A Brief MUSIM History
Support for the Human Systems Integration lab started at NASA Ames Research Center in bldg. 211 in early 1998, with
funding that was arranged for by Dr. Sandy Hart.
The first simulator built by Silicon Valley Simulation
was a rotorcraft simulation for the then joint NASA/Army branch. The rotorcraft simulator was based on the now
defunct Coryphaeus Software tools Easyscene and Designer’s Work Bench. In late 1998 or early 1999, the branch moved to bldg. 210, where the Rotorcraft Part Task Laboratory simulator was
used in several simulations for a variety of research projects. It was developed on and executed on
SGI Octane computers.
Due to funding considerations, the next phase of the lab de-emphasized the rotorcraft research and began an emphasis
on Unmanned Aerial Vehicle (UAV) research, now frequently referred to Unmanned Aerial Systems (UAS). The new emphasis
resulted in a new simulation called the UAV Simulation (USIM), still using SGI Octanes. The USIM was based on the
US Army’s Shadow UAV . Key portions of the
Shadow operator’s GUI were copied directly from pictures and manuals of the Shadow UAV. One research study was conducted
using the new USIM, before the lab was moved to the basement of building 243. The run time visual displays were
SGI Performer based and the math model was developed
in-house by Terry Welsh . The software architecture, as shown
below, employed TCP/UDP comms and shared memory to pass data between the different processes that composed the simulation.
The two dimensional graphics (GUI) were developed using the The USIM Derivative 'SOUSIM'
In a major effort to get away from proprietary hardware architectures and software libraries, the USIM was subsequently
ported to a “Linux on Intel” environment. The first attempt was named lpDSIM. The lpDSIM was a based on the SGI
USIM but ran on Linux. In mid 2003, a more refined version was developed and affectionately named SOUSIM (Son Of USIM).
All subsequent USIM simulations (both Shadow and Perseus/Altair) were based on the SOUSIM. The lpDSIM and SOUSIM were
still tied to SGI Performer runtime visuals. This changed in the next iteration on the architecture.
A major architectural change occurred around 2005, that was subsequently referred to as the Multiple UAV Simulation, or
MUSIM. The MUSIM is noted for having no proprietary licenses required to run the baseline simulation. It runs
as several processes under the GNU/Linux operating system. The visual processes are based on Open Scene Graph
( www.openscenegraph.org ). The operator interface is based on the
Fast Light Tool Kit (FLTK) ( http://www.fltk.org ). All the development
tools are standard GNU/Linux tools, distributed with the Linux distribution. For the most part, we standardized on the
then current SUSE Linux distribution but we have also run with
Red Hat Workstation and Red Hat Fedora distributions. As time and necessity permit, we update the Linux distro to current releases. The
new MUSIM also eliminated all shared memory communications between core processes, substituting TCP and UDP Ethernet comms.
The operator interface also received a major upgrade with the transition to MUSIM. The desktop display and GUIs are
no longer modeled after the US Army’s Shadow interface, as was the USIM. The new interface was designed and developed
entirely in house as a joint venture between the researchers and developers. As of this writing, the MUSIM can simulate
one, two or three UAVs concurrently. Some effort has been given to develop an interface that can be used by one operator
to manage ‘n’ UAVs, where n is larger than three, but to date there has been limited software development of the concept.
The following figure shows the basic software architecture shared between all USIM versions, as well as the MUSIM. Although
the architecture is similar, the underlying technology is very different.
V1.0
