Background Suppression and Strong Phase Codes in Incoherent Scatter Lag Profile Inversion

High range resolution incoherent scatter spectra are routinely measured by means of alternating codes and random codes. These radar transmission modulations are cycles of phase-coded pulses whose lagged products form complementary code sets, enabling decoding of incoherent scatter lag profiles by means of matched filtering. Numerically optimized near-perfect modulations are potential successors of the alternating codes and random codes because they enable new measurement techniques, such as so-called multipurpose experiments. The near-perfect modulations cannot be decoded by means of matched filtering, but they are designed for analysis by means of lag profile inversion. Two improvements to this combination are introduced in this letter: Suppression of background noise correlations is implemented as part of lag profile inversion, removing the need for dedicated background measurements, and the concept of strong phase codes is adopted to near-perfect modulations, allowing one to neglect the receiver impulse response in lag profile inversion.