A DISTRIBUTED COMMON GROUND SEGMENT FOR EDUCATIONAL NANOSATELLITES. Quinn McGehan, Megan O Sullivan, Michael Mozingo, Michael Trowbridge

Transcription

1 1 A DISTRIBUTED COMMON GROUND SEGMENT FOR EDUCATIONAL NANOSATELLITES Quinn McGehan, Megan O Sullivan, Michael Mozingo, Michael Trowbridge

2 2 Theory and Background Megan O Sullivan

3 Relevant Requirements 3 DANDE science mission needs spacecraft s position Solution: STK model and ground time of measurements Problem: spacecraft clock drift, clock resets n Solution n Measure time offset periodically n Correct the measurement times on the ground (post-pass) Downlink science data from the spacecraft Problem: Data produced faster than we can downlink it n Solution: Add more ground stations

4 The Solution 4 Multiple Ground Stations Ithaca, NY San Juan, Puerto Rico Boulder, CO

5 Benefits 5 Increased Access Time Vs.

6 Impact of Access Time 6 Location Pass time/day (min) Data Downlinked (Bytes) Boulder ,140 Cornell ,847 Puerto Rico ,661 Total ,648

7 Previous work : HERMES S-Band Ground Station 2011: DANDE AFRL demo, Verizon 3G USB dongle

8 8 System Architecture Quinn McGehan

9 General Architecture 9 ALLSTAR Future satellites DANDE Blue Cloud Farms CU Boulder UPR (Puerto Rico) Component Location RF Chain RF Chain RF Chain InControl Client CU Boulder Modem TNC/Modem TNC InControl Server CU Boulder TCP/IP TCP/IP Remote Gateway TCP/IP Remote Gateway Remote Gateway Remote Station Remote Gateway InControl Server Telem TNC Remote Station InControl FLITE Client workstations Mission Operators Radio/Antenna Remote Station

10 Security Concerns 10 InControl Server talks to Remote Gateway over the internet User commands, GUI InControl Server Gateway reconfiguration SOAP client Hardware Gateway TCP/IP Commands, Telemetry TCP socket Public segment encrypted with SSH Remote Gateway ssh (AES) TCP/IP ssh (AES) Unencrypted Encrypted SOAP Web Service TCP/IP socat,kiss and AX25 framing Commands, telemetry RS-232 To TNC

11 11 Experiment Michael Trowbridge

12 Experiment Goals 12 Need to command DANDE during testing No internet connection at AFRL test facility If we add a mobile data link to the path, Can the remote gateway run the FLITE client? Can Boulder command the spacecraft at AFRL? Do key DANDE commands work? How does throughput affect commanding? How does latency affect commanding?

13 Network connections 13 CU TCP/IP CU Firewall Public Internet Cell phone tower 3G/4G Data WiFi tethering Android Smartphone InControl Server ` InControl Client (MOCC) Remote Gateway, InControl Client ` RS-232 TNC Radio DANDE UHF/VHF

14 Mobile devices tested 14 Motorola Atrix 4G OpenGarden Wi-Fi hotspot Native Android Wi-Fi hotspot Motorola Droid X Native Android Wi-Fi hotspot Pantech UML290 4G LTE USB dongle Installed in Remote Gateway computer Photos:

15 Test Configurations 15 Test Device Configuration Carrier Connection 1 N/A Ethernet cable CU 100 mbps (control) 2 Motorola Atrix 4G OpenGarden T-Mobile EDGE (2G) Wi-Fi tethering 3 Motorola Atrix 4G Android mobile T-Mobile EDGE (2G) Wi-Fi hotspot 4 Motorola Droid X Android mobile Verizon 3G Wi-Fi hotspot 5 Pantech UML290 wvdial ppp client (USB) Verizon 4G LTE

16 Procedures 16 Connect the remote gateway to the internet 1 Measure throughput to the general internet (speakeasy.net) 2 Determine if the VPN client is needed 3 Test latency & throughput to the InControl server 4 Attempt to launch the remote FLITE client 5 Test the DANDE command/telemetry link over RF 6

17 Telemetry and Commands 17 Telemetry Monitor DANDE beacon frames Commanding Log in to the satellite Measure spacecraft time offset Upload a file using zmodem Download a file using zmodem

18 18 Results Michael Mozingo

19 Results Overview 19 Test Device Configuration Carrier Connection Connected Notes 1 N/A Ethernet cable CU 100 mbps Yes (control) 2 Motorola Atrix 4G OpenGarden Wi-Fi tethering T-Mobile EDGE (2G) Partial Test failure: OpenGarden blocked VPN connection 3 Motorola Android mobile T-Mobile EDGE (2G) Yes Atrix 4G 4 Motorola Droid X 5 Pantech UML 290 Wi-Fi hotspot Android mobile Wi-Fi hotspot wvdial ppp client (USB) Verizon 3G No Test failure: Unable to connect Wi-Fi Verizon 4G LTE Partial Test failure: Unable to connect over VPN

20 Functionality 20 Test Ethernet Atrix Atrix Droid X USB Initialize FLITE on remote GW Yes No No No No Hardware gateway connects Yes No Yes No No Dynamic DNS updates Yes Yes Yes Yes Receive beacon frames Yes Yes Login attempts needed 1 1 Time offset measurement works Yes No VPN client needed No Yes Yes Yes Yes Time to initialize jade display (sec) 4.3 Best functionality: Test 3, T-Mobile EDGE, Motorola Atrix 4G, Android Wi-Fi mobile hotspot

21 Droid X 21 Issue Unable to connect (Wi-Fi) NIC incompatiblity Solution Test with a different Verizon phone Get a new NIC for the remote ground computer We were able to connect to a different computer

22 Pantech 4G USB dongle 22 Issue Immature Ubuntu drivers vpnc unable to update routing tables Solution Use a 4G Wi-Fi Hotspot instead

23 Throughput to internet 23 Throughput (kbps) Downstream (kbps) Upstream (kbps) Ethernet T-Mobile EDGE (test 2) T-Mobile EDGE (test 3) Verizon 4G LTE (test 5) Tested using

24 Bandwidth to InControl Server 24 Bandwidth (kbps) Bandwidth (kbps) Ethernet T-Mobile EDGE (test 3) 102

25 Throughput Requirements 25 At 102 kbits/sec Commanding was successful File upload and download were successful Time Offset Measurement failed Failed pre-command check: NTP time out of sync Unable to find lowest threshold for commanding Transmit speed out of radio is 9.6 kbits/sec Could increase throughput with 3G and 4G connections

26 Latency to InControl Server Latency (ms) Latency (ms) Ethernet T-Mobile EDGE (test 2) T-Mobile EDGE (test 3)

27 zmodem File Transfers 27 Ethernet T-Mobile EDGE (test 3) Upload to DANDE (bytes/sec) Download from DANDE (bytes/sec)

28 Latency 28 Little variation in latency (~258 ms) Too high for spacecraft time offset measurement Most commands insensitive to latency File uploading and downloading is more sensitive Uplink dropped from 512 bytes/sec to 369 bytes/sec Downlink results are misleading

29 Testing Summary 29 Atrix connection was stable Low bandwidth and high latency 4G Verizon dongle promising Support in Ubuntu is immature Best of both options: Verizon 4G Wi-Fi hotspot DNS, VPN difficult in all test setups

30 Conclusion 30 Distributed ground network can transfer more data Lower latency in data downloaded Commanding is possible over mobile data links Functionality limited Limited equipment availability hindered our test Focus on modularity and flexibility

31 Future Work 31 Register gateway web services with a UDDI server Automate radio, antenna actuator control Create.deb package for the remote gateway Perform experiments using 4G Wi-Fi hotspots

32 Acknowledgements 32 L3 Communications Donation of InControl Software and licensing Mitch Seybold thanks for all the late night and weekend assistance with our InControl gateway!

33 33 Questions

34 34 Backup Slides

35 Control - Ethernet 35 Bandwidth (phobos iperf) (kbps) Downstream (speakeasy) (kbps) Upstream (speakeasy) (kbps) Latency (phobos), ms Dropped packet % (ping) 0 Can initialize FLITE on remote GW Yes Hardware gateway connects Yes Dynamic DNS updates remote GW address Yes Receive beacon frames Yes Login attempts needed 1 Time offset measurement works Yes VPN client needed No 15k zmodem download (bytes/sec) k zmodem upload (bytes/sec) 512 Time to initialize jade display (sec) 4.3 Date/time of test 4/8/2012

36 Atrix 36 Bandwidth (phobos iperf) (kbps) 102 Downstream (speakeasy) (kbps) 194 Upstream (speakeasy) (kbps) 95.0 Latency (phobos), ms Dropped packet % (ping) 0 Can initialize FLITE on remote GW No Hardware gateway connects Yes Dynamic DNS updates remote GW address Yes Receive beacon frames Yes Login attempts needed 1 Time offset measurement works No (NTP sync exception) VPN client needed Yes 15k zmodem download (bytes/sec) k zmodem upload (bytes/sec) 369 Time to initialize jade display (sec) N/A (test fail) Date/time of test 4/8/12 10:58 AM

37 Hermes VHF/UHF End-to-End CU network Remote GW /dev/ttys0 COMPUTER Port 2 (VHF) CAT5 Serial Audio CAT5 Kantronics KAM XL TNC PKT Yaesu FT-847 Radio CAT5 UHF UHF/VHF Antenna CORBA ssh, TCP Manually Configured Tester A InControl Server RF Tester B COM1 Serial Laptop running CUBESim DB9F->DB25M Adaptor DB25F Connector DB9F Connector Kantronics KPC3+ TNC Audio Headphone Jack Yaesu VX-7R 37

38 Hermes S-Band End-to-End DynDNS.org DNS updates CU network DNS queries Internet CAT5 Blue Cloud Farms Qwest DSL Modem/router RadioLabs GS5000 CAT5 PoE 5.8GHz RadioLabs GS5000 Linksys Hub CAT5 PoE CAT5 CAT5 Tester A MOCC Workstation CORBA InControl server ssh, TCP Windows Terminal Computer S-Band Antenna (Microhard 2420 mounted on feed) Serial COM1 Tester B Serial Laptop running CUBESim 38 Microhard 2400 Omni hand-held antenna S-Band ~2.4GHz