Was it ever specified if the Type-91 used the FIM-92A or -92B’s seeker as a base since I’ve found the following patent for the POST seeker (MIM-72G & FIM-92B and later)
Of which I’m working on a report that would qualify missiles using the POST seeker for the Contrast Seeker Lock-on range extension mechanic.
relevant excerpt from the patent.
The invention resolves the problems of the prior art by a dual mode seeker having point detection in a rosette or spiral scan. Signal processing electronics continuously select the most advantageous mode of operation from the signals of a dual detector and operate within this mode to home the missile.
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The missile control section 16, warhead 20, motor section 22 and tail section 24 do not constitute a part of the present invention and therefore details of their construction and function are not deemed necessary except for their operating which is directly related to the seeker head 12 and electronics section 14. If additional information is required in these areas, particularly the control section 16, it can be found in U.S. Ser. Nos. 395,112 and 397,674 both assigned to the same assignee as this application[ Hughes Missile Systems Co ]
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The signal information derived from the IR and UV channels is fed to a logic selector 148 which selects the proper mode for target tracking. The signal pulse information from either the IR channel or the UV channel is differentiated
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In operation, a pulse is generated by PbS detector 62’ and by Si detector 62" every time the instantaneous field of view is scanned over a target. The repetition rate of these pulses may vary, for example, from 10 pulses per second to 200 pulses per second. The target information generated by the detectors is then amplified by the pulse amplifiers 138, 138’. The amplified pulses are then coupled to the threshold detectors 140, 140’ which are set to trigger at a level just below the peak signal generated by the target. The peak detectors measure the amplitude of the highest contrasting object within the field of view and the resulting peak levels are used to set the thresholds of the threshold detectors. The information from the threshold detectors is coupled to logic selector 148 which selects the proper mode for target tracking. The logic involved in the logic selector circuit is such that, if the signals from both the IR and UV channels are simultaneously present at its input, the IR signal will be preferred over the UV signal. However, should the IR signal vanish for a time longer than 0.25 second, the UV signal will be accepted.
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Accordingly, where a target may not be irradiating sufficient infrared energy to be engaged by the missile operating in its normal IR mode, the target may be tracked by the UV mode.
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Preferably, the seeker will initially operate in the visual contrast mode until an adequate IR signal is available to home the missile. If a sufficiently IR radiating target is present, the seeker may select and receive in the IR mode.
Also happened to find this one for rolling airframe missiles.
