44results about How to "Engineering feasibility" patented technology

The invention discloses an efficient and compact pre-cooling heat exchanger for a pre-cooling gas sucking type engine. The efficient and compact pre-cooling heat exchanger for the pre-cooling gas sucking type engine comprises a pre-cooling heat exchanger body in the shape of a similar cylinder; the cross section of the similar cylinder is in the shape of a ring different in diameter; the longitudinal section of the similar cylinder is formed by two symmetrically arranged arc segments; the center angle of each arc segment is 45 degrees; the pre-cooling heat exchanger body comprises a cold flow outlet pipe, a cold flow inlet pipe and a plurality of heat exchanging pipes; each heat exchanging pipe is in the shape of an arc; the arc-shaped center angle of each heat exchanging pipe is 45 degrees; and the heat exchanging pipes are distributed into the similar cylinder in a crossed manner. The efficient and compact pre-cooling heat exchanger for the pre-cooling gas sucking type engine can have the engineer realizability on the premise that the heat exchanging effect is guaranteed, so that air incoming flow in front of a gas compressor can be pre-cooled, the high temperature over-running problem of gas compressor blades is solved, the engine thrust is increased, the flight envelop is extended, the welding difficulty is effectively reduced, the frosting blockage problem is effectively solved, the engineer realizability is achieved under the current technology, and after the efficient and compact pre-cooling heat exchanger for the pre-cooling gas sucking type engine is applied to the pre-cooling gas sucking type engine, the engine performance can be substantially improved.

The invention discloses a system and a method for detecting a low-speed small target under a sea cluster background. The method includes that S1, a radar transceiving unit acquires signals of the low-speed moving small target under the sea cluster background; S2, the radar transceiving unit sends received signals to a radar echo processing unit to be processed to generate radar echo data and sends the radar echo data to a detection unit; S3, the detection unit processes multiple continuous radar echoes and establishes corresponding time frequency domain two-dimension planar graphs to effectively eliminate false-alarm targets in different areas. The system and the method are suitable for detection of dim and small targets moving at low speed under sea cluster background interference during downward-looking detection of sea-surface targets through radar. By the system and the method, the problem of radar downward-looking detection of the low-speed moving small target under the sea cluster background can be solved; time frequency domain CFAR (constant false alarm rate) processing technology is adopted to decompose target echoes and sea cluster data to a time frequency domain two-dimension plane for processing.

The invention relates to a method of using sum and difference channels of a radar antenna for restraining radar side lobe interception. According to the method, antenna patterns of the sum channel and the difference channel of the radar main antenna are optimized, self-correcting signals of a radar system are used for obtaining amplitude and phase errors with the sum channel as the datum, and the amplitude and phase errors are used for error correction of the sum channel and the difference channel; according to the target position in the sum channel, the corresponding position, in the difference channel, of a target is searched for, and amplitude and phase correction is carried out on the complex number value of the position, where the target is located, in the difference channel by means of the amplitude and phase errors of the sum channel; the complex number modulus value of the position, where the target is located, in the sum channel is compared with the corrected complex number modulus value of the target in the difference channel to judge whether target echoes enter from main lobes or side lobes of the main antenna. Therefore, the radar system using the method can directly use the main antenna for recognizing side lobe targets without depending on an auxiliary antenna, the design difficulty of the radar antenna is effectively lowered, the number of the channels of the antenna is effectively reduced, and the reliability of the antenna is improved.

The method manages to solve the problem of high resolution and high arithmetical complexity existed in normal approach in order to reach main beam-forming and be capable of making real time process for multi high strength interferences. It comprises: a beam selector is used to make channel selection control in order to select several channels under interference; sending the signals from the selected channels into a process branch circuit; the selected signals firstly are converted down to 1.0 GHZ and are sent to band filter; the signals outputted from the filter are sent to the phase detector, and negative frequency spectrum is removed from the those signals, and the real signals are converted into the complex signals. The algorithm used in current system is implemented by using the correction of amplitude and phase, high resolution angle measurement and self-adaptive zeroing process.

The invention discloses a determination method and device for a flight path command of a flight vehicle. The determination method comprises the steps that according to voyage to be flown, provided by a guiding system, of the flight vehicle, a speed command parameter Vcx of the flight vehicle is calculated; according to the flight speed, provided by the guiding system, of the flight vehicle, a drag acceleration command parameter Dcx, a drag acceleration derivative order parameter cx, a height command parameter Hcx and a tilt angle command parameter thetacx of the flight vehicle are calculated; according to all the calculated command parameters, the flight path command of the flight vehicle is generated and sent to a control system of the flight vehicle. As the flight path command of the flight vehicle can be quickly given according to the flight speed and the voyage to be flown, the determination method and device are beneficial to guidance control over the flight vehicle.

The invention relates to a Monte Carlo simulation method for an active critical device in an approximate critical process, which is suitable for the field of neutronics physical analysis of a nuclearcritical device with an external neutron source. According to the invention, the method comprises the steps: decomposing a continuous neutron transport process into successive generations of analog calculation, and according to successive generations of system neutron effective proliferation factors and successive generations of physical quantity statistical counting, and carrying out the weightedsummation to obtain final calculation results of physical quantities such as nuclear critical device power level and neutron flux distribution are obtained. According to the method, Monte Carlo simulation of the transport process of the external neutron source in the approaching critical process of the nuclear critical device is achieved, and the situation that infinite transport calculation of the external neutron source of a certain generation is not terminated due to randomness of the Monte Carlo method is avoided; the Monte Carlo simulation method for the neutron transport process of theactive critical device is advanced and has engineering feasibility.

The invention discloses a GEO satellite external multilayer thermal insulation assembly earthing system and method. The judgment criterion of the number of multilayer thermal insulation assembly earthing devices on a monoblock multilayer thermal insulation assembly is designed, the GEO satellite external multilayer thermal insulation assembly earthing system comprising the multilayer thermal insulation assembly earthing devices, an earthing ridge and an O-shaped terminal is designed, and an installation method and the test criterion for guiding multilayer thermal insulation assembly earthing implementation are designed. By using the GEO satellite external multilayer thermal insulation assembly earthing system and method provided by the invention, on the premise that the surface charging potential control requirements during GEO satellite in-orbit operation period are met, the defects that a plurality of earthing wires are led out of the multilayer thermal insulation assembly, but limited satellite surface earthing points cannot meet the earthing wire lap jointing requirements for the multilayer thermal insulation assembly can be overcome; and the surface charging and discharging risks of the GEO satellite can be reduced, and GEO satellite in-orbit abnormal situation caused by surface charging and discharging effects is greatly relieved.

The invention relates to an unmanned aerial vehicle cluster formation flight method for saving communication bandwidth, which comprises the following steps that: a computer control program for processing strategy information and long and short messages of a long aerial vehicle in formation flight is pre-integrated in each unmanned aerial vehicle Fi in an unmanned aerial vehicle cluster based on an ad hoc network link; when the unmanned aerial vehicle Fi receives the long and short messages shared by other unmanned aerial vehicles Fj, the unmanned aerial vehicle Fi checks that the own identifier is the same as the long aerial vehicle identifier in the long and short messages, and the long aerial vehicle processes the strategy information and updates the own level information and shares the long message at the same time; the long message is message information which has position information and is shared by a lead aircraft, and the short message is message information which does not have position information and is shared by unmanned aerial vehicles as wing aircrafts. According to the method provided by the invention, the unmanned aerial vehicle can flexibly switch the long unmanned aerial vehicle, send the position as required and dynamically use the bandwidth, so that the sharing of invalid data is avoided, and the technical problems that the networking communication link is poor in stability and the communication bandwidth is occupied in the prior art are effectively solved.

The invention relates to a Mars detection ground antenna pointing correction method based on error quaternion, and the method comprises the specific steps: S1, defining the quaternion of spatial three-dimensional rotation, and building a detector mechanical coordinate system; s2, correcting the final X-axis driving angle alpha and Y-axis driving angle beta of the ground antenna by adopting a gradual error correction strategy based on the ground accurate measurement data; s3, based on the on-orbit calibration data, obtaining error angles d alpha under different X-axis driving angles alpha and error angles d beta under different Y-axis driving angles beta, and obtaining the relation between the error angles and the driving angles through one-time linear fitting to be corrected. According tothe method, correction is carried out on two aspects of a ground accurate measurement result and an on-orbit calibration result, the ground accurate measurement result correction is based on a rotation quaternion, the on-orbit calibration result correction is based on one-time linear error fitting, and errors under different driving angles can be effectively guaranteed.

The invention provides an FFT (fast Fourier transform) method based on point-by-point sequential step-by-step processing flow. The FFT method comprises the following steps: utilizing linear properties of the FFT to realize point-by-point sequential step-by-step processing; splitting N-point FFT into the addition of N FFTs with simple sequences; utilizing table lookup to reduce transformation time of the FFTs with simple sequences; finally, improving transform efficiency of the whole sequence. The method can pre-process first-in data in advance under the condition that a to-be-transformed sequence is incomplete, and the FFT transform results can be output after the sequence is complete. According to the method, the integral processing time of FFT is fragmented, and time of a preparation process of data is sufficiently utilized to complete transform work, so that the FFT method is especially suitable for a radar signal processing system of a pipeline processing structure.

The invention relates to a spent fuel dissolver critical safety analysis method considering fuel assembly burnup distribution. According to the method, burnup distribution of each axial section of each fuel rod of a maximum reactivity assembly is determined, the mass proportion of fuel in each burnup interval is determined, and the fuel is arranged in a layered mode from inside to outside according to the reactivity of the fuel (the fissile nuclide content), so that the composition of the fuel in a spent fuel dissolver is closer to the real situation, and a certain critical safety analysis conservative margin exists, so that the treatment capacity of the spent fuel dissolver can be improved or the use of neutron poison materials can be reduced under the condition of ensuring safety. According to the method, refined critical safety analysis of the spent fuel dissolver is realized. The method is an advanced spent fuel dissolver critical safety analysis method with engineering feasibility.

The invention relates to a distribution force optimization method for transforming a cylindrical surface into a parabolic groove surface. According to the method, the force enabling the arc to deform into the parabola is obtained, when n unknown forces are needed, in order to minimize the radial error of the simulation optimization result and the target ideal parabola, the parameter focal diameter ratio, namely the ratio of the paraboloid focus to the cylinder radius, is defined, the parabolic equation closest to the arc is determined, the parabola closest to the arc is taken as the target, the radial error is minimized through optimization analysis, and the corresponding distributed control force for eliminating the displacement error is obtained.