Design, Implementation, and Tests of KOMPSAT-2 S/W simulator
Sanguk Lee*, Sungki Cho, and Jae Hoon Kim
* Communications Satellite Development Center, ETRI, Taejon, Korea (Tel : +82-42-860-5653; E-mail: slee@etri.re.kr)
Abstract: In this paper, we will present brief design feature, implementations, and tests for verification of KOMPSAT-2 simulator, which is a subsystem of KOMPSAT-2 MCE. SIM is implemented on PC server to minimize costs and troubles on embedding onboard flight software into SIM, OOA/OOD methodology is employed to maximized S/W reusability, and XML is used for S/C characteristics, TC, TM and Simulation data instead of commercial DB. Consequently, we can reduce costs for the system, efforts embedding flight software, and maximize software reusability. SIM subsystem test was performed successfully.
Keywords: Simulator, Design, Implementation, Test.
1. INTRODUCTION In addition, the SIM supports simulation for the spacecraft status by providing the database containing various events and initialization data. SIM is composed of a PC, its peripherals and simulation software.
KOrean Multi-Purpose SATellite-1(KOMPSAT-1) had been launched in December 1999 and has been being operated normally by Mission Control Element(MCE), which was developed by Electronics and Telecommunications Research Institute(ETRI). Now, we are in system test phase of development of MCE for KOMPSAT-2, which is equipped Multi-spectral Camera (1m panchromatic and 4m multi-band) KOMPSAT-2 MCE is consisted of four subsystems such as TTC(Tracking, Telemetry, and Command Subsystem), SOS(Satellite Operation Subsystem)[1], MAPS(Mission Analysis and Planning Subsystem)[2], and SIM(Satellite Simulator Subsystem)[3].
SIM is one of the KOMPSAT-2 MCE subsystems and Figure 2 shows the functional architecture of SIM.
SIM
S/C MODEL SIMULATOR
KERNEL SIM GUI
Operator Ext.I/F
sos
Ground Simulation
TC
Simulated TM
MAPS
Orbit Propagation Data Remaining Fuel Data FSW
TM Data TC Data
TM PKT TC PKT Tracking Data
Reference time data TTC
External
Ground Station
TM SIGNAL TC SIGNAL
KOMPSAT-2 satellite
Launch Site
s-band s-band TC SIGNAL
TM SIGNAL
IRPE@KARI IRPE@USER Primary MCE
MAPS TTC
SOS SIM
Antenna Pointing Data Antenna Tracking Data
Command Plan, Mission Timeline SOH TM, GPS Data,
TC Logs TC TM
TC Simulated
TM TM, Antenna Tracking Data
TC, Orbit State Initial Orbit Element
Playback SOH TM, MSC Setup Data
Backup MCE
TTC MAPS
SIM SOS
TM TC
TC Simulated
TM Antenna Tracking Data Antenna Pointing Data
SOH TM,GPS Data, TC Logs
Playback SOH TM, MSC Setup Data Mission Timeline,
Orbit State Data, POD Result Data, Payload Operational
Request Confirm
Payload Operational Request, Antenna Angle Data
Orbit Propagation &
Remaining Fuel Data Orbit Propagation &
Remaining Fuel Data
Payload Operational Request, Antenna Angle Data
PAD TLM Data PAD TLM Data Mission Timeline,
Orbit State Data, POD Result Data, Payload Operational
Request Confirm IGS Site
DGPS Data
Weather Source
Weather Data
CDI
APS,FSUC,MMUC Mission Timeline,ECF data
IGS Site DGPS Data
Weather Source Weather
Data
CDI
APS,FSUC,MMUC Mission Timeline,ECF data Command Plan, Mission Timeline
Fig. 2. SIM Functional Architecture
2. SIM DESIGN
Design of SIM is carried out using OOA (Object-Oriented Analysis) / OOD (Object-Oriented Design) methodology and is described as the use case model, domain model, user interface design, logical view, implementation view, process view, and deployment view[4][5]. The UML notation is common language to specify, construct, visualize, and document for designing object-oriented software system by using Rational RoseTM. The standard OOA/OOD procedure has been applied to design KOMPSAT-2 SIM to maximize reusability, extensibility, and reliability.
Fig. 1 Schematics of the KOMPSAT-2 MCE
SIM is a comprehensive application software system that simulates the dynamic behavior of KOMPSAT-2 by the use of mathematical models. SIM is utilized for command verification, operator training, satellite control procedure validation, and anomaly analysis. SIM models each of satellite subsystems as accurate as possible with the constraint of real-time operation condition, and display status of satellite including orbit and attitude in alphanumeric and graphic form.
2.1 Use Case Model
SIM is a software system of simulating the dynamic behavior of KOMPSAT-2 by use of mathematical models.
SIM can be used as a virtual satellite harness for MCE system with low cost. SIM is utilized for command verification, operator training, satellite control procedure validation, and anomaly analysis. SIM models each of satellite subsystems as accurate as possible. Also, SIM displays status of satellite including orbit and attitude in alphanumeric and graphic format. Figure 3 shows the Use Case Diagram of SIM.
SIM operates in real-time to receive telecommands, to distribute them to corresponding subsystems, and to send the results to SOS in telemetry format. SIM supports user friendly GUI for input/output of the operator.
SIM is capable of operating in on-line as well as stand-alone mode. SIM also operates in variable speed operation modes in order to be used for anomaly analysis etc.
SOS (from Us e Cas e View)
SO S (from Use C ase View) Synchronize System Time
TTC (from Use Cas e View )
Log display (from dis pl...
Status display (from displ...
login (from log...
terminate (from log...
init data load (from init da...
init data edit (from init da...
init data setup (from set...
model setup (from set...
mode setup (from set...
anomaly setup (from set...
tc generation (from tc proce...
tc transmittion (from tc proce...
gene rate new TM page ( from tm proce ...
TM alphanumeric display (from tm proce...
TM plot display (from tm proce...
pause (from contr...
stop (from c ontr...
generate new SDT page (from s dt proc e...
SDT alphanumeric disp lay (from sdt proce...
SDT p lot di spl ay (from sdt proce...
ce les ti al tr ack display ( from dis pl...
ground track display ( from dis pl...
VR display ( from dis pl...
d ata convers ion ( from too.. .
unit conversion ( from too.. .
f ile fi lter ( from too.. .
playback conversion ( from too.. . Operator
(from Us e Cas e Vi...
update TC/TM ( from too.. . initial iz e
( from c on tr...
generate TM (from simula...
generate SDT (from s imula...
run (from contr...
simulate (from simula. ..
Fig. 3. Use Case Diagram of SIM 2.2 Domain Model
Domain Model describes how the Use Case is realized in Use Case Model. Domain Modeling can be expressed by Class Diagram, which describes how these classes interact with each other as shown in Figure 4.
CKInitDataMgr
CKTMMgr CKTCMgr
CKECU CKSDTMgr
Operator
<<Actor>>
KKPDStoreWindow
KTMSimDataStoreWindow simulation stop
initi alize, run, pause, stop
if receive first time tick, initialize component
IKOBC CKModel
IKRDU
CKOBC
IK InitDataMgr IKECU
CKRDU IKModel
KScheduler KTimer
IKTCMgr KMainWindow
IKTMMgr IKSDTMgr KSimulator
Figure 4. Class Diagram of Simulation Control 2.3 Logical View
Logical view of SIM decomposes into conceptual packages or logical components and describes connections between them. Figure 5 shows Logical View of SIM subsystem which is consisted of Kernel, UI, OBC(OnBoard Computer), RDU(Remote Drive Unit), ECU(Electric Control Unit), Models, TCProcess, SDTProcess, SecurityMgr, TMMgr, InitDataMgr, TCMgr, SDTMgr, EXTINTFACE, Tread, and Socket packages.
For the KOMPSAT-2 SIM, the onboard flight software is embedded into SIM as an independent process that has thread for interface with scheduler, and 1553B bus is emulated by COM(Common Object Model).
For example, we go through into more detailed design with CES(Conical Earth Sensor) as a sensor model. CES model belong to Sensor subpackage of Models Package, which is one of SIM subsystem packages. Figures 5 and 7
show top-down hierarchy from SIM top-level package down into the CES Class.
KERNEL UI
THREAD EXTINTEFACE
FSWECU FSWRDU FSWOBC
InitDataMgr
LogMgr
MODEL
SDTMgr SecurityMgr
SOCKET TCMgr
TMMgr
Fig. 5. Logical View of SIM Subsystem
As shown in figure 6, sensor package is inherited from generalized S/C H/W subsystem model for maximizing extensibility and reusability. Sensor Package consists of CES, TAC(Tachometer), POT(Potentiometer), FSS(Fine Sun Sensor), TAM(Three Axis Magnetometer), CSS(Coarse Sun Sensor), Gyro, and STA(Star Tracker Assembly) and they are inherited from sensor class. Each of sensor class has parameter class that defines characteristics of each sensor and provides extensibility.
KSCSubsyste m (from COMMONS) KAbstractM odel
(from COMMONS)
KPOT
KTAM
KSTA KCES
KFSS
KCSS KTAC
KGyro KCESParameter
KTACParameter
KT AM Parameter
KSTAParameter
KFSSParameter
KGyroParameter KPOTParameter
KCSSParameter KSenso
KCES_S r
KCSS_S
KFSS_S
KGyro_S
KPOT_S KT AC_S
KT AM _S
KSTA_S
Figure 6. Logical View of Sensor Package
Figure 7 shows detailed design of CES class and Figure 8 shows sequence diagram of calculateCount method of CES class in flow chart format.
KSensor KSCSubsystem
(from Commo ns) KAbstractModel
(from Commons)
K1CES Paramet er
KSun (from ENV) K1PCU (from EPS) KMoon
(from ENV) KEarth
(from ENV) KOrbit
(from FDS1) K1CES m_EarthFOV : double m_Status : int m_pitchError : double m_rollError : double m_warmupFlag : int relateModel() simulate() init() K1CES()
<<virtual>> ~K1CES() doAnomaly() doNormal() setDataToDataMgr() calculateCount() calculateLoad() calculateInterference() calcuateReduction() calculateStatus() setWarmupFlag()
#m_pKSun
#m_pKPCU
#m_pKMoon
#m_pKEarth
#m_pKOrbit
K1CES_S m_count[2] : int getCount() K1CES_S()
<<virtual>> ~K1CES_S()
KCESINITDATA (from Commons)
<<typedef>>
Fig. 7. CES and related Classes
ICCAS2003 October 22-25, Gyeongju TEMF Hotel, Gyeongju, Korea
Calculate earth half cone angle
Check the sun/moon interference and determine moon_presence
c heck the int ers ection between CES scan and earth horizon
check the min.
chord length
range reduction
Generates output with noise option Calculate pitch and roll pointing error
2.6 Deployment View Design
In deployment view, SIM architecture is described in the physical point of view. Figure 11 shows nodes, links between nodes, and their platform.
SIM (PC - windows 2000)
SIM.EXE SecurityMgr.DLL LogMgr.DLL TMMgr.DLL TCMgr.DLL FSWOBC.DLL FSWRDU.DLL FSWEPS.DLL MODEL.DLL SDTMgr.DLL InitDataMgr.DLL SDTProcess.DLL TMProcess.DLL
Fig. 8. Activity Diagram of calculateCount Method 2.4 Implementation View Deign
The Architecture of SIM from Implementation view of the system is described here. Implementation view describes the actual software module, their relations, and contents along with consideration of the requirements as shown in Figure 9.
Fig. 11 Deployment View of SIM
3. SIM IMPLEMENTATION
KScheduler. h
KSched uler.obj KScheduler.cpp
KSimulator.cpp KSimulator.h
KSimula tor.obj KTimer.cpp KTimer.h
KTimer .obj
SIM.EXE
3.1 SIM H/W Implementation Environment
The hardware configuration and equipment specifications for KOMPSAT-2 SIM are shown in Figure 12 and Table 1, respectively. Different from KOMPSAT-1 SIM, which was developed on HP workstation, KOMPSAT-2 SIM is developed on a PC server, which communicates with the other MCE subsystems, i.e. SOS, TTC, and MAPS, using TCP/IP protocol via MCE LAN.
A PC server as platform including in Window 2000 as an operating system will be used as H/W platform and software environment of KOMPSAT-2 SIM. The PC server also contains VR graphic display of the KOMPSAT-2 attitude and orbit motion.
Fig. 9. Implementation View of Control Package 2.5 Process View Design
SIM has the only one EXE file and number of DLL(Dynamic Link Library)s, which are running like independent processes as shown in Figure 10. Hereafter, EXE and DLLs are named after process. Process view describes execution structure of the SIM system along with consideration of the requirements related to performance, reliability, expandability, system management, and synchronization.
SIM Main Computer Operator's Console
Disk PC Server SOS
MCE Printer MCE LAN
MAPS TTC
Fig. 12 H/W Configuration and KOMPSAT-2 SIM
SIM.EXE
MODEL.DLL
IKModel
SDTMgr.DLL
IKSDTMgr
TMProcess.DLL IKTMMgr
SecurityMgr.DLL
IKSecurityMgr
SDTProcess.DLL LogMgr.Dll
IKLogMgr
InitDataMgr.DLL
IKInitDataMgr
FSWOBC.DLL
IKOBC TMMgr.DLL
TCMgr.DLL
IKTCMgr
Fig. 10. Process View of SIM
Table 1 SIM H/W Elements Usage Element Specification Simulator
Operation
Simulator Main computer
- Main Memory (above 1GB) - Hard disk (above 20G *2 ) - Above 1.0GHz Intel CPU Display
device
- Color graphic monitor (21”) Interface - Ethernet LAN transceiver
3.2 SIM S/W Implementation Environment
The SIM S/W environment is shown in Table 2. The SIM VR is implemented using Open GL.
Table 2 SIM S/W Environment Usage Element Specification
Operating
System - MS Windows 2000 Programming
Language
- C++ : GUI, Models - C : FSW embedded Data
Management - XML & Text files Library - Open GL : VR Display 3.3 SIM Implementation
KOMPSAT-2 SIM was implemented as one process that drove several DLLs as shown in figure 10. Those DLLs are implementation of elements packages for SIM in implementation and process views. Figure 13 is the main window configuration of the implemented KOMPSAT-2 SIM GUI.
Fig. 13 Main Window Configuration of KOMPSAT-2 SIM
4. KOMPSAT-2 SIM TEST 4.1 Test Philosophy
The philosophy used in the development of the subsystem test procedure is based on testing the subsystem softwares on a test-by-test basis. Although all of the subsystems in MCE are interrelated, the major focus in each subsystem test is tested as a single isolated system. During the testing, numerous operations are performed following the test steps in the test procedure. In general, test setup should be checked first and then the test execution follows in the test procedure for the specific test item. There are many checking points in the test procedure to verify a specific function and/or number
The KOMPSAT-2 MCE SIM subsystem inherits from the previous project, the KOMPSAT-1 MCE SIM, in some part.
And the KOMPSAT-1 MCE SIM has been successfully operated up to now. The some test items and some part of
test procedures are inherited from the KOMPSAT-1 MCE SIM subsystem test procedures.
4.2 Test Prerequisites
Prior to the performance of subsystem testing, the following criteria must be satisfied:
1) The SIM software shall be under configuration control.
2) The SIM Test Plan and Test Procedures shall be signed off and released.
3) The equipment and data required for testing shall be in place and connected.
4.3 Test Organization
Test organization for SIM subsystem test is shown in Fig.
14.
ITL (Integrated Test
Leader)
TCL (Test Conduct
Leader)
PA (Product Assurance
Personnel)
SR (Subsystem Representative)
TE (Test Executer)
Fig. 14 Test Organization for SIM Subsystem Test 4.4 Test Discrepancy Handling
When the test activity cannot proceed as specified in the test procedure, test discrepancy is issued. Test discrepancies are divided into four categories such as simple error, minor discrepancy, major discrepancy, and critical discrepancy. It is TCL’s decision along with SR’s and PA’s suggestion to assign the corresponding discrepancy into one of those discrepancy categories.
4.5 Test Results Test Report
The Acceptance Test of the KOMPSAT-2 MCE SIM was performed during 2 days in May 15 ~ 16, 2003. Before starting the official SIM test, test procedure was completed and signed off on May 14, 2003 and Test Readiness Review (TRR) meeting was held on May 14, respectively. Since the final version of K2 FSW is not released, eight test items in 25 test items are waived. The waived test items will be tested in the Upgrade Test. Normally, the test was started in the morning and completed before 5 PM. Daily test result review meeting was held after test.
The first test was carried out in 2 days for the 17 test items in the SIM test procedure. Totals of 15 test items were successfully passed and 2 test items were failed. All of the related TRSs, SCOs, and TDRs were issued and the software codes were changed. There were corrections of the test procedure.
ICCAS2003 October 22-25, Gyeongju TEMF Hotel, Gyeongju, Korea
Retest was performed after the completion of the software code change for the two failed items and one SCO item. All of the retests were successfully passed by the 16th of May, 2003.
Summary of the test (2003-05-15 ~ 2003-05-16)
Totals of 17 SIM test items were tested. Retest was performed for the failed test items after simple modification of the source code, when applicable. Table 3 shows the summary of the test.
Table 3 Summary of the test
Test Date Test Items Success Fail TRS
2003-05-15 11 10 1 1
2003-05-16 6 5 1 1
After 1st test 17 15 2 2
2003-05-16
(Retest) 2 2 0 0
After Retest 17 17 0 2
Test Anomalies
This section itemizes the failed item during the test and summarizes the departures and causes of the failures, and the resolution for the pass. Total of 2 failures out of 17 SIM test items were occurred during the test. The followings show the contents, causes, and resolution of the failed items.
A. Telemetry Process and Trend Analysis(TSIM-011) Departure (TRS-001)
The single item plot of the playback TM was not displayed
Cause of the Departure Data range scaling error.
Resolution
Software change was required by SCO-001.
Comments
Software change was completed.
The retest was successfully completed.
B. Simulation Data Analysis and Display (TSIM-013) Departure (TRS-002)
SDT data “AAELRANGZECI” values are fixed at zero (TP page 71, step 65).
Cause of the Departure Data filtering error.
Resolution
Software change was required by SCO-002.
Comments
Software change was completed.
The retest was successfully completed.
5. CONCLUSIONS
The brief design feature, implementations, and tests for verification of KOMPSAT-2 simulator, which is a subsystem of KOMPSAT-2 MCE. SIM is implemented on PC server to minimize costs and troubles on embedding onboard flight software into SIM. OOA/OOD methodology is employed to maximized S/W reusability and expendability. XML was used for S/C characteristics, TC, TM and Simulation data instead of commercial DB.
The subsystem test was performed to verify the SIM according to test procedure, which was prepared to meet SIM requirements items and it was passed. Each of test items was mapped to the SIM specifications via verification matrix.
Consequently, we can reduce costs for the system, efforts embedding flight software, and maximize software reusability.
KOMPSAT-2 MCE system will be delivered to KARI for variable test such as acceptance test, RF compatibility test, end-to-end test, and so on.
ACKNOWLEDGMENTS
The authors gratefully acknowledge the supports by ministry of information and communications.
REFERENCES
[1] Hee-Sook Mo, Ho-Jin Lee, and Seong-Pal Lee,”Development and Testing of Satellite Operation System for Korea Multipurpose Satellite- I,” Etri Journal, Vol. 22, No. 1, March 2000.
[2] Chang-Hee Won, Jeong-Sook Lee, Byoung-Sun Lee, and Jong_won Eun,”Mission Analysis and Planning System for Korea Multipurpose Satellite-I,” Etri Journal, Vol. 21, No. 3, September 1999.
[3] Wan Sik Choi, Sanguk Lee, Jong Won Eun, Hanjun Choi, Dong Suk Chae,”Design Implementation and Validation of the KOMPSAT Spacecraft Simulator,” KSAS International Journal 1(2) :50-67, 2000.
[4] Sanguk Lee, Sungki Cho, Jae Hoon Kim, and Seong-Pal Lee, “Object-Oriented Design of KOMPSAT-2 simulator including onboard Flight Software,” 14th International Conference in System Science. Wroclaw, Poland. 2001.
[5] Odell, J. J. and Martin, J. Object Oriented Method: A Foundation. Prentice-Hall, 1995.
