CELLULAR.TXT CELLULAR AUTOMATIC POSITION REPORTING SYSTEM (APRS) Document version: 8.4.2 7 July 99 Author(s): Bob Bruninga, WB4APR ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ This file is OBSOLETE: Any one with a cell phone, a MIM/Mic-Lite module and APRS could be tracked nationwide. The position is updated either automatically on schedule, by driver initiation, or on demand from a remote location. In addition to the position, a status message selected from litterally dozens of pre-arranged messages can be sent. The cost of each position/status report is the same as the minimum 1 minute rate with your cellular carrier. Today this is typically less than 50 cents. The vehicle interface circuit is about the size of a match box and interfaces your GPS to any cellular phone either accoustically or via an external microphone connection. It does not require an expensive data interface that is available for only the top-end phones. The system uses a common data tone burst to encode all of the mobile information in a one second tone burst. THis tone is either accoustically coupled to the Cell phone handset or electrically connected to the microphone circuit. Thus the tone is always available whenever a call is established. There are several recommended arrangements: 1) On demand. The vehicle cell phone is placed in auto-answer mode. Whenever the position of the vehicle is needed, the phone is called. THis can be done on schedule, or on demand by the remote APRS system. 2) Vehicle Driver - The cell phone is preprogrammed with the phone number of the dispatcher into a memory button. Whenever the driver wants to report his position or status, he presses the auto-dial button. The MIM/Mic-Lite can have a number of status switches which can be set to indicate any number of pre-arranged messages. The messages are field programmable. In addition, 3 to 5 channels of analog telemetry or up to 8 contact closures can be included in a brief telemetry packet. The Dispatcher Interface (DI) is a box that connects the APRS display computer to the phone line to receive the incoming mobile reports. Using the DI, APRS can maintain a track on up to 80 or more mobiles depending on their reporting rate. Maps anywhere in the country are available at various levels of detail. Since the primary application is the interstate traveler, the basic system comes with maps of the entire USA with all major roads and interstates. The cost of the MIM/Mic-Lite GPS and telemetry interface circuit is $79 and the Dispatcher Interface is around $220. For more information on the MIM/Mic-Lite device, read Mic-Lite.txt or MIM.TXT or TELEMTRY.TXT. For more information, contact Bob Bruninga WB4APR 115 Old Farm Ct Glen Burnie, MD 21060