Pose and Shape Reconstruction of a Noncooperative Spacecraft Using Camera and Range Measurements

Recent interest in on-orbit proximity operations has pushed towards the development of autonomous GNC strategies. In this sense, optical navigation enables a wide variety of possibilities as it can provide information not only about the kinematic state but also about the shape of the observed object. Various mission architectures have been either tested in space or studied on Earth. The present study deals with on-orbit relative pose and shape estimation with the use of a monocular camera and a distance sensor. The goal is to develop a filter which estimates an observed satellite's relative position, velocity, attitude, and angular velocity, along with its shape, with the measurements obtained by a camera and a distance sensor mounted on board a chaser which is on a relative trajectory around the target. The filter's efficiency is proved with a simulation on a virtual target object. The results of the simulation, even though relevant to a simplified scenario, show that the estimation process is successful and can be considered a promising strategy for a correct and safe docking maneuver

NASA Automated Rendezvous and Capture Review. Executive summary

In support of the Cargo Transfer Vehicle (CTV) Definition Studies in FY-92, the Advanced Program Development division of the Office of Space Flight at NASA Headquarters conducted an evaluation and review of the United States capabilities and state-of-the-art in Automated Rendezvous and Capture (AR&C). This review was held in Williamsburg, Virginia on 19-21 Nov. 1991 and included over 120 attendees from U.S. government organizations, industries, and universities. One hundred abstracts were submitted to the organizing committee for consideration. Forty-two were selected for presentation. The review was structured to include five technical sessions. Forty-two papers addressed topics in the five categories below: (1) hardware systems and components; (2) software systems; (3) integrated systems; (4) operations; and (5) supporting infrastructure

Guidance, Navigation and Control for UAV Close Formation Flight and Airborne Docking

Unmanned aerial vehicle (UAV) capability is currently limited by the amount of energy that can be stored onboard or the small amount that can be gathered from the environment. This has historically lead to large, expensive vehicles with considerable fuel capacity. Airborne docking, for aerial refueling, is a viable solution that has been proven through decades of implementation with manned aircraft, but had not been successfully tested or demonstrated with UAVs. The prohibitive challenge is the highly accurate and reliable relative positioning performance that is required to dock with a small target, in the air, amidst external disturbances. GNSS-based navigation systems are well suited for reliable absolute positioning, but fall short for accurate relative positioning. Direct, relative sensor measurements are precise, but can be unreliable in dynamic environments. This work proposes an experimentally verified guidance, navigation and control solution that enables a UAV to autonomously rendezvous and dock with a drogue that is being towed by another autonomous UAV. A nonlinear estimation framework uses precise air-to-air visual observations to correct onboard sensor measurements and produce an accurate relative state estimate. The state of the drogue is estimated using known geometric and inertial characteristics and air-to-air observations. Setpoint augmentation algorithms compensate for leader turn dynamics during formation flight, and drogue physical constraints during docking. Vision-aided close formation flight has been demonstrated over extended periods; as close as 4 m; in wind speeds in excess of 25 km/h; and at altitudes as low as 15 m. Docking flight tests achieved numerous airborne connections over multiple flights, including five successful docking manoeuvres in seven minutes of a single flight. To the best of our knowledge, these are the closest formation flights performed outdoors and the first UAV airborne docking

Guida, navigazione e controllo per il docking autonomo di un Cubesat

Negli ultimi anni è cresciuto sempre più l'interesse verso le manovre di docking autonomo. In ambito aerospaziale esse son importanti e hanno interesse scientifico perché permettono lo sviluppo di strutture più grandi, oppure la rimozione di detriti in orbita. I campi di applicazione sono molteplici, ed ecco che Experimental Rendezvous in Microgravity Environment Study (ERMES) ha tra i principali obiettivi quello di progettare e testare una manovra di docking autonomo tra due CubeSats mock-ups. I due mockup son provvisti di un sistema di Guida, Navigazione e Controllo e delle interfacce di docking meccanico. Durante la manovra, lavorano in una configurazione Target-Chaser, dove il Chaser è la parte attiva e il Target è cooperativo. Inoltre il Chaser è provvisto di un sistema di propulsione basato su cartucce \ce{CO_2} usa e getta, mentre il Target è dotato di tre ruote di reazione. Questa tesi propone una architettura software per implementare un sistema GNC collaborativo basato su Robot Operating System (ROS). Si crede infatti che un sistema basato su ROS possa avantaggiare lo sviluppo dell'esperimento. Infatti, grazie alla disponibilità di librerie Open Source ad esso correlate, è possibile aumentare la complessità dei sistemi di computazione di bordo senza impattare sui tempi di sviluppo. L'implementazione utilizza un sistema di navigazione basato sulla fusione delle informazioni provenienti da due IMU e dal riconoscimento di AprilTag, posti sulla faccia del Target, con l'obiettivo di migliorare la localizzazione e la stima dello stato del sistema. Viene inoltre proposto un test per verificare la corretta integrazione delle componenti, e descritti test futuri per migliorare le prestazioni in certe condizioni.In recent years there has been growing interest in autonomous docking manoeuvres. In aerospace they are important and of scientific interest because they allow the development of larger structures or the removal of debris in orbit. The fields of application are manifold, so Experimental Rendezvous in Microgravity Environment Study (ERMES) has as its main objective the design and test of an autonomous docking manoeuvre between two free-flying CubeSats mock-ups. The two mock-ups involved in the experiment are both equipped with a Guidance Navigation and Control (GNC) system and mechanical docking interfaces. During the manoeuvre, they work in a Target-Chaser configuration, where the Chaser is active and the Target is cooperative. In addition, the Chaser is equipped with a cold gas propulsive system based on expendable CO2 cartridges, while the Target is equipped with three reaction wheels. This thesis proposes a software architecture to implement a collaborative GNC system based on the Robot Operating System (ROS). The implementation proposal uses navigation based on the fusion of information from two IMU and a AprilTag detection system, with the aim of improving state estimation. In fact, it is believed that a ROS-based system can benefit the development of the experiment: thanks to the availability of related Open Source libraries, it is possible to increase the complexity of the on-board computation systems without impacting on the development time. The implementation uses a navigation system based on the fusion of the information coming from two IMUs and from the recognition of AprilTags, placed on the face of the Target, with the aim of improving the localization and the estimation of the system status. A test to verify the correct integration of the components is also proposed, and future tests to improve performance under certain conditions are described

Incorporation of GNSS multipath to improve autonomous rendezvous, docking and proximity operations in space

Automated rendezvous and docking (AR&D;) operations are important for many future space missions, such as the resupply of space stations, repair and refueling of large satellites, and active removal of orbital debris. These operations depend critically on accurate, real-time knowledge of the relative position and velocity between two space vehicles. Unfortunately, Global Navigation Satellite System (GNSS) capabilities remain severely limited in close proximity to large space structures due to significant multipath effects and signal blockage. Although GNSS is used for the initial stages of approach, other instruments such as laser, radar and vision-based systems, are required to augment GNSS during AR&D; over the last few hundred meters. This dissertation evaluates the feasibility of GNSS multipath-based relative space navigation. Methods for separating and interpreting reflected signals are demonstrated using GNSS data collected during Hubble Servicing Mission 4 (HSM4), a model of the mission geometry, electromagnetic (EM) ray tracing, and a custom GNSS software receiver. EM ray tracing is used to show that a number of signals sufficient for ranging are reflected by the Hubble Space Telescope (HST) during HSM4, and the properties of these reflections are used to generate simulated GNSS data. The impact of reflected signals on code correlation shape, code tracking error, and pseudorange measurement is demonstrated using the simulated and experimental data. Relative navigation is demonstrated using simulated reflected signal measurements and the dependence of relative navigation on the reflecting object’s scattering properties is illustrated. From the tracking of data from two oppositely polarized antennas, both simulated and experimental, it is determined that multipath measurements are limited by system properties such as antenna polarization quality and front end bandwidth. Design considerations involved in optimizing a receiver to measure reflected signals are discussed

Infrared based monocular relative navigation for active debris removal

In space, visual based relative navigation systems suffer from the harsh illumination conditions of the target (e.g. eclipse conditions, solar glare, etc.). In current Rendezvous and Docking (RvD) missions, most of these issues are addressed by advanced mission planning techniques (e.g strict manoeuvre timings). However, such planning would not always be feasible for Active Debris Removal (ADR) missions which have more unknowns. Fortunately, thermal infrared technology can operate under any lighting conditions and therefore has the potential to be exploited in the ADR scenario. In this context, this study investigates the benefits and the challenges of infrared based relative navigation. The infrared environment of ADR is very much different to that of terrestrial applications. This study proposes a methodology of modelling this environment in a computationally cost effective way to create a simulation environment in which the navigation solution can be tested. Through an intelligent classification of possible target surface coatings, the study is generalised to simulate the thermal environment of space debris in different orbit profiles. Through modelling various scenarios, the study also discusses the possible challenges of the infrared technology. In laboratory conditions, providing the thermal-vacuum environment of ADR, these theoretical findings were replicated. By use of this novel space debris set-up, the study investigates the behaviour of infrared cues extracted by different techniques and identifies the issue of short-lifespan features in the ADR scenarios. Based on these findings, the study suggests two different relative navigation methods based on the degree of target cooperativeness: partially cooperative targets, and uncooperative targets. Both algorithms provide the navigation solution with respect to an online reconstruction of the target. The method for partially cooperative targets provides a solution for smooth trajectories by exploiting the subsequent image tracks of features extracted from the first frame. The second algorithm is for uncooperative targets and exploits the target motion (e.g. tumbling) by formulating the problem in terms of a static target and a moving map (i.e. target structure) within a filtering framework. The optical flow information is related to the target motion derivatives and the target structure. A novel technique that uses the quality of the infrared cues to improve the algorithm performance is introduced. The problem of short measurement duration due to target tumbling motion is addressed by an innovative smart initialisation procedure. Both navigation solutions were tested in a number of different scenarios by using computer simulations and a specific laboratory set-up with real infrared camera. It is shown that these methods can perform well as the infrared-based navigation solutions using monocular cameras where knowledge relating to the infrared appearance of the target is limited

Dynamics and Control of Satellite Relative Motion in Proximity Operations

In this dissertation, the development of relative navigation, guidance, and control algorithms of an autonomous space rendezvous and docking system are presented. These algorithms are based on innovative formulations of the relative motion equations that are completely explicit in time. The navigation system uses an extended Kalman filter based on these formulations to estimate the relative position and velocity of the chaser vehicle with respect to the target vehicle and the chaser attitude and gyro biases. This filter uses the range and angle measurements of the target relative to the chaser from a simulated LIDAR system, along with the star tracker and gyro measurements of the chaser. The corresponding measurement models, process noise matrix, and other filter parameters are provided. The guidance and control algorithms are based on the glideslope used in the past for rendezvous and proximity operations of the Space Shuttle with other vehicles. These algorithms are used to approach, flyaround, and to depart from a target vehicle in elliptic orbits. The algorithms are general and able to translate the chaser vehicle in any direction, decelerate while approaching the target vehicle, and accelerate when moving away. Numerical nonlinear simulations that illustrate the relative navigation, attitude estimation, guidance, and control algorithm\u27s, as well as performance and accuracy are evaluated in the research study

Guidance and Navigation for Rendezvous and Proximity Operations with a Non-Cooperative Spacecraft at Geosynchronous Orbit

The feasibility and benefits of various spacecraft servicing concepts are currently being assessed, and all require that the servicer spacecraft perform rendezvous, proximity, and capture operations with the target spacecraft to be serviced. Many high-value spacecraft, which would be logical targets for servicing from an economic point of view, are located in geosynchronous orbit, a regime in which autonomous rendezvous and capture operations are not commonplace. Furthermore, existing GEO spacecraft were not designed to be serviced. Most do not have cooperative relative navigation sensors or docking features, and some servicing applications, such as de-orbiting of a non-functional spacecraft, entail rendezvous and capture with a spacecraft that may be non-functional or un-controlled. Several of these challenges have been explored via the design of a notional mission in which a nonfunctional satellite in geosynchronous orbit is captured by a servicer spacecraft and boosted into super-synchronous orbit for safe disposal. A strategy for autonomous rendezvous, proximity operations, and capture is developed, and the Orbit Determination Toolbox (ODTBX) is used to perform a relative navigation simulation to assess the feasibility of performing the rendezvous using a combination of angles-only and range measurements. Additionally, a method for designing efficient orbital rendezvous sequences for multiple target spacecraft is utilized to examine the capabilities of a servicer spacecraft to service multiple targets during the course of a single mission

Pose Performance of LIDAR-Based Relative Navigation for Non-Cooperative Objects

Flash LIDAR is an important new sensing technology for relative navigation; these sensors have shown promising results during rendezvous and docking applications involving a cooperative vehicle. An area of recent interest is the application of this technology for pose estimation with non-cooperative client vehicles, in support of on-orbit satellite servicing activities and asteroid redirect missions. The capability for autonomous rendezvous with non-cooperative satellites will enable refueling and servicing of satellites (particularly those designed without servicing in mind), allowing these vehicles to continue operating rather than being retired. Rendezvous with an asteroid will give further insight to the origin of individual asteroids. This research investigates numerous issues surrounding pose performance using LIDAR. To begin analyzing the characteristics of the data produced by Flash LIDAR, simulated and laboratory testing have been completed. Observations of common asteroid materials were made with a surrogate LIDAR, characterizing the reflectivity of the materials. A custom Iterative Closest Point (ICP) algorithm was created to estimate the relative position and orientation of the LIDAR relative to the observed object. The performance of standardized pose estimation techniques (including ICP) has been examined using non-cooperative data as well as the characteristics of the materials that will potentially be observed during missions. For the hardware tests, a SwissRanger ToF camera was used as a surrogate Flash LIDAR

Spacecraft Rendezvous and Docking Using Electromagnetic Interactions

On-orbit operations such as refuelling, payload updating, inspection, maintenance, material and crew transfer, modular structures assemblies and in general all those processes requiring the participation of two or more collaborative vehicles are acquiring growing importance in the space-related field, since they allow the development of longer-lifetime missions. To successfully accomplish all these on-orbit servicing operations, the ability to approach and mate with another vehicle is fundamental. Rendezvous strategies, proximity procedures and docking manoeuvres between spacecraft are of utmost importance and new, effective, standard and reliable solutions are needed to ensure further technological developments. Presently, the possibility to create low-cost clusters of vehicles able to share their resources may be exploited thanks to the broadening advent of CubeSat-sized spacecraft, which are conditioning the space market nowadays. In this context, this thesis aims at presenting viable strategies for spacecraft RendezVous and Docking (RVD) manoeuvres exploiting electro-magnetic interactions. Two perspective concepts have been investigated and developed, linked together by the use of CubeSat-size testing platforms. The idea behind the first one, PACMAN (Position and Attitude Control with MAgnetic Navigation) experiment, is to actively exploit magnetic interactions for relative position and attitude control during rendezvous and proximity operations between small-scale spacecraft. PACMAN experiment has been developed within ESA Education Fly Your Thesis! 2017 programme and has been tested in low-gravity conditions during the 68th ESA Parabolic Flight Campaign (PFC) in December 2017. The experiment validation has been accomplished by launching a miniature spacecraft mock-up (1 U CubeSat, the CUBE) and a Free-Floating Target (1 U CubeSat, the FFT) that generates a static magnetic fields towards each other; a set of actively-controlled magnetic coils on board the CUBE, assisted by dedicated localization sensors, are used to control the CUBE attitude and relative position, assuring in this way the accomplishment of the soft-docking manoeuvre. The second one, TED (Tethered Electromagnetic Docking), concerns a novel docking strategy in which a tethered electromagnetic probe is expected to be ejected by a chaser toward a receiving electromagnetic interface mounted on a target spacecraft. The generated magnetic field drives the probe to the target and realizes an automatic alignment between the two interfaces, thus reducing control requirements for close approach manoeuvres as well as the fuel consumption necessary for them. After that, hard-docking can be accomplished by retracting the tether and bringing the two spacecraft in contact