Kren Simulator Tutorial
Walk through the mission UI, reference frames, and workflows for building spacecraft, ground stations, and constellations in Kren.
1 Overview
This chapter introduces the Kren workspace and the main visualization panels you will use during a mission setup.
1.1 Kren
Kren is the mission-grade simulation core for aerospace workflows: orbit propagation, attitude dynamics, ground access, and constellation design.
Content forthcoming.
1.2 Main Windows
The main window hosts the timeline, 3D views, groundtrack, and plots. Use this layout as your primary mission console.
Content forthcoming.
1.3 Time Line
The timeline controls simulation time, play/pause, and scrubbing across the mission interval.
Content forthcoming.
1.4 3D Orbit View
The 3D orbit view renders spacecraft trajectories in inertial or Earth-fixed frames with optional groundstation overlays.
Content forthcoming.
1.5 Groundtrack
The groundtrack map shows sub-satellite points and access footprints over the Earth surface.
Content forthcoming.
1.6 3D Attitude View
The attitude view displays body axes, sensors, and solar panels relative to the local orbital or inertial frame.
Content forthcoming.
1.7 Plots
Plot panels chart telemetry-style quantities such as Euler angles, rates, eclipse flags, and power.
Content forthcoming.
2 Introduction
Core conventions used throughout Kren: coordinate frames, time scales, and ephemeris sources.
2.1 Reference System
Learn the body, orbital, and Earth-centered frames used for state vectors and attitude definition.
Content forthcoming.
2.2 Time References
UTC, GPS, and simulation epoch handling — including leap-second aware conversions where applicable.
Content forthcoming.
2.3 Ephemerides
Planetary and Earth orientation products that drive lighting, eclipse, and high-fidelity force models.
Content forthcoming.
3 Creating a Spacecraft
Build a spacecraft from orbit definition through disturbance models and visualization options.
3.1 Orbit
Define the initial orbit using TLE, Cartesian state, or classical orbital elements.
3.1.1 TLE
Import a NORAD Two-Line Element set and propagate with SGP4-compatible dynamics.
Content forthcoming.
3.1.2 Cartesian
Specify position and velocity vectors in the selected reference frame (km, km/s).
Content forthcoming.
3.1.3 Orbit Elements
Enter semi-major axis, eccentricity, inclination, RAAN, argument of perigee, and true anomaly.
Content forthcoming.
3.2 Attitude
Configure initial orientation and attitude modes (nadir, inertial, target tracking, and custom quaternion).
Content forthcoming.
3.3 Model
Attach a geometric model (for example STL) used for visualization and optional panel / shadow computations.
Content forthcoming.
3.4 Environment
Select gravity, atmosphere, and magnetic-field models that affect translational and rotational dynamics.
Content forthcoming.
3.5 Disturbance
Enable drag, solar radiation pressure, gravity-gradient, and residual magnetic dipole torques.
Content forthcoming.
3.6 Visualization options
Toggle body axes, FOV cones, sensor footprints, and trail length in the 3D views.
Content forthcoming.
3.7 Solar Panel
Define panel area, efficiency, and articulation for power and attitude coupling studies.
Content forthcoming.
4 Create Groundstation
Add a ground station by latitude, longitude, and altitude. Configure minimum elevation and link constraints for access calculations.
Content forthcoming.
5 Create Constellation
Build multi-satellite formations from catalog TLEs or custom Walker / manual layouts.
5.1 TLE base
Load a constellation from a TLE catalog file and manage members as a group.
Content forthcoming.
5.2 Custom
Design a custom constellation by plane count, satellites per plane, and phasing parameters.
Content forthcoming.
6 Computation
Run access and estimation tools against the current mission configuration.
6.1 Calculate Access Point
Compute visibility windows between spacecraft and ground stations over the selected time span.
Content forthcoming.
6.2 SatNogs Orbit Estimation
Use SatNOGS observations to refine orbit estimates for selected objects.
Content forthcoming.
7 Tools
Utility panels and helpers available from the Kren tools menu.
7.1
Section title and content forthcoming.