cinema pdr, ucb/ssl 1 august 22, 2008 cinema communications & ground systems manfred bester
DESCRIPTION
CINEMA PDR, UCB/SSL 3 August 22, 2008 Concept of Operations −Mission Orbit Spin Stabilized Spacecraft Baseline Orbit 650 km Circular at 72° Inclination −Pass Coverage Typically 4 Passes/day with 30 min Access Time Tracking via TLEs Downloaded from USSTRATCOM −Data Recovery Store-and-forward Scheme, Downlink at 1 Mbps Recoverable Science Data Volume 760 Mbits/day −Ground Segment MOC and Ground Station Located at UCB/SSL Look into Using Heritage Control System (ITOS)TRANSCRIPT
CINEMA PDR, UCB/SSL 1 August 22, 2008
CINEMACommunications & Ground Systems
Manfred Bester
CINEMA PDR, UCB/SSL 2 August 22, 2008
Agenda
• Agenda− Concept of Operations− S-Band Communications− Ground Systems− Flight Software− Future Work
CINEMA PDR, UCB/SSL 3 August 22, 2008
Concept of Operations
• Concept of Operations− Mission Orbit
Spin Stabilized SpacecraftBaseline Orbit 650 km Circular at 72°
Inclination− Pass Coverage
Typically 4 Passes/day with 30 min Access Time
Tracking via TLEs Downloaded from USSTRATCOM
− Data RecoveryStore-and-forward Scheme, Downlink at 1
MbpsRecoverable Science Data Volume 760
Mbits/day− Ground Segment
MOC and Ground Station Located at UCB/SSL
Look into Using Heritage Control System (ITOS)
CINEMA PDR, UCB/SSL 4 August 22, 2008
CINEMA Ground Track
CINEMA PDR, UCB/SSL 5 August 22, 2008
BGS 3mEng TLM/CMD2400-2450 MHz
BGS 11mScience TLM2200-2300 MHz
CINEMA
MOC at UCB/SSL
Communications Concept
CINEMA PDR, UCB/SSL 6 August 22, 2008
S-Band Communications
• S-Band Communications− Telecom Trades
− Transceivers− Flight Antennas− Flight Software− Ground Software
− Ground Stations− BGS 11m− BGS 3m
− Link Budgets− STDN and WiFi Links
− Spectrum Licensing
CINEMA PDR, UCB/SSL 7 August 22, 2008
STDN Telemetry LinkFrequency 2250 MHzModulation BPSKSpacecraft Antenna Gain -6.0 dBicSpacecraft EIRP -3.0 dBWRange 3000 kmPath Loss 169.1 dBPolarization and Pointing Losses 1.0 dBGround Station G/T (11-m Dish) 26.0 dB/KData Rate 1000 kbpsBandwidth 1000 kHzCoding Gain (Reed-Solomon) 4.3 dBBER 10-6
Required Eb/No 6.2 dBPredicted Eb/No 19.6 dBImplementation Loss 2.3 dBLink Margin 11.1 dB
S-Band Link Budgets
• Link Budgets for STDN and WiFi TLM LinksWiFi Telemetry Link
Frequency 2425 MHzModulation (Spread Spectrum) 8FSKSpacecraft Antenna Gain 1.0 dBicSpacecraft EIRP 0.0 dBWRange 3000 kmPath Loss 169.8 dBPolarization and Pointing Losses 0.5 dBGround Station G/T (3-m Dish) 10.0 dB/KData Rate 86 kbpsBandwidth 458.7 kHzCoding Gain (Rate-1/2 Convol.) 5.7 dBBER 10-6
Required Eb/No 4.2 dBPredicted Eb/No 11.7 dBImplementation Loss 2.0 dBLink Margin 5.5 dB
CINEMA PDR, UCB/SSL 8 August 22, 2008
STDN S-Band Link
• STDN S-Band Link− Transceiver Options: SpaceQuest, Emhiser− Heritage: CHIPSAT, Various Others− Spectrum Licensing: Need NTIA License− Trades
Advantages: Can Use BGS “As Is”High Link MarginLow Risk
Disadvantages: Onboard Software Changes
Ground Software Changes
SpaceQuest TX-2400 Transmitter
CINEMA PDR, UCB/SSL 9 August 22, 2008
WiFi S-Band Link
• WiFi S-Band Link− Transceiver Options: MicroHard− Heritage: GENESAT− Spectrum Licensing: Need Amateur Radio
License− Trades
Advantages: Reuse Existing Flight Hardware
and SoftwareDisadvantages: Need Additional Ground
StationUnknown Impact of Local
WiFi Interference
MicroHard MHX-2440 Transceiver
CINEMA PDR, UCB/SSL 10 August 22, 2008
S-Band Prototype Antennas
• First Prototype Model− Linear Polarized Patch Antenna
Overall Dimensions 70.2 x 70.2 mm2
− RT/Duroid 6002 Material OrderedThickness 3.048 mm, Copper Cladding 0.035 mm, εr = 2.94
− Fabricate Antenna at SSL− Test with BGS 11-m Antenna in Far Field
CINEMA PDR, UCB/SSL 11 August 22, 2008
S-Band Flight Antennas
• Flight Models− Circular Polarized Patches:
Need 4− Typical Gain Pattern:
Hemispherical with Taper− Performance Goals
See Table Below
Patch Antenna Performance GoalsParameter θ = 90° θ = 30° θ = 5°
Efficiency > 80% > 80% > 80%
Gain > 7 dBic > 0 dBic > -10 dBic
Axial Ratio < 1 dB < 6 dB < 10 dB
CINEMA PDR, UCB/SSL 12 August 22, 2008
Ground Systems
• Ground Systems− Mission Operations
− Command and Control System− Mission Planning Products− Ground Station
− Science Data Processing
CINEMA PDR, UCB/SSL 13 August 22, 2008
Flight Software FunctionsTasks Functions
Command Processing Real-time Commands, Execution of Stored Table Commands
Telemetry Downlink Interleaving of Real-time and Playback Data
Instrument Control Deployments, High Voltages, Other Parameters
Attitude Control ACS Modes
Power Control Monitoring of Power Subsystem, Control Switched Services
Thermal Control Monitor Temperatures
Engineering Data Recording Read-out and Record Sensor Data and Software Parameters
Science Data Acquisition Read-out and Store Science Data
Memory Management Manage Flash Memory
Flight Software Functions
CINEMA PDR, UCB/SSL 14 August 22, 2008
Future Work
• Future Work− Communications Design
Trades for Selection of Radios OngoingS-Band Antenna Prototyping Ongoing
− Ground SystemsGround Station Options Tied to Selection of
RadiosCommand & Control Systems
− Flight SoftwareReceived PharmaSat Code from ARCNeed to Look into Modifying CodeDevelop Code to Interface to High-rate
TransmitterConsider Other OptionsLook into CCSDS Compatibility