ISO 11451: “Road vehicles — Vehicle test methods for electrical disturbances from narrowband radiated electromagnetic energy”
ISO 11451 is a collection of documents that describe automotive test methods for testing at the vehicle level to show immunity to various levels of electromagnetic environment. You can purchase 11451-1 here, and the same site has the other parts available as well. The parts are all revised on their own schedules, with Part 1 (current version published in 2015) expected to have a new revision published in 2024.
ISO 11451 is applicable to any kind of passenger car or commercial vehicle, whether traditional internal combustion engine or electric. Its test methods cover the frequency range 10 kHz - 18 GHz, but it is more often applied within a narrower range, such as 1 MHz - 2 GHz. Table 1 lists the different test methods available.
*LUF = lowest usable frequency of a particular reverb chamber.
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Remember that the plane wave illumination at each frequency in ISO 11451 testing isn’t a constant continuous wave. Different modulations are applied to different frequency ranges to better capture real world threats.
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ISO 11451 defines a set of functional performance status classifications (seen below). Widely used in the automotive industry, these categories can be helpful in defining the success criteria for immunity/susceptibility testing for many complex systems, either at the platform or module level. When a device under test has many functions, some of them may be more critical than others. For instance, if the infotainment system gets knocked offline, that’s inconvenient for the user, and the manufacturer may want to address the issue if it happens at too low of a field strength, such that it might happen often. On the other hand, if the headlights can get turned off by any of the test exposures, that would be a major safety concern that would have to be addressed. Combining the criticality of different functions with the performance status classifications from ISO 11451 in a test plan can be a good way to predetermine which “failures” or “anomalies” are acceptable and which must be labeled failures and fixed. It’s a more detailed framework than the “must function normally” criteria found within some immunity/susceptibility test plans.
