Customer SolutionsLockheed Martin Uses NI LabVIEW Simulation Interface Toolkit and PXI for Flight Simulation Model Development
Author(s):Jesse Hopkins, Lockheed Martin Space Systems Company
Industry:Aerospace/Avionics, Government/Defense
Product:LabVIEW, LabVIEW Real-Time, LabVIEW Simulation Interface Toolkit, PXI/CompactPCI
The Challenge:Building a prototype integrated avionics unit (IAU) and a hardware-in-the-loop (HIL) simulator to test the light detection and ranging (LIDAR) control software functionality.
The Solution:Developing a real-time IAU controller prototype, or IAU real-time emulator (IRTE), with the National Instruments LabVIEW Simulation Interface Toolkit and real-time PXI system as well as LIDAR real-time emulator (LRTE) to simulate the IRTE behavior and testing.Creating a Precise System Lockheed Martin Space Systems Company (LMSSC) is developing microsatellite technologies for autonomous rendezvous and proximity operations (ARPO). In support of near-term flight demonstration opportunities, LMSSC began IRAD development of specialized software to control a scanning LIDAR as the primary instrument to support relative navigation for ARPO maneuvers. We quickly realized the need for a real-time flight software test environment that would simulate the interaction between LIDAR control software (LCS) running on the main spacecraft CPU, and the LIDAR instrument. The spacecraft CPU, part of the IAU, communicates with the LIDAR instrument via synchronous and asynchronous RS422 serial protocol. IRTE consists of LCS and an orbital dynamics simulation contained in a NI LabVIEW wrapper, embedded on an NI real-time PXI system. LCS and the orbit dynamics model, both developed in The MathWorks, Inc. Simulink® software, were easily integrated into the LabVIEW application using LabVIEW Simulation Interface Toolkit. From there, we built RS422 I/O drivers into the LabVIEW application to allow serial communication with LRTE. We followed a similar process to build LRTE. A LIDAR hardware model, also developed in SimuLink, was contained in a LabVIEW wrapper with RS422 drivers. LRTE also received orbit simulation data and other simulation controls from IRTE via reflective memory (connected with fiber-optic cables). The system proved to be very flexible; when we unexpectedly received actual flight-like hardware, we were able to quickly adapt the IRTE/LRTE system to test the hardware. We successfully controlled the actual LIDAR using IRTE and also successfully tested the actual IAU using LRTE. A duplicate of the LRTE was provided to the flight software (FSW) development/integration subcontractor for installation into the processor in the loop lab to support FSW requirements verification and assorted mission simulation scenarios. In addition, the system was easily controlled using the LabVIEW built-in Web-publishing tool. Using this tool, Lockheed engineers could interface to the PXI chassis from any desktop computer on the corporate network. LabVIEW Reduces Development Time We chose LabVIEW rather than traditional text based real-time development tools primarily because we believed the graphical nature of NI LabVIEW Real-Time would lead to faster system development time with the small staff of engineers allocated to our project. We used the LabVIEW Real-Time Module, LabVIEW Simulation Interface Toolkit, and two real-time PXI systems to build complete IRTE and LRTE systems at a fraction of the time that would have been required with traditional text based real-time programming. Although the project presented various technical problems and multiple changes in requirements, the LabVIEW graphical development environment and supporting applications helped our team solve the problems and ultimately deliver a robust and versatile product. Simulink® is a registered trademark of The MathWorks, Inc. For more information, contact: Jesse Hopkins Lockheed Martin Space Systems Company Tel: (303) 971-6513 Fax: (303) 971-8314 E-mail: beth.rabine@lmco.com |
