海洋原位光学信号高精度定量测量方法研究及传感器研制

发布时间：2018-11-13 14:41

【摘要】：海洋原位传感器是人类感知海洋的触角,是海底观测网的重要组成部分,对人类了解海洋认识海洋具有重要意义。原位光学传感器具有检测精度高、探头不易污染、稳定性高的优点而成为海洋原位监测仪器的主流。在恶劣的海洋原位环境下,海洋原位传感器的性能不仅在于传感器本体的测量灵敏度,更在于系统抗干扰能力。论文研究围绕传感器测量灵敏度与系统抗干扰能力这一对相辅相成而又互相制约的矛盾展开研究,寻求最优平衡。论文提出了微弱光学信号测量模型,在此基础上对海洋原位叶绿素a传感器、原位浊度传感器和原位CDOM(Colored Dissolved Organic Matter, CDOM,有色溶解有机物)传感器展开研究。论文的主要研究内容和创新点包括： 1.建立了原位光学传感器的微弱光学信号测量模型,从电子测量的角度将原位叶绿素a检测、原位浊度检测和原位CDOM检测统一,研究了调制序列、干扰和噪声之间的关系；解决了微弱光学信号测量的光路、结构、精密检测等传感器设计关键问题,研制了基于单频调制方案的微弱光学信号系列传感器,实现了阳光背景干扰下微弱光学信号的高精度检测。实验结果表明,基于单频调制系统的原位叶绿素a传感器测量灵敏度达到0.0081μg/L,线性度R2=0.9985,优于Seapoint、Wetlabs公司同类产品。 2.提出了带宽约束条件下基于伪随机序列的微弱光学信号测量方法及最小频谱幅值损失指标eN,优化了在有限带宽下m序列长度与测量精度的关系,提高了测量系统对窄带干扰的抑制能力。实验结果表明,伪随机序列在码长15bits和31bits时有最小系统测量噪声,码长31bits时比传统单频调制抗干扰能力提高了2.3倍。 3.应用有限带宽下伪随机序列调制测量的优化结果,设计了原位叶绿素a传感器、原位浊度传感器、原位CDOM传感器,采用码长为31bits的m序列调制,其灵敏度分别为:0.0103μg/L(叶绿素a标定)、0.0078FTU(福尔马肼标定)、0.137μg/L(硫酸奎宁标定)。 4.论文研制的原位叶绿素a传感器和原位浊度传感器应用于南海浮标长期观测实验,原位浊度传感器完成了“蛟龙号”深潜器下潜实验,仪器工作正常,初步验证了传感器具有较高的测量精度、抗干扰能力和可靠性。论文研究解决了在复杂强干扰环境下徽弱信号的精确定量测量问题,提出了一种新型的微弱信号检测抗干扰方法,实现了在不增加硬件成本的基础上传感器抗干扰能力的提高。该研究具有重要的科学意义和实际应用价值。
[Abstract]:Ocean in situ sensor is an important component of ocean bottom observation network, which is important for people to understand the ocean and understand the ocean. The in situ optical sensor has become the mainstream of marine in situ monitoring instrument because of its advantages of high detection precision, low contamination of probe and high stability. In the harsh marine in situ environment, the performance of ocean in situ sensor lies not only in the sensitivity of the sensor body, but also in the anti-interference ability of the system. This paper focuses on the contradiction between sensor sensitivity and system anti-jamming ability, which is a pair of complementary and mutually restricted contradictions, in order to find the best balance. In this paper, a weak optical signal measurement model is proposed. Based on this model, the ocean in situ chlorophyll a sensor, in situ turbidimetric sensor and in situ CDOM (Colored Dissolved Organic Matter, CDOM, colored dissolved organic matter sensor are studied. The main contents and innovations of this paper are as follows: 1. The weak optical signal measurement model of in situ optical sensor is established. The in situ chlorophyll a detection, in situ turbidity detection and in situ CDOM detection are unified from the point of view of electronic measurement. The relationship among modulation sequence, interference and noise is studied. The key problems of optical circuit, structure and precision detection for weak optical signal measurement are solved. A series of weak optical signal sensors based on single frequency modulation scheme are developed. The high precision detection of weak optical signal under the interference of sunlight background is realized. The experimental results show that the in situ chlorophyll a sensor based on single frequency modulation system has a sensitivity of 0.0081 渭 g / L and a linearity of 0.9985, which is superior to the similar products of Seapoint,Wetlabs. 2. The measurement method of weak optical signal based on pseudorandom sequence under bandwidth constraint and the minimum spectrum amplitude loss index (eN,) are proposed. The relationship between m sequence length and measurement accuracy is optimized under limited bandwidth. The ability of the measurement system to suppress narrowband interference is improved. The experimental results show that the pseudorandom sequence has the smallest system measurement noise in code length 15bits and 31bits, and the anti-jamming ability of code length 31bits is 2.3 times higher than that of traditional single-frequency modulation. 3. Based on the optimized results of pseudorandom sequence modulation measurement with limited bandwidth, an in situ chlorophyll a sensor, an in situ turbidimetric sensor and an in situ CDOM sensor are designed. The m sequence modulation with code length 31bits is used. The sensitivities were 0.0103 渭 g / L (chlorophyll a calibration), 0.0078FTU (Formalhydrazine calibration) and 0.137 渭 g / L (quinine sulfate calibration). 4. The in situ chlorophyll a sensor and the in situ turbidity sensor developed in this paper have been applied to the long term observation experiment of the South China Sea buoy. The in situ turbidity sensor has completed the dive experiment of Jiaolong deep submersible, and the instrument works normally. The sensor has high measuring precision, anti-interference ability and reliability. In this paper, the problem of accurate quantitative measurement of weak signal in complex and strong interference environment is solved, and a new anti-jamming method for weak signal detection is proposed, which can improve the anti-jamming ability of sensor without increasing the cost of hardware. This research has important scientific significance and practical application value.
【学位授予单位】：浙江大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：R318.6

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