System Description
System Diagram:
SYSTEM DESCRIPTION
1. NAVIGATION SYSTEM OUTLINE
a. Vehicle position tracking methods
It is essential that the navigation system correctly tracks the current vehicle position and displays it on the map. There are 2 methods to track the current vehicle position: autonomous (dead reckoning.and Global Positioning System (GPS) (satellite.navigation. Both navigation methods are used in conjunction with each other.
HINT: The combination of autonomous and GPS navigation makes it possible to display the vehicle position even when the vehicle is in places where the GPS radio wave cannot receive a signal. When only autonomous navigation is used, however, the mapping accuracy may slightly decline.
b. Autonomous navigation
This method determines the relative vehicle position based on the running track determined by the gyro and vehicle speed sensors located in the navigation ECU.
1. Gyro sensor Calculates the direction by detecting angular velocity. It is located in the radio and navigation assy.
2. Vehicle speed sensor Used to calculate the vehicle running distance.
c. GPS navigation (Satellite navigation)
This method detects the absolute vehicle position using a radio wave from a GPS satellite.
d. Map matching
The current driving route is calculated by autonomous navigation (according to the gyro sensor and vehicle speed sensor) and GPS navigation. This information is then compared with possible road shapes from the map data in the map disc and the vehicle position is set to the most appropriate road.
2. DVD (DIGITAL VERSATILE DISC) PLAYER OUTLINE (FOR NAVIGATION MAP)
a. The navigation ECU uses a laser pickup to read the digital signals recorded on a DVD.
HINT:
- Do not disassemble any part of the navigation ECU.
- Do not apply oil to the navigation ECU.
- Do not insert anything but a DVD into the navigation ECU.
CAUTION: Do not look directly at the navigation system's laser pickup. Be sure to only operate the navigation as instructed.
3. MULTI-DISPLAY OUTLINE
a. Touch switch
Touch switches are touch-sensitive (interactive.switches operated by touching the screen. When a switch is pressed, the outer glass bends in to contact the inner glass at the pressed position. By doing this, the voltage ratio is measured and the pressed position is detected.
4. AVC-LAN DESCRIPTION
a. What is AVC-LAN?
AVC-LAN, an abbreviation for "Audio Visual Communication Local Area Network", is a unified standard developed by manufacturers in collaboration with Toyota Motor Corporation. This standard pertains to audio and visual signals as well as switch and communication signals.
b. Purpose:
Recently, car audio systems have rapidly developed and functions has vastly changed.The conventional car audio system is being integrated with multimedia interfaces similar to those in navigation systems. At the same time, customers are demanding higher quality audio systems. The following is a brief overview of the standardization. The specific purposes are as follows.
1. To solve sound problems, etc.caused by using components of different manufacturers through signal standardization.
2. To allow each manufacturer to concentrate on developing products they do best. From this, reasonably priced products can be produced.
HINT:
- When a short circuit or circuit breakdown occurs in the AVC-LAN circuit, the audio system does not operate normally due to the communication cutoff.
- If an audio system is equipped with a navigation system, the multi-display unit acts as the master unit.
- The radio receiver assy provides resistance to make communication possible.
Car audio systems with AVC-LAN circuits have diagnostic functions.
- Each component has a specified number (3-digit) called a physical address. Each function has a number (2-digit) called a logical address.
5. COMMUNICATION SYSTEM OUTLINE
a. Components of the navigation system communicate with each other through the AVC-LAN.
b. The radio receiver has a of 60 to 80 ohms, which is necessary for transmitting the communication. This is essential for communication.
6. DIAGNOSTIC FUNCTION OUTLINE
a. The navigation system has a diagnostic function (the result is indicated on the master unit).
b. A 3-digit hexadecimal component code (physical address) is allocated to each component on the AVC-LAN. Using this code, the component in the diagnostic function can be displayed.
c. If a short circuit or open circuit occurs in the AVC-LAN circuit, communication is interrupted and the audio system will stop functioning.
7. BLUETOOTH OUTLINE
a. BLUETOOTH is a new wireless connection technology that uses the 2.4 GHz frequency band.This makes it possible to remotely connect a cellular phone (BLUETOOTH capable phone*) to the multi-display (BLUETOOTH system is built in), and use a hands-free function with the cellular phone in a pocket or bag.
HINT: *: Some versions of BLUETOOTH capable cellular phones may not function with this vehicle.
NOTE: The communication performance of BLUETOOTH may vary depending on obstructions or radio wave conditions between communication devices, electromagnetic radiation, communication device sensitivity, or antenna capacity.