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GPS-GSM
Mobile Navigator
Abstract
Block
Diagram
Description
This
GPS-GSM Mobile Navigator is the main part of a Port Navigation
System. The Port Navigation System is including many GPS-GSM
Mobile Navigators and a Base System - the Control Center. In
order to monitor ships around the port, the GPS-GSM Mobile Navigator
on ships receives GPS signals from satellite and then computes
the location information, which is sent it to the Control Center.
With the information, the Control Center knows where the ships
are. Besides receiving and transferring the GPS information,
the GPS-GSM Mobile Navigator can also give alarms to the Control
Center if emergency occurs, or receive other information from
the Control Center.
The
core of the GPS-GSM Mobile Navigator is an AT90S8515, which
controls all other parts to work properly. A GPS module receives
GPS signals every specific time and sends it to MCU by an RS-232
interface. By a GSM module the MCU communicates with GSM network,
and the interface between them is also RS-232. And another RS-232
interface is used to exchange data with PC. Since there is only
one RS-232 interface in the AT90S8151, a 3-channel multiplex
is used to switch the 3 work modes. All the location information
and other data are stored to an AT45D021, which is 2M-bit serial
data flash. Since the GPS-GSM Mobile Navigator saves GPS signals
every 20 seconds, the flash stores up to 2160 pieces of location
information in 12 hours. The MCU communicates with the data
flash by an SPI interface. A LCD displaying the system status
connects to MCU through 7 standard I/Os. And the GPS-GSM Mobile
Navigator also has 4 buttons to let users control the system.
Because AT90S8515 is a Flash MCU, the system remains 4 SPI pins
to make the AVR codes be updated easily. An I/O pin of AT90S8515
controls a buzzer to give alarms.
The
software development tool is BASCOM-AVR 1.11.6.2, which is a
BASIC compiler of AVR. The 16K-byte source code is compiled
to 6K-byte ISP program, which uses most of the ISP Flash of
AT90S8515.
The
detail information please see the "GPS-GSM Mobile Navigator
Documentation".
Features
- The GPS-GSM
Mobile Navigator receives GPS signals every 2 seconds from
satellite, and with the information the system computes the
Greenwich time, longitude and latitude, which are used as
the location information.
- The location
information the GPS-GSM Mobile Navigator acquires is stored
every 20 seconds in the flash memory, which has mass capacity
to memorize the track of the GPS-GSM Mobile Navigator (at
a Ship) even the power is cut off.
- Wireless
communication function
- The
wireless communication is based on the GSM network established
in the working area. The GPS-GSM Mobile Navigator exchanges
information with the control center in the valid region
by the valid service provided.
- By
the SMS (Short Message Service) provided by the GSM network,
the location information and the status of the GPS-GSM Mobile
Navigator are sent to the control center.
- Meanwhile,
the GPS-GSM Mobile Navigator receives the control information
from the control center by the same way.
- By RS-232
interface, the GPS-GSM Mobile Navigator sends the information
stored in the flash memory to PC if necessary.
- The GPS-GSM
Mobile Navigator gives alarms by buzzer or LCD in two ways,
one is receiving the alarm information from control center
to alarm, the other is alarming by the button control and
sending alarm information to control center.
- LCD is
used in the GPS-GSM Mobile Navigator to display the system
status.
- Powered
by rechargeable battery or DC input.
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