Transcript [] presentation

APRS in Wisconsin
The Automated Packet
Reporting System
by: Michael Martens, KB9VBR and
Mark Rasmussen, N9MEA
Overview
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Introduction
Protocol and Implementation
Software
Hardware
Network
APRS is:
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A one-to-many, unconnected packet protocol.
A tactical protocol designed for local RF use.
A protocol with many reporting capabilities.
A protocol with SMS capabilities.
A protocol also adapted to the Internet.
A protocol with extensive flexibility built-in.
A protocol still under development.
Introduction
• APRS, the Automated Packet Reporting
System, is an open system that uses
unconnected AX.25 radio packets to
transmit and collect data. This data is
usually overlaid on a map
Uses of APRS
• Using GPS data to track vehicle location
• Sending short, tactical bulletins and
messages between stations
• Transmitting data collected by a weather
station
The APRS Network
• Home stations
• Mobile and Portable GPS enabled stations
(trackers)
• Digipeaters (Wide-area and Fill-in)
• Internet I-Gates
• Automatic Weather Stations
What is needed to begin
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Computer with APRS software installed
Terminal Node Controller (TNC)
VHF transceiver and antenna
GPS required for mobile stations only
APRS Data Flow
APRS Frequencies
• VHF 144.39 MHz
• HF 10.151 MHz LSB
• Experimental work is being done on other
frequencies.
APRS Raw Packet
Originator
Application
Path
KB9DED>APW251,W9SM-10*,WIDE4-4,qAo,
N9SDL:=4457.01N/08938.76W- WinAPRS 2.5.1
-WIMARWAUSAU -251Location
Status
APRS Paths
• WIDEn-N (ex, WIDE3-3)
• WIn-N (ex WI2-2, keeps packets within the
state of Wisconsin)
• Named Path (KC9NW-10, KB9VBR)
• Relay and Trace (Obsolete, Do Not Use)
WIDE and WIDEn-N
• Digipeaters acknowledge WIDE paths
• Home stations should not set myalias to
Wide
• WIDEn-N is not the same as WIDE
(WIDE3-3 is not the same as
WIDE,WIDE,WIDE)
Named Paths
• Most efficient form of message propagation
• Only the station with the matching Alias
will digipeat the message
• AB9PJ-4, N9QIP-10, K9ABC-1
WIn-N
• Keeps APRS Packets within a geographic
location, in this case Wisconsin
• Reduces APRS overload as packets won’t
propagate beyond their geographic confines
• Great for public service event stations (eg
walks, parades, races, etc)
Best Path to Use:
• In the Wausau area: W9SM-1, WIDE2-2
• If you are mobile: WIDE1-1, WIDE2-2
• If you don’t want your packets to leave the
state WI2-2
How APRS Packets Propagate
APRS Real Time Propagation
http://www.mountainlake.k12.mn.us/ham/aprs
SSID
• Special Station Identifier (SSID) allows
multiple stations with the same callsign to
coexist on the network.
• Home stations have no SSID
• Digipeaters may use the ID -1 (W9SM-1)
• Mobile Stations may use the ID -9
(KB9VBR-9)
• Kenwood APRS radios may use -7
(WA9NBC-7)
SSID Suggestions
No SSID - Home Station, Home Station running I-Gate.
-1 Digipeater, Home Station running a Wide1-1 Digi, WX Digipeater
-2 Digipeater [#2 or] on 70CM
-3 Digipeater [#3]
-4 HF to VHF Gateway
-5 I-Gate (Not home station)
-6 is for Operations via Satellite
-7 Kenwood D7 HH
-8 is for boats, sailboats and ships (maybe 802.11 in the future)
-9 is for Mobiles
-10 is for operation via the internet only
-11 is for APRS touch-tone users (and the occasional Balloons)
-12 Portable Units such as Laptops, Camp Sites etc.
-14 is for Truckers
-15 is for HF
APRS Software
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WinAPRS/MacAPRS
UI-View
APRSDOS
APRSpoint
Other platforms include: Palm, Linux, Java
WinAPRS/MacAPRS
• www.winaprs.org
• Very easy to use
• Uses USGS Tiger maps and integrates with
Precision Maps from Undertow Software
• Also uses old style APRSDOS vector maps.
UI-View
• www.uiview.org
• Lots of features, more complex interface
• Handles plug-ins. Vibrant developer
network
• Uses raster maps. Integrates with Precision
maps. Plug-ins for Street Atlas, Mapblast,
and Tiger Maps
APRSDos
• web.usna.navy.mil/~bruninga/aprs.html
• The original APRS application.
Development going back to 1992
• Very rudimentary maps
• Has satellite tracking features, network
utilization analysis, and direction finding
support
APRSpoint
• www.aprspoint.com
• Easy to use, familiar Microsoft style
interface
• Integrates with Microsoft Streets and Trips
exclusively
APRS Software
All APRS software applications are
shareware and require a registration fee
for continued use. Registration fees
range in cost from charity donation to
around $100. Some applications may
also require you to purchase a map
package.
APRS Hardware
• VHF Transceiver
• Terminal Node Controller (TNC)
• GPS for mobile operation
VHF Transceiver
• Any 2 meter radio will work as long as it
will work on 144.390 csq. You will need to
make a cable to connect mic audio, RX
audio, and PTT to the TNC.
APRS Enabled Radios
• Some radios have built in TNCs for direct
connection to a computer or APRS
interaction right on the display.
Alinco DR-135
Kenwood TH-D7A
Kenwood D-700A
TNC
• The TNC, also known as a radio modem
converts the digital information from the
computer and/or GPS into audio tones.
• The APRS network runs at 1200 baud
• The TNC communicates with the computer
via the serial port.
TNC
• The most common TNC is the Kantronics
KPC-3+
• TNCs can be purchased used on EBay for
about $40-50. Kantronics TNCs will be
higher in price.
• Older TNCs work great for home stations,
ex: AEA PK-12, MFJ 1270 series, KPC-3
• Tiny Trak 3 and 4 - Open Tracker 1+ and 2
Kantronics KPC-3+
• About $230 retail
• Has a dual port that allows simultaneous
computer and GPS connection
• Great TNC choice for running an APRS
computer in a vehicle
Kantronics KPC-3+
Tiny Trak 4 and Open Tracker 2
• About $65-$100 retail
• Has a dual port that allows simultaneous
computer and GPS connection
• Cheaper than a regular TNC but has
limitations
Tiny Trak 4
Open Tracker 2
Tiny Trak 3 and Open Tracker 1+
• About $32 or $33 (kit) - $42 or $46 (built) retail
• Has a single port that only allows connection to a
GPS
• Cheaper than a regular TNC but it only transmits
data
Tiny Trak 3
Open Tracker 1+
Global Positioning System (GPS)
• A GPS unit is required for real time mobile
tracking
• GPSs come in many different forms
• Any GPS with NMEA output will work
with APRS
Garmin Streetpilot
Garmin Etrex Legend
Home Station Equipment
• Watching on RF
– Radio
– TNC
– Computer
• Watching on the Internet
– Computer
Tracker Station Equipment
There are two ways to send out your position
when mobile.
• Dedicated APRS system
• Mic-E system
Dedicated Tracker Station
Equipment
• With computer
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Radio
TNC (High end unit)
Computer
GPS
• Without computer
– Radio
– TNC (simple unit)
– GPS
Dedicated Equipment Pros and Cons
• Pros
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Can watch other units on map and send messages
Position is sent out at predetermined intervals
Separate radio system in the car in case your 2M voice radio dies
Separate radio infrastructure in case your repeater goes down
Could also be used as Winlink or Packet station
• Cons
– Another radio in the car
– More 2M RF to interfere with your local repeater traffic
– Higher cost because of more equipment
Mic-E Station Equipment
• GPS
• Cheaper Encode only TNC
• Uses your normal voice radio, no extra
radio
Mic-E Pros and Cons
• Pros
– Don’t have to install another radio in the car
– Cheaper than the dedicated equipment way
– Can use the cheaper encode only TNC
• Cons
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Can not track other units on a map
Can not send messages to other units
Position only goes out when you talk on the radio
Position on map could be very old because you didn’t talk on the radio
More expensive for the repeater owners
Won’t work on all repeater systems
No back-up radio if your voice radio fails
If the repeater fails, no one sees your position
Putting it all together
• Mobile tracking unit
with integrated
GPS
computer.
Computer running WinAPRS
Transceiver tuned to 144.390 csq
KPC-3+ TNC
Putting it all together
• Portable tracker box
Tracker
GPS
Antenna
Radio
Putting it all together
Who could this be?
• Bike Mobile APRS
GPS
Radio/Tracker
Antenna
Putting it all together
• APRS Home Station
- notice no GPS
Computer
TNC
Radio
Digipeaters
Digipeaters extend the coverage of the
portable and mobile units much like a
repeater but operating on a simplex
frequency. They are usually located at a
high location on a tower but can also be
located at someone’s home to help fill in a
certain area.
Digipeaters in the NE District
Estimated APRS Coverage to a
Mobile
APRS Network
• I-Gates are internet gateways that expand
the reach of APRS worldwide.
• An I-Gate listens to the local RF channel
and relays the information into an APRS
Internet data stream.
• I-Gates also relay information from the
Internet data stream to a local RF station
Benefits of I-Gates
• Reduces RF network congestion
• Increases the trackability of mobile stations
• Allows RF access of weather service
bulletins and alerts
• Can set up an APRS station without a radio
and TNC
• Any APRS station can be queried at
www.findu.com (map.findu.com/kb9vbr)
Weather Service Messages
• The National
Weather EMWIN
data stream is
injected into the
APRS data
stream.
• Alerts and
messages can be
color coded on the
APRS maps.
APRS and the Internet
• UI-View
radar plug-in
superimposes
NWS radar
data onto the
APRS screen.
• WinAPRS
has a similar
feature.
Weather Stations
You can also send out your local weather
information if you have the right equipment.
• 2M radio on 144.390
• TNC
• Weather Station
• Possibly a computer
Weather Information
APRS Satellites
• PCSAT2 is the second
generation APRS
satellite
• PCSAT1, launched in
2001, is no longer
fully operational
• PCSAT2 launched
August of 2005 has
returned to earth with
STS-115 in 2006
• The ISS is capable of
digipeating APRS
when the radio is not
used for other
activities.
APRS Books
• APRS, Moving hams
on Radio and the
Internet
• A good basic
introduction to the
mode
• OUT OF PRINT
• ISBN 0-87259-916-7
APRS Books
• VHF Digital
Handbook
• Covers APRS, Packet,
D-STAR, and more
• 2008 printing, $19.95
• ISBN 0-87259-122-0
For Additional Information
• Wisconsin APRS discussion group:
groups.yahoo.com/group/wisconsinaprs
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web site: http://wisconsinaprs.net
KB9VBR APRS page: www.kb9vbr.net
Michael Martens: [email protected]
Mark Rasmussen:
[email protected]