Decentralized formation pose estimation for spacecraft swarms

Abstract

For spacecraft swarms, the multi-agent localization algorithm must scale well with the number of spacecraft and adapt to time-varying communication and relative sensing networks. In this paper, we present a decentralized, scalable algorithm for swarm localization, called the Decentralized Pose Estimation (DPE) algorithm. The DPE considers both communication and relative sensing graphs and defines an observable local formation. Each spacecraft jointly localizes its local subset of spacecraft using direct and communicated measurements. Since the algorithm is local, the algorithm complexity does not grow with the number of spacecraft in the swarm. As part of the DPE, we present the Swarm Reference Frame Estimation (SRFE) algorithm, a distributed consensus algorithm to coestimate a common Local-Vertical, Local-Horizontal (LVLH) frame. The DPE combined with the SRFE provides a scalable, fully-decentralized navigation solution that can be used for swarm control and motion planning. Numerical simulations and experiments using Caltech's robotic spacecraft simulators are presented to validate the effectiveness and scalability of the DPE algorithm.

Designing a User-Centered Interaction Interface for Human–Swarm Teaming

“…Besides the competing operator commands, there may also be intruder attacks by other UAVs or operators that need to be detected and eliminated from the decision-making process; (2) The effect of noise (communication, positioning, and sensing) on the performance of the swarm and detecting malfunctioning/lost UAVs need to be investigated as well; (3) Speed versus accuracy can be studied with several messaging qualities. (4) One of our next steps will be to co-create an interaction interface for human-swarm teams with experts from the industry and perform a more comprehensive user study; (5) Variations that may be induced by the operator bias in the human-in-the-loop experimentation; (6) In some use-cases it might prove useful to direct a subset of the swarm by a more complex communication protocol that allows access to certain members of the swarm without affecting the entire swarm; (7) We also plan to address some of these challenges and implement our approach on physical UAVs and evaluate the performance of the swarm in real world applications.…”

“…Our interfaces combine direct manipulation with autonomous UAV decision-making. We do not force the swarm to maintain a communication channel with the human UAVs at all times [7,8]. The operator, instead, uses the messages that the UAVs broadcast (to their nearest neighbor) to estimate the swarm's state.…”

Collaborative Pose Estimation of an Unknown Target Using Multiple Spacecraft

“…The maximum degree of the network may be controlled by specifying the maximum degree for each node, such that may be selected prior to the mission. Also, in practice, such a consensus algorithm has been shown to have sufficient convergence with finite iterations [25].…”

“…In the distributed sensor network paradigm, the independent measurements from decentralized platforms can be shared over the local communication network to be fused in an optimal fashion. As a related work [25], we recently presented the Decentralized Pose Estimation (DPE) and the Swarm Reference Frame Estimation (SRFE) algorithms, new approaches to decentralize the relative estimation using a spacecraft formation. The DPE improves the local formation estimate by considering the joint estimation over a relative sensing network, while the SRFE uses the information consensus approach [23], [24] to estimate the target position in a decentralized fashion.…”

Review of advanced guidance and control algorithms for space/aerospace vehicles

“…To deal with these open issues, a couple of important works have been reported in the literature [77][78][79][80]. For instance, the authors of [78] applied an inhomogeneous Markov 660 chain-based probabilistic swarm guidance algorithm to achieve the desired swarm behaviour for a large scale of space robotic systems.…”