GB/T 28787-2023Data communication protocol between intelligent terminal and dispatching center for urban bus and trolleybus (English PDF)

Foreword

This document was issued on 17 March 2023 by the State Administration for Market Regulation; Standardization Administration of the PRC and takes effect on 1 October 2023.

It is a GB/T standard: recommended rather than compulsory, but it is the text a Chinese reviewer applies when assessing a submission.

1 Scope

GB/T 28787-2023 specifies how a bus talks to the control room. Every urban bus now carries a terminal reporting its position, its schedule adherence, its passenger counts and the state of the vehicle, and the dispatching centre uses that stream to hold headways, to intervene when a service bunches, and to drive the arrival predictions passengers read at the stop. The traffic is unusual: thousands of vehicles reporting continuously over mobile networks that drop out in tunnels and under bridges, so the protocol has to be economical with bytes and has to define what happens to messages generated while the vehicle was unreachable. Standardising it also breaks the dependence on a single supplier — a city that changes terminal vendor should not have to change its dispatching system. This document specifies the protocol basis, the communication connection, the message processing and the data formats for communication between the on-board intelligent terminal and the dispatching centre for urban buses and trolleybuses. Under CCS L79, it is written for terminal manufacturers, for the vendors of dispatching platforms, and for the municipal transport operators who buy both.

This document specifies the protocol basis, communication connection, message

processing and data format for data communication between intelligent terminal and

dispatching center for urban bus and trolley bus.

This document is applicable to the data communication between intelligent terminal

and dispatching center for urban bus and trolley bus through wireless transmission

channels.

2 Normative references

The following referenced documents are indispensable for the application of this

document. For dated references, only the edition cited applies. For undated references,

the latest edition of the referenced document (including any amendments) applies.

GB/T 32852.1-2016, Urban passenger transportation terminology - Part 1: General

terminology

JT/T 808-2019, GNSS for operating vehicles - General specifications for vehicle

terminal communication protocol and data format

JT/T 1076-2016, GNSS system for operating vehicles - Technical specification for

onboard video terminals

JT/T 1078-2016, GNSS system for operating vehicles - Video communication

protocol

3 Terms and definitions, abbreviations

3.1 Terms and definitions

For the purposes of this document, the terms and definitions defined in GB/T 32852.1-

2016 as well as the followings apply.

3.1.1 origin station; primary station

On a bus line, a start-end station that is equipped with a master scheduler.

The total mileage traveled by a delivery vehicle during the operation service process,

including passenger mileage and empty mileage.

[Source: GB/T 32852.1-2016, 8.6]

3.1.11 dispatching center

A place for remote dispatching of operating vehicles on multiple lines.

[Source: GB/T 32852.2-2018, 3.3.2]

3.1.12 transit signal priority

According to the real-time monitored traffic conditions at intersections or historical

traffic data, combined with the real-time passenger state of bus operating vehicles and

the state of arriving earlier & later, priority signal timing is provided for bus operating

vehicles, so that buses and trolley buses can pass in priority over other vehicles.

3.1.13 display plate for vehicle running position

The vehicle is marked with the name of the route and the names of the stops. There is

an indicator light showing the current running position of the vehicle and the running

direction of the vehicle.

[Source: GB/T 32852.2-2018, 3.5.24]

3.2 Abbreviations

The following abbreviations apply to this document.

CAN: Controller Area Network

FTP: File Transfer Protocol

GBK: Chinese Internal Code Specification

HTTP: Hyper Text Transfer Protocol

ID: Identity

IP: Internet Protocol

LCD: Liquid Crystal Display

LED: Light Emitting Diode

RSA: An asymmetric cryptographic algorithm (developed by Ron Rivest, Adi Shamir,

Leonard Adleman, named after the names of the three)

TCP: Transmission Control Protocol

6.2 The classification, requirements and encryption mechanism of signaling data

messages in the protocol shall comply with the requirements of Chapter 7 of JT/T 808-

2019.

6.3 The real-time audio and video transmission channel agreement in the protocol shall

meet the requirements of 4.2 in JT/T 1078-2016.

6.4 The audio and video signaling data message communication shall use the

established link between the vehicle intelligent terminal and the dispatching center for

the transmission of positioning information. No new link shall be created. A new link

shall be created for the communication of audio and video code stream data message,

instead of the link for transmitting the positioning information.

6.5 The message definition in the protocol shall meet the requirements of Annex A.