We can consider how to evaluate the 77GHz mm Radar itself ASIL C safety mechanism evaluations, if theoriginal safety mechanisms methodology cannot meet the ASIL C's SPFM, LFM, or PMHF values ?

then how we can deal with it ?

First: typical physical architecture

FIG1 SYS architecture

Note: source from www.infineon.com/radar

Sowe can derive out the logical architecture for this progress:

FIG2 Logical Architecture

Second:Preliminary failure analysis

Set Top event as 'Erroneous 77GHz mm Radar CAN/Flexray signal passing to vehicle', we perform qualified FTA, and due to time limit, suppose we have following assumptions:

(1)another components will not be derived clearly for how it fails except the MCU

(2)only MCU timing and logic sequence failures will be analysed, another failurewill not be focused.

FIG3:FTA

Here we regard the

SM1: core1 itself watch dog, DC(SPF)=90%, DC(LF)=80%

SM2:core1 itself logical sequence monitoring, DC(SPF)=90%, DC(LF)=80%

SM3: core2 itself watch dog, DC(SPF)=90%, DC(LF)=80%

SM4:core2 itself logical sequence monitoring, DC(SPF)=90%, DC(LF)=80%

SM5: core3 itself watch dog, DC(SPF)=90%, DC(LF)=80%

SM6:core3 itself logical sequence monitoring, DC(SPF)=90%, DC(LF)=80%

SM7: And gate of PM safety Watchdog and MCU internal safety watchdog. and due to this mechanisms, so the following dual pointslatent ratio=100%

Table1 FMEA for failure analysis:

And rough conclusion can be synthesis as following:

Table2 conclusion, based on ISO 26262-2018, Chapter 5

What we can see is SPFM cannot match ASIL C requirements, only reach ASIL B, a huge problem.

Third: Safety Mechanism modification

Based on ISO 26262-2018, Chapter5, we can receive one modification of safety mechanisms combinations from following methodology:

FIG4: ISO 26262-2018 diagrams

After this combinations, then the FMEA will changeinto:

Table3: modified FMEA

And rough conclusion can be synthesis as following:

Table4 conclusion, based on ISO 26262-2018, Chapter 5

And here you can see, that after modification, the calculation method is SPFM=99%, LFM=90%, which can reach ASIL D requirements.

Also the PMHF value had decreased from 30FIT to 3FIT also, huge improved

Thanks all and good luck.