Monday, May 19, 2014
Bahan presentation tentang APRS oleh 9W2SMF di Seminar APRS
What is APRS?
APRS stands for Automatic Packet Reporting System (although it is frequently also called Automatic Position Reporting System.)
APRS was developed in the early 1990's by Bob Bruninga, WB4APR, for tracking and digital communications with mobile GPS equipped stations utilizing Amateur two-way radio.
Bob Bruninga – “Father of APRS”
His first experimental protocol was run on a VIC-20 program in 1984 to report the position and status of horses in a cross country endurance run for AMRAD
He developed the current APRS protocol as part of his research for the US Navy while an Instructor at the Naval Academy in Annapolis, MD. to assist in tracking boats in races on the local waterways.
The predecessor to the current “APRS” protocol was named APLS and released in 1991.
In the 13 years since its introduction, he has helped APRS to grow to the extent that it now encompasses just about every aspect of Amateur Radio.
He is still very active today, and continues to provide support and set standards.
What is APRS all about?
The APRS System was developed in order to assist amateur radio operators in tracking and monitoring position data.
APRS is used daily in order to assist in Search and Rescue through its tracking capabilities.
An original intent for APRS is its messaging capabilities, which can work even in a disastrous time when the Internet is down.
APRS can be used to transmit location data, course and speed info, and weather information in a timely fashion using a packet network.
More “About APRS”….
The Automatic Packet Reporting System consists of a very large land based wireless network.
This network has nodes nearly every 20-30 miles that relay signals through digipeaters.
APRS is used in space to track satellite data and GPS information from onboard GPS receivers.
It is also used to monitor telemetry values of weather stations for the National Weather Service (NWS)
APRS has the capability to quickly relay telemetry values to research centers without the Internet.
Different than Regular Packet
It uses graphical mapping and other data displays.
All communications use a “one-to-many protocol” so everyone is updated in real time.
Generic digipeating so knowledge of the network isn’t required.
APRS turns packet radio into a real-time tactical communications and display system for emergencies and public service applications.
What Equipment is required?
APRS was developed to work in a mobile environment, so it was designed to only use three pieces of hardware.
This consists of a transmitter/receiver (Transceiver), a Global Positioning System (GPS), and a terminal node controller (TNC).
A VHF Amateur Radio Transceiver operating on 144.390 Mhz. (USA).
Must be a “transceiver” as APRS uses a collision detection system to know when to send data.
Range of coverage depends on the power of the transmitter.
A standard GPS (Global Positioning System) unit.
There are 24 orbiting satellites used to pinpoint anyone's specific geographic location.
They also provide ground speed and altitude measurements.
Current accuracy ranges from 1-5 feet.
A TNC which is basically a radio (or “RF”) modem.
The TNC connects the transceiver to a GPS converting it’s data into AX.25 Packet protocol.
“TinyTracs” are simple “Transmit Only” stand alone APRS TNCs