36 results about "Ionospheric sounding" patented technology

The invention discloses a method for improving sky-wave radar sea surface ship target tracking and positioning precision. Cooperative ship target positioning and tracking information provided by an AIS (automatic identification system) and sea surface target positioning and tracking information detected by a sky-wave radar are associated and integrated after coordinate transformation and time unification, positioning error information of a cooperative ship target is acquired, and tracking and positioning errors of the ship target positioning and tracking information detected by the sky-wave radar are modified. The method has the advantages that an ionized layer detection device is omitted, system cost is reduced, error correction value space resolution rate acquired by the aid of a large quantity of AIS ship positioning information is high, sky-wave radar ship positioning and tracking precision is improved, space position errors of a non-cooperative ship target are modified, and the tracking and positioning precision is improved.

The invention discloses a non-coherent scattering radar signal processing method based on frequency hopping and multiphase alternate codes. The method mainly solves the problems that existing non-coherent scattering radar is low in height resolution ratio, long in detection period and limited in coding mode. According to the technical scheme, the method comprises the following steps that all sets of the multiphase alternate codes are modulated respectively according to different frequencies, and radar pulses arranged in sequence without any time slot are generated and transmitted through a radar transmitter; radar echo signals are filtered respectively according to transmitting modulation frequencies so as to obtain detection data, corresponding to the same height range, of all the sets of the multiphase alternate codes, post-detection filtering is carried out on each set of coding echo signals, a self-correlation function is worked out, multi-period accumulation and fuzzy revising are carried out, and therefore the power spectral density of scattered signals of an ionized layer is worked out. The method can increase the height resolution ratio of the radar, shorten the detection period of the radar, expand the signal coding modes and be used for detection of the ionized layer.

The invention discloses a multi-carrier signal form-based ionosphere detection method and system. The method includes the following steps that: (1) at a transmitting end, the baseband data of linear frequency modulation multi-carrier signals are constructed, an orthogonal up-conversion technology is adopted to generate continuous-sweeping frequency high-frequency analog radio frequency signals, the high-frequency analog radio frequency signals are subjected to power amplification, and the power amplified high-frequency analog radio frequency signals are radiated to the space through an antenna; and (2) at a receiving end, zero-intermediate frequency baseband data are generated through a broadband receiver, high-speed sampling, digital down conversion and decimation filtering, matched filtering is performed on sub-bands, the echo data of the sub-bands are obtained, or matched filtering is performed on the sub-bands with the joint of bandwidth, and echo data under the joint of the bandwidth are obtained. The real-time performance of the ionosphere detection system is improved, a detection working period is shortened, and therefore, optimal use frequency can be obtained more accurately when an ionosphere is in an unstable state; ionosphere detection bandwidth is improved; the distance resolution of the ionosphere detection system is improved; the finer structure of the ionosphere can be obtained; and the structure state of the ionosphere can be reflected more authentically.

The invention discloses a digital ionosonde, which is used for ionospheric sounding and data receiving processing. A digital down-conversion processing unit comprises a digital mixer, an integral decimation filter, a compensation filter and a programmable filter. Signals which are quantified by a digital-to-analog converter, and sine local oscillator signals and cosine local oscillator signals which are produced by a frequency synthesis unit are input into the digital mixer, output signals of the digital mixer are input into the integral decimation filter, the integral decimation filter performs preset multiples of decimation and lowpass filtering processing on mixed signals, the compensation filter performs amplitude compensation on the output signals of the integral decimation filter, and the programmable filter further performs decimation filtering processing. Therefore, the influence of I and Q channel unbalance caused by analog down-conversion is effectively eliminated.

The invention provides a high-sensitivity multifunctional incoherent scattering radar system based on a digital antenna array, which comprises an antenna array and a back-end processing controller, wherein the back-end processing controller is used to generate a transmission instruction according to a preset transmission parameter; the antenna array is used to generate a transmission signal according to the transmission instruction, transmit the transmission signal, receive a space electromagnetic wave signal and perform first signal processing on the space electromagnetic wave signal; and theback-end processing controller is further used to perform second signal processing on the space electromagnetic wave signal through signal processing according to a preset working mode, and the working mode includes a space target tracking mode or an ionosphere detection mode. The system provided in the invention is low in noise and high in sensitivity during a radar detection process.

The invention discloses a top ionosphere detection space-borne MIMO radar system which belongs to the field of radar technology and compromises a complete complementary sequence generator, a pulse period delayer, a modulator, emission antennae, reception antennae, a demodulator, a pulse compression system and an electron density distribution generation system. The complete complementary sequence generator simultaneously generates N pairs of complementary sequences. The pulse period delayer alternatively inputs two complementary sequences to the modulator. N pairs of signals are modulated at N carrier frequencies respectively and sent out by the N emission antennae, and the echo signals are received by the N reception antennae. The demodulator demodulates signals on the N carrier frequencies. The signals are sent to the electron density distribution generation system after pulse compression to generate a two dimensional ionogram. The space-borne MIMO radar system is used for the top ionosphere detection. Compared with the prior ionosphere detector, the space-borne MIMO radar system of the invention can generate two dimensional ionograms and has very high orientation resolution and high work efficiency.

An MIMO (multiple input multiple output) radar technology can perform beam forming at both a transmitting end and a receiving end, particularly can emit narrow beams in different directions at the same time, and just can meet demands of a sky-wave over-the-horizon radar (OTHR) on multilayer ionospheric sounding and inhibition of relatively strong clutter. A two-ionized-layer structure is applied to an MIMO OTHR system, and aimed at a characteristic of relatively high clutter-noise ratio (CNR) caused by influence of sea clutter and ionized layers on the OTHR, a set of signal processing method is proposed and comprises adaptive optimization of a transmitted waveform with a two-step method of a mutual information theory. Simulation verification discovers that the method remarkably increases the target detection probability and resolution, so that the MIMO-OTHR can utilize multipath echoes to improve target detection and other system performances.

The invention discloses an ISR (incoherent scatter radar) signal processing system based on alternate code modulation, and the system is mainly used for solving the problems that the traditional radar signal processing system cannot process an ionospheric scattering signal with large echo data amount and low signal-to-noise ratio and taking a soft target as the target. The system mainly comprises a DSP (Digital Signal Processor) module and an FPGA (Field Programmable Gate Array) module and a power supply module, wherein regarding alternate code modulation, the DSP module is mainly used for completing signal filtration, autocorrelation function calculation, autocorrelation accumulation and signal power spectrum calculation to obtain an autocorrelation function and a power spectrum evaluation result of an ionospheric plasma; the FPGA module is used for receiving and transmitting processing parameters and signal data, and performing digital down converter on the signal data; and the power supply module is used for supplying required work voltages for the FPGA module and the DSP module. The system has the advantages of high stability, high processing speed, strong data throughout and easiness for hardware implementation, can be used in the ISR signal processors, and performs ionospheric detection and parameter evaluation.

The invention belongs to the technical field of ionosphere detection, particularly relates to an ionosphere detection system based on a magnetized plasma incoherent scattering theory spectrum, and aims to solve the problem in the prior art that the ionosphere state cannot be accurately detected under different conditions. The system comprises an input module which acquires an ionosphere initial incoherent scattering theoretical spectrum; a model selection instruction module which generates a model selection instruction; an incoherent scattering theory spectrum module which pre-constructs an incoherent scattering theory spectrum model, performs model solving under different conditions to obtain each incoherent scattering theory spectrum sub-model, and obtains an ionosphere radar echo powerspectrum through the corresponding sub-model based on the ionosphere initial incoherent scattering theory spectrum and the model selection instruction; and an output module which extracts ionosphere state, motion, structure and disturbance information based on the ionosphere radar echo power spectrum and outputs the information. Different ionosphere conditions correspond to different sub-models, and the ionosphere information under different conditions can be accurately and quickly detected.

The invention belongs to the technical field of sea detection radars, and discloses an ocean and ionosphere integrated detection high-frequency radar system and a control method thereof. The ocean and ionosphere integrated detection high-frequency radar system comprises a display control platform, a time schedule controller, a comprehensive signal generator, an ionosphere detection subsystem and an ocean information detection subsystem. According to the invention, according to the principle of a high-frequency ground wave radar and an ionosphere vertical measuring instrument, a novel ocean-ionosphere information integrated detection high-frequency radar system is designed, ocean-ionosphere information synchronous acquisition is achieved, and data support is provided for scientific research such as near-earth ocean-atmosphere physical operation law and principle analysis; and by designing a unified time schedule controller and waveform parameters synchronous with each other, synchronous acquisition of ionospheric vertical measurement and ocean information is realized, mutual interference between the ionospheric vertical measurement and the ocean information is avoided, non-interference between ionospheric vertical measurement and ocean information acquisition is ensured, and ionospheric information and ocean information can be acquired synchronously.

The invention discloses a mid-latitude ionized layer detection method based on a high-frequency ground wave radar. The method comprises the following steps: step 1, according to an echo RD spectrum ofa high-frequency ground wave radar under an FMPCW system, estimating the electron concentration of an ionospheric irregular body through a function relationship that the echo power of the ionosphericirregular body is in direct proportion to the electron concentration of the ionospheric irregular body in combination with an IRI model or a vertical measuring instrument; step 2, estimating the plasma frequency of the ionospheric irregular body according to the electron concentration estimation of the ionospheric irregular body; and step 3, according to the RD spectrum of the high-frequency ground wave radar echo, estimating a refraction index of the high-frequency ground wave radar echo through the ionospheric irregular body plasma frequency estimation value, and then correcting an irregular Doppler frequency shift to realize estimation and variance estimation of the irregular body drift speed along the radial direction of the radar. The ionospheric detection function is added to the existing high-frequency ground wave radar, and a novel application field of the high-frequency ground wave radar is developed.

The invention relates to an ionospheric parameter inversion and large-scale model reconstruction method based on a wide-area distributed short-wave network. A short-wave cooperative communication signal transmitted in a network is collected synchronously; according to the signal quality received by each station, proper receiving stations are selected and signal delays between all transmitting stations and the receiving stations are estimated respectively; time delay data obtained by each receiving station are transmitted to a central station server; and then a current local ionospheric parameter is inverted in the central station server and large-scale ionospheric model reconstruction is performed accordingly. According to the invention, current ionospheric cutoff frequency, bottom heightand maximum electron concentration height parameter inversion and the upper-space large-scale ionospheric model reconstruction can be realized without any special design of an ionospheric detection device, so that lots of station construction, maintenance, management, and usage costs are saved; and the obtained ionospheric model parameters have the important application value in high-precision positioning of short-wave signals and sky-wave radar target tracking.

The invention relates to a space-borne ionospheric amplitude scintillation monitoring device. The device adopts a dual-frequency GPS satellite navigation receiver mounted on a low-orbit satellite, and uses the GPS receiver to perform satellite precise orbit determination and ionospheric scintillation monitoring. The navigation signal received by the satellite navigation receiver is processed to obtain the ionospheric amplitude scintillation detection parameters, obtain the ionospheric distribution, and improve the ionospheric scintillation and disturbance detection level. The device can make full use of GPS satellite navigation signals with global coverage and continuous Uninterrupted characteristics, improve the ability of atmospheric ionospheric monitoring data processing, the device can also take advantage of the fast flight speed of low-orbit satellites, achieve the purpose of short global ionospheric detection time, and improve the real-time performance of atmospheric ionospheric amplitude scintillation monitoring and global coverage.

The invention discloses an ionized layer parametric inversion method based on AIS target indication. The method includes the steps of obtaining the target positions and movement information of offshore ships on the basis of the AIS, detecting suspected ship targets on the basis of a sky wave radar echo spectrum and through the combination with the AIS target indication area, conducting correlation, fusion and matching on the ship targets detected by radar and the ships indicated by the AIS so as to obtain the route of a radar ship target group, detecting a quasi parabolic ionized layer model required for the ship target positioning on the basis of sky wave radar backscatter sounding, establishing a mean square error equation of the route of the radar ship target group, and obtaining the optimal solution of the ionized layer parameter on the basis of the optimization solution algorithm. By means of the method, the ionized layer parameter model can be obtained without more professional ionized layer detection devices, and the number of devices and the device cost are reduced. The static and dynamic information of a large number of offshore ships can be provided through a ship automatic identification system in real time, the amount of the information serving as input data of the parametric inversion algorithm is large, the inversion accuracy and stability of the ionized layer parameter are improved, and the spatial resolution of the ionized layer parametric inversion is improved.

The invention discloses a sky-wave over-the-horizon radar target and ionized layer parameter joint estimation method, which belongs to the field of radar technologies. According to the invention, a parameter to be estimated is set as a target and ionized layer joint parameter; an analytical model is used to transform the error of an ionized layer detection device into a target parameter estimation error; and the estimated parameter is corrected to realize ionized layer and target parameter joint estimation. The problem that joint ionized layer parameter error estimation cannot be carried out by the existing estimation method is solved. The ionized layer error information is effectively utilized. The estimation accuracy is improved.

The invention discloses a ground-based ionospheric network monitoring method, comprising: setting the order of magnitude of horizontal spatial resolution of ionospheric detection points in the detection area; The ionospheric oblique detection stations are uniformly set at a certain distance around the station; each ionospheric detection point is located in the middle of the ionospheric vertical detection station and the ionospheric oblique detection station; The ionospheric vertical detection station sends out the signal and is reflected by the ionosphere to determine the ionospheric state parameters at each ionospheric detection point. The invention can realize the high-resolution monitoring of the ionospheric foundation in the concerned detection area by rationally arranging a plurality of ionospheric oblique detectors. Since the ionospheric oblique sounder is used as the main monitoring method, it will not have adverse effects on the human body and radio equipment, and can provide more ionospheric information.

The invention belongs to the technical field of spatial light detection and satellite-borne detection devices, and particularly relates to a satellite-borne multi-probe ionosphere imager device whichcomprises a first camera, a second camera, a third camera, a photometer and a main frame, wherein the first camera, the second camera and the third camera work in different wave bands to form imagingof different channels for the ionosphere; the photometer is used for measuring the illumination intensity in the field of view and judging day-night alternation; and the main frame is used for fixingthe three cameras and the photometer and providing a heat dissipation function. By the adoption of the device, the problems that the reliability is poor due to the fact that ionosphere detection needsoptical filter wheel switching, and the detection time of different channels is inconsistent are solved.

The invention discloses a method for evaluating the maximum passable bandwidth of a short-wave sky-wave channel. The method comprises the following steps: step 1, carrying out electric wave environment detection; step 2, processing the ionospheric detection receiving signal; and step 3, evaluating the bandwidth availability. The invention discloses a short-wave sky-wave channel maximum passable bandwidth evaluation method based on electric wave environment detection. Transmission conditions of an ionized layer on signals with different bandwidths and interference conditions of short-wave bandfrequencies are comprehensively considered, the maximum passable bandwidth adapting to electric wave environment changes is provided for short-wave communication, and the requirement for reasonable bandwidth selection of short-wave communication is met.

The invention discloses an ionosphere detection method and system; the method comprises the following steps: using a USRP to emit electromagnetic waves of a set frequency and to receive electromagnetic wave reflected by the ionosphere, and recording emitted and received electromagnetic wave information; allowing the USRP to communicate with a computer through a gigabit internet access, and the computer uses the emitted and received electromagnetic wave information to calculate the ionosphere height, ionosphere electron density and ionosphere electron radial speed under the set electromagnetic wave emission frequency; changing the USRP emitted electromagnetic wave frequency, obtaining the ionosphere heights, ionosphere electron densities and ionosphere electron radial speeds under different electromagnetic wave emission frequencies, and drawing an ionosphere distribution map. The advantages are that the USRP communicates with the computer through the gigabit internet access, thus emitting and receiving electromagnetic waves, and primarily processing the signals; the computer can calculate complex signal processes and related detection targets, and the USRP and the programmed computer can detect the ionosphere with low cost; the ionosphere detection method is flexible, convenient, high in opening degrees, and easy to maintain.

The invention discloses a miniaturized ionospheric vertical detection device, comprising: a transmitting antenna unit, a receiving antenna unit and an ionospheric detection unit, wherein the ionospheric detection unit vertically transmits a frequency sweep signal through the transmitting antenna unit, and the frequency sweep signal encounters When it reaches the ionospheric area with the same frequency as the reflected echo signal, the receiving antenna unit receives the echo signal and transmits it to the ionospheric detection unit, and the ionospheric detection unit determines the ionosphere according to the frequency sweep signal and the echo signal. Frequency-height graph. The invention is convenient for mobile installation and erection, can change detection locations flexibly, obtains ionospheric parameters in different regions and locations, and provides real-time ionospheric data in key regions for civil and military use. The invention obtains maximum economic and social benefits with minimum development cost. with broadly application foreground.

The invention discloses a non-coherent scattering radar signal processing method based on frequency hopping and multiphase alternate codes. The method mainly solves the problems that existing non-coherent scattering radar is low in height resolution ratio, long in detection period and limited in coding mode. According to the technical scheme, the method comprises the following steps that all sets of the multiphase alternate codes are modulated respectively according to different frequencies, and radar pulses arranged in sequence without any time slot are generated and transmitted through a radar transmitter; radar echo signals are filtered respectively according to transmitting modulation frequencies so as to obtain detection data, corresponding to the same height range, of all the sets of the multiphase alternate codes, post-detection filtering is carried out on each set of coding echo signals, a self-correlation function is worked out, multi-period accumulation and fuzzy revising are carried out, and therefore the power spectral density of scattered signals of an ionized layer is worked out. The method can increase the height resolution ratio of the radar, shorten the detection period of the radar, expand the signal coding modes and be used for detection of the ionized layer.

A micro / nano-satellite for ionospheric probing is composed of an external spherical shell, antenna housings, antennas and a modular component, namely the CubeSat, wherein the outer spherical shell and the antenna housings are connected to form a spherical case of the whole satellite; the antennas are fixed to the external spherical shell and covered with the antenna housings; and the CubeSat is fixed to the center of the interior of the whole satellite through supporting rods on the external spherical shell. The micro / nano-satellite for ionospheric probing is a combination of the modular component and the customized components, is convenient to produce and machine, and has the advantages of low cost, simple structure, high universality and short production cycle. The micro / nano-satellite for ionospheric probing can probe ionized layers and the air density of atmosphere, thereby having high practicability. By the adoption of symmetrical distribution of the two omnidirectional antennas, the effect that the satellite can receive and dispatch signals in any posture is ensured, and requirements for a posture control system are reduced.

The invention relates to an ionosphere detection technology, in particular to an ionosphere Es layer high-resolution vertical detection method based on cross-spectrum analysis, which comprises the following steps of: transmitting a short-wave detection signal which has a narrower bandwidth and is coded and modulated to an Es layer above vertically by using a vertical measurement instrument in a sweep frequency or fixed frequency observation mode, intercepting an effective part of an echo, and carrying out cross-spectrum analysis on the effective part of the echo; and for each detection of each detection frequency, a spectrum estimation method is independently adopted to carry out high-resolution imaging, so that high-precision observation of the internal structure and the motion process of the Es layer is realized. According to the method, extra equipment and hardware cost are not needed, the range resolution of Es layer observation can be greatly improved, and compared with high-resolution imaging conducted through a traditional coherent accumulation technology or a multi-frequency interference technology, the method does not need high-frequency repeated detection to achieve energy accumulation or conduct joint operation through multi-frequency-point echo data; the time resolution is improved while the distance resolution is very high, and the short-time violent change in the Es layer can be observed conveniently.

A micro / nano-satellite for ionospheric probing is composed of an external spherical shell, antenna housings, antennas and a modular component, namely the CubeSat, wherein the outer spherical shell and the antenna housings are connected to form a spherical case of the whole satellite; the antennas are fixed to the external spherical shell and covered with the antenna housings; and the CubeSat is fixed to the center of the interior of the whole satellite through supporting rods on the external spherical shell. The micro / nano-satellite for ionospheric probing is a combination of the modular component and the customized components, is convenient to produce and machine, and has the advantages of low cost, simple structure, high universality and short production cycle. The micro / nano-satellite for ionospheric probing can probe ionized layers and the air density of atmosphere, thereby having high practicability. By the adoption of symmetrical distribution of the two omnidirectional antennas, the effect that the satellite can receive and dispatch signals in any posture is ensured, and requirements for a posture control system are reduced.

The invention discloses an ionized layer parametric inversion method based on AIS target indication. The method includes the steps of obtaining the target positions and movement information of offshore ships on the basis of the AIS, detecting suspected ship targets on the basis of a sky wave radar echo spectrum and through the combination with the AIS target indication area, conducting correlation, fusion and matching on the ship targets detected by radar and the ships indicated by the AIS so as to obtain the route of a radar ship target group, detecting a quasi parabolic ionized layer model required for the ship target positioning on the basis of sky wave radar backscatter sounding, establishing a mean square error equation of the route of the radar ship target group, and obtaining the optimal solution of the ionized layer parameter on the basis of the optimization solution algorithm. By means of the method, the ionized layer parameter model can be obtained without more professional ionized layer detection devices, and the number of devices and the device cost are reduced. The static and dynamic information of a large number of offshore ships can be provided through a ship automatic identification system in real time, the amount of the information serving as input data of the parametric inversion algorithm is large, the inversion accuracy and stability of the ionized layer parameter are improved, and the spatial resolution of the ionized layer parametric inversion is improved.

The invention discloses a sky-wave over-the-horizon radar target and ionospheric parameter joint estimation method, which belongs to the technical field of radar. The invention sets the parameter to be estimated as the joint parameter of the target and the ionosphere, uses an analytical model to convert the error of the ionosphere detection equipment into an estimation error of the target parameter, corrects the estimated parameter, and realizes joint estimation of the ionosphere and the target parameter. The invention solves the problem that the ionospheric parameter error estimation cannot be combined in the existing estimation method, enables the ionospheric error information to be effectively used, and improves the estimation accuracy.

The invention relates to ionospheric detection technology, in particular to a high-resolution vertical detection method of the ionospheric Es layer based on cross-spectrum analysis. There is a coded and modulated short-wave detection signal with a narrow bandwidth, and the effective part of the echo is intercepted, and the spectral estimation method is used for each detection of each detection frequency to perform high-resolution imaging, so as to realize the high-resolution imaging of the internal structure and motion process of the Es layer. Precision observation. This method does not require additional equipment and hardware costs, and can greatly improve the range resolution of Es layer observations. Compared with traditional coherent accumulation techniques or high-resolution imaging using multi-frequency interferometry, this method does not require a high number of repeated detections. In order to achieve energy accumulation or use multi-frequency echo data for joint operation, it has a high range resolution and at the same time improves the time resolution, which is convenient to observe the short-term drastic changes in the Es layer.

The invention discloses a top ionosphere detection space-borne MIMO radar system which belongs to the field of radar technology and compromises a complete complementary sequence generator, a pulse period delayer, a modulator, emission antennae, reception antennae, a demodulator, a pulse compression system and an electron density distribution generation system. The complete complementary sequence generator simultaneously generates N pairs of complementary sequences. The pulse period delayer alternatively inputs two complementary sequences to the modulator. N pairs of signals are modulated at Ncarrier frequencies respectively and sent out by the N emission antennae, and the echo signals are received by the N reception antennae. The demodulator demodulates signals on the N carrier frequencies. The signals are sent to the electron density distribution generation system after pulse compression to generate a two dimensional ionogram. The space-borne MIMO radar system is used for the top ionosphere detection. Compared with the prior ionosphere detector, the space-borne MIMO radar system of the invention can generate two dimensional ionograms and has very high orientation resolution and high work efficiency.