arnab,
I wanted to know the reason why mmv seeker is pursed in helina and not in nag?I am still trying to get advantages of each type of seeker vs others.
mmW Band: Frequency range: 75 to 300 GHz; Wavelength range: 4 to 1 mm (IEEE W Band+mm Band)
Infrared Band: Frequency range: 300 GHz to 430 THz; 1 mm to 700 nanometers (nm)
Lower frequency = Higher range, lower accuracy, lower power consumption, lower influence by weather conditions.
Higher frequency = Lower range, higher accuracy, higher power consumption, higher influence by weather conditions.
IIR has very small range and higher influence by weather conditions, that is why IIR is used only for terminal guidance.
Compared to IIR, mmW has higher range of detection, lower influence by weather conditions, but slightly lower accuracy.
However, if you compare mmW with Ku Band (IEEE; Frequency range: 12-18 GHz; Wavelength range: 2.5–1.67 cm) mmW has lower range of detection, higher influence by weather conditions, but slightly higher accuracy.
An ideal solution would have a dual spectrum seeker: An IEEE Ku Band "Target Detection" seeker and an IIR "Terminal Homing" seeker in one package. Else, instead of a dual spectrum seeker, a compromise is reached with mmW seeker with the advantages (and a few disadvantages) of both the bands (Ku+IR).