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This paper describes the development, construction, and measurement of the optics of a receiver operating between 67-90 GHz prototyped by the National Radio Astronomy Observatory (NRAO). The intent is to install this receiver on the Atacama Large Millimeter/submillimeter Array (ALMA) as a new band increasing the capability of ALMA. ALMA is an international radio telescope in the Atacama Desert of...
For the problem that the sensitivity greatly reduces when the bandwidth of wideband digital receivers increases and the problem of cross-channel signal caused by uniform channelized wideband digital receivers, a new receiver based on modulated wideband converter (MWC) discrete compressed sampling structure is proposed and the proposed structure is improved to compressively sample radar signals and...
Digital down conversion is one of the key technologies of pulse radar IF receiver, while the traditional DDC implementation methods with existing FPGA cannot meet the requirements for the hardware resource of bandwidth and filter accuracy. In recent years, the development of digital receiver becomes possible as the fast development of microwave integrated circuit technology and the rapid development...
Phased array radar systems typically utilize calibration network coupling to the transceiver for channel amplitude and phase calibration. The calibration network is stable and reliable, and the influence of the external factors is small, and the accuracy of the amplitude and the phase can be guaranteed. The design implements a generic digital transceiver calibration module, mainly composed of the...
This paper explores parameter estimation of a Swerling IV target in the presence of the Gaussian receiver noise. Two approaches, maximum likelihood (ML) and best linear unbiased estimation (BLUE), are presented, and the Cramér-Rao lower bound is explicitly derived. Compared with the ML, which involves nonlinear non-convex optimization, BLUE can dramatically reduce the computational complexity but...
Dual-functionality platforms have recently been proposed to jointly and simultaneously enable radar target illumination and establish wireless communication links. This duality serves as means to alleviate the spectrum congestion crisis. In this paper, we consider the problem of radar system design for dual-function radar-communications (DFRC). We develop a new transmit signaling scheme which permits...
We present in this paper the work done to test the synoptic capabilities of the GNSS-R interferometric technique as a means towards sea surface altimetry estimation, which is an integrated part of the assessment of the GEROS-ISS mission. For this purpose, a new software receiver has been developed and tested: SPIR. With the lessons learned after a first flight campaign, some system modifications were...
In this paper, we propose a low-complexity robust radar-embedded Sidelobe Level (SLL) modulation for a communication system as a secondary task for the radar. The robust radar-embedded SLL modulation aims the generation of transmit beampatterns, that satisfactorily match a given transmit profile (with high fidelity adjustment at the mainlobe), where each beampattern embeds a different SLL towards...
Spectrum sharing technology has received a lot of attention as a promising solution for the problem on the shortage of spectrum resources due to mobile traffic increase. For the purpose of coexistence without harmful interference to incumbent services, secondary users (SUs) in spectrum sharing systems should adjust their transmission power while complying with regulatory requirements. In this paper,...
In this paper, an active mixing UHF-Band 8 channels digital array module is introduced. Eight independent RF and digital transceiving channels are integrated. three-dimensional layout, standardization and modularization design are adopted. The power supply is only 28 V, signal control and data transmission go through optical fiber. Good measured results are obtained.
We present a three-dimensional scheme that can be used to compute a vertical radar profile from reflection and transmission data measured at two parallel surfaces of a dissipative medium. From this double-sided data set the reflection response of a fictitious medium with negative dissipation can be computed. The measured reflection response and the computed reflection response in the medium with negative...
We investigate the effect of radar interference on an uncoded data communication system where the optimal Maximum-A-Posteriori decoder is used and the bandwidth of the radar system is assumed to be much larger than the one of the communication system. Conclusions depend on how the radar interference power, measured by the Interference-to-Noise ratio (INR), compares with the intended signal power,...
The acquisition of reflected GPS signals on the ocean requires a high sensitivity receiver, high receiving antenna gain and averaging over a long period of time because of their low power. Typically, the receiver integrates 1 ms of signal coherently and averages 1000 of these results non-coherently, using a total signal time of 1 second to generate 1 delay-Doppler map, which is used to retrieve information...
In the paper there are represented some results showing ability to detect of buried mines with use of Forward Looking GPR prototype developed on the basis of Stepped Frequency Continuous Wave probing signal and aperture synthesis technique realized by moving subarray consisting of one transmitter and one receiver to different locations forming the antenna array aperture.
Modern radar warning receivers form the clusters by processing the incoming pulses using multiple parameter deinterleaving. Validation and identification of formed sequences obtained from formed clusters are made by time-of-arrival (TOA) deinterleaving. Especially, validation and identification of the sequences utilizing as minimum number of pulses as possible are of utmost importance. The improved...
In an effort to meet the growing demands of the mobile communications industry, the recent Federal Communications Commission (FCC) auction of the 1695–1710 & 1755–1780 MHz bands marked the continued commitment by regulators to make available frequencies previously reserved for the military to the general public. While good for the economy, the Advanced Wireless Services (AWS-3) auction presents...
Spectrum sharing between radar and communications systems is currently under investigation because of the high demand for new wireless services and shortage of available bandwidth. To effectively design their coexistence, it is crucial to understand how current unaltered radar and communication systems would affect one another. This paper investigates the effect of radar interference on an uncoded...
Binary phase coding is a promising technique to realize multiple-input multiple-output radars. However, for the case of frequency-modulated continuous-wave radars, using well-known orthogonal codes for transmit (TX) signal separation in the receiver does not lead to optimal results. In this work, we therefore present a two-step optimization approach to determine binary sequences and filter weights...
In this paper, we propose a robust radar-embedded Sidelobe Level (SLL) modulation for a communication system as a secondary task for a radar system. We propose an optimization formulation based on quadratic, point and first derivative constraints, which can efficiently generate K transmit beampatterns that match a desired transmit mainlobe output power profile and embed K different SLLs towards the...
Noise radars, due to advancements in radio frequency circuits and computational power, have become available in recent years. The main advantages of a noise waveform are the lack of range and Doppler ambiguities, low probability of interception and good electromagnetic compatibility. When several transmitters use different noise waveforms in the vicinity, the receiver noise floor rises according to...
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