In the future, automobiles will have even more contact with their environment, other automobiles, the infrastructure, and external services. The success of this development depends on a decisive condition: A wide variety of automotive components and functions must be coordinated and work flawlessly together. Rohde & Schwarz has identified five trends that lead to specific requirements for T&M (test and measurement) equipment.
Developments in state-of-the-art driver assistance systems are increasingly influencing network design in vehicles. With at least 100 control units, the existing network architecture is reaching its limits. A domain controller can potentially replace the functions of many control units by providing functions for high-speed communications, sensor merging and decision making, and support high-speed interfaces for cameras, radars, and LiDARs.
This makes digital design testing of components even more important. Signal and power supply integrity are vitally important with digital designs. Growing integration complexity and diverse signal and crosstalk scenarios require fundamental measurements to ensure proper system functionality even under worst-case conditions.
Electronic control units (ECUs) are interconnected via various bus systems. These buses support the data communications of the coordinated control system. However, autonomous driving places significantly higher demands on the data rates. Presently this is still accomplished using the 100/1000BASE-T1 standard, but data rates will rise to the gigabit range in the future.
Automotive OEMs and Tier 1 suppliers are therefore heading toward a uniform solution that allows higher data throughput, less latency, and lower weight to reduce complexity and increase cost efficiency.
To verify the functioning and quality of data streams, future motor vehicle engineers must be able to easily trigger, decode and examine signals, measure crosstalk, and perform compliance tests.
The increase in bandwidth is also driving the development of new chipsets and redefining the physical parameters of cables and connectors. Higher transmit frequencies are needed for faster Ethernet data rates. This increases the importance of EMC (electromagnetic compatibility) and EMI (electromagnetic interference) measurements.
Requirements for compliance testing are also rising. The Ethernet products of suppliers to vehicle manufacturers are subject to very strict test requirements. In many cases these can only be met with high-end test solutions.
Radar sensors’ main advantage relative to cameras and LiDARs is better weather independence. The goal is imaging 4D radars that combine high angle and range resolution with high-resolution detection of the speed and motion direction of objects.
This leads to rising demands on T&M equipment. For example, the distance needed for direct far-field measurements increases exponentially with growing antenna aperture, making these measurements impractical. The ideal solution is an extremely compact test chamber with a high-precision reflector that creates perfect far-field conditions at a short distance.
Rising safety requirements and the associated liability for SAE levels 3 to 5 automated driving require ever-better test quality for development and production. A comprehensive solution for verification testing of all ETSI (European Telecommunications Standards Institute) and FCC (Federal Communications Commission) regulations creates certainty. Due to high market penetration and new modulation methods, interference is an increasingly important consideration. Relevant scenarios can be simulated and investigated in the lab with signal generators and target simulators.
Vital distance ranges cannot be covered by sensor calibration with corner reflectors, so active target simulation will be used almost exclusively for this purpose in the future.
The new connectivity
Most vehicle manufacturers are now increasingly using cellular V2X (C-V2X) technology, which now includes 4G LTE and in the future 5G.
C-V2X applications need reliable radio transmission to achieve the required data throughput and convey data on time. To ensure this, receivers must be able to decode signals even under difficult transmission conditions. Simulation of these conditions in the lab requires high-performance T&M equipment that is able to generate and analyze C-V2X signals, create challenging fading conditions, and simulate satellite signals for extremely precise positioning.
A workable ITS (intelligent transportation system) requires interoperable transmit and receive units. This is ensured by a continuous quality and validation process that is applied to all integration steps during development and production in preparation for certification at the end. The T&M equipment must demonstrate the functionality and performance capability of the components before they are integrated into modules and OBUs (onboard units). The radio units are qualified using signal generators, analyzers, and production test solutions as part of the non-signaling tests.
The protocols and protocol compliance are part of the signaling tests and are checked with communications testers. The ITS application protocols are governed by regionally different standards. The test solutions must therefore take into account that every market has its own requirements.
5G in the automotive sector
5G simplifies connectivity between vehicles and drivers, vehicles and other road users, vehicles and the traffic infrastructure (traffic lights, road signs, etc.), and between vehicles and online services. All of this requires guaranteed network resources and network slicing to ensure that safety-related notifications to autonomous vehicles take precedence over infotainment.
The challenges for T&M equipment are therefore the same as for 5G in general. The 5G air interface uses beamforming, which means directional antennas that emit a signal in a particular direction to boost the effectiveness of the overall system. This is where OTA (over-the-air) tests come into play. The device under test and the measurement antenna are placed in a shielded anechoic chamber, far enough apart to allow far-field conditions to be achieved as much as possible. This is no problem with a small modem for a car, but is much more complicated when the device under test is an entire truck.
T&M equipment also ensures secure communications such as could happen if an unauthorized person hacked into the data link. This means the quality of service must be ensured in all cases. The security of the application is tested by OTT (over-the-top) logging of the data packets, analyzing the connections from the server to the terminal device, and checking how they are encrypted.
Along with safety and security aspects, these challenges cannot be met without the introduction of innovative automotive test solutions that support knowledge transfer from drive tests to test benches for reproducibility and test automation.