To determine the readiness of the missile weapons system, a series of tests has been developed under the SMS program. These tests are known as system maintenance tests (SMTs). They are used to evaluate the ability of a weapons system to perform effectively. If SMTs uncover a problem, corrective action is required. Quite often troubleshooting must start at the system level. It then works its way down to the individual piece of equipment at fault.
SMTs, in conjunction with separate equipment level tests, provide a thorough check of the entire weapons system. The tests are designed (for the most part) not to overlap each other. In other words, a particular equipment level check is not rechecked by an SMT. Also, SMTs are scheduled at the minimumfrequency or period necessary to ensure reliability.
Since system testing is a form of maintenance, SMTs come under the Navy's planned maintenance system (PMS). Hence SMT scheduling and format are identical to equipment-level maintenance actions. Each SMT is letter-number coded according to its required time interval. The letter D stands for daily check, W for weekly, M for monthly, and so forth.
For certain weapons systems, weekly tests are designed to check different equipment combinations, setups, and modes of operation. This concept requires that these weekly tests be scheduled over a 6-day period, Monday through Saturday. Quite often there will be 12 different weekly tests, identified W-1 through W-12. Depending on how a ship sets up its maintenance schedule, W-1 and W-7 would be held on Monday. On Tuesday, you run W-2 and W-8; Wednesday it's W-3 and W-9; and so forth. In this concept, each GMFCS and guide arm (on dual-arm launchers) is exercised daily with a different problem.
A typical missile system test program normally includes (but is not limited to) the items listed below:
Daily system operability test (DSOT)
Search radar readiness
Supplemental (auxiliary) firing readiness
Casualty mode operation
Ship parameters (gyro inputs)
Fire control radar parameters
Live target tracking (AAW)
Balloon tracking (designation accuracy)
Surface target tracking
Overall system testing is centered around the daily system operability y test (DSOT), (Actually, a DSOT is one of the 12 weekly scheduled checks, W-1 through W-12, mentioned earlier.) The DSOT is designed to exercise almost all of the functional circuits related to the primary mode of system operation. The DSOT is very important and we'11 examine it in detail shortly.
Other system tests check the areas of the system not covered by DSOT. For example, weapons systems have different modes of operation. Antiair warfare (AAW) is the normal mode, usually. Antiship missile defense (ASMD), surface warfare (SUW), antisubmarine warfare (ASW), and shore modes are optional. There may also be a casualty mode to permit system operation should certain equipments be inoperable. Each mode is tested to ensure its continued reliability. The periodicities of these tests are usually greater, such as monthly, quarterly, or longer.
SMTs check the equipment in two major areas-alignment requirements and electrical operability requirements. Alignment requirements consist of in-space RF alignments and internal (shipboard) alignments. In-space RF alignments verify that RF beams from the search, fire control, and guidance radars all coincide. This coinciding action is very important. Assume a search radar is tracking a target at 180° true bearing. Also assume a fire control radar beam is 10° out of alignment with the search radar. At designation, the fire control radar is searching empty space, 10° off target. Acquisition could be impossible.
Internal or shipboard alignments are mechanical and electrical in nature. They affect individual equipments and the interactions between different equipments. For example, consider a GMLS power drive system with its synchros and receiver-regulators. Synchronization will never be achieved with misalignments between the computer and the GMLS.
Alignment procedures are provided to correct any in-space RF or internal misalignments. However, they are only performed on an as-needed basis, when discovered by faulty test results.
The quality of system test results can be determined by system responses and parameter tolerances. (Parameter-any set of values that determines the normal or desired characteristics and behavior of something.) Test result data may be obtained from indicators, lamps, dials, meters, and computer readouts (printouts). Analyzing the data provides the technicians with a" yardstick for measuring the success or failure of a particular test.