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System Design of a Digital High-Speed Modular Satellite Downlink
Sören F. Peik
- Inst. of Aerospace Technology Bremen
Outline
The DATARAIN System Conclusions Design for Space Motivation
System Design of a Digital High-Speed Modular Satellite Downlink - - PowerPoint PPT Presentation
System Design of a Digital High-Speed Modular Satellite Downlink - - PowerPoint PPT Presentation
System Design of a Digital High-Speed Modular Satellite Downlink Sren F. Peik Inst. of Aerospace Technology Bremen Outline Motivation Design for Space The DATARAIN System Conclusions Motivation Satellite for Scientific Missions Mass
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Motivation
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Satellite for Scientific Missions
Ground Station 1 Ground Station 2
Telemetry Instruments ~1 GBits/s Mass Storage ~1 TBit Downlink ~100Mbit/s
User Down Link Intersatellite Link Telemetry Link
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101101011 Ground Station
1000 MBit/s
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Design for Space
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Challenge 1: Space Environment
Vacuum Temperature Vibration Radiation
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Challenge 2: Bandwidth Efficiency
f [MHz] 8025 8400 CCSDS
DSN
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Challenge 3: Reliability
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Challenge 4: Doppler Shift
v
5 1 0 1 5 2 0 8 . 1 9 9 8 8 . 1 9 9 8 8 . 1 9 9 9 8 . 1 9 9 9 8 . 2 8 . 2 0 0 1 8 . 2 0 0 1 8 . 2 0 0 2 8 . 2 0 0 2
C e n t e r f r e q u e n c y o v e r t h e t r a n s m i s s i o n t i m e
t [ m i n u t e s ] f [ G H z ]
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- CCSDS Compliant
- Space Qualifiable Transmitter
- Low Mass, Low Power System
- X-Band System 8025-8040 MHz,
Options for other Bands
- Achievable Rates using α=0.35 Roll-off:
Modulation Bit/Hz
- max. Data Rate
QPSK 2 Bit/Hz 555,56 MBit/s 8 PSK 3 Bit/Hz 833,34 MBit/s 16 QAM 4 Bit/Hz 1111,12 MBit/s
Requirements:
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The System
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Transmitter Channel DATA IN Receiver DATA OUT
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Transmitter:
IF- Board RF- Frontend Antenna
8 GHz 1.4 GHz
Baseband Processor
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Blockdiagram
LO
IF-Filter Anti Aliasing Filter IQ-Mod.
DAC LO DAC FPGA
RF-Filter P.-Amp. Mixer Image rejection Filter
LO I n t e r f a c e P C Power Supply 3.3V 5V
Base Band Board IF-Board RF-Front-End X-Band RF-Front-End C-Band
12V
I Q
I n t e r f a c e
RF-Filter P.-Amp. Mixer Image rejection Filter
LO
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Baseband Processor
DAC LO DAC FPGA I n t e r f a c e P C
Base Band Board I Q
I n t e r f a c e
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Baseband Processor
Clock FPGA Power Supply I+ I- Q- Data Input Configuration Interface Q+ D/A Converter
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Simulation versus Measurement
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16 APSK
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IF Board
LO
IF-Filter Anti Aliasing Filter IQ-Mod.
IF-Board I Q
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RF Front End
RF-Filter P.-Amp. Mixer Image rejection Filter
LO
RF-Front-End X-Band
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RF Spectrum
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Receiver ADC and FPGA IQ-Demodulator LP-Filter LP-Filter
- Freq. Generator
BP-Filter Mixer AGC
- Freq. Generator
LN-Amp. DATA Mixer BP-Filter
- Freq. Generator
BP-Filter
Receiver
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Conclusions
- Space Calls for a Deliberate Design
- High Speed Links are a Challenge for
Digital and Analog System Sections
- We still Need Analog Design
(Electromagnetic Waves are Analog)
- Interaction of Digital and Analog Sections is
a Must
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