Instantaneous Radar Polarimetry with Multiple Dually-polarized Antennas

Abstract

Abstract-Fully polarimetric radar systems are capable of simultaneously transmitting and receiving in two orthogonal polarizations. Instantaneous radar polarimetry exploits both polarization modes of a dually-polarized radar transmitter and receiver on a pulse by pulse basis, and can improve the radar detection performance and suppress range sidelobes . In this paper, we extend the use of instantaneous radar polarimetry for radar systems with multiple dually-polarized transmit and receive antennas. Alamouti signal processing is used to coordinate transmission of Golay pairs of phase codes waveforms across polarizations and multiple antennas. The integration of multiantenna signal processing with instantaneous radar polarimetry can further improve the detection performance, at a computational cost comparable to single channel matched filtering.

Doppler Resilient Golay Complementary Waveforms

“…Alamouti matrices of Golay pairs were constructed in [7] and [8] for instantaneous radar polarimetry to enable target detection in range based on full polarimetric properties of the target on a pulse by pulse basis. Alamouti signal processing is used to coordinate the transmission of (N/2) Golay pairs…”

“…We determine a sequence of Golay pairs that forces the low-order terms of the Taylor expansion (around zero Doppler) of the composite ambiguity function to zero. We then extend this construction to multiple dimensions and integrate it with instantaneous radar polarimetry [7], [8], where the dimensions are realized by employing two orthogonal polarizations. Here, we construct a sequence of two-by-two Alamouti matrices [9], where the entries involve Golay pairs and for which the matrix-valued composite ambiguity function vanishes at small Doppler shifts.…”

Optimal Polarized Beampattern Synthesis Using a Vector Antenna Array

“…As plotted in Fig. 14, when increases from 1 to 2, polarization control is enabled while the power gain remains the same (for , we choose the array of electric dipoles pointing along the axis). For the vector sensor arrays (when ), all three curves for different array size 6,12,18 show that such gain is almost linearly proportional to . We, thus, conclude that the EMVA array has the advantage of i) enabling control of the beampattern polarization; ii) virtually increasing the array size, since multiple EM fields at each antenna are exploited.…”

“…We can write in the form (6) where is the azimuth angle and is the elevation angle. For each , we further choose It is easy to see that forms a right-hand coordinate system; see Fig.…”

“…radar to be able to control the transmit waveform polarization, which in addition enables the transmit polarization diversity [6], [10], [11]. Among current radar systems, polarimetric radar that transmits waveforms with both horizontal and vertical orientations has been developed and adopted in a wide range of applications [12].…”