Flight dynamics system design

摘要

Flight Dynamics Systems (FDS) are an integral component of every satellite ground system — they model and manage the orbital position and movement of satellites. As a global provider of satellite space and ground systems, Lockheed Martin has developed and deployed numerous FDSs for a wide-range of satellite systems. These in-house custom solutions were developed at a time when extensive analysis indicated that comparable commercial-off-the-shelf (COTS) capabilities did not exist in the market. Today, vendors are providing comparable, lower-cost, reliable, robust FDS capabilities. This project focuses on exploring the use of COTS products that can be more easily adapted to different satellites to reduce development time and life-cycle costs. The project evaluates how well each product satisfies Lockheed's needs, both in fulfilling technical requirements and in adaptability to Lockheed's existing systems. A comprehensive review of commercial off-the-shelf (COTS) flight dynamics systems identified three possible candidates as possible replacements for the current approach. These solutions, produced severally by Analytical Graphics Inc., A.I. Solutions, and GMV, were evaluated against a set of requirements and objectives developed in coordination with Lockheed Martin. Two systems, Satellite Toolkit (STK) from Analytical Graphics, and FreeFlyer from A.I. Solutions, were selected for prototype development in part due to their extensive number of prior installations and also limited access to GMV software. Prototype interfaces for STK and FreeFlyer were developed to simulate those systems' interactions with a notional satellite constellation and associated software suite, through several specific use cases. The goal of creating and testing the prototypes is to more deeply evaluate the challenges associated with customizing and adapting a COTS FDS through experiencing those challenges first-hand. Analysis revealed that STK's Java-based interfaces are more suite- to Lockheed's requirements, facilitating the required transfers natively. The socket-based connections available in FreeFlyer are sufficient for data exchange but increase processing overhead because of required intermediary steps.