The mode BSV for high/medium altitudes, all-aspect intercepts (Hc<>=Hs), pulse width ~4 µsec, PRF 1Khz, switching altitude Hs>4,5km, Beam width in search 2,5°. Scan patters depend on NAVED AVT/RUCH switch position. Beam width in STT 1.7°.
The modes BSV-delta H4, BSV-delta H1 for high/medium altitudes are useful for searching targets on earth background not using the Doppler shifts (MTI). For all-aspect intercepts, switching altitude is 4.5km>Hs>1,5km. It uses half/third PRF compared to BSV mode. The “differential compensator device” (DKP) filters false ground signals out. For greater search range the parametric amplifier can be switched on. The receiver sensitivity gains of 5-10% (dB/mW).
The modes BS (I BS, II BS, III BS) for high/medium altitudes are used for all-aspect intercepts (Hs<>=Hc) in case of false targets (clouds) and for picking up targets on earth background by using reference coherent signal received by radar side-lobes. The “III BS” mode has the largest search range of 65km, the “I BS” the smallest one of 27km. The most used mode is the “II BS” with 45km search range. The "III BS" mode works only as a search mode. The FFT Doppler filtering techniques are used to select moving targets flying on the earth background. The so-called “blind speeds” are overcome by changing PRF pulses during each scan line. More than 90% of “blind speeds” are covered, what ensures good MTI.
The mode SMV for medium/low altitudes, only rear-aspect intercepts (Hs
The mode MV is used to engage targets flying at low altitudes on the earth background. It is only for rear-aspect intercepts (Hs>Hc), The switching altitude Hs<1.5km, switch “Delta H”<0, pulse width ~1 µsec, Beam width in search 2,5°. The MV mode uses the MTI based on Doppler shifts.
The modes TP (T I, T II, T III, T-phi 0-I, T-phi 0-II) are used in case of radar damage, jamming or hidden approach. The device TP-26Sh is used for target searching/tracking. Leading the aircraft into the target area is done via ARL-SML/Voice commands.
The search scan pattern in mode “T I“ is 60º in azimuth and 15º in elevation.
The search scan pattern in mode “T II” is 15º in azimuth and 6º in elevation.
The mode “T III” is automatically switched if the target is acquired in the “T II” mode. The “T III” mode has different parameters (target selection impulses-lines) compared to T II/T I.
If the target is acquired by IRST, the N003E radar switches to quasi-search mode. The radar antenna is slaved to IRST sensor and is providing the data for the launch of R-23T. The HUD brightness (IRST signal) can be set via the “USIL T” switch.
The modes (T-phi 0-I, T-phi 0-II) are used when radar activity isn`t required. The R-23T missile seaker is slaved to the IRST.
The mode NVG is used for navigation flights under RSBN, or “return to base” commands (VOZVRAT). The HUD display is showing “K”(curse), “G”(inclination) symbols which the pilot has to follow.