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Tracking dynamics on the GPS signal is still a big challenge to the receiver designer as the operating conditions are becoming more volatile. Usually, the Phase-locked loop (PLL) is used in GPS receivers to track an incoming signal and to provide accurate carrier phase measurements. However, in high dynamic situations, the conflict between improving PLL tracking performance and the ability to track the signal necessitates some compromises in PLL design. Optimizing the stand-alone system for dynamics, generally, degrades the accuracy of measurements. The advanced signal processing techniques as maximum likelihood (ML) and extended Kalman filter (EKF) can be used to track a common trajectory exhibiting high dynamics. However, the estimated values of these algorithms can not be used directly to demodulate the signals. A combination of both inertial measurement unit (IMU) and GPS is an attractive method to deal with the problem of high dynamic tracking. Unfortunately, these units of IMU are often very expensive. In this paper, a new Kalman filter aided phase-lock loop is proposed to address this issue. Doppler derived from EKF is used to aid the carrier tracking loop for improving the performance under dynamic conditions. While the cost is significantly reduced compare with the IMU method. Simulations show that the method is feasible.

Levoglucosan (LG) obtained from lignocellulosic biomass exhibits great potential as a specific tracer for biomass burning aerosols and as a raw material for synthesizing stereoregular polysaccharides. One potentially viable source of LG is pyroligneous acid (PA). This study investigated the effects of heating temperature on the extraction capability and the chemical composition of distillate and residual fractions. The results demonstrated that vacuum distillation extracted the acids, alcohols, ketones, aldehydes, and other organic matter. When the heating temperature was above 80 °C, the moisture content of the residual fraction was unchanged. The chemical composition of residual fraction was analyzed by gas chromatography-mass spectrometry (GC-MS). The analysis showed that the relative content of the LG, as obtained from the 90 °C distillation temperature, was 75.6%. Thus, it can be used as raw material for subsequent purification.

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