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In this paper, we propose a novel array interpolation method in logarithmic domain for enhanced direction of arrival (DOA) estimation. Array interpolation techniques are broadly utilized in the DOA estimation for achieving better angular resolution. Generally, to generate interpolated array elements from original array elements, the method of linear least squares (LLS) has been used. When we use the...
The moment method is used to calculate the radiation pattern of a linear array for a number of array element configurations which include single monopole whips, single diamond shaped monopoles and three-element Yagi monopole whips over a perfect ground plane. Investigation of the far field radiation pattern is carried out for the cases of main lobe steering and pattern shaping (using Tschebyscheff...
Advancements in high level integration of MMIC in package have led to the development of a system comprising of a multi-channel transceiver with antenna in package (AiP). Multi-channel systems provide additional advantage by enabling digital beamforming for direction of arrival estimation at 60 GHz. Different beamforming techniques are studied and practically implemented with a radar platform to find...
Random stepped FM radar that transmits random frequency narrowband pulses can avoid interference between adjacent radar systems. The random stepped FM radar also offers spectrum hole since it consists of independent pulses with different frequency. Thus it is expected to coexist with the existing radar systems. In this paper, we propose to adopt Khatri-Rao product array processing to spectrum hole...
Space Fence, currently under construction on Kwajalein Atoll, will revolutionize Space Situational Awareness (SSA) using advanced phased array radar technology in two of the largest phased arrays to ever be constructed. Space Fence will provide catalog completeness, accuracy and timeliness with vastly improved performance in Low Earth Orbit (LEO) and capability to support missions in Geosynchronous...
By pulling some of the signal detection processing that occurs at the final processor in a pulse-detecting system into each node for pre-processing, the amount of digital sample data that must be sent to the final processor can be greatly reduced. This capability would expand the amount of achievable beam-bandwidth for a fixed amount of digital I/O available between hierarchical beamforming nodes...
This paper describes the Front-X, a dual-polarized X-band Phased Array Weather Radar system currently being developed at Colorado State University. The architecture of this mobile radar is presented, with a description of the antenna array, waveform synthesis and digital receiver/pulse compressor modules. Initial observations made with the phased array weather radar are also shown.
The concept of transform sensing was recently proposed to operate radars which consist of multiple antenna elements, for high efficiency and resolution. Using transform sensing, phase delays between and amplitudes of elements are no longer constant as in conventional phased array radars. The purpose is to produce any type of spatial sensing pattern that can be applied to the space for efficient sensing...
Compressed sensing (CS) based reconstruction methods have been in much focus over the last years as they provide a mean to work with limited amount of data. In this article we present an application of CS and sparse reconstruction in a radar setup to form range-Doppler maps. We characterize a radar system where instead of transmitting a train of pulses the pulse transmission occurs in a sparse manner...
This work examines a variety of canonical, randomly distributed phased arrays in linear, planar, and volumetric topologies. We investigate their distributed beamforming capabilities in modern mobile autonomous systems. Sum-difference radiation patterns are generated and analyzed for suitability in applications such as amplitude monopulse scanning, direction of arrival estimation, and target tracking...
We present an iterative method for joint antenna-array calibration and direction of arrival estimation using millimeter-wave (mm-Wave) radar operating at 77 GHz. The calibration compensates for antennaarray coupling, and phase and gain errors, and does not require any training data. This method is well suited for applications, such as automotive radars, where multiple antenna elements are packaged...
Modern active phased array radars are made to optimize the size, weight and power without compromising its capability to combat with advanced electronic warfare. To accomplish this task, the signal is digitized at element level or at sub-array level and processed with the help of advanced digital signal processor. Proving the capabilities of this firmware at bench level helps to reduce the overall...
Digital array radars (DAR) with element-level digital transmission and reception present new opportunities for more advanced radar functionality and performance. In order to reduce RF front-end complexity while also reducing the need for high sample rates, the analog IQ demodulation receiver, or homodyne, is proposed so that only a single local oscillator (LO) is needed per element. An important homodyne...
This paper presents a new approach to solving the rank constrained beamforming problem. Instead of relaxing the problem to a feasible set of the positive semidefinite matrices, we restrict the problem to a space of polynomials whose dimension is equal to the desired rank. The solution to the resulting optimization is then required to be full rank, allowing a simple matrix decomposition to recover...
In order to reduce the date access conflicts and improve the memory access efficiency in radar signal processing, a linear varying step-size data management strategy combined with a hierarchical memory structure is proposed. By proposing the logical mapping strategy between the reconfigurable arrays and the multi-bank memory, the memory access performance of reconfigurable processor is improved and...
In this paper, we focus on the effective Space-Time Adaptive Processing (STAP) method in nonhomogeneous clutter environment. The nonhomogeneous clutter leads to the lack of sufficient training data for clutter covariance matrix estimation in traditional STAP methods. By utilizing the sparsity of the distribution of clutter in angle-Doppler domain, we build a factor graph model and develop a message...
For frequency diverse array (FDA) pattern synthesis, smaller aperture or fewer elements are expected to obtain the desired beampattern performance. This paper propose a new FDA beampattern synthesis approach by ℓ1-norm minimization and convex optimization. Given array aperture, a virtual uniform linear FDA array with much smaller element spacing and corresponding frequency increment is created first;...
An X-band FMCW sensor is developed with beam-scanning capability to reliably detect the vehicles with different shapes. Two-element transmitting antenna array is designed with single phase shifter and an unequal power divider to reduce the cost and achieve compact size of 4.5 cm × 4 cm. Experiments successfully confirm precise identification of the incoming vehicle and its occupancy.
In this paper, we propose and design a coaxial-line fed slot array with a waveguide-to-coaxial transition using a crank-shaped slot. We analyze the 8×8-element trapezoidal array with the designed transition. The bandwidth for VSWR less than 1.5 is 2.1% in the waveguide for boresight radiation and 2.0% in the waveguide for tilted radiation from 77 to 81 GHz.
Noise power and noise figure are detailedly analysed and deduced in theory for mult-port network in active electrically scanned array(AESA) radar, especially in AESA radar. Mathematical expressions of output noise power and total noise figure of network are given out under various conditions. Accordingly, this provides a basis of theories for multi-port network and radar receiver system design, the...
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