Recent advances in far-field fluorescence microscopy have led to substantial improvements image resolution, achieving a near-molecular resolution of 20 30 nanometers the two lateral dimensions. Three-dimensional (3D) nanoscale-resolution imaging, however, remains challenge. We demonstrated 3D stochastic optical reconstruction (STORM) by using astigmatism determine both axial and positions individual fluorophores with nanometer accuracy. Iterative, activation photoswitchable probes enables...

Different from conventional phased-array, which provides only angle-dependent beampattern, frequency diverse array (FDA) employs a small increment across the antenna elements and results in range-angle-dependent beampattern. This beampattern offers potential to localize targets two dimensions terms of slant ranges azimuth angles. However, it is difficult obtain target location information standard FDA radar due couplings range angle responses. In this paper, we propose transmit subaperturing...

Recently, nested and coprime arrays have attracted considerable interest due to their capability of providing increased array aperture, enhanced degrees freedom (DOFs), reduced mutual coupling effect compared uniform linear (ULAs). These features are critical improving the performance direction-of-arrival estimation adaptive beamforming. In this paper, a new sparse configuration based on maximum inter-element spacing constraint (MISC) is proposed. The MISC generally consists three ULAs plus...

Phased-array antennas are known for their capability to electronically steer a beam with high effectiveness, but steering is fixed in an angle all range cells. This paper reviews frequency diverse array (FDA) antennas. Different from phased array, FDA uses small increment, as compared the carrier frequency, across elements. The use of increment generates factor that function angle, time, and range, allowing antenna transmit energy over desired angle. In addition analyzing characteristics,...

Phased-array radar is widely used in localizating non-cooperative targets, but the range and angle of targets cannot be directly estimated from its beamforming output due to an inherent ambiguity, i.e., two-dimensional localization non- cooperative obtained conventional linear phased-array peaks. This paper proposes a simple range-angle by uniform array (ULA) double-pulse frequency diverse (FDA) radar. The FDA transmits two pulses with zero non-zero increments, respectively. azimuth slant...

Time and frequency modulated arrays have numerous application areas including radar, navigation, communications. Specifically, a time array can create beampattern with low sidelobes via connecting disconnecting the antenna elements from feed network, while diverse produces range-dependent pattern. In this paper, we aim to introduce these advanced signal processing community so that more investigations in terms of theory, methods, applications, be facilitated. The research progress...

Phased-array is widely used in communication and radar systems, but the beam steering fixed an angle for all ranges. In this paper, we propose a range-angle dependent beampattern synthesis scheme linear frequency diverse array (FDA) using discrete spheroidal sequence, with aim to focus transmit energy desired two-dimensional spatial section. Different from conventional phased-arrays, FDA employs small increment, compared carrier across elements. The method allows over range or sector. This...

Multiple-input multiple-output (MIMO) radar enjoys the advantage of increased degrees-of-freedom and spatial diversity gain, but it cannot effectively resolves targets closely spaced in same angle cell (but different range cells). Frequency diverse array (FDA)-MIMO can handle this problem by exploiting its range-dependent beampattern. FDA-MIMO was, thus, suggested for range-angle estimation targets. Nevertheless, is necessary to provide theoretical performance analysis such a relatively new...

Multiple-input and multiple-output (MIMO) radar has received renewed attention in recent years, but little work on MIMO synthetic aperture (SAR) remote sensing been reported. This paper presents a scheme of space-time coding orthogonal frequency division multiplexing (OFDM) SAR for high-resolution imaging. system employs configuration the elevation direction Alamouti azimuth direction, along with use OFDM waveform diversity displaced phase center antenna (DPCA) techniques. As an transmission...

The frequency diverse array (FDA) using linearly increasing increment yields an "S"-shape range-angle beampattern, which provides the potential capability to suppress range-dependent interferences. However, FDA transmit beampattern is coupled in range and angle dimensions, may degrade output signal-to-interference-plus-noise ratio performance. In this letter, we propose a symmetrical synthesis approach multicarrier increments convex optimization, named convex-multilog-FDA, achieve dot-shaped...

Due to its range-angle-dependent transmit beampattern, frequency diverse array (FDA) provides potential applications for joint range and angle estimation of targets range-dependent interference suppression. However, a standard FDA using linearly increasing increments will generate range- angle-coupled S-shaped beampattern. This letter proposes focused beampattern synthesis by optimizing the with genetic algorithm. Both single-dot multidot-shaped beampatterns can be synthesized in this way....

Phased-multiple-input and multiple-output (MIMO) radar is a flexible technique which enjoys the advantages of MIMO without sacrificing main advantage phased-array radar. However, phased-MIMO limited to range-independent directivity; this limits performance mitigate non-desirable range-dependent interferences. In paper, we propose new with frequency diversity for beamforming. The essence proposed divide diverse array transmit into multiple subarrays, each subarray coherently transmits...

Multiple-input multiple-output (MIMO) synthetic aperture radar (SAR) has received much attention due to its interesting application potentials, but effective waveform diversity design is still a technical challenge. In MIMO SAR, each antenna should transmit unique waveform, orthogonal the waveforms transmitted by other antennas. The have large time-bandwidth product, low cross-correlation interferences, and peak-average ratio. To reach these aims, this paper proposes an frequency division...

Different from conventional phased-array providing only angle-dependent beampattern, frequency diverse array (FDA) produces angle-range-dependent and time-variant transmit beampattern. Existing investigations show that FDA offers improved performance in interference suppression target localization, but the beampattern will bring interferences to subsequent matched filtering. More seriously, range-dependent signal phase may be canceled out filtering process. In fact, traditional...

Although phased-array antennas are widely used in communication, radar, and navigation systems, its beampattern is a function of angle only thus there no range information. To circumvent this limitation, we design frequency diverse array (FDA) antenna system for range-angle imaging targets. Our approach exploits the nonuniform FDA as transmitter to provide range-dependent uniform receiver which results angle-dependent beampattern. Range-angle targets achieved from cooperative...

Phased-array is widely used in communication, radar, and navigation systems, but the beam steering fixed an angle for all range cells. Frequency diverse array (FDA) provides a range-dependent beamforming, it cannot estimate directly both of target. This paper proposes subarray-based FDA with aim to localize target range-angle domain.We divide whole into two subarrays, which employ different frequency increments. In doing so, target's are estimated from transmit-receive beamforming output...

In this letter, we devise an efficient approach for estimating the directions-of-arrival (DOAs) of coherent signals using coprime arrays. Specifically, firstly derive augmented uniform linear array (ULA) via interpolation. Subsequently, define a Toeplitz matrix that is formed correlation information interpolated ULA theoretical outputs, and recover by solving nuclear norm minimization problem. After low-rank recovered, are well resolved MUSIC algorithm. Simulation results demonstrate...

Range-ambiguity suppression is a technical challenge for high-pulse-repetition-frequency (PRF) synthetic aperture radar (SAR). This letter proposes practical approach to mitigate the range ambiguities in high-PRF SAR by using orthogonal frequency-division multiplexing (OFDM) waveform diversity. The system scheme, design, and range-ambiguity-to-signal-ratio performance are detailed. eliminates ambiguities, instead of just suppressing them like other techniques. proposed OFDM chirp diverse has...

To ensure link reliability and signal receiving quality, robust adaptive beamforming (RAB) is vital important in mobile communications. In this paper, we propose a new RAB algorithm based on interference-plus-noise covariance (INC) matrix reconstruction steering vector (SV) estimation. method, the INC reconstructed by estimating all interferences SVs powers, as well noise power. The interference are estimated using Capon spatial spectrum together with principle, subsequently powers...

Deep learning algorithms have been widely utilized for synthetic aperture radar (SAR) target detection. Nevertheless, the traditional feature extraction methods and deep achieve improved ship detection accuracy at a cost of increased complexity lower speed. As speed also is meaningful, especially in real-time maritime rescue emergency military decision-making applications, we propose new framework faster region-based convolutional neural network (R-CNN) method to handle this problem. A...

Nested arrays have recently attracted a growing concern owing to their ability of achieving extended aperture and enhanced degrees freedom (DOFs) compared conventional uniform linear (ULAs). In this paper, we devise source localization scheme under the simultaneous existence near-field (NF) far-field (FF) sources using symmetric double-nested array (SDNA). First, direction-of-arrivals (DOAs) FF are estimated 1-D MUSIC spectrum. Then, NF components can be extracted by applying oblique...

Inspired by a cognitive radar in exploiting its environment to update current operation parameters and frequency diverse array (FDA) offering range-dependent beampattern due the employment of increments across elements, this paper proposes moving-target tracking approach achieve radio stealth using an FDA antenna for surveillance applications. Since systems are highly visible intercept receivers, traditional high-gain phased-array beam is replaced series low-gain beams with spoiled reduce...

As is well known, nonuniform linear arrays have significant advantages in array aperture and degrees of freedom over uniform arrays. Using their difference coarrays, subspace-based approaches can be utilized to perform underdetermined high-resolution direction-of-arrival (DOA) estimation. However, the depend on covariance matrix reconstruction coarray domain, which are not statistically efficient when number sources more than one less sensors. In this paper, overcome drawback, we devise an...

Road traffic sign detection and recognition play an important role in advanced driver assistance systems (ADAS) by providing real-time road perception information. In this paper, we propose improved (Single Shot Detector) SSD algorithm via multi-feature fusion enhancement, named MF-SSD, for recognition. First, low-level features are fused into high-level to improve the performance of small targets SSD. We then enhance different channels detect target enhancing effective channel suppressing...