33results about How to "Strong anti-multipath interference ability" patented technology

The present invention provides a multi-source combined indoor location method based on a UWB (Ultra WideBand) and a VLC (Visible Light Communication), and relates to the technical field of indoor location. The problem is solved that long-term usage of a location system causes low precision. The location system comprises a UWB device, a VLC device and a location terminal. The location terminal comprises a UWB location terminal, a VLC location terminal and a data fusion unit; and the UWB location terminal and the VLC location terminal are formed by LOS/NLOS (Line of Sight/Non-Line of Sight)determination modules and data processing units. The multi-source combined indoor location method can achieve indoor seamless high-precision location, can reduce the disturbing influence of the location system on other communication systems, has no harm for a human body, can improve the system privacy, can improve the high-speed communication possibility, and can be widely applied.

The invention brings forward an underground work personnel accurate positioning system and work method mixing WIFI-UWB positioning technologies. The system mainly comprises five major modules, i.e., a WIFI fixation device, a UWB fixation device, a center server, a WIFI receiving apparatus and UWB positioning label of a mobile point to be detected, and a ground monitoring center. The method comprises the following steps: S1, according to an RSS-based WIFI positioning technology employing a triangular positioning method, determining the position of a point to be detected in a triangular area; S2, the UWB fixation device in the area where the mobile point to be detected is disposed measuring the position of the point to be detected by use of a TOA-based positioning technology, and determining a circular curve taking a measurement distance as a radius; and S3, combining the obtained triangular area and the circular curve, and performing analysis according to four different conditions of zero intersection point, one intersection point, two intersection points and three intersection points to obtain accurate coordinates of the mobile point to be detected. According to the invention, the underground work personnel positioning accuracy is improved.

The invention discloses a multi-mode antenna for satellite navigation. The integral multi-mode antenna is divided into a first layer, a second layer, a third layer, a fourth layer and a fifth layer which are sequentially arranged from top to bottom. The first layer is a radiating layer and is of a double-layer short-circuit patch structure, an upper-layer patch of the radiating layer is positioned on the top of a first layer of dielectrics, and a lower-layer patch is positioned at the bottom of the first layer of dielectrics and is connected with the upper-layer patch by a short-circuit arm; the second layer is a dielectric layer for supporting the radiating layer and is positioned between a feed probe and the lower-layer patch; the third layer is an L-shaped probe feed layer and comprises four L-shaped probes, a horizontal portion of the third layer is printed on a dielectric layer, and a perpendicular portion of the third layer penetrates through the dielectric layer to be connected with a secondary feed network; the fourth layer is a secondary dielectric strip-line feed network layer and comprises two broadband 90-degree phase shifters; the fifth layer is a primary dielectric strip-line feed network layer and comprises a broadband 180-degree phase shifter; and the fourth layer is connected with the fifth layer by a metal probe. The antenna has the advantages of good low-elevation axial ratio characteristic and high multi-path interference resistance.

The invention provides a precise synchronization-unrequired coal mine underground spread spectrum accurate ranging method and a device. According to the precise synchronization-unrequired coal mine underground spread spectrum accurate ranging method, a parallel and tracking loop-free pseudo-noise code synchronization accurate measurement algorithm is adopted, such that higher time resolution can be obtained based on rough synchronization without precise synchronization process required, and therefore, ranging pseudo code speed can be decreased, and bandwidth occupied by ranging pseudo codes is limited below 100MHZ, and thus, meter-level positioning accuracy can be achieved. The device for realizing the method comprises a communication control module and a wireless response module; the communication control module, adopting a high-performance FPGA as a core processor, mainly comprises a transmitter and a receiver; and the wireless response module de-spreads received signals through adopting a search-track-free synchronization mode without a separate processor required. The precise synchronization-unrequired coal mine underground spread spectrum accurate ranging method and the device of the invention can inhibit serious electromagnetic interference under a coal mine, and are advantageous in robust hardware designs, redundant algorithms, high-accurate ranging and strong real-time property, are suitable for a coal mine underground personnel precise positioning system.

The invention discloses a deep space measurement and control system and a deep space measurement and control method on the basis of frequency-domain equalization and relates to the technical field of deep space measurement and control. The method comprises the steps that a ground station respectively carries out frequency spreading, constellation mapping and Fourier transform on measurement and control information and a time service code to generate two paths of frequency-domain signals, then forms time-domain signals after respectively carrying out oversampling, inverse Fourier transform and addition of a cyclic prefix on the frequency-domain signals, and transmits the time-domain signals; an aircraft obtains the measurement and control information, the time service code and two paths of m sequences; the aircraft processes the data information and the time service code to form a downlink signal and transmits the downlink signal; the ground station sequentially carries out time and frequency synchronization, channel estimation, removal of the cyclic prefix, Fourier transform, frequency-domain equalization and inverse Fourier transform on the downlink signal to obtain an equalizing time-domain signal and then carries out demapping and dispreading to obtain new data information and a new time service code; the ground station carries out phase comparison and calculates a distance. The deep space measurement and control system and the deep space measurement and control method have high resistance to multipath interference, can effectively improve a band utilization rate and solve the measurement and control difficult problem under the deep space remote low-elevation-angle condition.

A GNSS choking coil antenna based on a wave absorbing material is disclosed. The antenna comprises a multipath suppression plate, a plurality of first wave-absorbing units, an antenna unit, a plurality of second wave-absorbing units and a plurality of third wave-absorbing units. The plurality of first wave-absorbing units are annularly arranged along a center of the multipath suppression plate andare vertically arranged on an upper surface of the multipath suppression plate. The antenna unit is arranged on the upper surface of the multipath suppression plate and is located in a ring formed byarranging the plurality of first wave-absorbing units. The plurality of second wave-absorbing units are annularly arranged along the center of the multipath suppression plate and are obliquely arranged on the upper surface of the multipath suppression plate. The plurality of third wave-absorbing units are annularly arranged along the center of the multipath suppression plate and are arranged on an outer peripheral surface of the multipath suppression plate, and the plurality of third wave-absorbing units are vertical to the plurality of first wave-absorbing units. By using the GNSS choking coil antenna of the invention, most of multipath signals can be absorbed, most of surface waves formed on the outer peripheral surface of the multipath suppression plate can be absorbed, an interferenceof the surface waves is reduced, and a multipath suppression capability of the antenna is effectively improved.

The invention relates to an OFDM synchronous training sequence processing method and device. The method comprises the steps that multiple times of cycle shift is performed on an OFDM synchronous training sequence so that multiple cycle shift sequences are obtained; a cycle prefix is added before each cycle shift sequence so that candidate sequences are obtained; average gradient of a timing metric function of the candidate sequences is calculated; and the candidate sequence with the maximum average gradient acts as the OFDM synchronous training sequence after processing.

The invention relates to an unmanned aerial vehicle data link communication system based on spread-spectrum communication. The system comprises an unmanned aerial vehicle, a wireless communication module and a ground station. The unmanned aerial vehicle is provided with a flight control module and a sending/receiving end connected with the flight control module; the sending/receiving end comprisesan MCU and a radio frequency transceiving unit; the radio frequency transceiving unit is an SX1278 chip; and the SX1278 chip adopts a CSS spread-spectrum communication encoding mode. Compared to theprior art, the unmanned aerial vehicle data link communication system has the advantages of high resistance to multi-path interference, high sensitivity, low power consumption, long transmission distance and the like.

The invention provides a high-speed industrial communication system based on OFDM and a control method. The high-speed industrial communication system based on the OFDM communication system comprisesa plurality of node devices and at least one two-wire system field bus. Transmission ports of the node devices are connected to the two-wire system annular field bus. The plurality of node devices areconfigured to communicate with each other in an OFDM modulation mode. Each node device sends modulated data signals to the two-wire system annular field bus in a broadcast mode, and the other node devices directly receive the data signals from the two-wire system annular field bus. The two-wire system annular field bus based on OFDM is used so that the problem of network disconnection caused by accidental disconnection of bus nodes or transmission lines can be effectively solved, meanwhile, high multi-path interference resistance is achieved, and multi-user, high-real-time and high-reliability data transmission can be achieved.

The invention discloses a method for transmitting data by using a radio signal and a wireless communication device, relates to the field of data transmission, and aims to solve the problems that when the data is too much or the data transmission position is relatively far, the data is easy to be disordered, the data is transmitted for multiple times and the safety performance is low in the prior art. According to the technical scheme, the system comprises wireless communication equipment, the wireless communication equipment comprises a plurality of data transmission base stations, the outer sides of the data transmission base stations are provided with data recorders, the tops of the data transmission base stations are provided with spread spectrum frames, and the output ends of the plurality of data transmission base stations are provided with data acquisition ends. According to the data transmission method and device, label adding processing is carried out on data, the area and the position to which a compressed packet needs to be transmitted are judged according to information in a label in the transmission process, the data do not need to be decompressed and read, the data transmission speed is increased, the data are protected, and the whole data transmission efficiency can be improved.

The invention discloses a wireless high-precision long-distance outdoor positioning system, which belongs to the technical field of outdoor wireless positioning and comprises a positioning tag, a base station I, a base station II, a base station III, a switch module and an upper computer module, wherein the positioning tag is arranged on a measured object, and the positioning tag comprises a tag main control unit, a tag UWB unit, a first wireless communication unit, a first serial port conversion unit and a tag power supply unit; and the base station I, the base station II and the base station III are arranged at preset positions in a positioning space, and each of the base station I, the base station II and the base station III comprises a base station main control unit, a base station UWB unit, a wireless communication unit II and a serial port conversion unit II. The wireless high-precision long-distance outdoor positioning system utilizes the UWB technology as the core technology of the positioning system, the DWM1000 chip serves as radio frequency transceiving hardware, centimeter-level accurate positioning can be achieved, Kalman filtering and the Chan algorithm are fused for positioning calculation, and the positioning precision of the positioning system in the severe indoor environment can be improved.