Release Notes

Table of Contents

GMAT R2014a Release Notes
New Features
Improvements
Compatibility Changes
Known & Fixed Issues
GMAT R2013b Release Notes
New Features
Improvements
Compatibility Changes
Known & Fixed Issues
GMAT R2013a Release Notes
Licensing
Major Improvements
Minor Enhancements
Compatibility Changes
Known & Fixed Issues
GMAT R2012a Release Notes
New Features
Improvements
Compatibility Changes
Known & Fixed Issues
GMAT R2011a Release Notes
New Features
Improvements
Compatibility Changes
Fixed Issues
Known Issues

GMAT R2014a Release Notes

The General Mission Analysis Tool (GMAT) version R2014a was released May 2014. This is the first public release since April 2013, and is the 8th release for the project.

Below is a summary of key changes in this release. Please see the full R2014a Release Notes on JIRA for a complete list.

New Features

Trajectory Colors and Labels

In GMAT R2014a, you can now specify colors for each segment of your trajectory independently, so you can clearly see where a segment begins and ends. This can help define portions of a trajectory, such as before or after maneuvers. All color handling has also been moved from the graphics resources (OrbitView and GroundTrackPlot) to the resources and commands controlling the trajectory (e.g. Spacecraft, Planet, Propagate).

On Spacecraft, the color specification has moved to the Visualization tab. See the circled area in the screenshot below. Colors for celestial bodies (Planet, Moon, Asteroid, etc.) are specified similarly.

The trajectory color associated with a particular trajectory segment can be changed by changing the color for that particular Propagate command. It will override the color for the Spacecraft being propagated for that segment only, and it will return to the default color afterwards.

Additionally, colors can now be specified either by name ('Blue') or by RGB value ([0 0 255]).

This release also adds participant labels in the graphics as well. As long as OrbitView.ShowLabels is enabled, each celestial body or Spacecraft in the plot will show its name next to it.

See the following example:

Create Spacecraft aSat
aSat.OrbitColor = 'Blue'

Create Propagator aProp

Create OrbitView aView
aView.Add = {aSat, Earth}
aView.XYPlane = off
aView.Axes = off
aView.EnableConstellations = off
aView.ShowLabels = on

BeginMissionSequence
% plots in blue
Propagate aProp(aSat) {aSat.ElapsedSecs = 900}                     
aSat.OrbitColor = 'Green'
% plots in green
Propagate aProp(aSat) {aSat.ElapsedSecs = 900}             
 % plots in red        
Propagate aProp(aSat) {aSat.ElapsedSecs = 900, OrbitColor = Red}  

This example results in the following image:

See the Color reference, as well as the individual Spacecraft, CelestialBody, Propagate, and OrbitView references, for more information.

New Orbit State Representations

GMAT now supports six new common orbit state representations, developed with support by the Korean Aerospace Research Institute (KARI). The new representations are:

  • Long- and short-period Brouwer-Lyddane mean elements (BrouwerMeanLong and BrouwerMeanShort)

  • Incoming and outgoing hyperbolic asymptote elements (IncomingAsymptote and OutgoingAsymptote)

  • Modified equinoctial elements (ModifiedEquinoctial)

  • Alternate equinoctial elements (AlternateEquinoctial)

  • Delaunay elements (Delaunay)

  • Planetodetic elements, when using a body-fixed coordinate system (Planetodetic)

The new representations are available as options in the Spacecraft "State Type" list, and as options to the Spacecraft.DisplayStateType field.

See the Spacecraft Orbit State reference for more information.

New Attitude Models

GMAT now supports three new kinematic attitude models, developed with support by the Korean Aerospace Research Institute (KARI). The new representations are:

  • Precessing spinner

  • Nadir pointing

  • CCSDS Attitude Ephemeris Message (AEM)

The new representations are available as options in the Spacecraft "Attitude" list, and as options to the Spacecraft.DisplayStateType field.

See the Spacecraft Attitude reference for more information.

Dynamics and Model Improvements

GMAT now supports several new dynamics models and a new numerical integrator.

Targeting and Optimization Improvements

  • There are new boundary value solver options on DifferentialCorrector (Broyden, and ModifiedBroyden). Brodyen’s method and modified Broyden's method usually take more iterations but fewer function evaluations than NewtonRaphson and so are often faster. See the Differential Corrector reference for more information.

  • There are new parameters that check for convergence of solvers. See the Calculation Parameters reference for more information.

Below is a script example that illustrates the new algorithm and parameter options.

Create Spacecraft aSat
Create Propagator aPropagator

Create ImpulsiveBurn aBurn
Create DifferentialCorrector aDC
%  This algorithm is often faster, as is ModifiedBroyden
aDC.Algorithm = Broyden  

Create OrbitView EarthView
EarthView.Add = {Earth,aSat}
EarthView.ViewScaleFactor = 5

Create ReportFile aReport 

BeginMissionSequence

%  Report targeter status here
Report aReport aDC.SolverStatus aDC.SolverState
Target aDC
    Vary aDC(aBurn.Element1 = 1.0, {Upper = 3, MaxStep = 0.4})
    Maneuver aBurn(aSat)
    Propagate aPropagator(aSat,{aSat.Apoapsis})
    Achieve aDC(aSat.RMAG = 42164)
EndTarget
%  Report targeter status here
Report aReport aDC.SolverStatus aDC.SolverState

Improvements

Dependencies in Assignment Command

You can now define settable parameters by using a dependency on the LHS of an assignment command:

Create Spacecraft aSat

BeginMissionSequence

aSat.EarthFixed.X = 7000
aSat.EarthMJ2000Eq.VZ = 1

Other Improvements

  • You can now set true retrograde orbits when using the Keplerian representation.

  • You can now use the quaternion Rvector parameter on the right hand side of an assignment command.

  • You can now use a Spacecraft body fixed coordinate system as the coordinate system for an OrbitView.

  • The number of Spacecraft that that can be displayed in OrbitView is no longer limited to 30.

  • The documentation for OrbitView has been significantly expanded. See the Orbit View reference for details.

  • You can now save an XY plot graphics window to an image file.

  • The supported set of keyboard shortcuts has been greatly expanded. See the Keyboard Shortcuts reference for more information.

  • You can now use many more common ASCII characters in GMAT strings.

  • You can now generate orbit state command summary reports using coordinate systems that have any point type as the origin of the selected coordinate system. Previously the origin had to be a Celestial Body.

Compatibility Changes

  • Color settings for Resources displayed in graphics are now configured on the Resource and via the Propagate command. OrbitColor and TargetColor fields on graphics resources are no longer used.. See the Spacecraft Visualization reference, and Propagate command reference for details.

  • AtmosDensity is now reported in units of kg/km^3. See the Calculation Parameter reference for details.

Known & Fixed Issues

Over 123 bugs were closed in this release. See the "Critical Issues Fixed in R2014a" report for a list of critical bugs and resolutions in R2014a. See the "Minor Issues Fixed for R2014a" report for minor issues addressed in R2014a.

Known Issues

All known issues that affect this version of GMAT can be seen in the "Known Issues in R2014a" report in JIRA.

There are several known issues in this release that we consider to be significant:

IDDescription
GMT-2561UTC Epoch Entry and Reporting During Leap Second is incorrect.
GMT-3043Inconsistent validation when creating variables that shadow built-in math functions
GMT-3108OrbitView with STM and Propagate Synchronized does not show spacecraft in correct locations
GMT-3289First step algorithm fails for backwards propagation using SPK propagator
GMT-3350Single-quote requirements are not consistent across objects and modes
GMT-3556Unable to associate tank with thruster in command mode
GMT-3629GUI starts in bad state when started with --minimize
GMT-3669Planets not drawn during optimization in OrbitView
GMT-3738Cannot set standalone FuelTank, Thruster fields in CallMatlabFunction
GMT-4520Unrelated script line in Optimize changes results (causes crash)
GMT-4408Failed to load icon file and to open DE file
GMT-4520Coordinate System Fixed attitudes are held constant in SPAD SRP model during a propagation step