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Frequenz-agile, performante Echtzeit-Radiodatenverbindung
zwischen Flugzeug und Bodenstation!
Motivation 2
Real time transmission of airborne sensor data
Geo-referenced information
Wide coverage area
Adaptive mission processing
Cost effective solution
Suitable for small planes
LOS Ground Terminal
ADSB-Decoder
M-PSKModem
ACU
AZ, ELPedestal control
link
BidirectionalLOS data link
ADS-B
AircraftGPS Position
ADS-BTransponder
Onboard GPS
Sensor Platform
LOS Airborne Terminal
LAN
LAN
Ground Operator
Operator
GroundImage
Processing & Visualization
ImageProcessing
Architecture 3
Requirements 4
Optical and thermal images with a ground resolution of 10cm, @500m
compressed by a factor 10 to 30 results in up to 8 Mbit/s; 2 Images per second
Return link for protocol ACK, Monitoring and control of the on-board equipment and communication to the on board operator , < 500KBit/s
Un-compressed vs. Compressed Ortho Image 5
Requirements High frequency agility from 1,9 to 6 GHz because of different national regulations and license costs Range at least 30km with line of sight High spectral efficiency Small antenna and low weight for the airborne unit Bidirectional IP Interface
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Frequencies High frequency agility from 1,9 to 6 GHz because of different national regulations and license costs 1900-1920 MHz and 2010- 2015MHz (CEPT) Other candidates: 2070-2110 MHz and 4400-4516 MHz 5080MHz 5,8 GHz Japan
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TDD Front End
Antenna
Solid State RF Switch
SW
15V In
RX
TX
ANT
HPA15V -> 5V
15V -> 12V
0
50 Ohm
1
TX/RX Switch
High PowerSolid State RF Switch
1
0
LNA2 to 12 GHz
+12V+5V +5V
+5V
+12V
To / from RFDaughterboard
HighpassFc = 2GHz
8
FDD: - two frequencies are necessary! + simple front end TDD: + single frequency ! + Up / downlink BW variable – circulator (difficult because of wide band demand); Switch required. ( isolation!)
Access system 9
TDD Framing Structure 10
Link Budget Frequency 1,9 GHz to 6 GHz 3dB-Bandwidth 10,8 MHz Channel filter roll-off 0,35 Duplexing TDD Modulation scheme QPSK FEC Duo-binary Turbo code Coderate 4/5
Margin 5,7dB
Tx Power P1dB 31 dBm Maximum downlink data rate 8 Mbit/s
Maximum uplink data rate 0,5 Mbit/s
Maximum Distance 30 km
11
Hardware solution based on a SDR 12
Down conversion
+ FilterAmplifier
1.9 GHz to 6 GHz 0-32 dB fsample = 4* fsymbol
Up-Conversion
+ Filter
ETH1
Data Encapsulation
Turbo EncoderETH0 ETH1
ETH1
Transmit Chain in PC
Ö&M Timing EstimationCorrelation
NDA FESTRife Boorstin
dfTs
Turbo Decoder InterpolationDelay N
SymbolsPhase Tracker
Data Decapsu
lation
tauPosition Start of Frame
SymbolsETH0
Samples os4
Bit to Symbolmapping
I
Q
I
Q
QPSK bit to Symbol Mapper &
Zero Padding
fsample = 2* fsymbol
Packetizer
FPGA RX DSP Chain
ADC100 MHZ
14 bit
RRCOSro=0.35HBF1 HBF2
DAC100 MHZ
16 bit
RRCOSro=0.35HBF1HBF2
DigitalMixer
(w. NCO)
DigitalMixer
(w. NCO)
CIC1 – 128
CIC1 - 128
CBX Daughterboard
Amplifier
FPGA TX DSP Chain
USRP N210 + CBX Daughterboard
Receive Chain in PC
TDD Switch Control
TX
RX
SW
To / from RFFront End
13
Multi ground station network: Forward- link
Internet
Einsatz zentrale
SNR=4dB SNR=7dB
12
4
12
43
12
4
12
43
Router
12
43
Bodenstationen im Radioschatten
des Flugzeuges
14
Internet
Einsatz zentrale
SNR=4dB SNR=7dB
12
12
Router
12
Bodenstationen im Radioschatten
des Flugzeuges15
Multi ground station network: Return- link
Tracking System Mono-pulse is good but expensive and need first access information (telemetry channel) Step track is cheaper then Mono-pulse, less performance but need telemetry channel for first access Operation with telemetry channel only (broadcast) Using ADS-B information (1090MHz)
16
17
Field trial at Red Cross Exercise Allensteig 18
19
Summary Real time response for disaster management Integrated and tested a LOS link from a DA42 Data-rates verified ASDS-B tracking works well
20
JOANNEUM RESEARCH Forschungsgesellschaft mbH
Institut für Informations- und Kommunikationstechnologien
www.joanneum.at/digital
Michael Schmidt [email protected] +43 316 876-1311
Vielen Dank für Ihr Interesse!
