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