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Designing an eCall system for TransSec

By 20th March 2020 No Comments

Among the major elements of TransSec is the support for pan-European emergency call (eCall) standard. The European Commission eSafety initiative aims to enhance the safety, security and efficiency of road transport, with eCall being a cornerstone of the overall initiative. Since 31 April 2018, all new cars are required to be equipped with eCall technology. Up until this point, eCall has been focused towards smaller, domestic vehicles and on post-crash situations. The goal of any eCall system is to lower the time between the occurrence of a roadside and the response of emergency services to that incident.

A standard European eCall is formed by two elements: a voice component, and a data component. The voice component involves vehicle occupants directly speaking to operators at a public safety answering point (PSAP), while the data component is a transmission of vehicular data to the PSAP. The vehicular data is referred to as a Minimum Set of Data (MSD), and includes such details as the precise vehicle location, the time of the incident and the vehicle’s direction of travel.

Operation of the eCall service

Under pan-European eCall, there are two trigger mechanisms for eCall: automatic and manual. An automatic eCall is activated without any required input from vehicle occupants in such situations where on-board sensors or processing units detect a crash or other roadside incident involving the vehicle. In contrast, a manual eCall is triggered by pressing a button in-vehicle, and may be used in situations where, for example, an occupant is witness to a serious crash.

eCall in pre-crash events

The current implementation of eCall is to act in response to roadside events. While this does reduce the time between incident and emergency response, the situation remains that response is automatically sought only post-crash. The standard eCall trigger mechanisms appear at odds with the primary objective of TransSec, which is to prevent the misuse of heavy-goods vehicles using pre-crash risk assessment and emergency manoeuvring procedures. This presents an interesting dilemma: eCall is, first and foremost, a response mechanism intended to inform emergency services of a situation as soon as possible to maximise responsiveness. The ideal outcome for a use case involving TransSec that any incident is prevented in its entirety.

The eCall system for TransSec essentially performs as an early-warning system. When the TransSec array of onboard sensor systems calculate a crash risk, notification is sent to the eCall system to trigger an emergency call. At this point, the TransSec eCall system builds the MSD in compliance with CEN EN 15722 and transmits the data to a PSAP, including TransSec-specific data to inform emergency services of the severity of the risk and facilitate advanced response to any potential fallout.

The hardware & software

The TransSec eCall system uses commercial off-the-shelf components to build an eCall device which fits seamlessly into the TransSec ecosystem, facilitating communications between TransSec components and the eCall device to trigger any required alerts and can be integrated into any vehicle.

TransSec eCall IVS application structure

The hardware for the in-vehicle system (IVS) is comprised of a Raspberry Pi, with connected USB modem for data communications and a 7-inch touchscreen display for user interface and interaction with the eCall application. We have developed a full software package for the eCall IVS which handles the management of emergency call sessions, whether automatic or manually triggered via the user interface.

TransSec eCall IVS application

For the purpose of demonstrator testing, a PSAP simulator was built to aid in the monitoring of eCall message transmission and data validation.

TransSec eCall demonstrator PSAP application

The PSAP simulator is used to decode and display any incoming eCall MSD messages. This tool was primarily used to verify that any MSD encoding done prior to message transmission was in line with the standard eCall Minimum Set of Data as defined by CEN EN 15722 and that no encoding errors had occurred.


ECall is a major component of the European Commission eSafety initiative and TransSec fully embraces the system with our own spin on emergency call, customised to fit the goals of the project and define an eCall service suited to pre-crash warning transmission.

The innovative pre-crash eCall system helps to add an extra layer of safety and security to TransSec, with the plan for seamless integration within the overall package to aid in achieving our goal of enhanced road transport security and to put a stop to the misuse of heavy-goods vehicles on the road.