315 results about "Antenna measurement" patented technology

A method and system can locate an RF transponder based on phase differences between signals transmitted to the RF transponder. The method transmits from a first transponder to a second transponder first and second signals at first and second frequencies, respectively. The second signal is compared with the first signal and a distance between the first and second transponders is determined based on the phase difference between the first and second signals. In one embodiment, the first transponder is an interrogator, the second transponder is an RF tag, and the RF tag determines the phase difference between the two signals. In another embodiment, the first and second transponders are the interrogator and RF tag, respectively, but the interrogator determines the phase difference between the two signals after the two signal are reflected back to the interrogator. The method can also determine a position (distance and direction) of the RF tag by measuring the distances from two different locations of the interrogator to the RF tag. In one embodiment, the two distances are measured from two spaced-apart antennas of the interrogator. In another embodiment, the interrogator is moved from one known location to another known location. With distance measurements from both known locations, the location of the RF tag can be determined by simple geometry.

Antenna selection control apparatus for a diversity antenna system including at least two antennas. The received power strength is measured from a selected antenna and compared with a reference power level. The reference power level is adjusted depending upon the signal to noise ratio of received signals, and if the selected antenna falls below the adjusted threshold another antenna is selected.

An antenna measurement range and a method of calibrating same is proposed which at least substantially reduces the effects of echoing or multi path. The method of calibrating the range comprises the steps of: generating and radiating a training signal; receiving the radiated training signal and comparing the received signal with the expected signal; determining a set of equaliser coefficients to be used in these circumstances to eliminate or minimise the error between the expected training signal and the received signal; and storing the set of equalisation coefficients and associating them with the rotational or translational position of the antenna under test so that the coefficients can be applied to subsequent radiation pattern measurements. In one embodiment, the measurement nodes are dispersed in a three dimensional array about the antenna under test and a set of coefficients arrived at for each node to be applied to the subsequent radiation pattern measurements.

A method and apparatus for determining a parameter of interest of an earth formation during drilling of a borehole. A first toroidal coil antenna induces a current along a path that includes a bottomhole assembly and the formation. A second toroidal coil antenna disposed at the drillbit and oriented at a non-zero angle to the longitudinal axis of the bottomhole assembly measures an electrical signal resulting from the current, the electrical signal being a parameter of interest of the formations.

The invention discloses a near-field antenna measurement method for any curved surface scanning. An antenna and a movable probe are driven to rotate through a rotary round table to perform scanning, and circular, linear and any curved surface motion ways can be adopted, so that the near-field test method can be suitable for any curved surface scanning; a scanning surface is not limited to a plane, a cylindrical surface or a spherical surface, and any curved surface can be adopted; various antennas can be measured. In the near-field antenna measuring method for any curved surface scanning, sampling points are taken as a plurality of points which are uniformly distributed in a parameter space, and then electric fields of any point are calculated through bilinear interpolation, so that a far electric field of the antenna can be calculated according to a Huygens equivalence principle, and near-field to far-field transformation is simple, convenient and easy to realize.

Systems and methods for position detection of a in-vivo sensing device. A magnetic field generator generates magnetic fields which are measured by an antenna. The position of the in-vivo sensing device is determined from the magnetic field intensity values.

The present disclosure relates to an apparatus and associated methods to produce analgesia in a mammal by providing an electrical nerve stimulus utilizing a pulsed input of low level electrical current, wherein the level of current is measurable with the measurements utilized to at least adjust the strength of the current according to selected parameters. Additionally, the use of magnets to produce a magnetic field to further control chronic and acute pain. In exemplary implementations, the apparatus maintains continuous monitoring of the electrical characteristics of TENS at the site of input and output, and the electrical input can be modified during treatment to obtain desired electrical input. More particularly the disclosure relates to an electromagnetic apparatus incorporating pulsed direct current, two or more electrodes, and at least two dipole antennas wherein the dipole antenna circuits receive and analyze signal from the dipole antennas, using the information from signal analysis within the methods for producing analgesia in mammals. The strength of the current that the patient is receiving at the targeted site as the actual field is measured by the dipole antennas and adjustment is not dependent on subjective measurements to ascertain whether the proper amplitude, frequency and pulse duration are being applied.

An antenna measurement and control system for use with a transmitting antenna, the system comprising a sensor configured to determine an indication of the radiation emitted by the antenna; control circuitry connectable to the antenna and configured to selectively vary, or disengage, the power supplied to the antenna, and a processor connectable to the sensor and control circuitry, wherein the processor is configured to control the control circuitry in response to the determined indication of the emitted radiation.

An Antenna measurement system incorporating high speed tracking laser-based global positioning capture synchronized with radio frequency (RF) measurements. A high speed tracking laser is used for collecting RF probe position data synchronously with corresponding near-field RF measurements. The probe may be moved across an arbitrary surface surrounding or adjacent to a device under test (DUT); however, it is not necessary for the probe position to be perfectly coincident with the surface, or any of the discrete points which make up the surface. Here, the probe position is determined relative to a global positioning coordinate system which is defined by a set of monuments which are in known positions relative to the global positioning coordinate system, and not the DUT. Any difference between the actual position of the probe, in the global position coordinate system, and a given one of the discrete measuring points, in the global position coordinate system, on the surface surrounding or adjacent to the DUT can be accounted for during post processing, thus eliminating the need for advanced or intermittent calibration to achieve precise near-field measurements.

The invention provides a feed source locating and focus offset device for compact range measurement. The device is used for precise location and focus offset motion of a feed horn in an electromagnetic measurement process of a compact range. The device mainly comprises left and right transverse movement along the X axis, front and back longitudinal movement along the Y axis, rotation and translation around the Z axis and pitching movement around the phase center of a feed source. Accurate locating and focus offset of the feed source are realized through movement of five freedom degrees, and focus offset measurement is completed. By means of servo control, polarization rotation and uniform rotation at a certain rotation speed of the feed horn can be realized, and RCS (radar cross-section) measurement or antenna measurement is completed. The device comprises an X-axial moving unit, a Y-axial compensation unit, a Z-axial rotating and height adjusting unit, an offset arm, a feed source pitching unit and a feed source polarization unit. Different from a fixed feed source locating device, the device can not only be used for precise location of the feed source during measurement of the compact range in a traditional manner, but also be used for measurement of new demand ways such as focus offset and the like; the device has the advantages of high measurement efficiency, high locating precision and simple and reliable control process.

The invention discloses a shortwave transmitting antenna three-dimensional directional diagram aerial mobile measurement system and method. The system comprises a field intensity measurement system which is composed of a loop antenna and a field intensity instrument host and an unmanned aerial vehicle platform and other parts. Computation is performed by a field intensity signal preprocessing module, a standard directional diagram computing submodule, a spatial spectrum processing submodule, a digital beam forming submodule and a transmitting antenna calibration factor computing submodule. The omnidirectional loop antenna is mainly adopted to measure field intensity signals, acquire and store the field intensity signals and preprocess the field intensity signals, then the signals are further processed through the spatial spectrum estimation technology, and finally testing is performed on the unmanned aerial vehicle platform. The index is provided for assessment of a shortwave transmitting antenna directional diagram, and online automatic monitoring of the antenna directional diagram can be realized without influencing the real-time performance and the effectiveness of the shortwave transmitting antenna so that the system and the method have the characteristics of being simple in equipment and convenient to operate.

The invention belongs to the fields of antenna measuring technique and satellite navigation and positioning, and relates to a correction method for the absolute antenna phase center of an outdoor GNSS (Global Navigation Satellite System) receiver based on a precision mechanical arm. In view of the problem that conventional outdoor GNSS observation cannot obtain a high-precision correction model for the absolute antenna phase center of a receiver, a majority of common errors are eliminated through ultra-short baseline observation, the absolute phase center offset (PCO) of a receiver antenna and the separation of phase center variation (PCV) are realized through rapid rotation and inclination of the high-precision mechanical arm, finally the PCO is resolved through a least squares algorithm, and fitting calculation of the PCV is carried out for observation residual. According to the correction method, outdoor operation can be carried out, the correction precision of 1mm for the PCO and PCV can be reached, the correction method is suitable for accurate calibration of the PCO and PCV of the receiver capable of tracking the signals of satellite navigation systems such as a GPS (Global Positioning System), a BDS (Beidou Navigation System), a GLONASS (Global Navigation Satellite System) and Galileo, and thus the systematic measuring error caused by imprecision of the PCO and PCV of the receiver can be eliminated, and the user positioning precision is further improved.

A method for measuring a compact range antenna by three reflectors comprises the following steps of: determining a system mapping function according to the distribution of a feed source field and the distribution of a system outlet field; tracking and analyzing the electromagnetic wave emitted by the feed source by adopting a dynamic waveband tracking theory; and determining all mirror surface parameters of a first forming auxiliary reflector and a second forming auxiliary reflector by the system mapping function, the feed source field wavefront parameters and the main reflector surface parameters. The embodiment of the invention also discloses a system for measuring compact range antenna by three reflectors. The system and the method can be applicable to the feed source higher than 300GHz, and lead the system outlet field to have large quiet zone utilization coefficient (achieving more than 70%), high cross polarization isolation degree, compact structure and wide measurement frequency bands.

According to one embodiment of the present invention, a method by which a wireless communication device including a plurality of antennas transmits and receives a wireless signal in an unlicensed band in a wireless communication system comprises the steps of: performing a clear channel assessment (CCA) by using the plurality of antennas for a predetermined time interval in the unlicensed band; and transmitting the wireless signal through the unlicensed band when it is determined that the unlicensed band is in an idle state in which the unlicensed band is not occupied by other wireless communication devices, wherein the step of performing the CCA can comprise the steps of: acquiring one reference value by using energy sensing indicators (ESIs) measured through the plurality of antennas; and comparing the reference value with a CCA threshold value so as to determine whether the unlicensed band is in an idle state.

There is provided a radar level gauge using microwaves for measuring a level of a surface of a product in a tank, comprising an antenna for transmitting microwaves to the surface and receiving microwaves reflected by the surface, a measurement circuitry feeding said antenna through a hollow wave guide and said wave guide including at least an antenna wave guide member, at one end couplable to the antenna and at its other end having an opening in an intersection across the wave guide, wherein the radar level gauge further comprising: a dielectric barrier extending along said intersection across the opening of said antenna wave guide member for non-conductively separating said antenna wave guide member from the measurement circuitry, said dielectric barrier having a first side facing the wave guide in a direction towards the antenna wave guide member and said dielectric barrier having a second side facing a direction substantially away from said antenna wave guide member.

The invention discloses a quantum coherence effect-based antenna gain measuring device. The device comprises an electromagnetic wave absorbing chamber, an atomic gas chamber, a laser light source subsystem, a spectral signal measurement subsystem, a power measurement subsystem, an antenna gain measurement subsystem and a plurality of support platforms. According to the device disclosed by the invention, an optical device is used for triggering an energy spectrum, so that atoms are induced. An energy spectrum is obtained through photoelectric detection. Meanwhile, the wave-absorbing material isadopted to prevent an electromagnetic scattering body from affecting the measurement. Through measuring the feed-in net power of a measurement antenna and the net power of the coupling port of a directional coupler, the data acquisition of the transmitted spectrum of the detection light is completed. A power meter is connected with a computer through a GPIB bus, so that the reading of the feed-inpower value of the antenna is completed. Through an antenna gain measurement model (img file = 'DDA 0001510521350000011.T'wi = '355 'he = '170 '), the gain measurement is completed. Compared with a traditional antenna measuring system, the device has the advantages of high measurement precision, low construction cost, small occupied area and the like.

Provided is an antenna near-field measurement method based on an unmanned plane, which collects the space coordinate information of an unmanned plane with a beacon, and signal information from the beacon received by an antenna to be measured, thereby establishing the relation between the receiving pose of the antenna to be measured and a signal source space position, and realizing near-field measurement. The antenna near-field measurement method is specific to near-field measurement, has the advantages of simple operation, high cost performance, wide adaptability and high test precision, and is especially suitable for large-scale antenna measurement.

The invention discloses a compact range antenna measuring system which comprises a feed source which is arranged in a microwave anechoic chamber and a planar wave generation unit formed by a plurality of meta-material layers which are overlapped with one another, wherein each meta-material layer comprises a substrate and a plurality of artificial hole micro-structures on the substrate; and electromagnetic waves generated by the feed source are converted into planar electromagnetic waves after passing through the planar wave generation unit. A reflecting surface in the prior art is replaced by the planar wave generation unit made from meta-materials, and the refraction characteristics of the planar wave generation unit are simulated by a computer according to test requirements, so that an antenna testing turntable is provided with a quasi-plane-wave testing area with excellent performance after the electromagnetic waves generated by the feed source are refracted by the planar wave generation unit. Thereby, the manufacturing of a high-precision reflecting surface and a high-difficulty processing technique are omitted, and thus the manufacturing cost of the compact range antenna measuring system is greatly reduced.

The invention discloses an electromagnetic measurement comprehensive darkroom for electromagnetic compatibility test and antenna measurement. The structure is that the top surface and all side surfaces of the darkroom are fully paved with full-frequency-band wave-absorbing materials, and the bottom surface of the darkroom is fully paved with movable full-frequency-band wave-absorbing material; the full-frequency-band wave-absorbing material unit is of the tetraquetrous cone shape, the top opening angle is 17-20 degrees, the surface resistance is 50-100ohm, and non-woven fabrics serve as the bearing base material. The electromagnetic measurement comprehensive darkroom can meet the test environment required by the electromagnetic compatibility test and the antenna measurement at the same time, one room has two functions, and the cost can be saved compared with constructing an electromagnetic compatibility darkroom and a full-anechoic darkroom respectively; meanwhile, the relevant costs of land utilization, subsequent maintenance and the like can be saved.

The invention provides a sparse singular value decomposition scanning radar forward-looking imaging method, which is used for the radar imaging technology field. A radar forward-looking echo signal is analyzed and scanned, and an azimuth echo model of a target scattering coefficient and antenna measuring matrix operation is constructed, and then an azimuth high resolution problem is converted into a matrix inversion problem. A target function is constructed by adopting the sparse singular value decomposition method provided by the invention. The solution of the echo azimuth signal is realized by adopting an iterative strategy. A limitation of conventional TSVD methods of contradiction between resolution improvement and noise suppression is broken through, and sensitivity of an imaging result to noises is reduced, and therefore the azimuth resolution improvement is realized.

The invention discloses a system for automatically monitoring the states of base station antennae. The system is characterized by comprising an antenna measurement control unit, a data transmission terminal and a server, wherein the antenna measurement control unit comprises sensors of all the antennae, a signal processing center and a motor driving mechanism; the data transmission terminal is provided with an SIM (subscriber identity module) card for identifying the antenna measurement control unit and is used for packaging acquired state data of each base station antenna, transmitting the packaged state data to the server through a GPRS (general packet radio service) channel, and simultaneously transmitting an antenna tuning command sent by a server side to the corresponding base station antenna measurement control unit to remotely control and adjust the antennae; and the server is used as a base station antenna monitoring terminal and a data base terminal, is provided with a data base and monitoring software, has a GPRS function, and can be used for receiving and transmitting GPRS data, and communicating with the data transmission terminal through the internet and the GPRS channel. The system disclosed by the invention can be used for automatically monitoring and controlling the base station antennae.

A method and apparatus for downhole resistivity imaging uses an antenna coupled to a power source through a directional coupler. Measured reflectivity values are indicative of the antenna impedance and the formation resistivity, particularly if some compensation is made for the antenna inductance.

The invention provides a method for detecting the course angle of an aircraft. The method allows the course angle of the aircraft to be obtained through calibrating an original course angle measured by dual RTK antennas, and comprises the following steps: 1, encoding the dual RTK antenna as a first RTK antenna and a second RTK antenna, defining a direction of the first RTK antenna pointing to the second RTK antenna as an antenna vector, and defining a direction of a tail pointing to a head as a fuselage direction; 2, taking an included angle between the antenna vector and the fuselage direction as correction angle data; 3, acquiring the original course angle of the aircraft through cooperating the dual RTK antennas with an RTK module; and 4, correcting the original course angle by the correction angle data, and converting the corrected original course angle into the course angle of the aircraft. The method has the advantages of realization of the detection and the correction of the course angle of the aircraft, ensuring of the course correctness of the aircraft, high precision and good real-time performance.

The invention discloses a GPU (graphic processing unit) implementing method based on backward projection InSAR (interfering synthetic aperture radar) imaging registration. The GPU implementing method based on the backward projection InSAR imaging registration comprises the following steps: projecting measured data of different antennae into the same imaging space for imaging by a backward projection algorithm; in the imaging process, performing high-phase-retention imaging and image registration on the different InSAR antennae and realizing integration of InSAR imaging and registration; and in combination of a GPU parallelizing technology, implementing fast processing of the backward projection algorithm. Compared with the conventional InSAR interference phase generation, the GPU implementing method based on the backward projection InSAR imaging registration has the advantages of good phase retention, integration of imaging and registration, improvement on algorithm efficiency through parallelization, and the like; by the GPU implementing method based on the backward projection InSAR imaging registration, quick generation of a high-precision InSAR interference phase is realized; and the GPU implementing method based on the backward projection InSAR imaging registration is applicable to the fields of synthetic aperture radar imaging, geochemical remote sensing and the like.

There is provided a multi-antenna measurement method of measuring a device under test having at least two receive antennas and capable of considering the spatial correlation between antennas in a simpler configuration. Two different uncorrelated signal sequences “a” and “b” are generated by the pseudo base transceiver station 4. These signal sequences “a” and “b” are transmitted as radio waves from positions (positions of transmitting antenna elements 31 and 32) of the two base angles of the isosceles triangle toward the device under test 1 provided at a position of the apex angle respectively to measure the received antennas by receive antennas of the device under test 1. This method is easy to calibrate and can consider the spatial correlation between antennas in a simpler configuration.

The invention discloses a long term evolution (LTE) antenna intelligent measurement system, which comprises an emitter subsystem, a rotary table subsystem, a radio frequency subsystem, a servo drive subsystem and a computer subsystem. The emitter subsystem comprises an emission polarization device. The rotary table subsystem comprises a seven-dimensional motion device, a locking device and a to-be-tested antenna mounting bracket. The radio frequency subsystem comprises a vector network analyzer and a multi-way switch. The servo drive subsystem comprises a servo driver and a multi-axis control card. The computer subsystem comprises a computer, a network card, a real-time controller (RTC), a control software and a data processing software. The servo drive subsystem is connected with the emitter subsystem and the rotary table subsystem at the same time. The computer subsystem is connected with the servo drive subsystem and the radio frequency subsystem at the same time. The antenna intelligent measurement system is fast in measurement speed and high in measurement precision. Meanwhile, the system can be used for the LTE antenna measurement during the development and production process.

The invention relates to a multiple-antenna measurement system and method based on a network analyzer and an RF (radio frequency) switch. According to the invention, the RF switch in a time-domain platform and the network analyzer in a frequency-domain platform are effectively combined. On the premise of having the advantages of frequency domain measurement, the system can be used for utilizing remote control to realize unmanned measurement and avoiding man-made interference in a measurement process on one hand, and can be used for realizing automatic measurement based on a labview software platform and effectively improving the measurement efficiency on the other hand.

Apparatus is provided comprising at least one antenna for receiving a low frequency electromagnetic field. A measuring circuit is connected to the at least one antenna for measuring the strength of the low frequency electromagnetic signal received by the antenna. A memory stores a representation of the noise in the output of the measurement circuit. A corrector corrects the measurement provided by the measuring circuit in accordance with the noise representation stored in the memory.