JP7640952B2 - Bus stop display system - Google Patents

Description

The present invention relates to a system that transmits information, including the location of a moving bus, to an information terminal at a bus stop and displays the location of the bus and the estimated time of arrival.

The following equipment is typically installed on route buses:
1) A public address system that memorizes the stops scheduled for the bus operation and announces the name of the next stop to passengers. The announcement is activated by the driver.
2) A drive recorder that records video from inside and outside the vehicle. A tachograph that records time, speed, and distance traveled. Some are integrated with a drive recorder. A GPS antenna is usually connected to the drive recorder to record location information.
3) Equipment for the bus location system to grasp the location of vehicles under the jurisdiction of the office. It has a GPS antenna and a wireless communication device. In some cases, this function is realized by attaching a wireless communication device to the drive recorder.
The above 1) and 2) are currently installed in almost all vehicles, but 3) is still in the process of becoming more widespread.

Conventionally, the system for displaying vehicle information at bus stops required the above-mentioned bus location system device, and the bus stop's location information was sent from the bus stop to the LTE terminal at the bus stop via a wireless communication network (currently the LTE communication network). Or, the bus stop's LTE terminal would access the vehicle location information in the bus stop's server.
Indeed, prior patent literature has taken this approach.

JP 2014-10533 A JP 2019-121289 A

In order to display the estimated arrival time and vehicle location for each route at bus stops, an LTE terminal is required on the vehicle side, a bus location server at the bus stop, and an LTE terminal is also required at the bus stop side, which incurs monthly operating costs due to communication charges to the wireless carrier for the number of LTE terminals. The bus stop side also requires considerable equipment.

In general, an LTE terminal requires approximately 1W (watt) of power when receiving, so in a system where the bus stop is unpowered and receives power from solar panels, the displayed information needs to be updated frequently and communication needs to be constant, which means the solar panels and storage batteries would need to be large-scale, resulting in huge equipment costs.

On small routes, where most bus stops are simple, with only a boarding sign and a timetable posted on a pole, there is an issue that displaying estimated arrival times is too costly. This proposal aims to realize a system that displays arriving vehicles at low cost, even on small routes.

The following are the means to solve the problems of reducing the power consumption of the information terminals at the bus stops and reducing communication charges.

In recent years, the LPWA (Low Power Wide Area) communication method has emerged, which allows for "long-distance communication with low power consumption." LPWA types can be broadly divided into unlicensed band (specific low power radio) methods that do not require a license and wireless methods (LTE catM1) provided by communication carriers that do require a license. This proposal describes the LoRa communication method as an example, which allows communication between edge devices in unlicensed bands with lower power consumption without incurring communication fees.

LoRa communication terminals consume very little power and do not incur fees to wireless operators, making it possible to operate unpowered information display terminals at bus stops at low cost.
However, a method in which a center server at a business office or other base communicates with all bus stop terminals goes against the low-cost concept of this proposal , so we adopt a method in which location information is sent directly to bus stops from buses in motion. However, due to restrictions on the communication method, even in the most widely transmitting mode, the amount of data sent at one time is 59 bytes, and the bit rate is 250 bps. This proposal makes it possible to operate within this transfer rate.

Unlike distributing vehicle position information, updating a timetable involves a large amount of data. Figure 4 shows an example of a timetable, but due to restrictions on the communication method, it is difficult to update it as a "picture," so only the times that have changed are changed. For example, if there is a change in the 11:00 time slot, a command (example) like the one in Figure 2 is sent.

Unlike location information distribution, timetable updates are done right in front of the bus stop.
The definition of data rates for the LoRa method is shown in Figure 5. Since location information is distributed over a wide area, DR0 in the figure is used, but if in front of a bus stop, it is desirable to use the maximum rate possible for the wireless communication unit. It is possible that data can be updated using normal operating vehicles without having to prepare a special vehicle for updates. DR0 to DR5 are common modes for the LoRa method, so for example, DR5 can transmit within 1 second.

This proposal makes it possible to implement and operate at low cost the display of the next arriving bus's position and estimated arrival time at unpowered bus stops with a small number of routes.

Example of location information distribution data for a public transport vehicle Example of data to send when updating a bus stop timetable Overall Systems Diagram Example of bus stop display terminal LoRa Data Rate Definition

Figure 3 shows the overall system diagram.
Three bus stops are depicted, and it is intended that the display terminal at bus stop 1 will display the position and estimated arrival time of a public bus vehicle 4 traveling between the stop and the previous stop, stop 3.

The equipment installed in the bus is shown in the vehicle-mounted device side 12 in Figure 3. The vehicle side is equipped with a drive recorder 14 connected to a GPS antenna 15 as standard, and a stop name broadcasting device 13 that stores stop names and travel itineraries. In this example, the LoRa antenna 18 and LoRa communication module 17 are connected to the stop name broadcasting device 13, and the stop name broadcasting device 13 controls the LoRa communication module 17 to transmit the location information shown in Figure 1 to the bus stop based on the travel itinerary and latitude and longitude information obtained from the drive recorder 14, or the distance from the previous stop calculated from the vehicle speed pulse 16.

The stop name broadcasting device 13 stores the operation schedule, so the destination of the location information shown in Figure 1 can be limited to stop 1 and stop 2. It can also be sent as a broadcast that does not limit the destination. In that case, the data received at the stop side is selected and displayed based on the route number and stop number.

Figure 1 shows an example of location information transmission data. When transmitting from a moving vehicle that passes in front of a radio wave obstruction, it is necessary for the transmitting terminal to send as little data as possible frequently. The minimum information required is the route number, vehicle number, and vehicle position. The vehicle number is not necessarily required, but it is included in case vehicles are traveling overlapping.

An explanation of FIG. 1 "Example 1 of location information transmitted from vehicle" is given below.
What should be displayed at bus stops is how far the vehicle is between stops, and because the distance between stops is known in advance, a number is defined for every stop on the route, and the distance between stops is divided into 10 parts, so that if the vehicle is 3/10ths of the way between stop 36 and stop 37, for example, the five bytes 036.3 are sent. This method is possible with the bus stop name broadcasting unit 13 in Figure 3.

However, if the stop name broadcasting device 13 is made by another company, this function cannot be added, so the LoRa communication module in Figure 3 distributes location information obtained from the GPS antenna 15.
This format is shown in "Example 2 of Position Information Transmission Data from Vehicle."
The route number and vehicle number are obtained from the stop name broadcasting unit 13.
Even if the stop name broadcasting unit 13 is manufactured by another company, the route number and vehicle number can be obtained through the interface of the communication standard of the Japan Automobile Body Industries Association (JAB).
This example data includes the route number, vehicle number, and latitude and longitude information from GPS.
The data increases from 16 bytes in data example 1 to 28 bytes in data example 2.

The display device at the bus stop determines the route number from the received information, and if the route number is the target route number and the bus stop number that should be displayed, displays a vehicle icon according to the position ratio.
In the case of "Example 1 of location information transmission data from vehicle," the expected arrival time is displayed according to a comparison table of expected times that is predefined based on the ratio of stop numbers and locations. If the stop is farther away than the one that should be displayed, it is not displayed.

In the case of "Example 2 of location information transmission data from vehicle," if the route number is the target, the latitude and longitude of the bus stop is compared with the received latitude and longitude information to calculate the distance, and the current position of the bus among the nearby stops is calculated and displayed. The expected time is also displayed according to a comparison table of expected times that is specified in advance. If the stop is farther away than the one that should be displayed, it will not be displayed.

The components at the bus stop side are shown in Figure 3, bus stop side 5. The power generated by the solar cell 6 is stored in the storage battery 7. The control microcomputer 8 appropriately selects the power from the solar cell 6 and the power from the storage battery 7 to power the electronic paper display unit 11 and the LoRa communication module 9 to which the LoRa antenna 10 is connected.

Figure 4 shows an example of the electronic paper display of the bus stop in Figure 3. It shows the location of the next bus by route using an icon and the estimated arrival time. Timetables by route are displayed. If there is no bus at the four bus stops before the bus stop, there is no icon, and the estimated arrival time is not displayed.

Timetable updates are not done every day, so the following steps are followed.
DR5 5475bps in Figure 5 is a data rate at which rewriting is completed when a vehicle in normal operation stops at a bus stop, but there is a possibility that the transfer will fail if a vehicle passes by without getting on or off. In that case, instead of updating the timetables for all stops in one operation, a system is used in which the transfer of update data begins several days before the date of the timetable change, and the display of the stops is changed all at once on the date of the change according to the clocks in the display terminals of the stops.

A system that displays the estimated arrival time and current bus location at unpowered bus stops can be realized at low cost.

1 Stop 1
2 Stop 2
3 Stop 3
4 Bus 5 Block diagram of bus stop terminal 6 Solar cell of bus stop terminal 7 Storage battery of bus stop terminal 8 Control microcomputer of bus stop terminal 9 LoRa communication module of bus stop terminal
10 LoRa antenna at bus stop terminal
11. Electronic paper display unit of bus stop terminal
12. All on-board devices in the bus
13 Bus stop name announcement device
14. Drive recorder in bus
15 GPS antenna in bus
16 Bus speed pulse
17 LoRa communication module in the bus
18 LoRa antenna inside the bus

Claims (2)

A bus stop information terminal comprising a display device having a solar cell, a storage battery for storing the power generated by the solar cell, and a means for appropriately selecting and receiving power from the solar cell and the storage battery, and a communication means for the display device being a communication device that does not require a radio station license, has variable communication speed and capacity, and is characterized by low power consumption, wherein the display content is transmitted directly to the bus stop information terminal using communication means that is slower in communication speed but capable of long-distance transmission from a route vehicle having a means for determining its position on the route, and the display system displays the predicted time of upcoming arrivals of vehicles and the current position of the vehicles using information that includes at least the route number and position information.
A display system for bus stops , comprising: a display means for displaying information on a bus stop that is transmitted directly to the bus stop information terminal when a route vehicle having a means for grasping its position on the route reaches a predetermined position near the bus stop information terminal, the display means having a shorter communication distance but a faster communication speed than the communication means for transmitting the estimated arrival time and vehicle position information of the route vehicle described in claim 1 , and the information that needs to be rewritten infrequently, such as changes to a timetable, is rewritten by the display means.

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