Mobile Satellite Communication Station

Presenter’s Name: Alex Mulcahy, Andrew Clavijo, Paulo Borges, Michael Kunis, Javier Aguera, Kristopher SanfordPresenter’s Title: Arial Narrow 20 pt.

SCHOOL OF ENGINEERINGwww.scu.edu

Road Map

Description System purpose Subsystems

– Description– Requirements– Design and Process– Testing

SYSTEM PURPOSE

Background

Robotics Systems Lab Nano-Satellite Operation – NASA nano-satellites

Low cost Short development time Test new technologies Educational institution involvement

Robotics System Laboratory

Operate nano-satellites– S-band radio communication– Download

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 ***

The Project

Mobile Satellite Communication Station

SYSTEM DESCRIPTION

System Description

Mobile Satellite Communication Station– Support RSL mission operations– Allow coverage based on satellite trajectory– ***add***

System Description

*** add diagram of trailer and parts ***

System DescriptionDetailed Component Block Diagram

System Description

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

S-BAND ANTENNA

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

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

S-BAND : Design

Support Structure

S-BAND : Design

S-BAND : Design

Diameter Frequency Pointing Error Req Eb/No Noise Temp3 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

S-BAND : Design

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

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

S-BAND : Design

3 Meter Dish Downlink 2.4 Meter Dish Downlink

Elevation (degrees) Link Margin (dB)0 -2.0

2.5 0.010 1.8

45 9.9

90 12.6

Elevation (degrees) Link Margin (dB)0 0.5

2.5 1.510 4.3

45 12.4

90 15.1

S-BAND : Design

Support Structure

S-BAND : Design

Support Structure

S-BAND : Testing

SOFTWARE DEFINED RADIO (SDR)

Interoperability: communicate with multiple radiosEfficient 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?

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

SDR Basic Functionality

Hardware (B200) Software

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)

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.

System Design

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

How the data is stored?

Flat File (text file) TCP/ IP Connection Web Server Mobile iOS Compatibility

Web Server

iOS Application

AUTO-CALIBRATION

AUTO-CALIBRATION : Description

Required to operate on uneven ground Software calculates for specific reference frame Accounts for yaw, pitch, and roll of vehicle

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

AUTO-CALIBRATION : Description

SCU Station Operations Mobile Ground Station Operation

AUTO-CALIBRATION : Requirements

Pointing accuracy– Less than 1° of error

Information accessible by all subsystems ***autonomous?*** ***add***

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

AUTO-CALIBRATION : Design

AUTO-CALIBRATION : Design

AUTO-CALIBRATION : Design

AUTO-CALIBRATION : Design

AUTO-CALIBRATION : Design

AUTO-CALIBRATION : Testing

Future Development?

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

Pictures needed Cont.

Software architecture diagram

Description

Block diagram System Responsibilities

Requirements

List requirements List which have been achieved/not achieved

Design

Schematics Design specifics

Testing

Testing methods Results Future testing

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

Show ability to increase time with spacecraft– Also dictated by mission requirement