Qiao Xiaolin

Development of an ion mobility spectrometer with a paper spray ionization source.

Paper spray (PS) ionization is a recently developed ion source that has been used to analyze samples in their native environments at ambient pressure without requiring sample preparation or pre-separation. The design of an ion mobility spectrometer (IMS) coupled with PS ionization can help expand IMS applications to on-site detection of complex liquid samples. We report a paper spray ionization ion mobility spectrometer prototype that consists of a PS source and an ion mobility spectrometer optimized using a numerical simulation. The performance of the design was evaluated by measuring 2, 6-di-tert-butylpyridine (2, 6-DtBP). The mobility spectra of the 2, 6-DtBP exhibited a single-product ion peak with reduced mobility calculated at 1.42 cm(2)∕(V s) and a linear response of 0.1-10 μg∕ml, with an estimated detection limit of 0.05 μg∕ml. The Relative Standard Deviation for 1 μg∕ml was 5.7% over 11 measurements. The highest resolving power (47) was measured for 2, 6-DtBP. Based on these preliminary results, the present PSIMS design is expected to become a tool of choice for the rapid analysis of complex liquid samples.

Joint polarization-DOA estimation using sparse antenna array

The algorithm of joint polarization-DOA estimation based on polarization sensitive sparse antenna array is presented. This algorithm realizes DOA and polarize angle joint estimation by MUSIC, avoiding restriction to the array structure and parameter association of the ESPRIT. The array is composed of crossed dipoles which distributed un-uniformly. The use of the sparse antenna array reduces calculation and increases resolution. Computer simulation confirms its availability.

Polarimetric Scattering Properties of Chaff Clouds for Non-coherent Radars

Non-coherent radar backscattering from chaff clouds is studied, employing a polarimetric radar cross section. Two orthogonally polarimetric scattering cross sections are derived. Both mathematical analysis and measurements show that the depolarization phenomenon is remarkable in radar echo of chaff clouds.

Scheme of adaptive polarization filtering based on Kalman model

Abstract A new kind of adaptive polarization filtering algorithm in order to suppress the angle cheating interference for the active guidance radar is presented. The polarization characteristic of the interference is dynamically tracked by using Kalman estimator under variable environments with time. The polarization filter parameters are designed according to the polarization characteristic of the interference, and the polarization filtering is finished in the target cell. The system scheme of adaptive polarization filter is studied and the tracking performance of polarization filter and improvement of angle measurement precision are simulated. The research results demonstrate this technology can effectively suppress the angle cheating interference in guidance radar and is feasible in engineering.

Design of a new dual-polarization antenna on missile

Dual-polarization antenna on missile is useful in some applications such as target detection and counter-countermeasure. But it is difficult to design and fabricate because of the limited space in the missile. This paper discusses the design of a new X band dual-polarization Cassegrain antenna for guidance radar on missile, including the calculation of the parameters of the ortho-mode transducer. The ortho-mode transducer is adopted, which enables the antenna to transmit and receive vertical and horizontal polarization signal. The measurement of the new antenna shows that its polarization isolation is high enough to meet the need and the other performances are almost the same as those of the original simple-polarization antenna.

The Effect of Snapshots on Toeplitz Music Algorithm with MRA

Under the situation of minimum-redundancy array (MRA), snapshot will impact on the estimation performance of the direction of arrival (DOA). In respect of Toeplitz multiple signal classification (MUSIC) algorithm’s principle, this paper has analyzed the correlation coefficient to the Toeplitz MUSIC algorithm influence, and through deducing the relation between snapshot and correlation coefficient, we conclude the snapshot, sampling time, sampling rate’s influence to the Toeplita MUSIC algorithm indirectly. Finally we validate the conclusion through simulation experiments.

The Monopulse Angle Estimation Based on the Radon-Ambiguity Transform

On the condition of amplitude-comparison monopulse radar system, for measuring the direction of multicomponent sources in the space which have same modulation format, an algorithm of Direction-of-Arrival (DOA) estimation based on Radon-Ambiguity Transform is proposed. The typical signal model is built up, and when the time-of-arrival is very approximate, it is discussed how to extract the signal amplitude of each source. And then the algorithm’s results of angle measurement is given.

Millimeter Wave Polarimetric Monopulse Radar Debugging System

For testing millimeter wave polarimetric monopulse radar and testing algorithms for polarimetric radar, millimeter wave polarimetric monopulse radar debugging system is proposed in this paper. Polarimetric radar, as a kind of radar with strong counter-countermeasure capability, is more and more popular used nowadays. The cost of polarimetric radar is more expensive than traditional single-polarimetric radar. Millimeter wave polarimetric monopulse radar debugging system is a kind of assistant instrument. With it, the research cost and period both can be reduced. In the paper, the millimeter wave polarimetric monopulse radar debugging system is introduced in detail. Firstly, the conception of millimeter wave polarimetric monopulse radar debugging system is given; secondly, according to different functions, the debugging system is divided into three modules to be introduced; thirdly, the system key techniques and the performance are given.

Anti-Full Polarization Active Jamming

For anti-full polarization active jamming, a new polarization signal processing technology is proposed in this paper. The single polarization active jamming can be identified by polarimetric radar, but the full polarization active jamming is effective to deceive polarimetric radar. Therefore, the new detection technology is necessary to be adopted against full polarization active jamming. The purpose of the paper is to present a new method for anti-full polarization active jamming. The polarization coding technology, as a new method used in polarimetric radar, is proposed and a new polarization demodulation method by included angle of polarization state between transmitter signal and echo signal on the Poincare polarization sphere is given in the paper.

Study on scattering characteristics of chaff for radar

In this paper, polarization scattering characteristics of chaff are investigated based on dipoles scattering model. Scattering cross section (SCS) and radar cross section (RCS) are respectively defined considering practical operating mode of radar systems. The results show that various formulas of chaffs RCS existing in different documents are classified definitely. Chaffs RCS applicable to various radar systems are discussed.