Research on GPS Automatic Bus Voice Reporter
1 INTRODUCTION At present, the bus systems in major cities in China basically use computerized station stoppers with manual intervention. First, set up and down lines according to the operating line; while driving, the bus driver presses the corresponding button to stop when he arrives at the station. When entering the station, due to the large number of people, it affects the driver's work, resulting in missed and wrongly reported stations, which affects the quality of public transport services and has a large hidden traffic risk. Therefore, here is a design plan for a GPS automatic bus language station report. This solution uses a GPS global positioning system without manual intervention. When the vehicle is approaching the station, it can automatically realize the voice station report.
2 The principle of GPS bus reporting system GPS (Global PosiTIoning System), that is, the global satellite positioning system. Each GPS satellite always releases its position and time data signals. The user receiver measures the time delay of each satellite signal to the receiver, and calculates the distance between the receiver and different satellites according to the speed of signal transmission. When the data of at least 4 satellites are received at the same time, the three-dimensional coordinates, speed and time can be calculated. The GPS receiving module receives the positioning data sent by the GPS satellites, and can find the longitude, latitude, and corresponding Greenwich time positioning information in the GPS signal through simple string operations. Then, send the latitude and longitude information to the MCU for processing through the serial port.
Figure 1 shows the principle of GPS bus intelligent station annunciator. The GPS module receives the navigation information sent by the selected satellite and the time of the star clock correction parameters, and calculates the current latitude and longitude coordinate information of the vehicle. By comparing this coordinate information with the latitude and longitude coordinate information of the station stored in the single-chip microcomputer (the threshold can be set), the station name information can be found and broadcast by the voice system.
3 System device selection
3.1 GPS positioning module-Leadtek GPS-9543LP
At present, there are many GPS modules on the market. Because the system has no special accuracy requirements for GPS modules, for cost considerations, the relatively cheap LeadtekGPS-9543LP positioning module is selected. Its positioning accuracy is 10 m, which can meet the design requirements. Leadtek GPS-9543LP provides a dual-row 20-pin external interface, as shown in Figure 2. It has two sets of full-duplex asynchronous serial interface, which is convenient for communication with the single chip. After the power is turned on, the basic operation process is as follows:
(1) Self-test After power-on, start self-test and report the self-test result through the output channel. The process will detect RAM, Flash, receiver, real-time clock and crystal oscillator.
(2) After the initial self-test is completed, the satellite detection and tracking process will begin. The entire detection process is completely automatic. Under normal circumstances, GPS-9543LP will use 45 s time to obtain positioning information (only 8 s is needed when the ephemeris is known), and then transmit valid position, speed and time information through the output channel.
(3) After the navigation detection is completed, GPS-9543LP sends effective navigation information through the output channel, including latitude and longitude, altitude, speed, date / time, error estimation, satellite and receiver status.
(4) GPS-9543LP will automatically update satellite orbit data during satellite data collection operation.
GPS-9543LP uses the NMEA-0183 communication standard format developed by the National Marine Electronics Association. The output data adopts ASCII code, and the content contains information such as latitude, longitude, altitude, speed, date, time, course and satellite status. A $ GPGGA output statement includes 17 fields: statement identifier, world time, latitude, latitude hemisphere, longitude, longitude hemisphere, positioning quality indicator, number of satellites used, horizontal accuracy, altitude, altitude unit, geoid height, Altitude unit, differential GPS data period, differential reference base station label, checksum end mark (using carriage return character <CR> and line feed character
$ GPGGA, 114641, 3002.3232, N, 12206.157, E, 1, 05, 12.9, 53.2, M, 11.6, M, * 4A
It means using the "$ GPGGA" format statement, the world (Greenwich) time is 11:46:41, and the position is at 30 degrees north latitude 2.323 2 minutes. Longitude 122 degrees east, 6.157 minutes, effective positioning, 5 satellites received, horizontal accuracy 12.9 m, antenna height 53.2 m above sea level, location height 11.6 m above ground level, checksum 4AH.
The data stream received from the GPS board is a text string. According to the structure and characteristics of the various recorded sentences defined by the GPS output data NMEA-0183 communication standard format, the programming program analyzes the useful information. Since each data segment in the frame is separated by a comma, it is generally judged whether it is the frame header by searching for the ASCII code "$" when processing the buffered data. After identifying the type of frame header (GPGGA), determine which type of positioning and navigation parameters are currently being processed by the number of commas experienced, and make corresponding processing.
3. 2 speech synthesis module XF-S4240 speech synthesis module is an embedded Chinese speech synthesis module. The module receives the text to be synthesized through three ways: asynchronous serial port (UART), SPI interface and I2C bus, and directly synthesizes it as voice output. XF-S4240 adopts 3.3 V power supply, supports texts in 4 internal code formats including GB2312, GBK, BIG5, and UNICODE. It has an intelligent text analysis processing algorithm, which can correctly identify and process weights and measures symbols of values, numbers, and time Strong multi-sound word processing ability; can pronounce both male and female voices; supports software to adjust speech rate, intonation, volume; supports multiple control commands, including: synthesis, stop, pause synthesis, continue synthesis, etc. The commands are composed of 3 parts as shown in Table 1, and there are 6 commands in total. The detailed contents are shown in Table 2 and Table 3.
4 The hardware circuit of the GPS bus intelligent voice stopper The system uses the common AT89C52 single-chip microcomputer as the controller. The device is inexpensive and has 8 KB of EPROM inside. Both the GPS module and the voice module use an asynchronous serial communication mode to communicate with the microcontroller, which simplifies the hardware connection. Because AT89C52 has only one serial port, the serial port of AT89C52 needs to be expanded. The P3.0 and P3.1 of the single-chip microcomputer are used to control the RXD of the GPS and voice modules, respectively, and the low level is effective as shown in Figure 3. Only when a certain control pin is at a low level, the corresponding module has the right to use the serial port, so that the serial port can be time-multiplexed.
In the GPS positioning module Leadtek GPS-95431JP, the system is mainly concerned with longitude, latitude, and satellite number information, and it is only necessary to extract this information with a comma as an identifier. Whether the GPS data is valid is determined by detecting whether the number of searched satellites is greater than or equal to 4. If you want to display time information on the car, you can also extract real-time hour and minute information (the difference between world time and Beijing time is 8 h). Since the speech synthesis module supports the text format, as long as the required synthesized Chinese characters (such as "forward to the station", "please prepare to get off", etc.) are converted to GB2312 code, the format of the command from the microcontroller to the speech The module can send data, and it communicates with AT89C51 through a full-duplex asynchronous serial port.
5 System software programming The system adopts Keil C structured programming, which mainly completes: receiving GPS module data, obtaining latitude and longitude information and voice report station from GPS data. The station's latitude and longitude information, the station name is stored in the form of an array. The main program mainly completes the serial port initialization and sets the baud rate 4 800 Kb / s. In the interrupt service program, the read latitude and longitude coordinate information is compared with the stored site coordinates. When the set threshold is reached, the serial port right is given to the voice module, and the voice program can be called to broadcast. After the announcement, the serial port right is handed over Back to the GPS module. If the serial port right is handed over to the voice module, it can be realized with two sentences: P3 = P310x01 and P3 = P3 & 0xfd; similarly, return the serial port right to the GPS module. Available P3 = P310x02 and P3 = P3 & 0xfe statements. The system program flow is shown in Figure 4, Figure 5, and Figure 6.
6 System debugging The whole system is composed of GPS module part and voice broadcast module part. Debug these two modules first, and then work together after commissioning. The latitude and longitude information of the station should be measured somewhere 50 meters before the arrival of the station (the latitude and longitude information measured by the GPS of this system can be displayed on the LCD to make a latitude and longitude display instrument), so that the broadcast information can be started when the bus arrives at the station . At the same time, due to the close location of the upstream and downstream stations, the station name information is the same. In order to avoid repeated broadcasts in and out of the station, after comparing the latitude and longitude information measured by GPS with the station information, the first two of the station name information found should be checked. The word is compared with the first two words of the station name broadcasted last time, and it is confirmed that it is a different station name before broadcasting. In this way, it is possible to realize automatic broadcasting without manually setting up and down lines.
7 Conclusion Using AT89C51 single-chip, GPS-9543LP global positioning module and XF-S4240 speech synthesis module, the bus voice automatic reporting system is realized. According to the specific requirements of the bus stop, the system can continue to be improved. This device can completely liberate the driver from the task of reporting the station and reduce the hidden danger of communication, so the system design has a good application prospect.
Disposable Medical Masks
FDA&CE certificate
Suitable for respiratory protection, filtering dust, haze, bacteria, droplets and other harmful particles in the air.
HIGH QUALITY – The filter membrane is made of safety standard materials, three-layer disposable masks, which can be used by children and adults, can maintain health and safety when working or going out, can well protect the health of the respiratory system and protect your breathing.
FAQ:
Advantages:
1. WE ARE FACTORY! We have our ownshare factory in shenzhen, Very welcome to visit if available.
2. OEM & ODM
3. Short delivery time
4. Environmentally-friendly material
5. Good workmanship
6. We always ship by international express, air and sea.
7. We serve with best quality and service.
Shenzhen Dianjiang Engineering Co. LTD , https://www.isourceled.com