APRS - Automatic Position Reporting System
Presented by
Lee De Forest Amateur Radio Club
July 1, 2013
APRS - Automatic Position Reporting
System
What is APRS?
What started out in 1990 as a digital-equivalent of voice networks has
evolved into the RF-equivalent of the Internet. Imagine being able to
send a short message to anyone, anywhere, anytime.
• Automatic Position Reporting System
–Developed (and trademarked) by Bob Bruninga WB4APR
• Based on AX.25
–Unnumbered Information packets (UI)
–UI ‘s are unacknowledged
• VHF and HF mobile and fixed operation
• Uses GPS (mobile) or fixed coordinates
• Other terms:
–Mic-E -- Mic Encoder, TNC-less encoding of location, course and speed
–MIM - Micro Interface Module -- Telemetry TNC on a chip
July 1, 2013
APRS - Automatic Position Reporting
System
More about APRS
• Can be used to send simple text messages
– May be directed to a specific address or “broadcast”
– Text messages are acknowledged
• Beacon can contain other information:
– Weather station
– Station status text, e.g., email address, QTH, etc.
• Protocol contains encoding for displayed icon
• Can filter on “groups”
– use special, “designated” messages
– limits what is displayed
• Applications:
– Locating stations in disaster, public service events, etc.
– Tracking moving stations
– Simple messaging
July 1, 2013
APRS - Automatic Position Reporting
System
What is needed for APRS?
• Simple: just a computer with Internet connection
• More complex:
– Hardware
• VHF -or- HF transceiver
– antenna with vertical polarization
•
•
•
•
APRS-ready TNC -orAny APRS software-compatible TNC
Computer if using APRS software
Optional: NMEA-compatible GPS receiver
– Software
• Depending on radio/TNC, possibly none
-or-
• WinAPRS -or- MacAPRS
• APRS+
• PocketAPRS for Palmtop computers
July 1, 2013
APRS - Automatic Position Reporting
System
Typical Hardware
Garmin GPS units
StreetPilot
MFJ Data Radio and
Kantronics KPC-3
eMap
Kenwood
TH-D7G
July 1, 2013
GPSmap 162
TM-D700A
APRS - Automatic Position Reporting
System
GPS requirements
• What is NMEA?
– National Maritime Electronics Association
– Defines standardized protocol used by GPS receivers to send
coordinates and receive waypoints
• TNC or computer receives coordinates from GPS receiver
• GPS map displays received stations
– Received from TNC or computer as waypoints
– Displays callsign of APRS station
July 1, 2013
APRS - Automatic Position Reporting
System
WinAPRS Screen Shots
July 1, 2013
APRS - Automatic Position Reporting
System
APRS+SA Screen Shots
DeLorme Street Atlas
Display
Station List
July 1, 2013
APRS - Automatic Position Reporting
System
How is APRS distributed?
• For small groups, just point-to-point
• For larger areas, uses digital repeaters and routing
protocols
– Digital repeaters (digipeaters or digis) are wildcard named
“RELAY” and “WIDE”
• RELAY can talk to WIDE or to any local
• WIDE talks to WIDE
– Anyone can run RELAY
– WIDEs tend to be fixed and well known.
• VHF-HF gateways
• Internet gateways
– When configuring an APRS station for “packet path”
• Use “RELAY,WIDE,WIDE” or,
• Specific callsign of RELAY or WIDE station, if known
July 1, 2013
APRS - Automatic Position Reporting
System
How is APRS distributed?
• Listing of raw packets from WA6NIA-14
WA6NIA-14>APD214,RELAY*,WIDE,WIDE:=3346.12N/11806.37Wk191/000/Mic-E/M0/Off duty.. ]"42}dennis wa6nia@arrl.net
WA6NIA-14>APK101,RELAY,K7GIL-1,W6KRW-2*:@100347z3346.11N/11806.36Wk191/000/Mic-E/M0/Off duty>
WA6NIA-14>APD214,RELAY*,WIDE,WIDE:=3346.12N/11806.37Wk191/000/Mic-E/M0/Off duty.. ]"4,}
WA6NIA-14>APK101,RELAY,K7GIL-1,W6KRW-2*:@100352z3346.11N/11806.36Wk191/000/Mic-E/M0/Off duty>
WA6NIA-14>APD214,RELAY*,WIDE,WIDE:=3346.12N/11806.37Wk191/000/Mic-E/M0/Off duty.. ]"4.}dennis wa6nia@arrl.net
WA6NIA-14>APD214,RELAY*,WIDE,WIDE:=3346.11N/11806.38Wk191/000/Mic-E/M0/Off duty.. ]"4(}
• Shows position info, repetitive message (email)
• Shows two specific WIDE digis ...K7GIL-1 and W6KRW-2
– Also shows the generic wildcard routes: RELAY and WIDE
July 1, 2013
APRS - Automatic Position Reporting
System
Where do I find APRS on the air?
• HF
– Typical operation is on 30 meters - 10.151 MHz (this is actually
inside the band limit … uses AFSK on LSB)
• VHF
– National APRS freq - 144.390 MHz
– This is a very active frequency in Southern California
• Something new! ARISS - International Space Station
– Uplink: 145.990
– Downlink: 145.800
– Route info: NOCALL
July 1, 2013
APRS - Automatic Position Reporting
System
Internet Resources
• Information
–
–
–
–
http://web.usna.navy.mil/~bruninga/aprs.html
http://www.aprs.net
http://aprs.rutgers.edu
http://aprs.org
• APRS servers on the ‘net
– www.aprs.net and mirrors
• connects with Telnet from WinAPRS or APRS+
• Provides real-time, world-wide display
– www.findu.com
• Can be accessed by anyone
• example: http://map.findu.com/wa6nia-14
• Software sources
– TAPR:
http://www.tapr.org
– PocketAPRS
http://www.pocketaprs.com
• WinAPRS
• APRS+
July 1, 2013
APRS - Automatic Position Reporting
System
Demo Configuration
• In the conference room
– Kenwood TH-D-7G (WA6NIA-1)
• Dual-band (VHF/UHF) data radio with built-in APRS-capable TNC
• Garmin eMap GPS receiver with interconnecting cable
– Notebook with WinAPRS
– Palm III with PocketAPRS
• In the parking lot:
– Kenwood TM-D700A (WA6NIA-14)
– Garmin Street Pilot GPS with interconnecting cable
• (No waypoint display … NMEA out only)
July 1, 2013
APRS - Automatic Position Reporting
System
Demo
• WA6NIA-14:
– beacons on five minute intervals
– parked in FU parking lot
• WA6NIA-1
– should display WA6NIA-14 and possibly others
• stations displayed depends on nearby RELAY or WIDE digi
July 1, 2013
APRS - Automatic Position Reporting
System