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The UNSW-EC0 Ground StationBen Southwell
Australian Centre for Space Engineering Research
The UNSW-EC0 Ground Station. 2018 CubeSat Innovation Workshop, UNSW, 10- 11 July 2018.Ben Southwell
The Ground Station
• Amatuer radio station (VK2UNS)– Student & Staff operators
• Evolved during UNSW-EC0 dev and operations– UNSW-EC0 dev : commands
and system interfaces– Operations: 4am passes are
quite motivating– HW & SW
• GS has logged over 277 hours of operations since going fully autonomous
The UNSW-EC0 Ground Station. 2018 CubeSat Innovation Workshop, UNSW, 10- 11 July 2018.Ben Southwell
The Ground StationOriginal System
• Gpredict & Hamlib– Free (GPL)– Buggy (crash / freeze /
unexpected behaviour)– Single Threaded (IO blocking
nightmare)– Rigid
• CSP-TERM– Slightly modified (additional
commands made during dev)– Manual
CSP-TERM
Inter process KISS over USBRS232
Gpredict
hamlib
The UNSW-EC0 Ground Station. 2018 CubeSat Innovation Workshop, UNSW, 10- 11 July 2018.Ben Southwell
The Ground StationThe ‘at’ System
• Unix ‘at’ command– Used to schedule CSP-TERM – CSP-TERM + batch
• Python module– multithreaded – Eventually replaced the need
for Gpredict
• Not user friendly
• Technically outperforms prev solution
CSP-TERM
Inter process KISS over USBRS232
Gpredict
hamlib
cronat
batchfile
The UNSW-EC0 Ground Station. 2018 CubeSat Innovation Workshop, UNSW, 10- 11 July 2018.Ben Southwell
The Ground StationCurrent System
• Web based interface– remote control
• Automated scheduling, downloads, uploads & commands
• Scalable client / server architecture
• multithreaded python daemon– auto blackout recovery– email service– HW catalogue (like hamlib)– configurable (deploy anywhere)
The UNSW-EC0 Ground Station. 2018 CubeSat Innovation Workshop, UNSW, 10- 11 July 2018.Ben Southwell
The Ground StationCurrent System
CSP-TERMdaemon
batchfile
Web Servercmd
queueftp
queue
rotctl rigctl
FTP Serverpass logsDownloads
Uploads
SSH Server
rsync
batchresult
SMTP Client
HW Catalogue & Drivers
pyGSgs
conf
Downloads
Beacons
The UNSW-EC0 Ground Station. 2018 CubeSat Innovation Workshop, UNSW, 10- 11 July 2018.Ben Southwell
GS PC
KR-5600
Op. TeamMission Server
GS PC
Archival Server
Internet
Dev Server
Cam
Cam
Router
TNC rotctl
LNA
Radio
coax (FM)PTTIF (Audio GFSK)KISS over USBRS232EthernetIO & Motor Power
KR-5400
The UNSW-EC0 Ground Station. 2018 CubeSat Innovation Workshop, UNSW, 10- 11 July 2018.Ben Southwell
Antenna PointingSky Heatmaps
• Satellite spends most time at low elevation• Southern sky is busiest• 277 Hours of operations in last 10 months (Inc. EM time)
The UNSW-EC0 Ground Station. 2018 CubeSat Innovation Workshop, UNSW, 10- 11 July 2018.Ben Southwell
Antenna PointingHistograms
The UNSW-EC0 Ground Station. 2018 CubeSat Innovation Workshop, UNSW, 10- 11 July 2018.Ben Southwell
Evolution of UNSW-EC0 Linkcom rssi
• The ‘com rssi’ command polls EC0– Returns RSSI and
RFERR
• Useful to– Close the loop– Monitor equipment
• We only run one com rssi cmd / pass by default– 2 relocations– 1 photo campaign– 1708 & 1806
incomplete
The UNSW-EC0 Ground Station. 2018 CubeSat Innovation Workshop, UNSW, 10- 11 July 2018.Ben Southwell
Evolution of UNSW-EC0 LinkRSSI
• Received Signal Strength Indicator (RSSI)– indicative of link
• No significant change
The UNSW-EC0 Ground Station. 2018 CubeSat Innovation Workshop, UNSW, 10- 11 July 2018.Ben Southwell
Evolution of UNSW-EC0 LinkRF Error
• RFERR allows us to see the error in uplink frequency
• Nanocom is much more tolerant of errors than the Kenwood
• Need to confirm if Kenwood or NanoCom is drifting
The UNSW-EC0 Ground Station. 2018 CubeSat Innovation Workshop, UNSW, 10- 11 July 2018.Ben Southwell
Questions?
The UNSW-EC0 Ground Station. 2018 CubeSat Innovation Workshop, UNSW, 10- 11 July 2018.Ben Southwell
• Kenwood TS2000– Meets Legal Requirements
for automation– 2 VFOs + no PTT contextual
control
• 2 x 20 element yagis– 16.8dB RHCP
• 20 dB LNA– PTT sw >> VOX sw
• Controller Arduino based– Originally ran GS232– Now ROT2PROG
• Hard Stop at the South– Flip mode
• No motor velocity control– Bang Bang only
• Pot feedback– noisey– MAV filter
The Ground StationHardware
The UNSW-EC0 Ground Station. 2018 CubeSat Innovation Workshop, UNSW, 10- 11 July 2018.Ben Southwell
Base Station
• Kenwood TS2000– UHF / VHF– Meets Legal Requirements
for Automation (morse & timer)
– 2 VFOs + no PTT contextual control
• 2 x 20 element yagis– 16.8dB– RHCP– UHF (430-438MHz)
• 20 dB LNA– PTT sw >> VOX sw
The UNSW-EC0 Ground Station. 2018 CubeSat Innovation Workshop, UNSW, 10- 11 July 2018.Ben Southwell
Rotator
• Controller Arduino based– Originally ran GS232– Now ROT2PROG
• Hard Stop at the South– Flip mode
• No motor velocity control– Bang Bang only
• Pot feedback– noisey– MAV filter