Zhejiang University

Lingyun Ye

Kaichen Song

Jinlong Yu

Xinglin Sun

Ju Wang

Xinyue Tan

Haojie Wu

Caixia Li

Meng Niu

Tiantian Huang

A phase frequency detector-based high-precision feedback frequency measurement apparatus and method: a Field Programmable Gate Array (FGPA) roughly measures a frequency fx of a measured time-frequency pulse by an equal-precision frequency measurement method; a Direct Digital Synthesizer (DDS) automatically synthesizes a frequency fx′ according to the fx roughly measured by the FPGA; the fx and the fx′ are sent to a phase frequency detector for performing phase frequency detection and then sent to the FPGA after passing through a charge pump, a low-pass filter circuit, and an (Analogue-to-Digital) A/D converter; the FPGA processes a frequency difference obtained by the phase frequency detector and then transmits the processed frequency difference to the DDS to form a negative feedback frequency measurement system so that the DDS continuously adjusts the fx′ according to a frequency difference measurement result until the output of the DDS is stable. Therefore, precise measurement of the time-frequency pulse to be measured is realized.

Phase frequency detector-based high-precision feedback frequency measurement apparatus and method

A bidirectional optical-carrying microwave resonance system based on a circulator structure and a method for detecting angular velocity by said system. A high-stability optical-carrying microwave of which polarization states in forward and reverse directions are perpendicular is generated in an optical fiber ring by utilizing a regenerative mold locking technology, a cavity length control technology, and a polarization state separation technology, and the optical-carrying microwave is used for measuring a rotational angular velocity. The circulator structure is adopted and the bidirectional optical-carrying microwave resonance is achieved by means of a bidirectional regenerative mode locking technology. A reciprocal bidirectional optical-carrying microwave resonance system is achieved on the basis of a non-reciprocal error elimination technology of a wide-spectrum optical interferometer. The polarization state separation technology is adopted to achieve dual-wavelength separation of optical signals and the perpendicular polarization state is adopted for opposite transmission in a sensitive ring, so that the detection capability of the sensitive ring is improved. The cavity length control technology is adopted to lock a microwave oscillation frequency in one direction to a high-stability standard-time reference source, so that a relative cavity length of an optical resonant cavity is stabilized. The system has the characteristics of high practicability, high measurement precision and the like.

Bidirectional optical-carrying microwave resonance system based on circulator structure and method for detecting angular velocity by said system

Disclosed is a single-axis rotational inertial navigation system based on bidirectional optical communication and wireless power supply. The system comprises a bidirectional optical communication unit, a wireless power supply unit, a motor driving unit, an inertial measurement unit, a rotating-end information acquisition and processing unit, and a fixed-end information receiving and processing unit. According to the system, in the same transmission channel, information interaction between a rotating end and a fixed end is achieved by adopting infrared light communication and visible light communication; and medium-power high-efficiency wireless energy transmission under a specific distance is achieved by adopting a magnetically coupled resonant wireless power supply method. The design of a high-accuracy motor driving unit is achieved by adopting the design of combining a frameless torque motor with an incremental circular grating and double reading heads.

Single-axis rotational inertial navigation system based on bidirectional optical communication and wireless power supply

A polarization-maintaining fully-reciprocal bi-directional optical carrier microwave resonance system and an angular velocity measurement method thereof. In the system, highly stable optical carrier microwaves are generated in a clockwise direction and a counterclockwise direction in the same resonant cavity, and are used to measure the angular velocity of rotation of a carrier apparatus. A fully reciprocal ring-shaped resonant cavity structure is used to achieve a fully reciprocal bi-directional optical resonance system. A polarization state separation technique is used to separate an optical signal into two wavelengths, and optical signals with perpendicular polarization states are transmitted in opposite directions in a sensing ring, thereby improving the measurement capability of the sensing ring. Bi-directional optical carrier microwave resonance is achieved by using a phase tracking structure and a regenerative mode locking technique. A cavity length control technique is used to lock the oscillation frequency of microwaves in one of the directions to a highly stable standard time reference source, thereby achieving a stable relative cavity length of an optical resonant cavity. The described key techniques greatly improve the signal-to-noise ratio of bi-directional oscillation difference frequency signals caused by the Sagnac effect. The system and the method are practical and have high measurement precision.

Polarization-maintaining fully-reciprocal bi-directional optical carrier microwave resonance system and angular velocity measurement method thereof

A stacking modular instrument bus device includes N instrument sub-modules, N+1 customized bus connectors, a first bus termination module and a second bus termination module. The N instrument sub-modules are connected with each other in series through the N&#x2212;1 customized bus connectors to form an instrument sub-system, two ends of the N instrument sub-modules are respectively connected with the first bus termination module and the second bus termination module through one customized bus connector; each of the instrument sub-modules includes a bus unit and a functional unit. The present invention can freely stack and combine all the instrument sub-modules in the manner of building blocks, which is divorced from the conventional backboard type structure and becomes more flexible. Every instrument sub-module has the independent and complete instrument structure and form the system itself. The bus unit of the instrument sub-module is detached from the functional unit thereof.

Stacking modular instrument system

The present invention provides an angular velocity detection method adopting a bi-directional full reciprocal coupling optoelectronic oscillator, which is implemented on an optical carrier microwave gyroscope. The optical carrier microwave gyroscope is a bi-directional resonant optical carrier microwave angular velocity measurement device sharing one optical fiber loop. The core of the method lies in that the Sagnac effect is sensed using a bi-directional optical carrier microwave resonant cavity, where the optical carrier microwave resonant cavity employs a coupling optoelectronic oscillator to achieve a bi-directional full reciprocal optical fiber path, and non-reciprocity error of the resonant cavity is eliminated effectively. The angular velocity detection method has features of high-precision, easy implementation and low costs.

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Hangzhou, China

Lingyun Ye