1. Mobile Satellite Communication
Station
Presenter’s Name: Alex Mulcahy, Andrew
Clavijo, Paulo Borges, Michael Kunis, Javier
Aguera, Kristopher Sanford
Presenter’s Title: Arial Narrow 20 pt.
SCHOOL OF ENGINEERINGwww.scu.edu

2. Road Map
 Description
 System purpose
 Subsystems
– Description
– Requirements
– Design and Process
– Testing

3. SYSTEM PURPOSE

4. Background
 Robotics Systems Lab Nano-Satellite Operation
– NASA nano-satellites
 Low cost
 Short development time
 Test new technologies
 Educational institution involvement

5. Robotics System Laboratory
 Operate nano-satellites
– S-band radio communication
– Download

6. Robotics Systems Lab (RSL)
 RSL Ground Station at SCU
– Single point of communication
– Static facility
 Early orbit operations
– Increase number of satellite contacts
– Assist with satellite de-confliction
 Multiple satellite accommodation
– Failure of facility *** change possibly ***

7. The Project
 Mobile Satellite Communication Station

8. SYSTEM DESCRIPTION

9. System Description
 Mobile Satellite Communication Station
– Support RSL mission operations
– Allow coverage based on satellite trajectory
– ***add***

10. System Description
 *** add diagram of trailer and parts ***

11. System Description
Detailed Component Block Diagram

12. System Description
 Design Goals
– High Mobility
– Operate S-band for nano-satellites
– Auto-calibration system
– Software defined beacon radio capabilities

13. S-BAND ANTENNA

14. S-BAND : Description
 Main method of satellite communication
 MHX 2420 Radio
– 2.4000-2.4835GHz frequency band
 DHP 2.4 meter Aluminum Dish
– 4 panel dish
 SPID RAS rotor
– 360 degrees azimuth range
– 90 degrees elevation range

15. S-BAND : Requirements
Requirement Design
Target
Units
Dish Dissemble Time 24 hr
Dish Assemble Time 24 hr
Support Structure Weight 50 kg
Collapsed Volume 1.575 m3
Antenna Gain ***is this right** 26.2 dB
Personnel Required 2 Person(s)
Link Margin at 10° elevation ***add*** dB

16. S-BAND : Design
 Support Structure

17. S-BAND : Design

18. S-BAND : Design
Diameter Frequency Pointing Error Req Eb/No Noise Temp
3 meter 2.4 GHz 0.5 degrees 13.5 dB-Hz 440 K
2.4 meter 2.4 Ghz 1 degree 13.5 dB-Hz 440 K

19. S-BAND : Design

20. S-BAND : Design
 Eb/ No - ratio of received energy-per-bit to
noise density
 P - transmitter power
 Ll - transmitter-to-antenna line loss
 Gt - transmit antenna gain
 Ls - propogation path length between
transmitter and reciever
 La - a function of factors such as rainfall
density
 Gr - receive antenna gain
 k - Boltzmann constant
 Ts - system noise temperature
 R - data rate

21. S-BAND : Design
3 Meter Dish Uplink
Elevation (degrees) Link Margin (dB)
0 7.7
10 11.5
25 15.9
45 19.5
90 22.3
2.4 Meter Dish Uplink
Elevation (degrees) Link Margin (dB)
0 5.2
10 9.0
25 13.4
45 17
90 19.8

22. S-BAND : Design
3 Meter Dish Downlink 2.4 Meter Dish Downlink
Elevation (degrees) Link Margin (dB)
0 -2.0
2.5 0.0
10 1.8
45 9.9
90 12.6
Elevation (degrees) Link Margin (dB)
0 0.5
2.5 1.5
10 4.3
45 12.4
90 15.1

23. S-BAND : Design
 Support Structure

24. S-BAND : Design
 Support Structure

25. S-BAND : Testing

26. SOFTWARE DEFINED RADIO
(SDR)

27.  Interoperability:
communicate with multiple
radios
 Efficient use of resources: it
can adapt the waveform to
maximize a key metric
 Cognitive Radio: Increase
the available spectrum
 Reduced obsolescence: load
software remotely
 It costs about US $ 1,000
Why SDR?

28. Replace existent HAM Radio.
Implement Doppler Shift compensation given geolocation.
Compact to fit the Recreational Vehicle.
Maximum of 10 minutes to get the system up and running.
Have at least a 80 % rate of decoded packets.
Be able to record passes.
Multiple satellite accommodation.
Develop user-friendly GUI and stable software.
Multiple satellite accommodation
SDR Requirements

29. SDR Basic Functionality
Hardware (B200) Software

30. Hardware Features
• The first fully integrated USRP device with continuous RF coverage
from 70 MHz – 6 GHz.
• Full duplex operation with up to 56 MHz of real time bandwidth
(61.44MS/s quadrature).
• Fast and convenient bus-powered connectivity using SuperSpeed USB
3.0.
• GNURadio and OpenBTS support through the open-source USRP
Hardware Driver™ (UHD)

31. Coding Strategy
 GNURadio
 Signal processing blocks connected to each other (just like Simulink)
 Open source
 C++ and Python infrastructures are generated automatically
 Possible to generate a GUI.
 One-way handshaking: pull or push data through blocks.

32. System Design

33. GUI Features
 Waterfall Display / Spectrogram
 Frequency Spectrum & Constellation Display
 Time Domain Display
 Real Time AX.25/APRS Packet Viewer
 On-the-fly manual adjustments:
– Base frequency
– Frequency offset
– Filter window type
– Visualization settings

37. How the data is stored?
Flat File (text file)
 TCP/ IP Connection
 Web Server
 Mobile iOS Compatibility

38. Web Server

39. iOS Application

40. AUTO-CALIBRATION

41. AUTO-CALIBRATION : Description
 Required to operate on uneven ground
 Software calculates for specific reference frame
 Accounts for yaw, pitch, and roll of vehicle

42. AUTO-CALIBRATION : Description
 Required to operate on uneven ground
 Software calculates for specific reference frame
 Accounts for Yaw, pitch, and roll of vehicle
 Provides GPS coordinates for pass time generation

43. AUTO-CALIBRATION : Description
SCU Station Operations Mobile Ground Station Operation

44. AUTO-CALIBRATION : Requirements
 Pointing accuracy
– Less than 1° of error
 Information accessible by all subsystems
 ***autonomous?***
 ***add***

45. AUTO-CALIBRATION : Design
 Satellite Toolkit (STK)
– Orbit propagation
– Generates azimuth, elevation and range
 APM 2.6 ArduPilot Sensor Package
– Magnetometers, Compass, and GPS
– Wireless communication
 Matlab
– Creates rotation matrix from sensor values
– Corrects STK frame using rotation matrix
 MySQL Database

46. AUTO-CALIBRATION : Design

47. AUTO-CALIBRATION : Design

48. AUTO-CALIBRATION : Design

49. AUTO-CALIBRATION : Design

50. AUTO-CALIBRATION : Design

51. AUTO-CALIBRATION : Testing

52. Future Development?

53. Pictures needed
 Trailer
 Dish/mast
 Assembly/disassembly
 Block diagram SDR
 Block diagram entire system
 Block diagram of auto cal
 Auto cal animation
 Assembly disassembly animation
 Stress analysis

54. Pictures needed Cont.
 Software architecture diagram

56. Description
 Block diagram
 System Responsibilities

57. Requirements
 List requirements
 List which have been achieved/not achieved

58. Design
 Schematics
 Design specifics

59. Testing
 Testing methods
 Results
 Future testing

60. REQUIREMENT FOR BEFORE THE
SOLUTION
 Az tracking rates
 link
 Setup time
– Based on mobile requirements
 El tracking rates
 Mobile requirement
– Travel distance
 Support crew (pick tralier accordingly)
– 2-4 people for 2-4 weeks
– Travel