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In this research, we introduce a signal processing framework for joint GMTI and SAR algorithms that is based on orthogonal (transmit and receive) waveforms. Traditionally, radar systems are configured to operate either in GMTI or SAR processing mode, but not both simultaneously. This is due to the fact that operational parameters for these two modes are quite different. For example, exoclutter GMTI...
A new method is described that allows for the non-interfering spectrum coexistence of radar and a wireless communication system employing multiuser subscriber waveforms. To simultaneously achieve compatibility and requisite radar performance, the radar “subscribes” to the network and utilizes K independent subscriptions. In the case of a cellular network, this would correspond to K independent cell...
Commercial OFDM signals of opportunity have been studied for numerous radar applications, including SAR imaging. This paper demonstrates the utility of long term evolution (LTE), digital video broadcast (DVB), and digital audio broadcast (DAB) signals for producing passive SAR images by employing a previously derived OFDM matched filter model. Both full matched filters and partially matched filters...
The tomographic image of a single cylindrical PEC object is obtained using diffraction tomography theorem after multiple transmissions of independent and identically distributed (iid) UWB random noise waveforms. The final tomographic image of the cylinder is successfully achieved by averaging all obtained images from multiple transmissions. For each transmission, iid band-limited white Gaussian noise...
Unmanned aerial vehicles (UAVs) have become one of the most popular and promising means for both military and civilian posts and academic research areas. Localization of the UAVs and persistent tracking of a UAV have vital importance to provide a UAV with navigation information and help to cope with getting lost permanently. Indeed, inertial navigation system (INS) and global positioning system (GPS)...
Echoic flow is an inherently cognitive method for linking action and perception in radar and sonar systems. In this paper, we describe a first demonstration using echoic flow to guide a robotic vehicle autonomously around an unknown course. We briefly introduce the key concepts that underpin echoic flow and describe how echoic flow can be used to form a cognitive guidance system. Full-scale experiments...
This paper considers the radar detection and tracking of weak fluctuating targets in heterogeneous clutter via dynamic programming based track-before-detect (DP-TBD). The target fluctuating satisfies the well-known Swerling I model and radar clutter is modeled by G0 distribution, which is widely used to model heterogeneous clutter received by small grazing angle or high resolution radar. In this case,...
The spreading first-order sea echo spectrum in shipborne high-frequency surface wave radar (HFSWR) severely impacts the measurement of surface currents. Space-time processing techniques like space-time multiple signal classification (ST-MUSIC) algorithm, usually studied for two-dimensional high resolution radar imaging, are the effective methods for solving the problem. The rank of the sea echo covariance...
This study presents the use of contiguous aperture antenna radome as a method of generating circularly polarized signals from a linear polarization antenna which locates under the structure. The simulated results of the novel structure with single antenna and 2∗2 antennas array are demonstrated for L-band operation. It is shown that 3dB axial ratio bandwidth of 42 MHz and 32 MHz can be achieved with...
New Discrete Frequency-Coding Waveform sets are proposed. They are designed via digitizing the instantaneous frequency of Piecewise Linear FM code sets. The proposed waveform sets are shown to have good autocorrelation and cross-correlation properties that are similar to existing Discrete Frequency-Coding Waveform sets, but are superior in their Doppler tolerance and detection capabilities.
Traditional approaches for interference suppression will enjoy the added benefits when more domains are involved in antenna array. However, the information from range domain and its collaboration with other domains are rarely explored, and their potentials in improvement of radar performance are under-estimated. In this paper, we introduce the concept of polarization sensitive frequency diverse array...
Traditional ground target identification from a standoff platform using SAR is limited due to inadequate integration angles and severe target motion. For UHF operation the integration angle requirements are magnified. However, this same phenomenology that limits the application of SAR opens the door for inverse SAR (ISAR). The principal challenges facing ISAR's applicability to moving ground target...
In this paper, a novel data acquisition and imaging method based on compressive sensing (CS) is utilized for impulse borehole radar (IBR). With the sparse transform we present for the IBR systems, only 50% or even less samples are demanded to be collected and transmitted to reconstruct the target space. It reduces the required sampling rate and data transmission rate of IBR systems. Moreover, the...
The paper proposes a ground moving target detection and estimation method aiming at Ultra Wide Band and -Beam (UWB) Synthetic Aperture Radar (SAR) systems. The method is developed on the moving target detection by focusing technique and requires a SAR system flying with two different speeds during the integration time. The method allows us to detect ground moving target, even hidden by clutter, and...
In this paper, a new two-dimensional phase unwrapping method of interferograms with discontinuities is present. The method is based on the minimum cost flow method and uses the mask produced from phase derivative variance as the new cost function. The phase derivative variance is regarded as the most reliable measure of phase quality when the correlation map is not available and it can highlights...
A signal reflected from a radar target is modified according to the impulse response function of the target. This interaction may be thought of as a linear filter acting on the incident signal. Filters are not exactly invertible, which means that there is no continuous function between the filter output and its input. Likewise, there is no invertible function between the outputs of 2 different filters...
Passive Radar systems use the target illumination by third-party transmitters, e.g. FM radio or terrestrial TV broadcast stations, for target detection and localisation. Due to the great number and wide frequency spacing of the different broadcast services, the resulting multistatic and multiband illumination of air targets can be used to generate a wide-area air picture and to achieve a sound tracking...
This paper proposes superdirective adaptive mode-selective processing in oversampled 2D transmitting (Tx) and receiving (Rx) antenna arrays, enabled by MIMO radar technology, for skywave OTHR applications. The actual reactive power in Tx antenna arrays is controlled by considering two main principles: (1) avoiding extreme steering angles in conventionally beamformed (for a single waveform) sub-arrays...
Transform sensing is proposed for the phased array radar to form certain beam patterns for sensing the space more efficiently. Using the transform sensing, the received signals will be the result of transformation of individual echo signals instead of the original raw data. Therefore signal processing can perform in an online fashion to render attractive advantages. First, the volume of the raw data...
The effect of antenna rotation speed on detecting a fast moving target in sea clutter using a non-coherent X-band radar is studied. The scan-to scan integration is applied using the sigma S6 radar processor. A helicopter (HELO) is used as a fast moving target by mimicking a landing approach to an offshore platform. The radar data was recorded using two X-band radars with horizontal polarized antennas...
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