APRS

APRS

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  WHAT IS THEAPRS 4S6GGS The APRS system was invented and introduced by Bob Bruninga, an amateur radio operator (WB4APR). Officially, APRS is the abbreviation Automatic Position Reporting System. www.4s5gs.gayan@gmail.com 6/25/2012
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  The APRS systemwas invented and introduced by Bob Bruninga, an amateur radio operator (WB4APR). WB4APR USA Robert.E.Bruninga 115Old.FarmCt Glen.Burnie.MD21060 USA. 4S6GGS Email – 4s5gs.gayan@gmail.com
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  Bob Bruninga History(WB4APR).  1960s Playing with radio, xtal sets, Tubed CB sets and converted car radios  1963 Novice: WN4APR with ARC-5 Command sets on 40/80m  1973 Playing with VHF FM in Japan and building radios  1975 Wrote first RTTY BBS, later added phone, then RF ASCII  1978 Worked with AMRAD group developing AX.25 in USA  1982 wrote first data map program plotting navy ship positions on APPLE2 in Japan.  1983 wrote VIC-20 VHF/HF BBS and Gateway and defined 200 Hz shift due to development of mods to dozens of surplus VADCG bell 103 modems with cross-county links to W0RPK, W9TD, and K7PYK on 10.149 MHz Remained on the air 5 years through 1989 under the FCC STA for automatic packet HF operations. Developed larger system on the Commodore C-64 for BBS's used around the world through the 90's.  1984 Developed CETS (Connectionless Emergency Traffic System) on Vic-20 and C-64 for digital packet commas in support of 100 mile cross country endurance run for AMRAD.  1986 or so, used CETS for amateur packet radio support of the FEMA National Disaster Medical System exercises in DC area.  1988 or so, ported CETS over to the new IBM AT PC and began to add maps and position plotting of stations.  1990 or so. Began hand making maps of the USA for CETWS use.  1992 Changed name of CETS to APRS and presented paper at DCC in Teaneck NJ where I first met Sproul Brothers who later wrote Mac and WinAPRS.  1994 Developed MIM Module with N3MIM and Mic-E protocol. Proposed WIDEn-N digipeating  1996 or so worked with TAPR to produce Mic-Encoder and Paccomm to indroduce callsign-substitution RELAY, WIDE, TRACE digipeating 4S6GGS Email – 4s5gs.gayan@gmail.com
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   1998 Workedwith Kantronics to introduced WIDEn-N digipeating and Kenwood to introduce the TH-D7 APRS warlike Talkie  2000 Kenwood introduced the D700 APRS mobile radio  2001 Introduced APRS touch-tone, APRS reporting of IRLP and Echolink. Developed PCSAT-1.  2004 Began the New-N Paradigm to rid APRS of all old legacy digipeating algorithms and focuse on user education for one standard  2005 Began initiative to include operating Frequency in all packets.  2006 Developed PCSAT-2 to fly on outside of ISS  2007 Developed ANDE, RAFT and MARScom amateur satellites for deployment by Space Shuttle  2008 Yaesu introduced the VX-8R APRS walkie-Talkie.  2008 Introduced the Universal Ham Radio Text Messaging Initiative to tie together the two-dozen or more existing amateur radio text messaging capabilities. 4S6GGS Email – 4s5gs.gayan@gmail.com
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  Officially, APRS isthe abbreviation for Automatic Position Reporting System. Some feel APRS should be the abbreviation for Automatic Packet Reporting System. Originally the system only reported positional information. However, in recent years, APRS has become more than a standard for reporting the simple location of an object. It is now used for APRS Features  Station Status  Station Positions  Messages  Bulletins  Stations Heard  Station Tracking  APRS Satellites  DX Clusters  Internet and Igates  Frequency Coordination  Protocol  Reporting weather  Digital Advance Fox Hunting E.g. It like  Internet Access Locations of objects that have no actual APRS systems aboard, like starting locations for races, check points for those races, etc. Basically, an APRS system requires a location sensor (GPS, but sometimes just a person with a map), a Packet radio transmission system on one end and a packet radio receiver and a computer on the other end of the system. The first system collects its current location and encodes it in a standardized format as a string of text and transmits that information as a beacon. The transmission is NOT directed at any one station but rather beaconed out for all listening stations to hear and interpret. A second system receives the information using APRS software and then decodes the packet and, typically, places an icon on a map showing the transmitting station's location. This page is only meant to provide this snapshot overview of APRS. Visit the links below to get more detailed information on this technology. APRS is a real-time tactical digital communications protocol for exchanging information between a large number of stations covering a large (local) area. As a multi-user data network, it is quite different from conventional packet radio. 4S6GGS Email – 4s5gs.gayan@gmail.com
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  APRS is differentfrom regular packet in four ways. First by the integration of maps and other data displays to organize and display data, second, by using a one-to-many protocol to update everyone in real time, third, by using generic digipeating so that prior knowledge of the network is not required, AND FORTH, since 1997, a worldwide transparent internet backbone, linking everyone worldwide. APRS turns packet radio into a real-time tactical communications and display system for emergencies and public service applications (and global communications). Normal packet radio has only shown usefulness in passing bulk message traffic (Email) from point to point. It has been difficult to apply conventional packet to real time events where information has a very short life time and needs to get to everyone Although the recent interfaces to the Internet make APRS a global communications system for live real-time traffic, this is not the primary objective. But like all of our other radios, how we use APRS in an emergency of special event is what drives the design of the APRS protocol. Although APRS is used 99% of the time over great distances, and benign conditions, the protocol is designed to be optimized for short distance real-time crisis operations. APRS is a full featured automatic vehicle location and status reporting system too. It can be used over any 2-way radio system including HAM, CB, Marine Band, and Cellular Phone. Sat. Aeronautical APRS Tracking Example What's a Tracker? A tracker is the means by which a mobile station can be tracked. It may consist of a radio, antenna, TNC and GPS but since most of the time the mobile just transmits unconnected UI frames, the receiver part of the TNC is redundant. Therefore more and more stations are using small-dedicated tracker units instead of full-featured TNCs. These trackers can have various operating abilities. The simplest will just transmit a UI packet indicating their position every few minutes, others have more functions 4S6GGS Email – 4s5gs.gayan@gmail.com
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  4S6GGS Email –4s5gs.gayan@gmail.com
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  Digipeaters NMEA Data APRSrecognizes raw ASCII data strings conforming to the NMEA 0183 Version 2.0 specification, originating from navigation equipment such as GPS and LORAN receivers. It is recommended that APRS stations interpret at least the following NMEA Received Sentence types: GGA Global Positioning System Fix Data GLL Geographic Position, Latitude/Longitude Data RMC Recommended Minimum Specific GPS/Transit Data VTG Velocity and Track Data WPT Way Point Location Packet Timing Since APRS packets are error-free, but are not guaranteed delivery, APRS transmits information redundantly. To assure rapid delivery of new or changing data, and to preserve channel capacity by reducing interference from old data, APRS should transmit new information more frequently than 4S6GGS Email – 4s5gs.gayan@gmail.com
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  old information. There areseveral algorithms in use to achieve this: • Decay Algorithm Transmit a new packet once and n seconds later. Double the value of n for each new transmission. When n reaches the net cycle time, continue at that rate. Other factors besides “doubling” may be appropriate, such as for new message lines. • Fixed Rate Transmit a new packet once and n seconds later. Transmit it x times and stop. • Message-on-Heard Transmit a new packet according to either algorithm above. If the packet is still valid, and has not been acknowledged, and the net cycle time has been reached, then the recipient is probably not available. However, if a packet is then subsequently heard from the recipient, try once again to transmit the packet. • Time-Out This term is used to describe a time period beyond which it is reasonable to assume that a station no longer exists or is off the air if no packets have been heard from it. A period of 2 hours is suggested as the nominal default timeout. This time-out is not used in any transmitting algorithms, but is useful in some programs to decide when to cease displaying stations as “active”. Note that on HF, signals come and go, so decisions about activity may need to be more flexible 4S6GGS Email – 4s5gs.gayan@gmail.com
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  Technical information In itsmost widely used form, APRS is transported over the AX.25 protocol using 1200 bit/s Bell 202 AFSK on frequencies located within the 2 meter amateur band. Sample APRS VHF frequencies  144.390 MHz – Chile, Indonesia, North America [3] [4]  144.575 MHz – New Zealand  144.660 MHz – Japan  144.800 MHz – South Africa, Europe, Russia  144.930 MHz – Argentina, Uruguay  145.175 MHz – Australia  145.570 MHz – Brazil  145.525 MHz – Thailand 4S6GGS Email – 4s5gs.gayan@gmail.com