerance.

[0054] In specific embodiments, system 300 may include one or more built-in chip-scale tactical grade IMUs, internal high accuracy clocks (e.g., CSAC), and GNSS receivers as navigation aids. These features may displace other avionics boxes or circuit cards, and result in further reduction in spacecraft navigation hardware and interface requirements at low incremental size, weight, power, and cost.

[0055] System 300 may include additional features not shown in Fig. 3. For example, system 300 may include one or more USB 3.0 interfaces for interfacing with external devices (microphones, speakers, displays, cameras, solid state memory drives, media converters, coprocessors, controllers, etc.) or as another spacecraft command and data interface. System 300 may include one or more power out interfaces for low power accessories such as LED lights, motor drives, actuator signals, or other external devices. System 300 may include four or more cameras, the number of cameras corresponding to SoC capabilities.

[0056] System 300 may include IMUs, for example high integrity IMUs, triple-redundant IMUs, and / or self-checking IMUs. An IMU associated with system 300 may include three axes of gyroscopes and three axes of accelerometers. The gyroscopes may have performance consistent with tactical level requirements or better (e.g., a range of 400 + / 1 deg / sec minimum, in-run bias stability of 1.5 deg / hr maximum, scale factor accuracy of 0.02% maximum, bandwidth of 50 Hz minimum, bias over temperature of 0.3 de / sec maximum, and angular random walk of 0.2 degree / Vhr maximum). An accelerometer associated with system 300 may have performance consistent with tactical level requirements or better (a range of 8 g minimum and a bandwidth of 50 Hz minimum). A high integrity IMU may be an IMU which will, with high confidence, never transfer erroneous information, and if failed, will fail silent. This may be achieved by using multiple MEMS chip scale IMUs in parallel, with aliveness checks, best value selection logic, filtering, integrity checks, sanity limits, voting, and error correction coding embedded in radiation tolerant firmware. Since the optical portion of system 300 may provide high accuracy attitude quaternions and angular rates at 10 Hz or greater, the IMU may not require exquisite performance over long durations. However, the IMU may cover transientmission events and potential safe mode entries where optical navigation is compromised or impractical. Selection and integration of the high integrity IMU for system 300 may involve trade studies that consider individual MEMS IMU size, weight, power, and cost (SWAP-C); MEMS IMU radiation characterization and screening; circuit design and embedded firmware design for high integrity output; internal electrical interfaces, electromagnetic compatibility (EMC), electromagnetic interference (EMI), grounding; thermal interfaces and internal control, mechanical packaging and chassis integration; and individual MEMS IMU performance. Individual MEMS IMU performance may include range (and ability to change the range in flight), resolution, bandwidth and sample output rate, noise, noise density, random walk, bias, bias stability, repeatability, temperature sensitivity, scale factor, scale factor error, nonlinearity, orthogonality and cross-axis sensitivity, and g and g2 sensitivity. The IMUs may be on a dedicated inertial navigation slice or integrated into any other slice.

[0057] System 300 may include a clock (e.g., a high accuracy clock or chip scale atomic clock). The clock may be tailored to customer needs (e.g., have a power consumption of less than 120 mW, output of 10 MHz, synchronization of 1PPS output and 1PPS input, short term stability (Allan deviation) of 3.0 x 1010at T = 1 sec). A high precision onboard clock may be used to supplement optical navigation when used in combination with radio navigation techniques and / or high accuracy onboard ephemeris. The clock may be, for example, a chip scale ultra stable oscillators (USO) and / or a space rated CSAC. System 300 may discipline onboard clocks and timers to a high-quality absolute time source for extended periods of time, even when communication with Earth ground stations is impossible, impractical, or denied. Disciplining onboard clocks and timers provides users with important measurement references for a variety of tactical and scientific applications. The clock of system 300 may be a user-friendly high precision onboard clock. System 300 may use a backup battery to ensure the clock continues to run even if the system 300 is otherwise temporarily unpowered or power cycled. The backup battery may be coin cell sized. The clock can be on an inertial navigation slice or a GNSS slice.

[0058] System 300 may include a GNSS receiver. The GNSS receiver may be compatible with GPS, QZSS, GALILEO, GLONASS, and BEIDOU satellite systems. A built-in GNSS navigation capability and GNSS-provided precision time may be particularly useful for low Earth orbit (LEO)applications (e.g., the GNSS receiver may have an acceleration limit of 4 g minimum, altitude of 20,000 km minimum, orbital velocity of 10 km / s minimum, velocity accuracy of 0.05 m / s maximum, and dynamic heading accuracy of 0.3 deg maximum). System 300 may include a space-enabled GNSS solution with some or all commercial performance limits removed. The GNSS system may be suitable for orbital altitudes and velocities, and may be associated with sufficiently low cost, mass, power and volume to integrate into system 300. An antenna port (e.g., a subminiature version A (SMA) antenna port) may be included on a chassis of system 300, such that an external antenna may be provided (e.g., separately provided). The GNSS receiver can be on an inertial navigation slice or a GNSS slice.

[0059] System 300 may include one or more USB interfaces (e.g., USB 3.0), internal M I Pl- com patible machine vision sensors, external machine vision sensors, internal closed-loop heater controls, watchdog circuits, power conversion and distribution, over current / voltage protection, JTAG ports, multi-user multiple-input multiple-output (MU-MIMO), Wi-Fi ports, non-volatile memory (NVM) solid-state drives (SSDs), serial peripheral interface (SPI) ports, RS422 PHY, GigE PHY, 4 - 36V inputs, D-sub connectors, SMA coaxial cables, PCIe backplanes, test blocks, and SoCs. An SoC of system 300 may include one or more CPUs (e.g., 8 core CPUs), image signal processors (ISPs) (e.g., lObit HDR, Rec 2020 color gamut dual 13 MPix imagers at 30fps zero shutter lag), digital signal processors (DSPs) and neural processing engines (NPUs), graphics processing units (GPUs), and random-access memory (RAM).

[0060] System 300 may include auto-dimming features. Auto-dimming may be implemented for long duration sun stare and may be implemented on an individual basis for each imager, optic, lens, or sensor. Auto-dimming features may be able to dim by 85% as a minimum. Autodimming may be implemented via passive (e.g., progressive), solid state, or mechanical means.

[0061] System 300, with an internal IMU, precision clock, GNSS receiver, auto-dimming, and additional SoC performance and interfaces may allow for the replacement of the conventional spaceflight hardware such as sun sensors, star trackers, vision navigation processors, navigation cameras, IMUs precision clocks, and GNSS receivers.

[0062] Fig. 4 provides communications system 400 in accordance with specific embodiments of the inventions disclosed herein. Communications system 400 includes spacecraft 401 in spaceand an antenna system 402 on Earth 403. Spacecraft 401 operates using a system 405, which may incorporate aspects of system 100, system 200, system 300, or a combination thereof. Antenna system 402 transmits communication 404 to spacecraft 401. Communication 404 may be a software update which is received, for example, by an antenna of system 401. The software update may update a functionality of the optical navigation system. For example, the software update may update a functionality of an Al machine vision on a chip system of spacecraft 401. System 405 may include on board navigation, guidance, control, and supervision flight software products, as well as related ground system simulation and test software remotely operated on Earth 403. System 405 may additionally include 3rdparty openarchitecture or open-source applications.

[0063] System 405 of spacecraft 401 may include network circuitry (e.g., via ethernet or WiFi ) which may receive updates, for example via communication 404. System 405 may be securely updated in flight (e.g., in space, in the atmosphere), via secure communication 404, with advanced, software defined, machine vision and high-performance processing capabilities that enhance and expand mission capabilities. System 405 may be a software-defined system that is updated in flight with machine vision software modules including sun sensing, horizon sensing, star tracking, target centroiding (e.g., bearing and range), target tracking relative navigation (e.g., rendezvous and proximity operations), cis-lunar optical navigation (e.g., Earth or Moon centered inertial position and velocity), terrain relative navigation (e.g., precision landing), hazard detection (and avoidance), customer-defined machine vision or general purpose computing applications.

[0064] System 405 may operate for an extended duration of spaceflight beyond geosynchronous orbit (GEO). System 405 may be configured to operate anywhere in the solar system and may provide absolute and relative navigation system using only optical techniques. For example, the sun, horizons, and stars may be used for attitude knowledge. The sun, planets (near and far), moons, and stars may be used to determine position, velocity, and trajectory. System 405 may use illuminated objects for relative navigation, position, and orientation. System 405 may use illuminated surfaces for terrain relative navigation and hazard detection.

[0065] Software applications that may be incorporated into system 405 include surface relative localization (e.g., terrain relative navigation); hazard detection and avoidance; panoramic imaging of a landing site; digital terrain model (DTM) of the landing site; flight video and still image acquisition, compression, and data / image storage and management.

[0066] System 405 may be upgraded in-flight with new functionality, algorithms, cooperative behaviors, or increased performance. The deep neural network system may be trained in-flight using in-flight data. System 405 may create a map (e.g., map generator) of the environment while tracking the position of the flight system, for example by using simultaneous localization and mapping (SLAM).

[0067] System 405 may consolidate spacecraft optical navigation, video and imaging functionality, and may replace a conventional electro-optical hardware made up of sun sensors, star trackers, vision navigation processors, and navigation cameras.

[0068] Fig. 5 provides a flow chart 500 in accordance with specific embodiments of the inventions disclosed herein. At 501, at least one modular casing from a set of modular casings may be selected. The set of modular casings may include an optical processing slice, a networking slice, and an inertial navigation slice. The at least one selected modular casing may be an optical processing slice. The optical processing slice may be similar to the vision system slice 205.

[0069] At 502, the at least one modular casing from 501 may be placed in a stack, where each casing constitutes a slice of the stack. The stack may constitute any number of optical processing slices, networking slices, and inertial navigation slices. The at least one modular casing may be placed anywhere in the stack. The at least one modular casing may be the first, second, etc. slice in the stack or may be the only slice in the stack. The casings in the stack of modular casings may form a set of hermetic seals around a center of the stack. The slices of the stack may communicate internally via connections through the slices within the center of the stack and externally via connections through the casings.

[0070] At 503, a cap of the stack may be formed using an optical head, where an image sensor is part of the optical head. The optical head may be similar to optical slice 103 or optical head 202. The image sensor may be similar to optical sensor 107 or optical sensor 207. The opticalhead may include one image sensor or multiple image sensors and each image sensor of the multiple image sensors may be evenly spaced.

[0071] A system implementing the flow chart 500 may be based on commercially available and space-flight-compatible electronics components, with a custom mechanical, optical, imaging, operating system, and software configuration. Hardware components may be added to the system based on the performance of the most cost effective, space-compatible components available at the time of component selection. The system may offer tightly integrated hardware capabilities, thereby adding functionality and performance that represents the "best value" to a majority of potential customers. For example, the commercial electronics components may be tested, up-screened, and ruggedized for spaceflight. Incorporated hardware may be mature, have flight heritage, require little to no development, be easy to integrate, be easy to test, have low SWAP-C, and have performance that satisfies a majority of potential commercial, civil space, and defense customers. The core electronics system may be capable of hosting machine vision software, interfacing with two, three, four or more high resolution imagers, and capable of complying with traditional and emerging spaceflight power and data interfaces. Core imaging and computing electronics in a compact space-compatible form factor allow the integration of Al using deep neural networks trained to provide terrain relative navigation (TRN) and hazard avoidance (HAZ) navigation data (e.g., for an autonomous planetary lander).

[0072] Specific embodiments described herein may result in dramatic reduction in overall size, weight, power, cost and interface complexity for equivalent or greater functionality and performance compared to conventional methods and systems. The compact, general purpose vision system described herein in specific embodiments may be fundamentally upgraded in flight via uploads of new application software with entirely new functionality (e.g. threat detection for space situational awareness, cooperative navigation for rendezvous and proximity operations, autonomy for robotic manipulators, etc.). Specific embodiments described herein may incorporate high performance Al-based flight software for complex machine vision applications. Specific embodiments described herein may incorporate highly integrated and streamlined ground-based analysis, training, simulation, test, and verification software that provides a complete, end-to-end development and validation environment for flight systems.

[0073] While the specification has been described in detail with respect to specific embodiments of the invention, it will be appreciated that those skilled in the art, upon attaining an understanding of the foregoing, may readily conceive of alterations to, variations of, and equivalents to these embodiments. Any of the method steps discussed above can be conducted by a processor operating with a computer-readable non-transitory medium storing instructions for those method steps. The computer-readable medium may be memory within a personal user device or a network accessible memory. Although examples in the disclosure were generally directed to spacecraft, the same approaches could be utilized for other applications using a variety of sensors. These and other modifications and variations to the present invention may be practiced by those skilled in the art, without departing from the scope of the present invention, which is more particularly set forth in the appended claims.

Claims

WHAT IS CLAIMED IS:

1. An optical navigation system (100) for a spacecraft (401), comprising: an array of optical image sensors (207) to capture visible light data; and an artificial intelligence machine vision system (300) on a chip communicatively coupled to the array of optical image sensors (207) and storing at least one machine learning model to conduct optical navigation including sun sensing, horizon sensing, and star tracking using the visible light data.

2. The optical navigation system (100) of claim 1, further comprising: a dimming mechanism that reduces a quantity of light entering an optical image sensor (207) of the array of optical image sensors (207) based at least in part on a threshold quantity of light reaching the optical image sensor (207).

3. The optical navigation system (100) of claim 2, wherein: the dimming mechanism is electronic dimming circuitry.

4. The optical navigation system (100) of claim 2, wherein the artificial intelligence machine vision system (300) on a chip comprises: a sun tracking system, wherein the sun tracking system determines a relative positioning of the optical navigation system (100) based on image data from the array of optical image sensors (207).

5. The optical navigation system (100) of claim 4, comprising: a stack (201) of hermetically sealed slices; wherein the artificial intelligence machine vision system (300) is on a first slice of a stack (201), and the array of optical image sensors (207) is on a second slice of the stack (201).

6. The optical navigation system (100) of claim 1, wherein the artificial intelligence machine vision system (300) on a chip comprises: a star tracking system, wherein the star tracking system determines a relative orientation of the optical navigation system (100) based on image data from the array of optical image sensors (207).

7. The optical navigation system (100) of claim 6, wherein: the star tracking system determines the relative orientation of the optical navigation system (100) without performing spectrum analysis.

8. The optical navigation system (100) of claim 6, wherein: the star tracking system determines the relative orientation of the optical navigation system (100) without locking onto guide stars.

9. The optical navigation system (100) of claim 1, wherein the at least one machine learning model comprises: an encoding of an ephemeris.

10. The optical navigation system (100) of claim 9, wherein the at least one machine learning model conducts optical navigation relative to large and small planetary objects with known ephemeris, including terrain relative navigation, feature tracking, hazard detection, and simultaneous localization and mapping (SLAM) using the visible light data.

11. The optical navigation system (100) of claim 1, further comprising: a stack (201) of modular casings, wherein each casing constitutes a slice of the stack (201); and an optical head (202) forming a cap of the stack (201), wherein the array of optical image sensors (207) is part of the optical head (202);wherein the artificial intelligence machine vision system (300) on a chip is contained in one of the slices of the stack (201).

12. The optical navigation system (100) of claim 1, further comprising: two or more optical heads (202) positioned to obtain a 4n steradian image from the spacecraft (401); wherein the array of optical image sensors (207) is part of one of the two or more optical heads (202).

13. The optical navigation system (100) of claim 12, wherein: the optical navigation system (100) conducts optical navigation based on the 4n steradian image.

14. The optical navigation system (100) of claim 13, wherein: the optical navigation system (100) conducts optical navigation without performing attitude changes or maneuvers to capture information other than information provided by the 4n steradian image.

15. The optical navigation system (100) of claim 1, further comprising: a closed-loop heater associated with temperature-sensitive components of the optical navigation system (100).

16. The optical navigation system (100) of claim 1, further comprising: network circuitry; wherein the optical navigation system (100) receives WiFi or ethernet network updates to a functionality of the artificial intelligence machine vision system (300) on a chip using the network circuitry.

17. An optical navigation system (100) for a spacecraft (401), comprising:a stack (201) of modular casings, wherein each casing constitutes a slice of the stack(201); and an optical head (202) having an integrated array of image sensors and forming a cap of the stack (201).

18. The optical navigation system (100) for the spacecraft (401) of claim 17, wherein: the slices of the stack (201) include an optical processing slice and at least one of: a networking slice, and an inertial navigation slice (204).

19. The optical navigation system (100) of claim 17, further comprising: at least one first optical image sensor (207) positioned to obtain a first 2n steradian image from the spacecraft (401); wherein the at least one first optical image sensor (207) is part of the optical head(202).

20. The optical navigation system (100) of claim 19, further comprising:At least one second optical image sensor (207) positioned to obtain a second 2n steradian image from the spacecraft (401); wherein combining the first 2n steradian image and the second 2n steradian image creates a 4n steradian image from the spacecraft (401).

21. The optical navigation system (100) of claim 17, wherein: the casings in the stack (201) of modular casings form a set of hermetic seals around a center of the stack (201); and the slices of the stack (201) communicate internally via connections through the slices within the center of the stack (201) and externally via external connections (206) through the casings.

22. The optical navigation system (100) of claim 17, the integrated array of image sensors comprising: four image sensors evenly spaced on the optical head (202).

23. The optical navigation system (100) of claim 17, further comprising: a dimming mechanism that reduces a quantity of light entering an image sensor of the integrated array of image sensors based at least in part on a threshold quantity of light reaching the image sensor.

24. The optical navigation system (100) of claim 17, further comprising: an artificial intelligence system, comprising: a star tracking system, wherein the star tracking system determines a relative orientation of the spacecraft (401) based on image data from the integrated array of image sensors and without performing spectrum analysis and without locking onto guide stars.

25. The optical navigation system (100) of claim 24, wherein the artificial intelligence system further comprises: at least one machine learning model, the at least one machine learning model including an encoding of an ephemeris.

26. The optical navigation system (100) of claim 25, wherein the at least one machine learning model conducts optical navigation relative to large and small planetary objects with known ephemeris, including terrain relative navigation, feature tracking, hazard detection, and simultaneous localization and mapping (SLAM) using visible light data.

27. The optical navigation system (100) of claim 17, further comprising: a closed-loop heater associated with temperature-sensitive components of the optical navigation system (100).

28. The optical navigation system (100) of claim 17, further comprising: a network interface, wherein the network interface is a WiFi or ethernet interface and receives network updates to a functionality of the optical navigation system (100).

29. A method (500) for configuring an optical navigation system (100) for a spacecraft (401), comprising: selecting (501) at least one modular casing from a set of modular casings; placing (502) the at least one modular casing in a stack (201), where each casing constitutes a slice of the stack (201); and forming (503) a cap of the stack (201) using an optical head (202), wherein an image sensor is part of the optical head (202).

30. The optical navigation system (100) for the spacecraft (401) of claim 29, wherein: the at least one modular casing includes an optical processing slice; and the set of modular casings includes: a networking slice and an inertial navigation slice (204).

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