MIL-PRF-49166C(CR)
milliradians around the optical axis. The degradation due to the scanner shall be determined by
comparison of the MTF measurements with the test apparatus MTF.
4.5.8.1 Test apparatus MTF. The MTF for the test apparatus shall be determined by
rotating the optical imaging system to be aligned to the collimated beam. The maximum MTF of
the test apparatus shall be determined by an optimization search of the image.
4.5.8.2 MTF. The MTF of the scanner shall be measured in both azimuth and elevation
directions for each mirror surface and there shall be no refocusing allowed between the azimuth
and elevation requirements. In each direction and for each side, the ratio of the scanner MTF at
0.667 cycles/milliradian to the corresponding MTF measurement of the test apparatus
(see 4.5.8.1) shall be obtained. Failure to meet the requirement of 3.6.8 shall constitute failure of
this test.
4.6 Environmental tests. The environmental tests ( 4.6.1 through 4.6.4) shall be
performed in accordance with MIL-STD-810. Vibration tests will be performed in accordance
with the Test Method specified in Appendix A (see 4.6.5). The testing required during these
tests shall be as specified below. All performance tests specified shall be performed within 5
minutes of completion of environmental tests.
4.6.1 Temperature shock. The scanner shall be tested in accordance with MIL-STD-810,
Test Method 503.3, Section II, Procedure II-3, except that the temperature of step 1 and 3 shall
be raised to +95°C. The temperature shall be maintained at +95°C for a minimum of 4 hours until
the item has stabilized. The temperature of step 4 shall be lowered to -54°C and shall be
maintained at this temperature for a minimum of 4 hours until the item has stabilized. The scanner
shall not be operated during temperature shock tests (no measurements shall be taken during
tests). Failure to meet requirements of 3.7.1 shall constitute failure of this test.
4.6.2 High temperature. The scanner shall be tested in accordance with MIL-STD-810,
Test Method 501.3, Section II-3: Procedure I (storage): the temperature of step 4 shall be raised
to +95°C and maintained for a minimum of 48 hours. The scanner shall be operated during the
final 30 minutes of step 4 (no measurements shall be taken during step 4). Procedure II
(operation): the temperature of step 2 shall be +71°C (use Constant Temperature Exposure). The
scanner shall be operated at +71°C. The high temperature test criteria specified in 4.5.1.2 and the
average interlace waveform amplitude shall be measured in place of the table III tests during high
temperature tests. Failure to meet requirements of 3.7.2 shall constitute failure of this test.
4.6.3 Low temperature. The scanner shall be tested in accordance with MIL-STD-810,
Test Method 502.3, Section II-3: Procedure I (storage): the temperature of step 2 shall be -62°C
and shall be maintained for a minimum of 48 hours. Procedure II (operation): the temperature of
step 1 shall be -54°C. The low operating temperature for the interlace waveform criterion shall be
-30°C. The low operating test criteria specified in 4.5.1.2 and the average interlace waveform
amplitude shall be measured in place of the Table III tests during low temperature tests. Failure
to meet requirements of 3.7.3 shall constitute failure of this test.
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