There is a linear corresponding relationship between the refractive index of seawater and the salinity at a certain temperature, so the salinity can be calculated by measuring the seawater’s refractive index indirectly. Several ways to measure the salinity indirectly through the refractive index measurement using optical methods were introduced particularly, including fiber Bragg grating sensor detection, surface plasma wave detection techniques and detection technologies based on geometrical optics method. The salinity sensor structures, measurement precision of every salinity measurement methods were discussed, the factors that affect measurement accuracy were analyzed, as well as the problem in practical applications. Finally, the feasibility of seawater salinity real-time detection by optical technology was prospected.

The airborne particle measuring system has good timeliness, adaptability and stability in operation. Data of cloud droplets and precipitation particles monitored and recorded can be processed and displayed for real time. Structure and working principle of this system are introduced briefly. Theory of cloud droplets and precipitation particles detection in this system are described in detail, as well as technical characteristics of this system are analyzed. Potential errors in practical application are discussed, finally some notes and recommendations on the practical application as well as researches and developments of PMS systems are proposed.

Atmospheric coherence length is a very important parameter in the study of atmospheric turbulent intensity and laser propagation. To figure out the A-class measurement uncertainty of the atmospheric coherence measurement system, and confirm the reliability of the difference image motion method (DIMM), the atmospheric coherence length was measured by DIMM and turbulent integral method in the same propagation path. Results of both methods are similar in level and the time trend, so both methods can validate each other. The possible reason of atmospheric coherence length differences between two methods was analyzed. The A-class measurement uncertainty of the atmospheric coherence measurement system was calculated by Bessel method. The average relative extend measurement uncertainty of the system is smaller than 20% via the experiment. The results show that the atmospheric coherence measurement system can offer valuable references for the application of atmospheric optics propagation.

Airborne measurements of high-resolution spectral data are an innovative technology with high spatial resolution and informative features, and the high-resolution spectral data have high sensitivity of retrieving CO2 concentration near the surface of earth. The high-resolution atmospheric radiation software is used to calculate and choose the 1.57 μm (6315～6385 cm－1) waveband CO2 high-resolution spectra to retrieve CO2 concentration. The results show that the high-resolution spectral data can detect very small CO2 (1%) changes with sufficient signal to noise ratio and resolution. Also the effects of aerosols in atmospheric and surface temperature change on the high-resolution spectral data of CO2 are analyzed.

Three-dimensional fluorescence spectrometry described the relationship between fluorescence intensity and the wavelength of emission and excitation. More information of fluorescence spectrum can be provided. Characteristic fluorescence spectrum can be obtained by dividing data matrix of three-dimensional fluorescence spectra from complex mixture by the parallel factor analysis (PARAFAC) model, which can separate the spectrum from different kinds of fluorescence matters. By means of PARAFAC model and three-dimensional fluorescence spectroscopy, the determination of four components with overlapping spectra is described. It has been tested satisfactorily for the analysis of two binary and a quadruplex mixtures consisting of phenanthrene, anthracene, pyrene and fluoranthrene.

Several methods were used to measure the atmosphere corrosion rusty layer samples of the carbon steel and low-alloy steel which were placed under different air conditions for different periods of time. The phase variety, the degree of crystallization, the impedance of rusty layers and the alloying elements existing in the layers were analyzed. The anti-corrosion mechanism of the low-alloy steel was studied.

The infrared target operating state is divided into different measurement stages. First, choose a time to determine the state parameters of dynamic prediction, and then write out state transition equation of infrared target, and finally calculate the optimal function value. The core idea is to turn the target tracking into variables, to achieve optimal by time period, to track the best results in the scheduled time. Finally, the effectiveness of the algorithm is verified through simulation.

The thermal band 6 data of Landsat 5 is used to retrieve land surface temperature of Hefei with mono-window algorithm. The atmospheric water vapour content is high in summer. MODTRAN is used to simulate the relationship between water vapour content and atmospheric transmittance when the water vapour content is between 0.4 g/cm2 and 5.4 g/cm2. And then the simulation result and MODIS water vapor product are used in atmospheric correction and Landsat surface temperature retrieval. The uniform zone temperature is selected to compare with the MODIS temperature product. The comparison result shows that the contrast of vegetation is less than 1 K while construction is less than 1.1 K. The result can be used to atmospheric correction and then retrieve land surface temperature.

A triple-layer BP neural network was put forward based on the principle of the 8.5 μm, 11 μm, and 12 μm brightness temperature to retrieve the cloud phase in MODIS images. The cloud phase was retrieved based on the artificial neural network in high-latitude region(N30°～N55°) and low-latitude region(N0°～N30°) on January 15, 2008 and July 15, 2008 in China, and the result was compared with the cloud phase of MOD06 of NASA center. The result indicates that the inversion precision of the method is higher than 90%, and the uncertain scope of cloud phase is decreased.

A heterodyne photo detection method is proposed in order to improve the signal to noise ratio of a frequency-modulated-continuous-wave (FMCW) laser range finder. For this purpose, the non-linearity of the current-voltage characteristic of an avalanche photodiode (APD) is used. The photoelectric current is mixed with a local oscillator (LO) signal inside the APD working as an optoelectronic mixer. The signal from the LO can be injected inside the APD by an electrical channel. Experimental results are in agreement with the theoretical analysis, and this method shows that it can greatly improve the measurement distance in phase-shift laser range finder with non-cooperative target.

In view of severe radiation of ultraviolet radiation B, bad on-site working conditions, easily leading to missed detection of traditional phosphor magnet powder flaw detection methods, the light source of phosphor magnet power flaw detection for tyre surface is optimally designed. A UV-LED light source is adopted as the excitation light source, it achieves matching between the UV-spectrum and the excited spectrum of the phosphor magnet powder. 108 UV-LED lights source arranged in arrays to obtain the high intensity and uniform illumination. The LED lights source with filter glass can filter out harmful ultraviolet rays and useless visible lights. The results show that the designed UV-LED lights source can meet the requirements of phosphor magnet power flaw detection for tyre surface.

Characteristics of 1-wire technique were introduced. A temperature survey system based on 1-wire digital sensor DS18B20 and PIC16F73 MCU was designed. The hardware structure and the software design were also described. Compared with the traditional temperature control devices, this system has simpler structure, higher precision and better anti-disturbance performance. In addition, each DS18B20 has a unique serial code, which allows many DS18B20s to function on the same 1-wire bus.