US Naval Academy LABsats Bob Bruninga, WB4APR AIAA JHU/APL Educational Seminar 10 Nov 2006

USNA Satellites Bob Bruninga, WB4APR

Basic USNA’sat

Digital Transponder Telemetry system has 1200/9600 baud available STP Experiments can interface to serial ports here PCsat SCIENCE USNA-0203

The USNA Constellation

USNA PCSAT2 on ISS Launched Aug 2006, attached to ISS 1 Year of 3 Mbytes data per day Supported Packet and Voice Relay Returned Sept 2006

 The comm channels can potentially draw from over 30,000 experimenters for easy assessment of loading and scaling issues.  Not only the sensors and users exist, but the global Internet collection and distribution system also exists from PCSAT1 & 2.  Our Satellites provide a low cost educational transponder supporting not only GPS position reporting but also remote WX stations and other data link experiments and other University and School Experiments.

Space User Baseline PCSAT validates our links Vandegriff SCIENCE USNA-0203 PCSAT2 User Plot 18 Apr 06 See

Global Internet Linked Ground Stations All downlinks available live on web via Participating internet linked Ground Stations pcsat.aprs.org SCIENCE USNA-0203

Types of Labs Antenna Labs: Link, Patterns, Gain, Beamwidth, SWR Electrical Power sys:.. Solar Cells, batteries and Regulators Transmitters: TX power and antenna matching Receivers: Receiver sensitivity, selectivity and Bandwidth Comms: FSK, AFSK,PSK ; and TDMA and FDMA Telemetry: Signals, decoding, equations 5 channel A/D Command / Control:... Using the 3 commandable ON/OFF circuits. CPU and Experiments:. Aux serial port – processor, GPS, etc GPS interface: Using a GPS input for position determination Attitude Control: Passive/active Magnetorquing & wheels. Thermal Control: Absorbtivity, Emissivity, Conduction.

LABsat Examples

Ground Stations Laptop Ground Station for RAFT

Antenna Tests  Uses small 2.4 GHz camera/transmitters  First observe dipole link (1000’)  Place dipole at dish focus and measure gain  Swing dish to see Beamwidth

Antenna Tests Using PI network to match spacecraft antenna for best SWR Using GPS signals to plot antenna pattern of GPS

Antenna Tests RF LABsat model on rotor Rotator and S/A to plot pattern Dipole 1 Antenna Phasing experiment

Transmitter Tests Power out Efficiency Temperature Spectrum and EMI

Receiver Tests

Demodulation - FSK  All Seven Student LABsats on the air  Sharing a single TDMA channel  Using FSK for demodulation

Demodulation - PSK LABsat configured as HF to UHF linear transponder Indoor LABsat RX PSK-31 Waterfall Spectrum display on Student’s workstation

KPC-3+ Telemetry System

Used for Data LoggingSolar Panel Lab

Satellite Power Systems Solar Panel IV curve Series/Shunt Regulators NiCd Charge/Discharge

Attitude Control Labs Thruster Firing

Passive Magnetic Stabilization

MagneTorquing Stabilization

Momentum Wheel Stabilization

Serial Data Telemetry

APRS Global Network Google for “USNA Buoy” Select USNA-1 This data is LIVE Google WB4APR-9

 The comm channels can potentially draw from over 30,000 experimenters for easy assessment of loading and scaling issues.  Not only the sensors and users exist, but the global Internet collection and distribution system also exists from PCSAT1 & 2.  Our Satellites provide a low cost educational transponder supporting not only GPS position reporting but also remote WX stations and other data link experiments and other University and School Experiments.

Antenna Deployment

Typical ISS Passes

USNA Satellites Bob Bruninga, WB4APR