ESAMA

Advanced EMC immunity tests for aerospace systems in complex electromagnetic environments

 The standard Electromagnetic Compatibility (EMC) tests that are used in the aerospace sector do not reproduce the electromagnetic complexity of the scenarios in which their electronic systems operate. Hence the concern for equipment that, even compliant with standardized immunity tests, may present malfunctions when they are subjected to real complex interference. The objective of this project is to improve the immunity EMC tests by defining new setups to involve this complexity.

 As a first step, aerospace electronic systems will be analysed and classified from the point of view of EMC. Their functionality, their immunity, the type of malfunction caused by interference and even the risk related to possible failures will be considered. The typical sources of interference of aerospace scenarios and how they are considered in conventional immunity tests will also be studied.

 This analysis will allow us to identify situations with complex electromagnetic environments insufficiently covered by standardized tests, which apply the different types of disturbances in isolation in independent tests. Considering these situations and the taxonomy established for the systems studied, some combinations of different interferences will be defined and applied simultaneously to different ports of the equipment under test, so that these tests provide information on the response of the tested systems when operating in environments electromagnetically complex.

 Once these new test configurations have been defined, they will be applied to different representative aerospace subsystems of each group established in the previous classification, evaluating their response when subjected to complex disturbances. The systems to consider are very diverse and they are not equally critical in the case of a failure. For this reason, it will be advisable to carry out a risk analysis from the point of view of functional safety to define the particular test configurations required.

OBJECTIVES:

[UPC-O1] To analyze the complex Electromagnetic Environment (EME) in aerospace applications.

 The first step to analyzing aerospace systems from the EMC point of view is to find the significant characteristics of aerospace scenarios in terms of their immunity to Electromagnetic Interference (EMI). The specificity of aerospace systems and the disturbances present in these complex electromagnetic environments will be considered. Systems and subsystems are often defined and classified according to their functionality. In this project, they will be treated considering aspects such as their susceptibility to EMI, the kind of malfunction caused by the interference, or even the risks related to their malfunctioning.

Regarding the EME, the analysis will focus on the typical sources of interference and how they are considered in the aerospace EMC standards.

[UPC-O2] To develop new EMC immunity test methods to evaluate the performance of aerospace systems in complex EMC environments.

New EMC immunity test methods are planned to be developed to evaluate the performance of aerospace systems in complex EMC environments. In areas like medical devices or automotive electronics, there is a rising concern that electronic devices may comply with immunity standards but suffer from malfunction when exposed to real complex EMI. Aerospace scenarios are also affected by complex and simultaneous sources of interference. This is why we will propose new EMC immunity setups to simultaneously apply a combination of interfering signals to the device under test.

Results from the previous objective [UPC-O1] should let us identify some situations with complex environments not covered suitably by present standard immunity tests, which apply a single interfering signal at a time. Considering these situations, as well as the taxonomy of subsystems found from the previous analysis, we will define suitable combinations of disturbances and the way to couple them to different ports of the device under test in order to obtain significant information about the performance of aerospace systems when they are operated in complex EME.

[UPC-O3] To evaluate the proposed EMC immunity test methods in representative subsystems to evaluate their performance in complex environments.

The proposed EMC immunity test methods will be evaluated in representative subsystems regarding their performance in complex environments. Aerospace systems include many subsystems different in nature. They involve, for instance, shielding materials and structures, grounding, and bonding elements, strongly connected with how interference affects electrical wiring and interconnecting systems and critical control electronic systems. They all have different responses when exposed to electromagnetic fields and with different consequences in the case of failure. In addition, some of them may present non-linear behaviour to electromagnetic sources. In this case, their response to complex simultaneous interferences cannot be inferred by the superposition of the effects of standard immunity tests that consider only a single interference at a time. An example of these systems is the electric power distribution units that may become a critical interfering source, but, at the same time, their malfunction can compromise the aircraft’s safety.

To study this problem, we plan to define some basic and representative subsystems, making a risk analysis from the point of view of their functional safety. This information allows us to define particular immunity setups for every family of subsystems.

[UPC-O4] To evaluate the EMC of subsystems on-board aerospace platforms.

The EMC of subsystems onboard aerospace platforms will next be evaluated using the novel test methodology defined for each family of subsystems to assess the immunity of onboard systems in aerospace platforms. Conventional tests specified in standards such as RTCA-DO160 consider devices under test as stand-alone devices on a test bench as well as the test of the whole platform. We will define the test to be carried out in both situations: stand-alone configurations and installed on an aerospace platform.

Finally, a reference guide will be written to help aerospace engineers define specific electromagnetic immunity analyses following this methodology.