Exploring APRS: The Automatic Packet Reporting System

History and Origins of APRS

The Automatic Packet Reporting System (APRS) was developed by Bob Bruninga, WB4APR, a senior research engineer at the United States Naval Academy, in the late 1980s. Initially, Bruninga created APRS to track the position of ships using the AX.25 protocol, which eventually gained popularity within the ham radio community2. The system was first implemented on an Apple II computer in 1982 to map high-frequency Navy position reports.

Early Applications

The first significant use of APRS was in 1984, when Bruninga developed a more advanced version on a VIC-20 to report the position and status of horses in a 100-mile endurance run. This early version was known as the Connectionless Emergency Traffic System (CETS). Over the next few years, Bruninga continued to refine the system, which was later ported to the IBM Personal Computer1.

Evolution into APRS

During the early 1990s, CETS evolved into the Automatic Position Reporting System, and with the advent of GPS technology, the name was changed to the Automatic Packet Reporting System to better reflect its broader capabilities. APRS was designed to be a real-time digital communication system for sharing information of immediate value in the local area, such as GPS coordinates, weather data, and text messages1.

Network and Global Reach

APRS operates on a single shared frequency, with data being repeated locally by digipeaters for widespread local consumption. Additionally, APRS data is ingested into the APRS Internet System (APRS-IS) via Internet-connected receivers (IGates), allowing for global distribution and access1. This network enables APRS to provide a shared live view of data, combining information from various sources.

Legacy and Impact

Bob Bruninga maintained the main APRS website until his death in 2022. His work laid the foundation for APRS, which remains a prominent protocol in amateur radio. The APRS Foundation, established by TAPR (Tucson Amateur Packet Radio), continues to maintain and develop APRS resources2. The system’s real-time data transmission capabilities make it invaluable for emergency communications, public service events, and various other applications.

For more detailed information, you can visit the Wikipedia page or check out the Ham Radio Prep guide.

How APRS Works

APRS operates by transmitting small packets of data over radio waves. These packets can include a variety of information, such as:

• GPS Coordinates: Allowing for real-time tracking of mobile stations.
• Weather Data: Providing updates from weather stations.
• Text Messages: Enabling short communications between operators.
• Telemetry Data: Sharing information from various sensors.

These packets are typically transmitted on a single shared frequency and can be received by any station within range. To extend the range of these transmissions, APRS uses digipeaters—stations that receive and re-transmit packets. Additionally, APRS data can be fed into the APRS Internet System (APRS-IS), allowing for global distribution and access via the internet.

Applications of APRS

APRS has a wide range of applications, making it a versatile tool for amateur radio operators:

1. Real-Time Tracking: APRS is commonly used for tracking the location of vehicles, boats, and even weather balloons. This is particularly useful for events like marathons, parades, and search-and-rescue operations.
2. Weather Reporting: Many amateur weather stations use APRS to transmit real-time weather data, which can be displayed on maps and used for forecasting.
3. Emergency Communications: APRS is invaluable in emergency situations, providing a reliable means of communication when other systems may be down. It can be used to coordinate disaster response efforts and share critical information.
4. Public Service Events: APRS is often used to support public service events, providing real-time updates on the location and status of participants and resources.

The Screenshot above shows the WX (weather station) MM0ZIF this data is sent from Weather Display software at my QTH (Home)

APRS Software for Different Platforms

To get started with APRS, you’ll need software that can handle the protocol. Here are some popular options for various platforms:

PC:

• PinPoint APRS: A modern APRS solution with unique features, PinPoint is free for individual use and supports various map providers.
• UI-View: An APRS client that supports TNCs in terminal mode, KISS mode, AGWPE host mode, and BPQ host mode.
• Xastir: A highly customizable program for receiving and plotting APRS position packets, supporting many map formats.

Mac:

• QTH.app: An APRS client application exclusively for macOS, offering features like map navigation, APRS-IS connectivity, and support for various TNCs.
• YAAC (Yet Another APRS Client): A platform-independent Java application that can be used as an APRS client, RF-Internet gateway, or AX.25 digipeater.

Android:

• APRSdroid: An Android application that allows reporting your position to the APRS network, displaying nearby stations, and exchanging APRS messages.

iOS:

• PulseModem A: An open-source iOS APRS client that connects to the APRS-IS network and can work without the internet by connecting the audio port to your amateur radio.
• aprs.fi: An iPhone and iPad application providing real-time access to APRS position information, weather reports, telemetry graphs, and more.

Web Based Apps:

• aprs.fi: A comprehensive APRS tracking website that provides real-time maps, data export tools, and various other features for APRS enthusiasts.
• N2RWE Live Real-time APRS Map: Offers a real-time, responsive map view of APRS data, including CWOP (Citizens Weather Observer Program) and other APRS-IS sources.
• APRS Track Direct: Provides a fast and easy-to-use map with APRS data from APRS-IS, CWOP-IS, and other sources.

Setting Up APRS

Getting started with APRS requires a few key components:

1. Radio: A VHF/UHF radio capable of transmitting and receiving APRS packets. Many modern radios have built-in APRS functionality.
2. TNC (Terminal Node Controller): A device that converts data from your computer or GPS receiver into a format that can be transmitted over the radio. Some radios have integrated TNCs.
3. GPS Receiver: For mobile stations, a GPS receiver is used to provide real-time location data.
4. Software: APRS software is available for various platforms, including Windows, macOS, Linux, and even mobile devices.

Once you have the necessary equipment, you can configure your setup to transmit and receive APRS packets. Many operators also set up digipeaters and internet gateways to extend the reach of their APRS network.

Conclusion

APRS is a powerful and versatile tool for amateur radio operators, offering a wide range of applications from real-time tracking to emergency communications. Its ability to transmit and share data in real-time makes it an invaluable resource for both hobbyists and professionals. Whether you’re tracking a weather balloon, coordinating a public service event, or simply exploring the capabilities of your radio, APRS provides a robust platform for digital communication.

For more detailed information and resources on APRS, you can visit the or check out the Beginner’s Guide to Using APRS for Ham Radio.