APRS101APRS101, Hamradio Krótkofalarstwo
[ Pobierz całość w formacie PDF ]
AUTOMATIC POSITION REPORTING SYSTEM APRS PROTOCOL REFERENCE Protocol Version 1.0 The APRS Working Group Authors Document Version Approved Version 1.0.1 Filename aprs101.pdf Date of Issue 29 August 2000 Copyright ©2000 APRS Working Group All rights reserved Technical Editor Ian Wade, G3NRW APRS Protocol Reference Protocol Version 1.0 by the APRS Working Group Edited by Ian Wade Published by Tucson Amateur Packet Radio Corp 8987–309 East Tanque Verde Road, #337 Tucson AZ 85749-9399 United States of America ISBN 0-9644707-6-4 TAPR Publication Number: 99-4 Copyright ©2000 APRS Working Group All rights reserved APRS ® is a registered trademark of Bob Bruninga. WinAPRS ™ , MacAPRS ™ , X-APRS ™ , PalmAPRS ™ and APRS/CE ™ are trademarks using the APRS ® name, licensed from Bob Bruninga. This document may be copied for non-commercial purposes only, and must include the above copyright statement and trademark statements in full. FOREWORD This APRS Protocol Reference document represents the coming-of-age of WB4APR’s baby. Starting with a simple concept — a way to track the location of moving objects via packet radio — programs using the APRS protocol have grown into perhaps the most popular packet radio application in use today. It’s also become one of the most complex; from the simple idea grew, and still grows, a tactical communications system of tremendous capability. Like many ham projects, the APRS protocol was designed as it was being implemented, and many of its intricacies have never been documented. Until now. This specification defines the APRS on-air protocol with a precision and clarity that make it a model for future efforts. The work done by members of the APRS Working Group, as well as Technical Editor Ian Wade, G3NRW, should be recognized as a tremendous contribution to the packet radio art. With this document available, there is now no excuse for any developer to improperly implement the APRS protocol. As an APRS Working Group member whose role was mainly that of observer, I was fascinated with the interplay among the APRS authors and the Technical Editor as the specification took form. Putting onto paper details that previously existed only in the minds of the authors exposed ambiguities, unconsidered consequences, and even errors in what the authors thought they knew. The discussion that followed each draft, and the questions Ian posed as he tried to wring out the uncertainties, gave everyone a better understanding of the protocol. I am sure that this process has already contributed to better interoperability among existing APRS applications. Everyone who has watched the specification develop, from the initial mention in April 1999 until release of this Version 1.0 document in August 2000, knows that the process took much longer than was hoped. At the same time, they saw the draft transformed from a skeleton into a hefty book of over 110 pages. With the specification now in hand, I think we can all say the wait was worth it. Congratulations to the APRS Working Group and, in particular, to G3NRW, for a major contribution to the literature of packet radio. John Ackermann, N8UR TAPR Vice President and APRS Working Group Administrative Chair August 2000 i Table of Contents APRS PROTOCOL REFERENCE TABLE OF CONTENTS PREAMBLE ........................................................................................................................... 1 APRS Working Group ...............................................................................................................1 Acknowledgements ...................................................................................................................1 Document Version Number .......................................................................................................1 Release History.........................................................................................................................2 Document Conventions .............................................................................................................2 Feedback ..................................................................................................................................2 AUTHORS’ FOREWORD ...................................................................................................... 3 Disclaimer .................................................................................................................................3 THE STRUCTURE OF THIS SPECIFICATION ..................................................................... 5 1 INTRODUCTION TO APRS............................................................................................... 7 What is APRS? .........................................................................................................................7 APRS Features .........................................................................................................................8 2 THE APRS DESIGN PHILOSOPHY.................................................................................. 9 Net Cycle Time..........................................................................................................................9 Packet Timing .........................................................................................................................10 Generic Digipeating.................................................................................................................11 Communicating Map Views Unambiguously............................................................................11 3 APRS AND AX.25............................................................................................................ 12 Protocols .................................................................................................................................12 The AX.25 Frame....................................................................................................................12 4 APRS DATA IN THE AX.25 DESTINATION AND SOURCE ADDRESS FIELDS........... 13 The AX.25 Destination Address Field......................................................................................13 Generic APRS Destination Addresses ....................................................................................13 Generic APRS Address with Symbol .......................................................................................14 APRS Software Version Number.............................................................................................14 Mic-E Encoded Data ...............................................................................................................15 Maidenhead Grid Locator in Destination Address....................................................................15 Alternate Nets .........................................................................................................................15 Generic APRS Digipeater Path ...............................................................................................15 The AX.25 Source Address SSID to specify Symbols .............................................................16 5 APRS DATA IN THE AX.25 INFORMATION FIELD ....................................................... 17 Generic Data Format...............................................................................................................17 APRS Data Type Identifier ......................................................................................................17 APRS Data and Data Extension ..............................................................................................18 Comment Field........................................................................................................................20 Base-91 Notation ....................................................................................................................20 APRS Data Units.....................................................................................................................21 APRS Protocol Reference — APRS Protocol Version 1.0 Document Version 1.0.1: 29 August 2000 [ Pobierz całość w formacie PDF ] |
Podobne
|