Direct Line to the Helpers

IAV calibrates emergency call systems in vehicles and provides certification support

As from the end of March 2018, new vehicles in the EU must be equipped with an emergency call system. IAV provides its customers with support in introducing the new function in passenger cars and commercial vehicles – from advance engineering, integration and calibration to testing and help with getting certification.

The new function is able to and meant to save lives. If the vehicle detects a crash, the emergency call system automatically contacts an emergency call center and provides data on the state of the vehicle and the place where the incident has occurred. A voice function is also integrated: via a hands-free speaking system, staff at the emergency call center can listen into the vehicle and make contact with vehicle occupants. For this purpose, the emergency call system has its own loud- speakers and, if necessary, its own power supply. Only the microphones already fitted in the car are normally used for communication with the helpers.

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Communication even under adverse conditions

The emergency call system places particularly high demands on voice quality. “Communication must also be possible in loud ambient noise – even with noise levels of 90 dBA on a main road”, says Dr. Thomas Rohdenburg, technical consultant for voice communication in the car at IAV. “For us this means that although the algorithms in the emergency call system are basically the same as those in a nor- mal hands-free speaking system, we must ensure optimum communication at the time of calibration.” This applies to characteristics such as output volume, the quality of voice communication to the emergency call center, frequency response as well as the suppression of feedback.

Whether or not the emergency call system satisfies all of the statutory requirements even under the most adverse boundary conditions is verified when the systems are calibrated. IAV supports its customers throughout the development process. “We tailor the algorithms to each vehicle model because there are wide differences in acoustics”, Rohdenburg reports. “Then we perform exactly the same tests that are prescribed later on for certification.” Three audio measuring stations with state-of-the-art technology are available for this purpose at IAV’s Gifhorn development center. Passenger cars and commercial vehicles can be checked in soundproofed measurement chambers, with recorded driving noises providing realistic measurement conditions. “Our testing facilities are, of course, secure for prototypes”, Rohdenburg emphasizes. “All areas are secured so that no confidential information can be leaked out.”

Support in the certification laboratory

Having completed calibration in this way, the vehicles can be tested in the certification laboratory. IAV experts are normally on hand because the acoustic behavior of prototypes or pilot production vehicles can differ from the production models. “If necessary, we can still adjust calibration of the emergency call system in the certification laboratory so that it meets all of the requirements”, Rohdenburg explains. “This way, we can make sure that certification goes successfully.”

So far, the IAV team has provided support in over a dozen certifications – particularly in Russia where an emergency call system has already been mandatory in new vehicles since 2016. “We have many years of experience in calibrating hands-free speaking systems”, Rohdenburg says. “For emergency call systems we are at our customers’ side from the start of the development process to the point of certification – that’s a real unique selling point.”

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