[LUNAR Announce:] FW: [AeroPac Members] A Virtual Classroom Overview

Fri Jul 15 20:20:19 UTC 2011

Lunar folks

FYI

Charlie KI6PQQ
LUNAR #1405, http://www.lunar.org 
Aero-Pac # 699 http://www.aeropac.org 
NAR [L3] #85655, http://www.nar.org 
Tripoli [L3} #11202 www.tripoli.org

From: kenbiba at me.com
Date: Fri, 15 Jul 2011 10:15:29 -0700
To: aeropac-members at mylist.net
CC: RJTwiggs at gmail.com; lynnc at universe.sonoma.edu; Paul.Hopkins at johnmuirhealth.com; bigredbee at gmail.com
Subject: [AeroPac Members] A Virtual Classroom Overview

As many of you know (and some of you have contributed time and skill), AeroPac is the proud owner of  a "Virtual Classroom".   The Virtual Classroom began as an idea of Professor Bob Twiggs (inventor of the CanSat and instigator of ARLISS) to extend the science and engineering experience of ARLISS across the Internet to create a "virtual classroom".   Through a grant from the California Space Authority, contributions from Sonoma State University and the hard work of AeroPac members - we are about to have a fully realized capability.

I thought I would give a 2011 update on what it is and what it can do.    It will be operational at 2011 Aeronaut, XPRS and ARLISS.

The Virtual Classroom is a mobile communications tool, based on former mobile TV van, that can deliver telemetry tracking, video streaming, mobile Internet to track and share stratospheric balloon flights, rocket flights, satellites and other science and engineering experiments that do not take place in a standard laboratory with a wide audience and collaborators on the Internet.

Let' see what it can do.   BTW - you should see the comments I get asking me what I am doing as I work on this in San Francisco.

And remember - the VC is asset for the entire Club and for ARLISS and our students - please make use of it.

Internet Service

The foundation of the VC is a core Internet service.    The VC provides a dual IP backbone to the Internet - either a 1.2m VSAT or a 4G cellular modem.   Both provide about 2 Mbps downstream and 1 Mbps upstream (the VSAT a bit less and the cellular modem a bit more).   The Internet backbone is streaming video and VoIP capable, though the sat link has much longer end-to-end delay of 500+ msec roundtrip.   The satellite link has a limitation of about 400 kbps for the streaming video uplink - the VC is not HD capable today.    The VSAT dish has the uber cool geek feature of "one button" deploy - internal GPS, compass and tilt sensors automatically point the dish and acquire Internet service - in about a minute.

The VC creates a "bubble" of WiFi service around it to access its services from an 2.4 GHz 802.11 g/n WiFi device.    The foundation is a 100 Mbps 5 GHz 802.11n backbone that can extend the VC service for many kilometers is desired.

The core user WiFi service is 2.4 GHz 802.11n covering the VC van, AeroPac's camp (out to about .75 km) and extended further through remote repeaters.   At AeroPac launches this will include coverage at the away cell.   Access to local servers is many Mbps, however Internet access is limited by the relatively narrow Internet backbone pipe.

Telemetry and Tracking

Tracking and communication with  rockets, balloons, and payloads is one of the key capabilities of the VC.   Mounted on the mast is an array of antennas feeding van configured radios providing telemetry and communications service in four bands:

Ham 2m 140-148 MHz Voice and APRS via Kenwood D700 transceiver using a 4 dBi circularly polarized quadrifilar helix antenna
Ham 70 cm 435-440 MHz Voice and APRS via Kenwood D700 transceiver using a 4 dBi circularly polarized quadrifilar helix antenna
APRS 70 cm 435-440 MHz APRS RX via Kenwood D7 receiver with 15 dB mast mounted LNA fed from 4 dBi circularly polarized QFH antenna
xStream 902-928 MHz Digi (formerly Maxstream) xStream mast mounted transceiver with circularly polarized 8 dBi antenna
WiFiinSky 2.4 GHz A experimental 2x2 multiply polarized MIMO WiFi radio and antenna suite designed for high performance data in the sky

These antennas are particularly designed to communicate with spaceborne and airborne objects, tumbling, rotating and to compensate for the substantial signal loss of polarization and antenna pattern mismatch.    The antenna coverage patterns and polarization are optimized for this application and can easily double to triple coverage from more conventional systems.

These radios systems feed a dedicated Windows 7 server in the van dedicated to telemetry collection and forwarding to the Internet.   The VC is an APRS IGate and forwards (and receives) APRS tracking data to the world-wide APRS-IS database.

Tracking telemetry forwarded to the APRS-IS is visible on the aprs.fi website - and a window to this website is accessible from the AeroPac web page - tracking projects equipped with compatible telemetry (2m and 70cm APRS - Beeline, and GPRSFlight) in near real time world wide.

The architecture of the VC telemetry system permits the straightforward addition of new radios (for example Zigbee).

Video Streaming

The VC has four H.264 streaming video cameras for capturing events:   one mast mounted with 10x electronic zoom, two remote battery operated (intended for covering away pads and LCO) and a van cabin mounted webcam.   These video sources, as well as a wireless remote to the LCO microphone, are streamed to a Windows 7 video server for mixing, transcoding and streaming to a uStream video server.

Links to the uStream video feed can be embedded in web pages - as on the AeroPac.org web site.

"Roving reporter" capabilities are supported by the uStream on iPhone 4s - using VC WiFi to connect back to the uStream video distribution server.

Collaborative meetings are supported via GoToMeeting - which works surprisingly well across the satellite link.

Social Networking

AeroPac has Twitter and Facebook accounts that are linked into a social network feed tied to the video stream.

Weather

The VC has a weather station and offers a local web site with current weather.   Winds aloft data and weather forecasts can be retrieved across the Internet connection.

GPS

The VC has a central GPS server for its internal services.    A Bluetooth GPS service is provided for wireless access to GPS from VC operators (front seat operators during balloon recovery for example).

Voice

The VC has 2m and 70cm basestation voice capability as well and 5 W handhelds for Ham (2m and 70cm) as well as GMRS service.

Printing

The VC has wireless print server with a color bubblejet printer.

Platform

2000 Ford van - donated ABC TV Los Angeles - extensively modified for internal electronics, V-10 engine, air conditioning, power distribution, 40' hydraulic antenna mast, 3.5 KW generator.

With current electronics suite, VC can operate off motor alternator power, internal 3.5 KW generator (loud),  external 2 KW Honda generator (quiet) or internal batteries for a short time (30 minutes).    When using 4G as Internet backbone access (so VSAT dish not deployed) the van can be used in fully mobile mode for balloon and payload tracking.

Tthe VC van can support three people in mobile operation - a driver and two operators.
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