sonar system MTBF

[DOAKD]

Does anyone have a feel a typical MTBF for a sonar system. I can't provide any details of the system except that is of medium complexity wrt size, weight, parts count etc.

thanks

 

[IRstuff]

I guess that another way to the answer is to consider a 6-month deployment and assume 24/7 operation of a passive sonar. That works out to 4320 hrs of operation.

Given the limited amount of room on a submarine for carrying spares and the criticality of the system for vessel survival, I could imagine that something on the order of 1500 to 2000 hrs would be a reasonable requirement.

TTFN

 

[kufahlb]

With no knowledge of typical sonar system reliability or the expected modes of subsystem/system failure ie., hardware, software, mechanical of such systems, it is difficult to speculate on reasonable reliability targets. The MTBF recommendation of between 1500hrs to 2000hrs appears inexplicably low. Assuming failures occur at a (arguably) constant rate, continuous mode of operation, and the true MTBF equal to 2000 hrs , the nominal probability of system failure is as follows:

Month 1: 30%
Month 2: 51%
Month 3: 66%
Month 4: 76%
Month 5: 83%
Month 6: 88%

The use of spares and subsystem redundancy might improve the availability of such systems as not to require high reliabilities. This tradeoff analysis is nevertheless useful in generating resonable and achievable system reliability requirements and goals.

 

[qassure]

Apart from probability methods, tests like time terminated test or failure terminated test can be conducted to find the MTBF. Since these tests costs time and money, how important is the system reliabilty may be the diciding factor for finding MTBF in this case.