46results about How to "Good anti-multipath effect" patented technology

The invention discloses an octagonal flat-type array antenna comprising an earth plate and a circularly-polarized four-point feeding network, wherein the earth plate is provided with a central radiating element assembly and two groups of coupling plates arranged by equal distance along the radial direction. The octagonal flat-type array antenna can receive signals transmitted by a plurality of navigation and positioning satellite constellations and meet the requirement for high-precision carrier phase measurement. A high-precision receiver antenna for GNSS (Global Navigation Satellite System) carrier phase measurement can be provided for users of ocean, land, air and space, and the octagonal flat-type array antenna can also be popularized and applied to a radio transmitting and receiving system with a stable radiating phase center and a circular polarization and hemisphere beam coverage requirement. The octagonal flat-type array antenna has the characteristics of stable radiating phase center, circular symmetry of radiation pattern, high roll-off, high front-to-back ratio and favorable wide angle circular polarization, has favorable anti-multipath and broadband operation capacity and is a novel GNSS high-precision carrier phase measurement type user compatible receiver antenna.

The invention discloses a method and a device for sending and receiving data in high-sensitivity narrow band wireless communication. The method comprises the steps of treating two continuously reversed linear frequency modulation signal as a synchronous sequence in a front synchronizing head, treating two same complex sine signals as reference symbols in the front synchronizing head, and then forming a frame to be sent tighter with baseband data to be sent through a sending end; modulating the frame to be sent to two in-phase orthographic carriers to form and send a radio frequency sending signal. With the adoption of the method, the angle features can be jointly demodulated without precise frequency offset estimation by the FFT algorithm and the phase; the various conditions and algorithm advantages are combined, so that the single bit calculation quantity is greatly reduced, and moreover, the receiving sensitivity can be improved, and the data transmission distance can be increased.

The invention includes steps: receiving a training sequence (midamble) data r in a time slot; carrying out channel estimation so as to obtain impulse response hfreq of channel influenced by frequency deviation; detecting component of midamble data transmitted; estimating impulse response h of channel not influenced by frequency deviation; estimating received midamble data r' not influenced by frequency deviation; carrying out estimation of frequency deviation through maximum likelihood method, and outputting estimated frequency deviation. Being adapted to system composed of multiple sub codes such as system of training sequence of TD - SCDMA, the invention possesses favorable antimultipath performance, simple and easy of implementation.

The invention discloses a mechanism for controlling media access of a wireless mesh network. A media access control structure based on the synchronous channel switching mechanism is constructed on a radio chip which supports multiple channels. In the process of network operation, an adaptation transmission mechanism based on the media access control structure is adopted to adaptively select a high-quality channel for communication and a selecting method of a channel switching mode is adopted to realize concurrent transmission to a great extent. Then the highly reliable mechanism for controlling media access of a wireless mesh network is formed and is applicable to the industrial field. The invention makes full use of the multi-channel ability provided by physical radio frequency hardware, optimizes the performance of the wireless network under the industrial communication environment of multi-network coexistence, multi-path phenomenon and strong electromagnetic noise and guarantees high-quality communication in the rugged industrial radio frequency environment.

The invention discloses a two-dimensional vacant code index modulation method based on machine learning. The two-dimensional vacant code index modulation method mainly comprises the following steps of1) carrying out serial-parallel conversion on the sending information bits u of a transmitting end; 2) establishing an optimal antenna subset based on an SVM, and constructing a label and antenna combination mapping table; 3) carrying out symbol modulation and index modulation on the sending information bit u after serial-parallel conversion, thereby determining a transmitting antenna, a modulation symbol and a spread spectrum PN code; 4) performing spread spectrum on the modulation symbol, and transmitting the spread spectrum to a receiving end; and 5) using the receiving end to receive thespread spectrum signal and perform the correlation characteristic detection on the spread spectrum signal; 6) performing estimation detection on the despread signal by using the CNN; and 7) demodulating and demapping the estimated demodulation symbol and antenna with the PN code index value so as to restore the source information bit. According to the method, the advantages of a spread spectrum technology in spatial modulation and code index modulation are combined, the multi-antenna channel link resources are utilized, and due to the fact that the spread spectrum technology is used, the method has certain anti-interference and anti-multipath capacity.

The invention discloses a vehicle-vehicle communication system based on an UWB. The vehicle-vehicle communication system comprises a main control unit, an information collecting unit, a data storage module, a wireless communication module and a power supply module. The output end of the power supply module is electrically connected with the input end of the main control unit and the input end of the wireless communication module, the main control unit is in bidirectional connection with the wireless communication module and the data storage unit, and the input end of the main control unit is electrically connected with the output end of the information collecting module. The vehicle-vehicle communication system based on the UWB has the advantages of being simple in structure, good in communication effect and the like, communication between vehicles is convenient, and the occurrence possibility of traffic accidents can be effectively reduced.

The invention discloses a precise distance measuring device based on UWB. The UWB signal adjustment module includes a signal differential coupling unit, a first microwave switch unit, a radio frequency power amplifying unit and a second microwave switch unit. The signal differential coupling unit and The first microwave switch unit is bidirectionally connected, the output end of the first microwave switch unit is electrically connected to the input end of the radio frequency power amplifying unit, and the output end of the radio frequency power amplifying unit is electrically connected to the input end of the second microwave switch unit. The invention has the advantages of simple and compact structure, low cost, can realize distance measurement based on UWB, has high distance measurement precision and wide measurement range.

The invention relates to a method and a sensor for detecting the relative sliding velocity between a plate and a mould in a stamping process. The method comprises the following steps of: (1) forming an area measured laser image on the measured surface of a steel plate; (2) acquiring the image information of continuously changed patterns and outputting the image information to a signal processor by using an image sensor; (3) analyzing the movement amount of a characteristic area by adopting a self-correlation image processing algorithm, and outputting displacement information; (4) outputting sliding velocity data by using a master control unit; (5) adjusting an acquisition frequency by using the master control unit; (6) obtaining a conversion function for a sliding velocity value and sliding velocity data: y=ax+b; and (7) obtaining an actual relative sliding velocity. By using the detection method and the sensor, the sliding velocity can be measured in a real-time and non-contact way in a plate stamping process. The method has high operability and can be used for determining the sliding velocity of the steel plate relative to the mould in plate stamping deformation by matching a corresponding test device, thereby meeting requirements on scientific research and test.

The invention discloses a building positioning method based on UWB (ultra-wideband) technology. The method includes TOA (time of arrival) distance estimate and weight selection by fuzzy logic, namely obtaining arrival time of a direct signal by weighting time of a first arrived signal and time of a strongest signal and calculating a weighting coefficient according to the fuzzy logic technology. Actual data indicates that positioning precision is highly enhanced by the method. Compared with traditional narrow bandwidth positioning system, the method has the advantages of high penetrating power, low power consumption, fine anti-multipath effect, high safety, low system complexity, high positioning precision and the like.

The invention relates to a nine-channel space spectrum super-resolution estimation monitoring and direction-finding mobile station system, which comprises a small double-cone omnidirectional monitoring antenna, a nine-unit direction-finding antenna, an amplifier, a monopole monitoring antenna, a nine-channel signal switching module, a filter combiner, am amplifier module, a nine-channel receiver, a monitoring and direction-finding controller, a DSP (Digital Signal Processor) processing module, an imbedded industrial computer, a GPS (Global Positioning System) antenna, a GPS module, a 3G (3rd Generation) antenna, a 3G router, a power supply module, a remote control unit, an exchanger, and the like. The system has the following advantages: the system achieves remote and automatic monitoring and direction-finding of radio signals; an imbedded computer system is integrally arranged so that the structure is compact and light; a direction-dinging assembly solves the coupling problem between the antenna arrays and prevents coupling and phase between unit antennas from being blurred; the structure is compact and light, and the spanning maintenance is convenient; the grid connection is flexible, and can support different wired/wireless network data transmissions; moreover, collection, compression coding, automatic task monitoring, statistic analysis and abnormal state alarm of wireless signals are realized.

The invention belongs to the technical field of fire-fighting communication, and particularly relates to a broadband wireless communication device for a fire-fighting robot. The broadband wireless communication device comprises a front-end transmission device and a rear-end receiving device. The front-end transmission device comprises a front-end power module, a front-end communication core board, a front-end video processing module, a front-end voice processing module, a front-end cavity filter, a front-end circulator, a front-end power amplifier and a front-end antenna. The rear-end receiving device comprises a rear-end power module, a rear-end communication core board, a rear-end voice processing module, a rear-end cavity filter, a rear-end circulator, a rear-end power amplifier and a rear-end antenna. According to the broadband wireless communication device for the fire-fighting robot, multi-channel audio and video transmission can be provided, high-speed data transmission is supported at the same time, and a communication protocol and a transmission system of the broadband wireless communication device are particularly suitable for multipath constructions like buildings with serious interference. According to the broadband wireless communication device, hybrid transmission of images, voices and data inside the same channel is supported, and the broadband wireless communication device has the advantages of being good in image real-time performance, high in voice compression ratio, short in data delay and the like.

An embodiment of the invention provides a UWB-based height-limiting height determination method, device and system. The UWB-based height-limiting height determination method comprises the steps of: acquiring a first distance between a target vehicle and a first UWB unit, wherein the first distance is determined through transmitting a distance measurement signal to the first UWB unit by a vehicle-mounted UWB unit; and acquiring a second distance between the target vehicle and a second UWB unit determined by sending the distance measurement signal to the second UWB unit by the vehicle-mounted UWB unit, and determining the height-limiting height of a road height-limiting frame according to the first distance and the second distance. By using the UWB-based height-limiting height determinationmethod and the system, the measurement of the height-limiting height of the road height-limiting frame can be realized; moreover, based on the features of insensitivity to channel attenuation, high penetrating performance, good anti-multipath effect and the like of the UWB , the interference in the distance measurement process can be reduced by the UWB, the measurement precision is improved, the height-limiting height of the road height-limiting frame can be accurately measured through using the UWB, the driving safety is ensured, and accidents are reduced.

Aiming at the tracking fuzziness problem of a Beidou B1C pilot channel QMBOC (6, 1, 4/33) signal, the invention provides and designs a B1C signal unambiguous tracking method based on a pseudo-exponential function, which comprises the following steps of: (1) carrying out carrier stripping and code correlation processing on the pilot channel QMBOC (6, 1, 4/33) signal; (2) the correlation value is sent to an exponential function module to be processed; (3) the discriminator processes an output value of the exponential function module; and (4) a discriminator result is processed by a loop filter to control a code loop NCO, and a local code phase is adjusted to form a closed loop. According to the invention, secondary peaks of correlation curves can be effectively eliminated, error locking points output by a discriminator are eliminated, correlation results of received signals and local signals are processed by using a pseudo-exponential function module, and unambiguous tracking of QMBOC (6, 1, 4/33) signals is realized. Meanwhile, compared with a traditional BPSK-like method, an SCPC method and an ASPeCT method, the B1C signal unambiguous tracking method based on the pseudo exponential function has better anti-multipath performance.

The invention discloses an unambiguous tracking method for a high-order BOC modulation navigation signal. The unambiguous tracking method comprises the following steps: counting operation periods of subcarriers; a variable-subcarrier half-cycle counting accumulated value Accsc is increased, and initialization is carried out; counting the counting difference of the subcarrier half-cycle counts Cnt2sc of the two FTF time mark signals as an incremental quantity, and accumulating the Accsc; continuously comparing the Accsc with the updated half-cycle fuzzy value Cntsc of the subcarrier; setting a locking state; if continuous equal times reach a lock-in threshold value, entering a lock-in state, replacing an original subcarrier half-cycle fuzzy value Cntsc with Accsc, and outputting a subcarrier observation value as a distance measurement observation value; setting a lock losing state; and if continuous unequal times reach a lock losing threshold value, entering a lock losing state, re-initializing the Accsc, and at the moment, outputting a code observation value as a distance measurement observation value. According to the method, the problem that traditional subcarrier tracking is fuzzy is solved, a good anti-multipath effect and stable high-precision distance measurement observed quantity can be obtained, and therefore the positioning precision is improved.