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Automatic Packet Reporting System

Network Overview

APRS (Automatic Packet Reporting System) is a digital communications protocol for the exchange of information between a large number of stations covering a large (local) area. As the data in multi-user network, it is quite different from conventional packet radio. Rather than using data related streams where stations communicate with each and other packets are acknowledged and retransmitted if lost, APRS operates entirely in a broadcast mode without connection, without number using AX.25 frames. Packages APRS is transmitted to all other stations to hear and use. transponder package, called digipeaters, form the backbone of the system APRS, and using technology to store and forward broadcast packets. All stations operate on the same radio channel, and forward packets through the network of digi digi, spreading outward from their point of origin. All radio stations reach of each receive digi Package. Each digi, the packet path is changed. The package will be repeated across a number of digital repeaters or hop-based on the very important "PATH" setting. Digipeaters keep track of the packets they transmit for a period of time, preventing and duplicate packets to be retransmitted. This keeps packets travel in endless loops within the ad hoc network. Finally, Most packages are heard by an APRS internet gateway, called IGate, and packets are routed to the Internet backbone APRS (where packets IGate heard duplicated by others are ignored) for display or analysis by other users connected to a server APRS-IS or on a website designed for this purpose. Although it appears that the use of packages without bond and without number, without acknowledgment and retransmission on a shared channel and sometimes congested resulting in a poor reliability due to a packet is lost is not the case because the packets are transmitted (broadcast) to everyone, and multiplied several times each digital transponder. This means that all digital repeaters stations and obtain a copy range, and then distribute it to all other digital repeaters and stations within their reach. The end result is that packets are multiplied more than they are lost. Therefore, packets can sometimes be heard at a distance from the origin station. Packages can be digipeated tens of kilometers or hundreds of kilometers, depending on the height and breadth of digital repeaters in the region.

When a packet is transmitted, it is duplicated many times over and rayon, taking all available paths simultaneously, until its development path that dictates the number of "hops" is used.

Positions / Objects

APRS contains only four types of packets: Position / objects Status, messages and queries. The position Packages / object contains latitude and longitude, and a symbol to be displayed on the map, and many fields Optional for altitude, heading, speed, radiated power, antenna height above average terrain, the antenna gain, and frequency Operating vote. Positions of base stations are configured in the APRS software. mobile stations (portable or mobile) will automatically have their location information of a gps receiver is connected to the APRS equipment.

The map display uses these fields to trace a communication range of all participants and facilitate the ability to communicate with users in the two situations of routine and emergency. Each package position / object can use any How many hundreds of different symbols. Position / objects can also contain information or weather can be any number of Dozens of standard weather symbols. Each symbol on a map APRS can display many attributes discrimination either by color or other technique. These attributes are:

Fixed or mobile

Dead-Reckoned or old

Message capable or not

Station or object

own object or one object to another station

Emergency, priority or special

Status / Messages

The packet status is a free-field format which allows each station to announce its current mission or application or contact information or other information or data from a immediate usefulness for peripheral activities. The message packet may be used for point to point messages, newsletters, announcements or even e-mail. Newsletters and announcements are treated specially and displayed on a "Community Bulletin Board" unique. This bulletin board is of fixed size and all the ballots are sorted all the posters on this screen. The purpose of this screen is to be consistent and identical for all viewers so that all participants see the same information simultaneously. As the rows are sorted on the screen, then individual posters may modify, update, or delete individual lines of their ballots at any time to keep the scoreboard updated all viewers.

All APRS messages are delivered in real time directly to recipients online. Messages are not stored and transmitted, but attempts to timed out. The delivery of these messages is global, since the APRS-IS delivers all packets to all other iGate worldwide and those posts will be coming back to RF via IGate any that is near the recipient.

Case a message can be sent to email and messages are removed from the real-time APRS-IS by the engine Email WU2Z and wrapped in a standard protocol for Internet Mail and sent in an email regular internet.

Network

In its simplest implementation, APRS is used to transmit data in real time, information and reports of the exact location of a person or an object via a data signal sent over amateur radio frequencies. In addition real-time production reports using the position attached GPS receivers, APRS is also capable of transmitting a wide range of data including weather reports, short text messages, radio direction finding bearings, telemetry data, short e-mail (send only) and storm forecasts. A Once transmitted, these reports can be combined with a computer and mapping software to see the transmitted data superimposed with great precision over a map.

Although the scorecard is the most visible feature of the APRS, the text messaging features and capabilities of local distribution information combined with the robustness of the network must not be neglected, the New Jersey Office of Emergency Management has an extensive network of stations APRS to allow text messaging between all county emergency centers operating in the event of failure of traditional communications.

Technical information

In its most widely used, is carried on the APRS AX.25 using Bell 202 1200 baud shift keying audio frequency (AFSK) on the frequencies in the 2 meter amateur band:

Bali Island: 144.390 MHz

Indonesia: 144.390 MHz

North America: 144.390 MHz 144.990 sometimes used as a substitute input frequency for low-power local stations

Australia: 145.175 MHz 144.390 MHz available for a secondary frequency, primarily for satellite and DX work.

New Zealand: 144.575 MHz (National APRS) and 144,650 (digipeaters) supports WIDEn-Nheck with the local population for more details

Argentina: 144.930 MHz

Brazil: 145.570 MHz

Europe: 144.800 MHz

Chile: 144.390 MHz (Santiago), 144.390 MHz (Los Andes, Calama and pesetas. Arenas), 145.010 MHz (Chilln)

Africa South: 144.800 MHz

Japan: 144.640 MHz

Thailand: 144.525 MHz

An extensive digital repeater, or "digi" network provides transport for APRS packets on these frequencies. Internet access stations (IGate) communicate on the network-air APRS APRS Internet (APRS-IS), which is used worldwide, the broadband backbone for APRS data. Stations can tap into this stream directly, and a number of databases connected to the APRS-IS allow web access to data and more advanced features of data mining. A number of low earth orbiting satellites and the ISS are capable of relaying APRS data.

device configuration

APRS infrastructure includes a variety of Terminal Node Controller (TNC) facilities set up by various amateur radio operators. This includes maps its radio interface to a computer, TNCs simple and "smart" TNC. The "smart" TNCs are able to determine what has already product with the packet (information unit) and may prevent repeat redundant packets in the network.

Reporting stations use a routing method called a "path" to disseminate information across a network. In a typical packet network, a station using a way stations known as "via n8xxx, n8ary." This causes the packet to be repeated by the two stations before stopping. In APRS generic codes are assigned to relay stations, which operate more automatic.

recommended path

Throughout North America (and in several other regions), the recommended path for mobile phones or mobile stations is now WIDE1-1, WIDE2-1. Fixed stations (houses, etc.) should not normally use a routing path if they do not need to be digipeated outside their region (and most do not). Otherwise, a path of WIDE2-2 or less should be used as requirements dictate. This path is reflected in the routing of packets through the component APRS radio, and fixed stations should carefully consider their choice of routing path (s) to avoid unnecessary clutter RF outside their listening area Local VHF.

Old Road

From the beginning, the generally accepted method of configuring the station was to allow stations short-range repeating packets requesting a path of "relay" stations and long-range were set to repeat both "Relay" and "WIDE" packages. This was accomplished by setting MyAlias station set to RELAY or WIDE, if required. This resulted a path of RELAY, WIDE for reporting stations. However, there was no double checking of packets or the substitution of aliases. This sometimes resulted tags to "ping pong" back and forth instead of propagating outside source. This caused lots of interference. In the absence alternative alias, you could not tell who had used digipeaters a lighthouse.

New Path

With the advent of new "smart" TNC, stations that were previously "WIDE" are now "WIDEn-N." This means a packet with a path of WIDE2-2 would be repeated by the first station WIDE2-2, but the path will be modified (decremented) to WIDE2-1 for the next station to repeat. The package continues to be repeated when the "-N" part of the path reaches "0". This new protocol has caused the former RELAY and wide paths become obsolete. Digi operators are invited to re-configure fill-in "relay" stations instead of responding to WIDE1-1. It follows a new path more effective WIDE1-1, WIDE2-1. While most of the world has adopted the "new WIDEn-N settings, there is an ongoing debate in the United Kingdom on the subject. The objective should be the universal parameters that will work everywhere.

The facilities available

There are few radios on the market that include a High AX.25 Terminal Node Controller and APRS software, and can work with or without the need for external GPS device. Three common models are Kenwood TM-D700A mobile, his replacement, Kenwood TM-D710A and handheld Kenwood TH-D7A (G). Yaesu has recently entered the market with their computer APRS of VX-8R.

The HamHUD includes a screen for displaying the position of other stations and weather reports, and a way to send and receive APRS messages, and an interface to a GPS receiver. It began in 1997 as a device for homebrew, but more recently, kits are available from time to time. It connects to a TNC which is in turn connected to a radio. The Alinco DR-135T is popular as the mounted inside T2-135 can be used with it, reduce the number of items that must be interconnected. SmartBeaconing has been developed for HamHUD by Tony Arnerich and Steve Bragg. It varies the rate of beacon based on speed, and add corner attachment. SmartBeaconing was also adopted by the TinyTrak Opentracker and the series.

The combined RTrak Opentracker a 1 + and a GPS receiver with a low power transmitter in one package. The original units as 500 mW, but the current version is at 350 mW.

Byonics presented an all-in-One combines a GPS receiver, radio controller and synthesized TinyTrak called 2m Micro Trak AIO that does not require installation by the user.

ArgentData now has a 5-watt VHF transceiver with Integrated tracker2 in a compact package. With the GPS non-display of a receiver connected, the T2-301 can be used as a monitoring tool. GPS receiver type display compatible, received position reports can be output as waypoints. With a Garmin Nuvi 350 GPS receiver, it can send and receive messages and APRS that the display of other stations as waypoints. The Nuvi 350 can be used this way with a stand-alone Tracker 2 (OT2m) or connected to a T2-135 who boards an Alinco DR-135 radio. T2-301 can also be used as a standalone digital repeater.

The APRS is a Skytrack APRS 144.800Mhz tag that includes an RF transmitter 8W, programmable PIC & u-block GPS receiver on a single PCB 72x56mm.

BigRedBee the GPS transmitter is the smallest 2 meter frequency agile fully integrated APRS transmitter available. Power output is 6 watts from a supply voltage of only 7.5 volts. It also has onboard data logging that can be downloaded for later viewing and via Google Earth. A low power version of 70 cm is also available.

Data Online

Much of the data transmitted on APRS can also be seen on the Internet.

History

Bob Bruninga implemented the first ancestor of the APRS on an Apple II in 1982. This first version was used to map the high frequency of position reports to the Navy. In 1984, Bruninga developed a more advanced version on a Commodore VIC-20 for reporting the position and status of horses in an endurance race 100-mile. During the next two years, Bruninga continued to develop the system, it now called the emergency Connectionless Traffic System (CETS). After a series of Federal Emergency Management Agency (FEMA) exercises using CETS, the system has been ported to the IBM PC. In early 1990, CETS, now known as the Automatic Position Reporting System, continues to evolve in its current form. As GPS technology became more widely available, "Position" has been replaced by "packages" to better describe the features the most generic system and focus on its uses beyond simple position reports.

related systems

The APRS protocol has been adapted and extended to support projects not directly related to its original purpose. The most notable of them are FireNet and PropNET projects.

FireNet APRS is a system based on Internet-protocol and most APRS software to provide customers even fight against fire, earthquake, and weather information in much higher volume and detail than the traditional APRS system is capable of carrying.

PropNET uses protocol AX.25 APRS and PSK31 more to study the radio frequency propagation. "Probes" PropNET transmit position reports, as well as information on the transmission power, altitude, and antenna gain, at different frequencies to allow stations monitoring to detect changes in propagation conditions.

Open Trac was created to offer an alternative to APRS was cleaner and more functional than APRS.

Further reading

Stan Horzepa, WA1LOU (1999). Loved APRS maps and Mobiles. ARRL. ISBN 978-0872597747.

See also

List of APRS nodes

Automatic Identification System – a reporting system used to position the vessel traffic

TCAS

References

^ Ab Dean R. Straw, N6BV, eds (2006). The ARRL handbook for radio communications. Newington, CT. p. 9.22. ISBN 0-97259-948-5.

External Links

APRS web site. APRS home page with all addenda and updates.

Florida West Central Florida APRS info and APRS-IS Server Tier2 APRSfl.net

Queensland, Australia APRS Information

APRS Wiki Site More specific configuration APRS

Using APRS for Windows Mobile PocketPC PDA with OpenStreetMap

APRS options PocketPC PDA with PocketPC PDAs using APRS

APRS APRS for Windows Mobile and WM OpenStreeMap on PDAs.

www.findu.com Web access worldwide APRS data in real time

Automatic Update APRS aprs.fi real-time view using Google Earth and Google Maps, available in 14 languages

OpenAPRS Web-based APRS data in real time using Google Earth Maps

APRS Packet OAPR Web search engine for the station, weather, telemetry and position of research and debugging.

DB0ANF Web access to the APRS station and network data

HamHUD An APRS message capable "heads up display high "LCD. SmartBeaconing was first developed for the HamHUD.

APRS server list publicly accessible servers hosting APRS-IS

APRS World Open Source Web-based APRS database

APRS APRS specification formal specification document

KCAPRS Start by organizing APRS

Home PropNET If the group is open and nobody is active there someone to hear?

Northwest APRS Homepage Pacific Northwest APRS another Wiki

APRS in Australia (VK) APRS National Site Information

Argentina APRS APRS Group Group Argentina (Spanish)

APRS APRS Brazil Brazilian Network since 1998 (in Portuguese)

Peet Bros. Company, Inc. Homepage Weather station hardware with direct support for APRS Interface / TNC

Official UI-View Site G4IDE SK Roger Barker was the author of UI-View

UI-View Web Resource M0CYP UI-View, including registration

Radioactive Networks GPS projects

Xastir popular open source APRS client for Linux, Windows, Mac OS X and more.

APRS ON4SAXA free online video for APRS

USAPhotoMaps A free Windows program

APRS aprs.qrz.ru Russia

APRS.cz APRS in Czech

APRS Network Analysis New Zealand

Ui-View New Zealand server

APRS General information

ZLhams Wiki

APRS Information in Japanese

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