Four-phase orthogonal code design for MIMO radar systems

Orthogonal Phase Coded Waveforms for MIMO Radars

“…The four phase codes discussed in the preceding section are shown [9] to have good aperiodic autocorrelation and aperiodic crosscorrelation properties. However the sequences are do not satisfy the orthogonality property.…”

“…This paper presents the design of four phase pulse coded waveforms with large family size, simpler generation and good aperiodic correlation properties. The correlation properties of these sequences for MIMO radar systems have been studied in [9]. The scope of this paper is to present the construction and code optimization of these sequences for achieving zero-lag orthogonality property required for uniform illumination of transmit power in space.…”

Fast Implementation of Transmit Beamforming for Colocated MIMO Radar

“…In practice, to obtain the prior knowledge about the target locations, orthogonal waveforms [19], 20] are used for MIMO probing. This is referred to as "initial probing".…”

“…The choice of U = 0 and U = 1 makes the contour of desired beampattern a circle and ellipse respectively at each desired direction along the f = f ' line. The function in (19) provides more degrees of freedom to control sidelobe levels compared to a tapering window approach used in [11]. The values f x , f y can be increased so that energy in Ŝ d (m, m') can be spread uniformly along m,m' so that r m,m | constant thus satisfying the uniform elemental power constraint [4].…”

MIMO radar ambiguity analysis of phase coded pulse waveforms

“…This section describes the construction of four phase sequence family (called Family A) originally proposed by Kumar [8] for spread spectrum applications and were later adopted for use with MIMO radar systems [9] due to their excellent aperiodic correlation properties. Polyphase codes designed previously [10]- [11] are "noise-like" and exhibit severe SNR degradation of the matched filter output due to Doppler shift.…”