Download cameron_hatcher - Colorado Space Grant Consortium

Simulating A Satellite
CSGC Mission Operations Team
Cameron Hatcher
Brandon Bobian
James Burkert
Aleks Jarosz
Computer Simulators




Two Simulators – Flight Computer and Hardware
Run on Linux Computers
The two computers send data back and forth
Send commands through Telnet and SCL interface
Flight Computer Simulator


Simulates the actual flight computer
Allows VXWorks




Real Time Operation System developed by WindRiver Systems
Software is run in same environment as the satellite
Can make commands to the hardware
Receives replies from the hardware
Hardware Simulator




Accepts requests from Flight Computer Simulator
Sends realistic replies
Has different equations to calculate values for sensors
Simulates every hardware sensor onboard the satellite


Ex. Temperature sensors and voltage sensors
Certain sensors are set to change dependent upon
tasks

Ex. Calculated remaining battery charge
Satellite Tool Kit (STK v5.0)


Modeling and visualization
software suite
Versatile piece of software

2-D and 3-D modeling



Mission design




Visualization windows
Modeling abilities
Sun vs. shade time
Access times
Scheduling
Mission simulation


Scenarios
Practice time for Mission
Operators
Mission Training
How STK will be used for mission simulation training

Simulating real time Data



Failure Management and Error Analysis (FMEA)




Display health and status of CX based off simulators
Recognizing raw telemetry data
Telemetry data analysis
Create problem scenarios
Test how satellite will react to different situations
Diagnostics


Use simulated telemetry to diagnose problems
Troubleshoot problems and create contingency plans
STK – Orbital Mechanics

Position





Telemetry Display
Position Covariance
Perturbations
Collisions
Attitude


Telemetry Display
Tip-off Predictions


Communication
Power
STK - Communications

Modeling




Ground Yagis
Satellite Transmit
Satellite Receive
Computations

Signal




Access Times
Gains
Interference
RF Environment



Refraction
Rain
System Temperature
STK - Power

Modeling




Size
Efficiency
Orientation (Pointing)
Computations




Solar Power
Effective Area
Solar Intensity
Angle of Incident Radiation
Spacecraft Command Language
(SCL)

SCL is a high level scripting
language that allows for
ease of use in scheduling
events and keeping track of
the systems sensors using
a SCL user defined
database
Scripts



Each script in SCL runs commands
The scripts are able to check key variables in the SCL
database.
All of the scripts have the capability to be put into a
schedule.
SCL Database




The SCL database is a user defined database that
contains any and all variables that the user wishes to
monitor.
The database is updated at regular intervals with
certain scripts that will update parts of the database
specific to a certain subsystem.
Contains all satellite sensor values
Calculated values
Rules and Constraints



A constraint limits the values that a variable can be
A rule is used to alerts the operator if a variable goes
beyond a certain range
If a variable goes into a critical range, a rule will take
corrective measures
 Ex. Shutting off non-critical systems, such as
cameras
ASPEN




Automated Scheduling and Planning ENvironment
Used to create schedules for SCL
Mission Operator originally creates schedule by hand
Using ASPEN schedule can be adjusted for any conflicts
that occur


Ex. Two commands trying to use the same relay
Schedules are compiled to an SCL executable format
Running a Simulation





Schedule is uploaded to the Flight Computer Simulator
and executed
Commands are sent between the two simulators
STK sends information to the hardware simulator
Mission Operators monitors SCL environment and
Telemetry GUI during pass times
Telemetry GUI monitors the SCL database

Any problematic values will be shown in red or yellow