CN108445483A - Water floats plant radar sensing system - Google Patents

Abstract

The present invention relates to water to float plant radar sensing system, floating on water growing plant based on radar monitors system, using floating material with the water surface to the difference of microwave echoes intensity, and pass through high resolving power, measuring and calculating flows through the water plant area of monitoring point in real time, and according to the water plant area for flowing through different monitoring points, aquatic plants growth model is established, it is final to realize prediction and the supervision of full basin.

Description

Water floats plant radar sensing system

Technical field

The present invention relates to water plants to renovate field, and in particular to a kind of floating plant radar sensing system of water.

Background technology

Water floats the key points and difficulties that plant is all river improvement all the time, alien species water calabash especially in recent years Reed, vitality is strong, and the speed of growth is exceedingly fast, and large stretch of water hyacinth swims in the water surface, goes downstream, unbroken dozens of kilometres, some water Face is very most to be covered by water hyacinth, and not only polluted water region environment, has an effect on navigation safety, even into urban planning Landscape waters, cause society extensive concern.

For this purpose, relevant department has carried out relevant renovation.Include patrolled with ship, vehicle patrols and video monitoring based on it is pre- It is alert；Cleaning work etc. based on the salvaging of interception concentration and ship cruise salvaging, the certain effect of regulation acquirement.But by water The outburst of the influence of the environmental factors such as text, weather, geography, water hyacinth has uncertainty, causes in some regions and period When water hyacinth largely concentrates outburst suddenly, blocks fishing operation strength and have too many difficulties to cope with for the moment.Therefore, relevant department is badly in need of establishing a set of In the intelligent management method of water plant early warning and comprehensive improvement, the water surface for flowing through sensing point is obtained using detection sensor Fluitante distributed intelligence, and by the information networking of more sensing points and fusion, other comprehensive multi-party meteorological, hydrographic informations are sentenced It cuts off the water supply the growth tendency and basin overall distribution situation of plant, establishes water plant management early warning mechanism, and rationally pacify with this Fishing strength is arranged, achievees the purpose that effective management and control water plant.

Invention content

It is an object of the invention to overcome the deficiencies of the prior art and provide a kind of water to float plant radar sensing system, is based on The floating on water growing plant of radar monitors system, using floating material with the water surface to the difference of microwave echoes intensity, and passes through height Resolving power, measuring and calculating in real time flows through the water plant area of monitoring point, and according to the water plant face for flowing through different monitoring points Product, establishes aquatic plants growth model, final to realize prediction and the supervision of full basin.

The purpose of the present invention is achieved through the following technical solutions：

Water floats plant radar sensing system, the radar sensing system by antenna system, radio frequency microwave system, data processing and Terminal display system forms；

The antenna system is made of transmitting antenna and reception antenna, and radar generates point frequency continuous wave and linear frequency modulation is continuous Wave signal, wherein point-frequency signal are only used for the tachometric survey of floater, and linear frequency modulation continuous wave signal realizes floating on water The area measurement of object, the signal are radiate via transmitting antenna, and signal enters reception antenna after water plant is reflected；

The radio frequency microwave system is made of receiving front-end, data acquisition module, frequency synthesis component three parts, through aquatic Signal after plant reflection accesses receiving front-end, through filter amplifier, numerical-control attenuator, low pass after the processing of three-level frequency mixer Filter exports；Data acquisition module is made of anti-aliasing filter, ADC, FPGA and Ethernet transmission module, for realizing Intermediate-freuqncy signal digitizes, and frequency synthesis component is by clock reference circuit, Waveform generating circuit, transmission channel, interface control circuit Composition, for improving the local oscillation signal needed for receiving front-end, the synchronizing clock signals needed for data acquisition module and linear tune The pumping signal of frequency；

Data processing and terminal display system are made of data processing module and terminal display module, and it is each to complete the floating plant of water The online real-time measuring and calculating and display of information.

As being further improved for this programme, the antenna system uses the planar array antenna system of bistatic, day Line forms horizontal narrow lobe, the pattern characteristics of vertical width lobe.

As being further improved for this programme, the planar array antenna system is planar waveguide array antenna, using son The structure of battle array block design, working frequency are K-band, and f0 ± 150MHz, f0 take 24GHz.

As being further improved for this programme, the antenna gain >=30dB, lobe width level≤1 ° is vertical≤5 °, Horizontal, vertical minor level≤- 20dB；Standing wave requires VSWR≤1.6, and polarization mode is vertical polarization, isolation between transmitting and receiving antenna ≥80dB；Beam position deviation electric axis in frequency band is directed toward deviation and meets≤0.2 °.

As being further improved for this programme, the three-level frequency mixer includes first order frequency mixer, second level frequency mixer, Three-level frequency mixer；

The rf excitation signal enters first order frequency mixer through limiter, low-noise amplifier, filter and is mixed to obtain The first intermediate-freuqncy signal of 7.75GHz bandwidth 300MHz；

The filtered device of first intermediate-freuqncy signal, amplifier enter second level frequency mixer and obtain the second of 750MHz bandwidth 500KHz Intermediate-freuqncy signal；

Second intermediate-freuqncy signal obtains 70MHz bands after filtered device, amplifier, numerical-control attenuator into third level frequency mixer The third intermediate-freuqncy signal of wide 5MHz；

The filtered amplifier of third intermediate-freuqncy signal, numerical-control attenuator, low-pass filter output.

As being further improved for this programme, the anti-aliasing filter is mainly used for preventing making an uproar when ADC bandpass samplings Sound aliasing, parameter are：Centre frequency F0=70MHz；BW-1dB=3~5MHz；BW-40dB<40MHz； BW-80dB <70MHz。

As being further improved for this programme, ADC sampled datas are entered three-level by the FPGA after Digital Down Convert Decimation filter is followed successively by 2 times of extractions, 5 times of extractions, 5 times of extractions, is equivalent to the sample rate of 2MHz, then passes through a height Set form is packed the data to after bandpass filter is sent to Ethernet transmission module.

As being further improved for this programme, the clock reference circuit generates 100MHz signals, warp by constant-temperature crystal oscillator The output of two power splitters of ADP-2-1W does comb spectrum driving source to the sources 12G all the way, is supplied respectively through tetra- road power splitters of SCA-4-10 all the way To 3.5GHz, CRO phase locked sources；LTC6946-2 outputs receive three local oscillation signal 820MHz；Transmitting excitation is exported through LTC6946-1 Signal 750MHz；13dBm signals are exported for signal processor when acquisition clock through amplifier.

As being further improved for this programme, the Waveform generating circuit work is as follows：

By CRO phase-locked loop circuits generation 3.5GHz signals generation is mixed after, amplification filtered with comb spectrum generation 12G signals Latter local oscillation signal, a local oscillation signal is filtered, amplification, for transmission channel and receiving module does a local oscillator after work(point；

Frequency sweep local oscillator divides two-way to do local oscillation signal through amplification, frequency multiplication, filtering generation 7GHz all the way by 3.5G；It gives all the way AD9914 makees clock, generates 600~900MHz signals, two kinds of signals are after the mixing of HMC558 frequency mixers through filtering, amplification, work( Divide and does two local oscillators to receiving module for transmission channel and output.

As being further improved for this programme, the transmission channel generates 750MHz and frequency sweep local vibration source by frequency synthesizer 7.6~7.9GHz is mixed, and is mixed with a local oscillator 15.5GHz after filtered amplification, and 23.85~24.15GHz signals are exported, after Filtered mixing, amplification are exported through isolator.

As being further improved for this programme, the property indices of system are as follows：

1) it encourages：24GHz ± 50MHz (23.85~24.15GHz), power：1~1.3W, phase noise：L(1K)≤ - 103dBc/Hz, L (100K)≤- 113dBc/Hz；

2) local oscillator：15.5GHz, power：13dBm ± 1dBm, phase noise：L (1K)≤- 108dBc/Hz, L (100K) ≤-118dBc/Hz；

3) two local oscillator：7.75GHZ (7.6~7.9), power：10dBm±1dBm；Phase noise：Better than a local oscillator；

4) three local oscillator：820MHz, power：10dBm ± 1dBm, phase noise：Better than two local oscillators；

5) clock：100MHz, power：13 ± 0.5dBm,

Phase noise：L (1K)≤- 140dBc/Hz, L (100K)≤- 150dBc/Hz；

6) amplitude coincidence in swept-frequency signal frequency modulation band bandwidth：≤1dB；

7) clutter is exported：Excitation >=60dBc, one local oscillator >=70dBc, two local oscillators >=70dBc, three local oscillators >=70dBc, clock ≥70dBc

8) harmonics restraint：Excitation >=55dBc, one local oscillator >=60dBc, two local oscillators >=60dBc, three local oscillators >=60dBc, clock ≥60dBc

9) power fluctuation：≤0.5dB

10) power consumption：≤30W；

11) point frequency and linear modulation alternately export each 1s, linear frequency modulation time 1ms, modulating bandwidth 300MHz, FM linear Degree≤2/1000.

As being further improved for this programme, the data processing module utilizes the difference in river and water plant albedo It is different, detect the water plant of floating on water.The water plant distribution situation of Measure section is flowed through by measuring, and disconnected at this Movement speed under face carrys out the area of COMPREHENSIVE CALCULATING water plant.

As being further improved for this programme, the data processing module to the linear frequency modulation continuous wave signal of 1S at Reason method is as follows：

Linear frequency modulation continuous wave signal realizes the area measurement of floater, and it is each to measure section dimension by broadband signal The echo strength of range points is detected in frequency domain, and water plant is determined by the way that whether there is or not the variations of the echo strength of water plant Area；

The continuously linear frequency modulation continuous wave signal of 1000 1ms of hair, handles the data of the data and 1000ms of 1ms；

S01：Under normal operation, one piece of water surface for floating plant without water is looked for, measures in azimuth beamwidth and each differentiates The reflected intensity of unit water, as detection benchmark threshold value；

S02：The echo-signal of 1ms is detected, the value obtained using in S01 is as benchmark thresholding, according to actual conditions It is being adjusted, is judging that each resolution cell has anhydrous floating plant；

S03：The intensity value for preserving each range points makes label to the range points for having water to float plant.

As being further improved for this programme, the data processing module to the point frequency continuous wave signal processing method of 1s such as Under：

S11：Power spectral density is asked to gathered data；

S12：It respectively takes the data of 1kHz to carry out Threshold detection in intermediate frequency 500KHz or so, thinks there is target more than thresholding, Under normal circumstances, general water speed is less than 0.1m/s, f_d=2v/ λ, therefore maximum doppler frequency is about 16Hz, consideration has wind etc. There are surplus both sides, and 1KHz, the detection benchmark threshold value that threshold value is obtained using in S01 respectively to be taken to be carried out as benchmark under abnormal conditions Fine tuning.

S13：Target velocity is found out according to detection frequency.

As being further improved for this programme, the data processing module calculates target area as follows：River width presses 50 meters It calculates, is divided for 0.6 meter by Range resolution unit, 1 ° of orientation velocity of wave width, then about 0.8 meter of farthest distance in azimuth beam；Meter It is as follows to calculate formula

R=river width；

θ=azimuth beamwidth；

Then at different distance, orientation width=2Rtan (θ/2) of azimuth beam covering；

S21：Target area is smaller

When target area be less than or equal to a Range resolution unit area (<=0.6*0.6) when, that measures at this time returns Intensity of wave is to change steeper bell-shaped curve, the flow measured at this time time dimension target length L in the same direction₂For：

Wherein：2 represent time of measuring interval 2 seconds, v_iIt is floating to represent water velocity=water that each time of measuring interval is found out Continuously there is the time interval number of target in plant measurement speed/sin θ, n representatives, and d is a fixed value, and it is different to refer to section dimension The lateral distance in azimuth beamwidth corresponding to range cell point；

The range cell occurred according to target, you can find out the length L of object section dimension₁=measure section dimension length * cos θ；

Then area：S=L₁×L₂

S22：Target area is larger

As a big target, the echo strength measured at this time changes the target that time and range cell are all continuously occurred Similar bandpass filter, both sides variation is steeper, and centre is shallower, the then time dimension target length L in the same direction with flow₂For：

L₂=2 × v_i

Wherein：2 represent time of measuring interval 2 seconds, v_iRepresent the water velocity that each time of measuring interval is found out.

The range cell occurred according to target, you can find out the length L of target range dimension₁=measure section dimension length * cos θ, if the object section dimension range cell surveyed is discontinuous,N, which refers to, measures the distance that section dimension has water to float plant Unit number；

The water that then each time interval is measured floats plant area：S_i=L₁×L₂

Then target area is：

N, which is represented, continuously there is the time interval number of target, and d' refers to corresponding to object section dimension different distance unit spot The maximum value of lateral distance in azimuth beamwidth, v refer to current goal last time detection speed, and m refers to area and computes repeatedly Time interval number, S' refers to computes repeatedly area by what water in beam angle floated plant, provides and flows through per half an hour It measures a gross area in section and preserves result.

As being further improved for this programme, the data processing module further includes to data transmission, processing, storage and showing Show that the time calculates, it is specific as follows：

For data by the time of cable incoming data buffer area, input signal is 16bit floating numbers, 1S total 2M after A/D Sampled point, therefore the data volume of required transmission is 32Mbit；

Data transmission is quasi- to use 10,000,000,000 nets, and the transmission rate of 10,000,000,000 nets is 10000Mb/s, if network transmission efficiency is 50%, 6.4ms need to be taken by transmitting the data of 32Mb；

Hard disk is write data into, computer hard disc memory rate 20MB/s deposits 2M point 16bit data and needs 200ms, from hard disk Data are read to memory, computer hard disc reading rate 30MB/s reads 2M point 16bit data and needs 140ms, CPU is stored to from interior, The transmission rate of PCI-E buses is 8Gb/s, and the data of 32Mb are 4ms from the interior time for being stored to CPU；

CPU carries out FFT processing to data and Threshold detection needs 600ms, display to be shown simultaneously using 1s data, required time Linear FM signal processing time for 50ms, therefore 1s is about 1 second.

Followed by the point-frequency signal of 1s, we only take wherein a bit of data processing, and it is about 200ms to ask speed, time；

Therefore the point frequency continuous wave processing time of the linear FM signal+1s of 1s is about 1200ms, so when the repetition of 2s Between interval can complete to handle, data will not be lost.

The beneficial effects of the invention are as follows：Water floats plant detection radar and realizes to floating on water plant in the rivers 100m wide, miscellaneous The real time on-line monitoring of object plane product.To the minimum detectable speed of floater down to 0.1m/s, Range resolution is less than 1m； The radar has the characteristics that：

1) the real-time measurement of floater is realized；

2) high certainty of measurement；

3) unattended, reliability is high；

4) maximum detectable range is more than 200m；

5) power consumption is small；

6) flow velocity for being suitably adapted for low flow velocity river measures.

Description of the drawings

Fig. 1 is detection principle figure；

Fig. 2 is section dimension measuring principle schematic diagram；

Fig. 3 is the horizontal lobe pattern of dual-mode antenna theoretical calculation；

Fig. 4 is dual-mode antenna theoretical calculation vertical diagram；

Fig. 5 is dual-mode antenna theory meter three-dimensional lobe pattern；

Fig. 6 is dual-mode antenna simulation model；

Fig. 7 is dual-mode antenna three-dimensional artificial lobe pattern；

Fig. 8 is dual-mode antenna artificial water plane lobe pattern；

Fig. 9 is dual-mode antenna emulation vertical plane lobe pattern；

Figure 10 is the beam position figure of tri- frequency points of f0-150MHz, f0, f0+150MHz；

Figure 11 is actual beam shape graph；

Figure 12 is clock reference circuit；

Figure 13 is Waveform generating circuit；

Figure 14 is transmission channel circuit；

Figure 15 is 3500MHz CRO oscillator phase curve graphs；

Figure 16 is receiving channel circuit；

Figure 17 is echo input standing wave curve graph；

Figure 18 is image frequency degree of suppression curve graph；

Figure 19 is data acquisition module block diagram；

Figure 20 is noise aliasing schematic diagram；

Figure 21 is data acquisition module block diagram；

Figure 22 water floats plant reference area schematic diagram.

Specific implementation mode

Technical scheme of the present invention is described in further detail with reference to specific embodiment, but protection scope of the present invention is not It is confined to as described below.

Water plant detection radar uses orientation narrow beam, realizes the minimum resolution cell for measuring section；The elevation angle is using wide Wave beam, energy covering is entire to measure section, and the echo strength that each range points are tieed up in section is measured by broadband signal.And pass through Whether there is or not the variations of the echo strength of water plant to determine the area of water plant.

Radar generates point frequency continuous wave and linear frequency modulation continuous wave signal, wherein point-frequency signal are only used for floater Tachometric survey, linear frequency modulation continuous wave signal realize the area measurement of floater.Signal is after power amplification, by emitting Aerial radiation is gone out, and signal enters reception antenna after water plant is reflected, and by receiver down coversion, after demodulation, becomes number Signal, signal processor handle and calculate the echo strength in different distance and movement speed, export cross-sectional distance-flow direction Distance-intensity distribution.

Its detection principle is as shown in Figure 1.

Radar, which is set up, to be directed toward with cross section of river there are angle theta,

Object section length=measurement cross-sectional length × cos θ；

Target flows to length=measurement section target length/sin θ.

Flow direction dimension measuring principle

The resolution cell in target length in the same direction=water (flow) direction resolution cell × detection duration with river direction Number=time of measuring interval × water floats resolution cell number/sin θ in plant measurement speed × duration.

(1) time of measuring interval is determined by detection radar, can accurately be obtained；

(2) the Doppler frequency fd that target can be measured under point frequency continuous wave signal pattern can be calculated according to operation wavelength λ Water floats plant measurement speed=fd × λ/2；

(3) resolution cell number in duration, it is each to differentiate using reflection echo under pure water conditions as background Unit establishes the thresholding in the resolution cell, and according to water surface height characteristic, establish threshold data library according to detection background, and Judge there is anhydrous floating plant in the resolution cell with this thresholding.

Tie up measuring principle in section

The linear FM signal that radar emission is modulated from f0-150MHz to f0+150MHz, if occurring 1 fixed mesh at R Mark, then the echo delay of target is 2R/C at R.Echo-signal forms fixed frequency difference after the past is oblique.Relationship such as Fig. 2 institutes Show：

When there is target at different distances, different frequency differences will be formed.By uniting to different frequent points echo strength Meter, and compared with calm water surface echo strength, confirm whether the range points are water plant.Last basis, which flows through, measures section Water plant echo points, determine water plant area.

Radar generates point frequency continuous wave and linear frequency modulation continuous wave signal, wherein point-frequency signal are only used for floater Tachometric survey, linear frequency modulation continuous wave signal realize the area measurement of floater.Signal is after power amplification, by emitting Aerial radiation is gone out, and signal enters reception antenna after water plant is reflected, and by receiver down coversion, after demodulation, becomes number Signal, signal processor handle and calculate the echo strength in different distance and movement speed, export cross-sectional distance-flow direction Distance-intensity distribution.

(1) form is scanned

Antenna bearingt is fixed, the elevation angle can nutation adjust, be directed toward different distances for main beam, adequacy test needs It asks.

(2) parameter measurement form

Frequency domain detection, point frequency test the speed, frequency modulation ranging.

(3) antenna feeder form

Two antenna of upper and lower piecemeal.Feed is concentrated to reduce loss.

(4) emit form

Power is small, solid-state transmitting, Integrated design.

(5) form is received

In order to reduce loss, using first amplifying, then frequency conversion, the form of rear A/D, Integrated design.Reduce transmitted data amount

(6) transmission form

Network interface transmits, and low data rate AD data are automatically stored.

(7) terminal form

Notebook carries, and C Plus Plus is realized, picture is adjustable.

(8) structure type

It is small and exquisite, quick detachable, easy to carry, have pitching instruction, perfect heat-dissipating.

Antenna system scheme

Paraboloid form can be used in continuous wave radar antenna, and planar array form can also be used, if transmitting subsystem is adopted With T/R packaging schemes, then antenna is advisable in the form of using planar array.In addition, as radar will realize multipolarization, then antenna is adopted Multipolarization function can be realized with paraboloid, to realize that multipolarization function will be extremely difficult using planar array, and complicated.

Parabola antenna has feed simple, and without graing lobe, frequency band is wider, and cost is relatively low, the small advantage of energy consumption.Paraboloid The emphasis of antenna, difficult point are reflecting surface and feed, and to be feeding network and polarization realize for the emphasis of array antenna, difficult point, right In high-gain radar antenna, number of arrays is more, it is desirable that more complicated feeding network.

From the aspect of isolation between antennas, the isolation of planar array can slightly be better than parabola antenna, because of planar array It is the radiation of multiple-unit distribution, edge power is weaker；Parabola antenna is that feed is concentrated transmitting and received, and feed is closely The lobe of formation will not be very weak in edge amplitude.

After proving, analyzing, antenna system uses the planar array antenna form of bistatic.Antenna system is by transmitting day Line and reception antenna two parts composition.Transmitting antenna and reception antenna are placed up and down, the signal that transmitting antenna generates transmitter It is radiated space.Reception antenna gives the target echo signal received to receiver.

Antenna the key technical indexes

(1) working frequency, K-band, f0 ± 150MHz；F0 takes 24GHz；

(2) antenna form, planar waveguide array antenna (use submatrix block design)；

(3) output channel and signal path and coupled signal paths；

(4) antenna aperture 0.76m × 0.16m (be subject to and meet index request)；

(5) antenna system uses bistatic system；

(6) antenna gain >=30dB；.

(7) lobe width it is horizontal≤1 °, it is vertical≤5 °；

(8) horizontal, vertical minor level≤- 20dB；

(9) standing wave requires VSWR：≤1.6；

(10) polarization mode vertical polarization；

(11) antennal interface and signal path：Standard BJ260 Waveguide interfaces；Coupling channel：SMA-K interfaces；

(12) isolation between transmitting and receiving antenna >=80dB；

(13) beam position deviation electric axis in frequency band is directed toward≤0.2 ° of deviation satisfaction；

(14) power capacity 2W.

(15) environmental suitability

Operating ambient temperature：- 10 DEG C~+50 DEG C.

Working environment humidity：Relative humidity：95% (at 40 DEG C).

(16) reliability

Passive device, full longevity part.

Three proofings：Waterproof, mould proof, salt spray proof do not generate and obviously go mouldy and corrode；

Ageing-resistant, the antifatigue, corrosion-resistant material of selection, media fraction carry out corresponding anti-aging processing；

(17) structure design

This equipment implements generalization, seriation, modularization idea in the design；

Meet the requirements such as anticorrosion, salt spray proof, the electromagnetic environment of project demand；

Fastener uses stainless steel material, prevents fastener from corroding；

The structure design of antenna array pays attention to sealing the measures such as waterproof；

Carry out structural reliability design, use standard series component as possible, same kind zero, portion, one integral piece should have it is good Good interchangeability；

On the basis of fully ensuring that structural strength and safety, reliability, structure is reduced by using new material technique Overall weight.

Antenna forms

To reach the overall test requirement of observation water plant, antenna system uses the antenna system of bistatic, antenna Form horizontal narrow lobe, the pattern characteristics of vertical width lobe.

Antenna system is mainly made of a transmitting antenna, reception antenna and antenna installation frame etc., transmitting antenna installation In antenna pedestal upper end, antenna aperture 0.76m wide × 0.16m high, for emitting receiving and transmitting signal, reception antenna is mounted on antenna pedestal Lower end, antenna aperture 0.76m wide × 0.16m high, for receiving target echo signal and giving signal to receiver.

Antenna system uses planar waveguide array antenna, and each antenna is respectively by antenna house, radiating surface battle array, coupled waveguide, feedback The compositions such as electric network and antenna mounting frame.Radiating surface battle array is composed of several leaky waveguides, at the back side of radiating guide The coupled waveguide that also some square crossings are placed, and each coupled waveguide is presented by a H-T connector or feeding network Electricity.Energy in this way is coupled to by feeder equipment input coupling waveguide, then by coupling gap in radiating guide, finally by spoke Gap radiation is penetrated to go out.

Based on the demand to target acquisition, antenna system uses the continuous wave working system of bistatic.Because of aquatic plant Object is swum on river surface, with the flowing of flow, can continuously flow through institute observation area.It is accurate in order to ensure detection Property, radar need to continuously be observed target, so antenna is also necessary for continuous wave working system.Connect to meet The job requirement of continuous wave individually separates transmitting antenna and reception antenna, and a hair one is received, and is worked at the same time.

In order to enhance adaptability of the product to climatic environment, focuses on environmental protection design, include mainly：Rain-proof, it is moisture-proof, Mould proof, salt spray proof, anti-corrosion etc..Antenna system should have antenna house, and electrical property design and structure design are carried out to antenna house, It effectively prevent the water inlet of waveguide front or other sundries.In addition it is that rainwater is avoided directly or indirectly to be splashed to important set in design Standby outer surface, scientific design arrange cable louding, prevent rainwater para-electric cable from entering inside equipment；It is respectively exposed to room in design Outer electronic equipment fully considers that leakproofness designs, and prevents rainwater from entering the damage for causing electronic equipment.Antenna structure should be adopted With technologies such as Design of ventilation, the drying for ensureing antenna plane is flowed by air.Passive feeder plant connection should use sealing to set Meter ensures the barrier propterty of component to the full extent.Using the preferable metal material of corrosion resistance, the contact of material is avoided Corrosion.When not allowing the metal material of contact to be assembled together, corresponding measure is taken to carry out anti-corrosion processing；

Avoid ponding structure, the outer cover of equipment from making appropriate inclined design, be designed at plane switching it is smooth downwards, can At energy ponding and retention moisture, osculum and gas vent are opened up；Gap structure and bridging arrangement are avoided and eliminated in design, Place to that can form crevice corrosion is sealed, coating processing；The outer seamed edge of all metalworks all changes into fillet；With advantageous In the skin of paint or the coat of metal that obtain appropriate adhesion-tight；For the part that surface need to paint, selection and metalwork binding force The paint kind of site operation that strong and performance is stablized, as acroleic acid polyurethane paints；For the metalwork without paint, suitable plating is selected Technique or chemical method carry out anti-corrosion processing；Operating condition requires to carry out surface coating under structural member, and fastener is using weather-proof Steel material.Exposed structure part is avoided as far as possible with weldering, and weld seam ensures continuously, and steel construction piece must use the spray of whole heavy antisepsis Aluminium (zinc) processing.

Antenna system correlation computations

(1) gain is estimated

According to antenna gain calculation formula：

A_s- antenna effective area

λ-antenna operating wavelength

η_x,η_y- antenna weighting aperture efficiency

η-antenna efficiency

Known parameters are substituted into formula, it is 35dB that can calculate antenna 0.76m × 0.16m gains.

(2) antenna array unit number selects

The bore of dual-mode antenna is 0.76m wide × 0.16m high, and waveguide is broadside Longitudinal Slot Arrays antenna, and waveguide is selected nonstandard Quasi-Waveguide, size are 8.4mm × 4.2mm × 0.95mm.To meet the requirement of standing wave array antenna, the spacing of unit seam is wave The half of guide wavelength.That is 18.70mm.Line source direction column unit number M, which is calculated, is：

M=(L-0.5* λ_g)/(0.5*λ_g)=(760-9.35)/9.35=80.28

It is 80 to take unit number M according to calculating.

Because waveguide broadside size is 8.4mm, the public wall thickness of waveguide is 0.95mm when overall processing, so, pass through calculating It is 14 to obtain line source line number.I.e. entire front antenna element is 14 × 80.

(3) antenna theory patterns calculating

For the antenna side lobe level needed for obtaining, the amplitude of the exciting current of each antenna element is according to certain photograph in array Function (such as Chebyshev Chebyshevs distribution, Taylor's Taylor distribution, the distribution of Hamming Hammings) is penetrated to be weighted, this Kind method is known as amplitude weighting method.

The lobe of usual Chebyshev's distribution antenna battle array has equal secondary lobe, and this lobe is corresponding to obtain Aperture distribution In, larger electric current is often formed on the unit at both ends, in engineering practice, is not easily achieved.Taylor utilizes modification secondary lobe structure Method, improvement has been made to this.His method is, several secondary lobe shift positions being uniformly distributed in lobe close to main lobe, Make them that there is approximately equal level, and farther secondary lobe then allows them according to the change in shape of lobe when being uniformly distributed, this Sample can avoid forming larger electric current on the unit at both ends.Therefore, generally use Taylor is distributed in engineering design.

Dual-mode antenna bore：0.76m wide × 0.16m high, according to antenna theory, to realize horizontal low-sidelobe level, and day Line gain will not decline too much again, and horizontal amplitude distribution selects Taylor function distribution more suitable, according to antenna theory, for M × N same antenna units composition planar array antenna directional diagram be：

In formula：d_x- along x-axis radiating element spacing；

d_y- along y-axis radiating element spacing；

K—2π/λ；

M-radiating element numbers along the x-axis direction；

N-radiating element numbers along the y-axis direction；

- radiating element directional diagram；

- cell array antenna aperture amplitude distribution function；

- cell array antenna aperture phase distribution function.

WhenWhen, i.e. F (θ, 0), F (θ, 90) be respectively planar array antenna horizontal directivity pattern and Height pattern.

Antenna antenna -20dB minor levels to be realized need at least then according to experience in design according to -25dB secondary lobe electricity Flat Taylor is distributed to carry out Theoretical Design, and must be realized by way of the accurate amplitude of antenna and phase compensation.It will The parameters such as unit number, spacing bring in Matlab programs as shown in Figure 3 and Figure 4, the dual-mode antenna reason that obtains theoretical antenna radiation pattern into It is as shown in Figure 5 by the three-dimensional lobe pattern of meter.

Antenna design of Simulation

The planar waveguide array antenna that working frequency is 24GHz is selected by analysis.Wherein, waveguide dimensions be 8.4mm × 4.2mm ×0.95mm.Waveguide wavelength λ_gFor 18.70mm.

By theoretical analysis and calculation, whole simulation calculation is mainly carried out by business software CST.It include mainly radiating guide With coupled waveguide conductance parameter extraction, radiating surface battle array simulation calculation, coupled waveguide simulation calculation, feeding network simulation calculation with And integrative simulation calculates.

The offset of radiating slot and the inclination angle of coupling slot are obtained in conjunction with actual amplitude distribution by conductance parameter extraction, Establishing dual-mode antenna simulation model, the results are shown in Figure 7 as shown in fig. 6, calculating three-dimensional lobe pattern, and dual-mode antenna emulates horizontal plane Lobe pattern is as shown in figure 8, dual-mode antenna emulation vertical plane lobe pattern is as shown in Figure 9.

From simulation result it is found that each antenna system technical indicator all meets design requirement.

The antenna performance of broadband signal is analyzed

Radar is using the linear FM signal of 300MHz, and centre frequency f0 is 24GHz, and the signal is in Waveguide slot day There is transmission group delay in line.Therefore, the deviation of beam position, simulation calculation f0-150MHz, f0, f0+150MHz can be caused The beam position of three frequency points is as shown in Figure 10.

It, and can not be in time domain point when frequency domain detection since 300MHz bandwidth is that occur in a signal period and continuous It opens, therefore, the deviation of beam position leads to the spreading deformation of lobe.Finally, actual beam of the antenna system to 300MHz signals Shape is as shown in figure 11.The wave beam deviation can be reduced by the form of submatrix piecemeal.It is expected that final 0.4 ° of left side of beam-broadening It is right.

Radio frequency microwave system is by receiving front-end, data acquisition module (also referred to as A/D modules below), frequency synthesis component three It is grouped as, is concentrated use in the D.C. regulated power supply power supply of complete machine, reception system and the loading together of emission system are placed in antenna branch In arm, outdoor environment is worked in.

Frequency synthesis component provides the local oscillation signal needed for receiving front-end, the synchronizing clock signals needed for ADC module, and Chirped pumping signal.

Frequency synthesis component by clock reference circuit, Waveform generating circuit (below also referred to as frequency sweep local oscillator), transmission channel, connect The compositions such as mouth control circuit and power supply processing, internal circuit is mainly by the constant-temperature crystal oscillator of high stability low phase noise, pectination The compositions such as spectrum, Digital Microwave phaselocked loop, mixing and filtering amplification channel, digital control and power supply filter circuit of pressure-stabilizing.

Clock reference circuit is as shown in figure 12：

Clock reference circuit generates 100MHz signals by constant-temperature crystal oscillator, and 12G is given all the way through the output of two power splitters of ADP-2-1W Do comb spectrum driving source in source；All the way 3.5GHz, CRO phase locked sources are supplied respectively to through tetra- road power splitters of SCA-4-10；LTC6946-2 Output receives three local oscillation signal 820MHz；Transmitting pumping signal 750MHz is exported through LTC6946-1；13dBm is exported through amplifier Signal is for signal processor when acquisition clock；

Waveform generating circuit is as shown in figure 13：

One local oscillation signal generates the filtered, amplification with comb spectrum generation 12G signals of 3.5GHz signals by CRO phase-locked loop circuits For one local oscillator of transmission channel and receiving module after filtering, amplification, work(point after mixing generates afterwards.

Frequency sweep local oscillator divides two-way to do local oscillation signal through amplification, frequency multiplication, filtering generation 7GHz all the way by 3.5G；It gives all the way AD9914 makees clock, generates 600~900MHz signals, two kinds of signals are after the mixing of HMC558 frequency mixers through filtering, amplification, work( Divide and does two local oscillators to receiving module for transmission channel and output；

Transmission channel is as shown in figure 14：

Transmission channel generates 750MHz by frequency synthesizer and is mixed with frequency sweep local vibration source (7.6~7.9GHz), filtered to put It is mixed with a local oscillator (15.5GHz) after big, exports 23.85~24.15GHz signals, by filtering mixing, amplified through isolation Device exports.

Performance indicator is as follows：

1) it encourages：24GHz ± 50MHz (23.85~24.15GHz), power：1~1.3W, phase noise：L(1K)≤ - 103dBc/Hz, L (100K)≤- 113dBc/Hz；

2) local oscillator：15.5GHz, power：13dBm ± 1dBm, phase noise：L (1K)≤- 108dBc/Hz, L (100K) ≤-118dBc/Hz；

3) two local oscillator：7.75GHZ (7.6~7.9), power：10dBm±1dBm；Phase noise：Better than a local oscillator；

4) three local oscillator：820MHz, power：10dBm ± 1dBm, phase noise：Better than two local oscillators；

5) clock：100MHz, power：13 ± 0.5dBm, phase noise：L (1K)≤- 140dBc/Hz, L (100K)≤- 150dBc/Hz；

6) amplitude coincidence in swept-frequency signal frequency modulation band bandwidth：≤1dB；

7) clutter is exported：Excitation >=60dBc, one local oscillator >=70dBc, two local oscillators >=70dBc, three local oscillators >=70dBc, clock ≥70dBc；

8) harmonics restraint：Excitation >=55dBc, one local oscillator >=60dBc, two local oscillators >=60dBc, three local oscillators >=60dBc, clock ≥60dBc；

9) power fluctuation：≤0.5dB

10) power consumption：≤30W；

11) point frequency and linear modulation alternately export each 1s, linear frequency modulation time 1ms, modulating bandwidth 300MHz, FM linear Degree≤2/1000.

Performance Analysis calculates as follows：

(1) one local oscillator leading indicator is analyzed

The factor of influence phase noise specifications mainly has the phase of the phase noise and phase demodulation chip low noise and VCO of reference source Position noise.Phase noise within the 10KHz of final output signal depend primarily on reference source phase noise and with phase demodulation core Piece bottom is made an uproar, and the phase noise other than 100KHz depends primarily on the phase noise of VCO.

1) the Primary Component index of phase noise is influenced：

A. voltage controlled oscillator：≤-130dBc/Hz@100KHz

B. constant-temperature crystal oscillator：≤-155dBc/Hz@1KHz

C. phase discriminator：-153dBc/Hz@10kHz offset@100MHz

2) Analysis of Phase Noise of a local oscillator：

A. in loop bandwidth phase noise calculation formula：floor+20Log(f0/fpD)+10LogfpD

Wherein Lfloor is the normalization low noise of PLL chips, and f0/fpD is output frequency divided by phase demodulation frequency i.e. times frequency Number N, fpD is phase demodulation frequency.

Bringing above-mentioned parameter into formula can calculate：

Phase noise in loop band is -226+20Log (3500/100)+10Log (100 × 106) ≈ -125dBc/H.

In addition the deterioration of Practical Project and the deterioration 2dB of other parameters are added, can obtain the phase noise in loop band For -123dBc/Hz.

B. the deterioration of the phase noise of reference source calculates (3.5GHz)：20Log (f0/fpD)=20Log (3500/100)= 31dBc/Hz

By with reference to phase noise to be -155dBc/Hz@1KHz be to calculate the phase noise after deteriorating：

- 155+31=-124dBc/Hz@1KHz；

Since with reference to the phase noise after deterioration, higher than the phase noise in loop band, the phase noise of final output is still It is -123dBc/Hz@1KHz depending on the phase noise in loop band；Since the signal of 3.5GHz is also mixed with 12GHz signals, The phase noise of final output depends on a signal source of difference, and 12GHz signals are frequency multiplication form, in addition comb spectrum is deteriorated For：- 155+20Log (12000/100)+4=109dBc/Hz@1KHz, so the phase noise of one local oscillator of final output is： - 109dBc/Hz@1KHz。

C. the outer Analysis of Phase Noise of loop band

Phase noise outside loop bandwidth depends primarily on the phase noise of VCO itself, and specific index can be according to VCO skills The phase noises of 100KHz~1MHz phases is estimated in art index.Phase noise estimation outside the loop band of the local vibration source is such as Under： 130dBc/Hz@100KHz.

2) the noise restraint analysis of a local oscillator：

The spuious of one local oscillator mainly has phase demodulation spuious and is mixed spuious 2 kinds, since the phase demodulation frequency of 3.5GHz phaselocked loops is 100MHz can be respectively distributed to deviate at output frequency 100MHz so phase demodulation is spuious, and specific calculating is as follows：

For the phaselocked loop of charge-pump type, spuious phase demodulation includes mainly two various aspects, first, leakage is spuious, second is that pulse is miscellaneous It dissipates, spuious formula is as follows：

Spur=10log (10^{LeakageSpur/10}+10^PulseSpur/10)

If phase demodulation leakage current is 1nA, calculate it separately below two are spuious.

LeakageSpur=BaseLeakageSpur+20log (Leakage/K φ)+20logCL (s) |

=16.0+20log (1nA/5mA)+20log | CL (s) |

=-118+20log | CL (s) |

PulseSpur=BasePulseSpur+40log (Fspur/1Hz)+20logCL (s) |

=-306dBc+40log (Fcomp/1Hz)+20log | CL (s) |

=-10+20log | CL (s) |

Spur ≈ PulseSpur=-10+20log | CL (s) |

Phase demodulation leakage current is the 1nA, -306dBc that BasePulseSpur is not to determine, but is worth left and right herein.Due to Phase demodulation frequency is 100MHz, and frequency is higher, and phase demodulation is spuious mainly to be determined by pulse is spuious, and loop bandwidth generally takes and is less than 500kHz can be very good to inhibit this spuious in this way in the low-pass nature of loop filter.According to previous experiences, this programme choosing With the loop bandwidth of about 500kHz, spurious reduction can be accomplished -85dBc or less.The spuious of mixing generation is shown in that filter is miscellaneous It dissipates shown in distribution map, mixing and filtering output factors are more than 75dBc.

(2) remaining index analysis

Two local oscillators, three local oscillators, emit pumping signal spuious and phase noise specifications can be better than a local oscillator index, nothing Technical difficulty.The index obtained according to verification experimental verification situation is as follows：

750M phase noise specifications：

124dBc/Hz@1KHz,

122dBc/Hz@100KHz,

820M phase noise specifications：

123dBc/Hz@1KHz,

121dBc/Hz@100KHz,

7G phase noise specifications (3.5GHz frequencys multiplication)：

- 155+31=6=-116dBc/Hz@1KHz；

-120dBc/Hz@100KHz；

Spuious index：≥75dBc.

Output power is determined by the output amplifier of each local oscillator, can be seen that there are larger by the technical indicator of amplifier Surplus, so being not difficult to realize.

DDS noise objectives and spuious：

Noise objective:- 128dBc/Hz@1KHz,

-133dBc/Hz@100KHz。

DDS is spuious:Broadband is spuious to be：55dBc

It is 75dBc that 20KHz stepping data are surveyed in the narrowbands 500KHz.

The key technical indexes of above-mentioned 3500MHz CRO oscillators is as shown in figure 15.

Receiving channel circuit is as shown in figure 16：

Receiving channel signal inputs 23.85GHz~24.15GHz through limiter, low-noise amplifier, filter, a mixing Mono- intermediate frequencies of 7.75GHz bandwidth 300MHz are obtained, amplifies into second level frequency mixer after filtered device and obtains the second intermediate frequency 750MHz Enter third level frequency mixer after (signal bandwidth 500KHz), filtered amplification, numerical-control attenuator and exports the second intermediate frequency 70MHz, warp Filter and amplification, numerical-control attenuator amplification are exported in low-pass filter.

Its key technical indexes is：

(1) echo frequency：24GHz±150MHz；

(2) one local frequencies：15.5GHz；

(3) two local frequencies：(7.75MHz±150MHz)；

(4) three local frequencies：820MHz；

(5) noise coefficient：≤ 4.5dB (low, room temperature) ,≤5dB (room temperature)；

(6) 5 bit switch of cavity design, for adjusting receiving channel gain, stepping 1dB, decay cumulative errors≤1dB；

(7) channel gain：50 ± 1dB, when decaying to 0；

(8) Pin1dB >=-20dBm (when decaying to 20dB)；

(9) Pout1dB >=+10dBm (when decaying to 0dB)；

(10) radio-frequency filter bandwidth：BW-1dB >=300MHz (f0=24GHz)；

BW-3dB≤500MHz；

Out-of-band rejection：≥60dB(f0±2G)；

(11) echo channel image frequency degree of suppression：>=70dB (corresponding with the first intermediate frequency and local oscillator)；

(12) receiving channel is to frequency synthesis component isolation：≥80dB；

(13) IF frequency：70MHz；

(14) if bandpas filter bandwidth：BW-1dB≥5MHz；

BW-40dB≤40MHz；

(15) limiter maximum bears power (CW)：≥1.5W；

(16) echo input port standing-wave ratio：≤1.5；

(17) power consumption：≤10W.

Technical indicator analysis calculates

(1) receiver bandwidth calculates

According to linear FM radar principle, the frequency spectrum that intermediate frequency is deviateed by measurement obtains the distance of effect target, calculates public Formula is as follows：

F in formula_bDifference frequency of the position apart from intermediate-freuqncy signal；Δ f is linear frequency modulation bandwidth；R is target range；When Tm is modulation Between；C is the light velocity.

According to radar general requirement, linear frequency modulation bandwidth is 300MHz, and maximum target distance is 200m, and the modulation time is 1ms, it is 400kHz that can calculate maximum offset frequency fb.According to actual demand, enough bandwidth are reserved, receiver bandwidth is designed as 500kHz。

(2) noise coefficient, gain, output P-1dB power

NF=NF1+ ((NF2-1)/GP1)+((NF3-1)/(GP1*GP2))+((NF4-1)/(GP1*GP2*GP3)；

Receiving channel：The first order is waveguide transitions, Insertion Loss 0.4dB；The second level is limiter 0.75dB, the third level For low noise block amplifier be the 1.8dB fourth stages it is echo filter device insertion loss 1.5dB, rear class frequency mixer 8dB etc..

Noise coefficient, gain, output P-1dB power calculations

Noise coefficient：3.73dB；

Gain：51.3dB；

Export P-1dB compression points：+11.88dBm

(3) limiter

Low-noise amplifier maximal input 18dBm, limiter index parameter are as shown in table 3：

Table 3

(4) echo inputs standing wave

It receives input standing wave and determines that echo standing wave ＜ 1.5, curve is as shown in figure 17 by limiter, low-noise amplifier.

(5) image frequency degree of suppression, as shown in figure 18：

Receive image frequency degree of suppression：Down coversion is received, opposite clutter is easily processed, and filtering is added after low-noise amplifier Device filters out the signal except 23.85GHz~24.15GHz, high-pass and low-pass filter has been added in intermediate frequency, to local oscillator, radio frequency Signal is inhibited, and adds bandpass filter in two intermediate frequency local oscillators, and a local frequency is 15.5GHz, down coversion, therefore Image frequency frequency is 7.15GHz~7.45GHz, is inhibited from filter, inhibits to be more than 90dBc.

A/D modules

A/D modules, i.e. data acquisition module, it is main to realize intermediate-freuqncy signal digitlization, due to receiver output signal intermediate frequency For 70MHz, and actually useful bandwidth only has 500kHz, and in order to reduce the data volume of rear end output processing.Accordingly, it is considered to Using lack sampling, and the mode for being drawn into low data rate is realized.

As shown in figure 19, data acquisition module includes mainly anti-aliasing filter, ADC, FPGA and Ethernet transmission module Four parts.Interface have clock input XS1, intermediate frequency input XS2, power input interface XS3, communication interface XS4 with synchronize connect Mouth XS5.

It is 12.5 that ADC, which requires significance bit, selects the LTC2207 of Linear companies, its Specifeca tion speeification as follows：

(1) input voltage range (Vpp)：2.25V(11dBm)；

(2) maximum sample frequency：105MSPS；

(3) without pseudo- peak dynamic range (SFDR)：82dB；

(4) noise floor (Noise Floor)：77.3dBFS；

(5) significance bit：12.9.

Anti-confusion filtering designs

Anti-aliasing filter is mainly used for preventing noise aliasing when ADC bandpass samplings.Anti aliasing bandpass filter Parameter is as follows：Centre frequency F0=70MHz；BW-1dB=3~5MHz；BW-40dB<40MHz；BW-80dB<70MHz

The aliasing schematic diagram of out-of-band noise is as shown in figure 20, is aliased into in-band noise intensity and is less than -77dB, less than ADC's 12.5 significance bits.

FPGA is realized

FPGA uses the XC7K325T-1FFG900I of the K7 series of XILINX companies, signal processing flow as shown in figure 21.

ADC sampled datas enter decimation filter, shared three-level decimation filter (2 times of pumpings after Digital Down Convert Take, 5 times extract and 5 times extraction), be equivalent to the sample rate of 2MHz, then packed the data to after a high-pass filter Set form is sent to transmission module.

Data are transmitted to computer by Ethernet transmission module by network interface.Computer is by unpacking software, by data solution It calculates, hard disk, and label time and signal format information is written according to the data length of 1s.Meanwhile the data can be also put into Specified memory is used for Back end data processing.

Data processing and terminal display system

Data processing and terminal display system show software sharing by data processing software and terminal.It is each to complete the floating plant of water The online real-time measuring and calculating and display of information.The data that terminal system arrives radar detection by processing, transformation, calculate, Required data and graphic product are produced, the hardware selection of system mainly considers the versatility and reliability of hardware platform, Use PC machines.The data of radar return are transmitted to PC machine by Ethernet.

The selection of software work platform should be taken into account versatility, compatibility and maintainability.It includes the operation of computer Two broad aspect of programming language of system and application program.The quality of software work platform selecting, directly affects software development The good operation of efficiency, portability and whole system.It is based on this consideration, we select Windows as operation System, Visual C++ are programming language.

The overall structure of data processing software system

All software of this system is built upon under WindowsXP/7, is developed using Visual C++, has unified behaviour Make interface.All settings are designed with menu driven fashion, are completed by system setting program, it can be supplied to user Interactive selection or input parameter, while also allowing user that result is saved on disk so that the various radars of setting are joined Number can be re-called and changed by system.

Real-time parameter is arranged and timing parameters setting generates real-time parameter table and timing parameters table, the two tables are by radar reality When processing routine call.Radar handles control radar working condition, data acquisition and display water plant distribution fact in real time, It includes foreground real-time processing software and backstage real-time processing software.Radar real-time handler sits collected origin pole Mark radar data is saved on disk.

Product parameters table is arranged by product parameters setting program to be generated.

Product generates table and generates setting program setting generation by product.

Initial data is the starting point that radar output products generate processing.All radar output products are all by producing accordingly Product generate processing routine, call this initial data, are generated under product parameters table and product generation table collective effect.

Under Full automatic product generating mode, required product list is arranged when system makees product treatment every time in user, System calls this table by the processing mode of batch job, generates corresponding graphic product file and data product documentation and achieves, It is distributed to corresponding user under the control of product distributing list so as to system or is set by network or other communications by other users It is standby to call.

Using unified user interface.Basic picture size is 640X480 (unit is picture element), if picture size changes Become, length and width will adjust at equal pace.Using 16 kinds of colours as the layering of product, provided for radar mosaic and radar network composite It is convenient.Tu Zhong product informations area includes：Color look-up table, time, date, display distance, antenna bearingt, antenna elevation angle, display Highly, repetition rate, radar station name etc..Additional information viewing area is mainly the information for showing some user's particular/special requirements, such as strong The intensity and location information of echo, afterproduct show file used, can also show figure, can when such as real-time strength observations The speed echo observed in real time with simultaneous display.

Graphical display workspace is display radar real time scan reflectogram and afterproduct figure.Basic size is 480X480 Pixel.Abscissa shows time shaft, and unit is the second.Ordinate shows that river surface width, resolution ratio are 1 meter.Draw every 1 second number According to, show real-time river surface radar return distribution situation and intensity, over time, figure carries out rolling update, display The radar return of a period of time is distributed and situation.Later stage establishes the correspondence of radar data and water plant distributions, that is, demonstrates water Plant distributions and strength conditions.

System setting includes real-time parameter setting, timing parameters setting, product parameters setting, product generation setting, product Distributing list setting etc..All these functions are all completed by system setting program.This program makes full use of the boundary of WindowsXP/7 Face function is supplied to user to select, changes, checks various radar parameters using drop-down menu type of drive.The ginseng of user setting Number correspondingly generates real-time parameter table, timing parameters table, product parameters table, product generation table, product point by system setting program It delivers.These parameter lists are called by different application programs, and control system completes different functions or generates different thunder Up to output products.User is not only greatly facilitated in this way and increases different functions, while also obtains the scalability of system It is perfect.File management is all data informations and product information caused by management this system, including automatic and man-machine Interaction two ways.

Original document is the data that radar real-time handler acquires during each run from signal processing, it is different In radar output products file, and different working methods is formed by original document and is different.File management is exactly to carry The program of file is formed by for managing a variety of different Radar Products on disk.

In order to improve the transmission speed of output products, system also provides the compression of processing file and restores function.Work as user When setting transmission mode as compress mode, automatically by compressing file before product transmission, then transmit again.Simultaneously when reception To file be compressed file when, restore it into unprocessed form automatically.

System uses a house dog software, and by the parameter setting of user, house dog software is using automatic or man-machine friendship Mutual mode is run.When automated manner is run, it is automatically deleted data and image file that user is set as out-of-date.Human-computer interaction side When formula is run, house dog software is not automatically deleted outdated file, but when disk space is less than user's setting value, it provides Alarm deletes unnecessary file so that user goes save file using file management.Documentor offer pair The setting of house dog software and data compression, be specifically provided with, the time of retention data, compression, remaining space size, retain House dog is told in the setting of the time of data, and in automated manner, the pervious file of this time can be deleted.Compression setting can Choosing is compressed and does not compress two ways in man-machine interaction mode, if remaining disk space is less than remaining space setting value, sees Door dog just provides warning message.The working method of house dog is set as automated manner and man-machine interaction mode.

Data processing module

Using the difference in river and water plant albedo, the water plant of floating on water is detected.It is flowed through by measuring The water plant distribution situation of Measure section, and movement speed under the section carry out the area of COMPREHENSIVE CALCULATING water plant.

(2) the linear frequency modulation continuous wave signal processing method of 1s

Linear frequency modulation continuous wave signal realizes the area measurement of floater.It is each that section dimension is measured by broadband signal The echo strength of range points is detected in frequency domain, and water plant is determined by the way that whether there is or not the variations of the echo strength of water plant Area.

The continuously linear frequency modulation continuous wave signal of 1000 1ms of hair, handles the data of the data and 1000ms of 1ms.

1. under normal operation, looking for one piece of water surface for floating plant without water, measures and each differentiate list in azimuth beamwidth The reflected intensity of first water, as detection benchmark threshold value.

2. the echo-signal to 1ms is detected, using the value that is obtained in 1. as benchmark thresholding, according to actual conditions into Row adjustment, judges that each resolution cell has anhydrous floating plant.

3. preserving the intensity value of each range points, label is made to the range points for having water to float plant.

(3) the point frequency continuous wave signal processing method of 1s

Point-frequency signal is only used for the tachometric survey of floater.

1) power spectral density is asked to gathered data；

2) it respectively takes the data of 1kHz to carry out Threshold detection in intermediate frequency 500KHz or so, is thinking to have target (just more than thresholding In the case of often, general water speed is less than 0.1m/s, f_d=2v/ λ, therefore maximum doppler frequency is about 16Hz, consideration has wind etc. different There are surplus both sides respectively to take 1KHz in the case of often).1. threshold value is finely adjusted using in 1.2 as benchmark.

3) target velocity is found out according to detection frequency.

(4) target area is sought

River width divides for 0.6 meter by 50 meters of calculating, by Range resolution unit, 1 ° of orientation velocity of wave width, then in azimuth beam most About 0.8 meter of distance at a distance.

1) target area is smaller

When target area be less than or equal to a Range resolution unit area (<=0.6*0.6) when, such as the mesh in Figure 22 Mark 1, the echo strength measured at this time is to change steeper bell-shaped curve, and the flow measured at this time time dimension target in the same direction is long Spend L₂For：

Wherein：2 represent time of measuring interval 2 seconds, v_iRepresenting the water velocity that each time of measuring interval is found out, (=water is floating Plant measurement speed/sin θ), continuously there is the time interval number of target in n representatives, and d is a fixed value, refer to section dimension not The lateral distance in azimuth beamwidth corresponding to same distance unit spot, as shown in figure 22.

The range cell occurred according to target, you can find out the length L of object section dimension₁=measure section dimension length * cos θ。

Then area：S=L₁×L₂

2) target area is larger

The target that time and range cell are all continuously occurred is as a big target, target 2 as shown in figure 22, target 3 and target 4.The similar bandpass filter of echo strength variation measured at this time, both sides variation is steeper, centre be it is shallower, then The time dimension target length L in the same direction with flow₂For：

L₂=2 × v_i

Wherein：2 represent time of measuring interval 2 seconds, v_iRepresent the water velocity that each time of measuring interval is found out.

The range cell occurred according to target, you can find out the length L of target range dimension₁(=measure section dimension length * Cos θ), if the object section dimension range cell surveyed is discontinuous,N, which refers to measure section and tie up, has water to float plant Range cell number.

The water that then each time interval is measured floats plant area：S_i=L₁×L₂

Then target area is：

N, which is represented, continuously there is the time interval number of target, and d' refers to corresponding to object section dimension different distance unit spot The maximum value of lateral distance in azimuth beamwidth, v ' refer to current goal last time detection speed, and m refers to area and repeats to count The time interval number of calculation, S' refers to computes repeatedly area by the floating plant of water in beam angle.

It is provided per half an hour and flows through a gross area for measuring section and preserve result.

(5) data store

1) initial data stores

Storage data are 16bit floating numbers, the data transfer rate of 2M per second, then 1 second 4MB, 1 hour 14GB, 24 hours one day Uninterrupted storage needs the memory space of about 340GB.The continuous data deposited three days then need 1020GB.Prototype test computer Hard disk 1.2T, therefore nearest three days data can only be stored in.After subsequently upper hardware, if it is desired to store more data, can examine Consider wireless data transmission, data are passed into data center and are stored, specific implementation method waits for further considering.

2) testing result stores

Including detection time (date Hour Minute Second), distance, strength information, testing result per second all stores, half small When for time interval (tentative, be specifically subject to follow-up test result), stored per half an hour into a file, it is every half small When provide flow through measure section water float plant area value.

(6) data transmission, processing, storage and display time calculate

In order to ensure the real-time of data processing, it is desirable that data transmission and processing shows that storage time can adapt to data acquisition Time.Entire data transmission flow is as shown in figure 21.The computer performance of principle prototype data processing is fixed tentatively in signal processing part Existing server equal performance, processor are Intel's E5,2.4G, 8 core, memory 64G.

The time that data pass through cable incoming data buffer area after A/D.Input signal is 16bit floating numbers, 1S total 2M Sampled point, therefore the data volume of required transmission is 32Mbi.

Data transmission is quasi- to use 10,000,000,000 nets, and the transmission rate of 10,000,000,000 nets is 10000Mb/s, if network transmission efficiency is 50% (each layer network protocol analysis occupied bandwidth), 6.4ms need to be taken by transmitting the data of 32Mb, write data into hard disk, computer hard disc Memory rate 20MB/s deposits 2M point 16bit data and needs 200ms.Data are read to memory from hard disk, and computer hard disc reads speed Rate 30MB/s reads 2M point 16bit data and needs 140ms.It is stored to CPU from interior, the transmission rate of PCI-E buses is 8Gb/s, The data of 32Mb are 4ms from the interior time for being stored to CPU, and CPU carries out FFT processing to data and Threshold detection needs 600ms.It is aobvious Show using 1s data while showing, required time is about 50ms.Therefore the linear FM signal processing time of 1s is about 1 second.

Followed by the point-frequency signal of 1s, we only take wherein a bit of data processing, and it is about 200ms to ask speed, time.

Therefore the point frequency continuous wave processing time of the linear FM signal+1s of 1s is about 1200ms, so when the repetition of 2s Between interval can complete to handle, data will not be lost.

The above is only a preferred embodiment of the present invention, it should be understood that the present invention is not limited to described herein Form is not to be taken as excluding other embodiments, and can be used for other combinations, modifications, and environments, and can be at this In the text contemplated scope, modifications can be made through the above teachings or related fields of technology or knowledge.And those skilled in the art institute into Capable modifications and changes do not depart from the spirit and scope of the present invention, then all should be in the protection domain of appended claims of the present invention It is interior.

Claims (16)

1. water floats plant radar sensing system, the radar sensing system is by antenna system, radio frequency microwave system, data processing and end Hold display system composition, it is characterised in that：

The antenna system is made of transmitting antenna and reception antenna, and radar generates point frequency continuous wave and linear frequency modulation continuous wave letter Number, wherein point-frequency signal is only used for the tachometric survey of floater, and linear frequency modulation continuous wave signal realizes floater Area measurement, the signal are radiate via transmitting antenna, and signal enters reception antenna after water plant is reflected；

The radio frequency microwave system is made of receiving front-end, data acquisition module, frequency synthesis component three parts, through water plant Signal after reflection accesses receiving front-end, through filter amplifier, numerical-control attenuator, low-pass filter after the processing of three-level frequency mixer Output；Data acquisition module is made of anti-aliasing filter, ADC, FPGA and Ethernet transmission module, for realizing intermediate-freuqncy signal Digitlization, frequency synthesis component are made of clock reference circuit, Waveform generating circuit, transmission channel, interface control circuit, are used for Improve the local oscillation signal needed for receiving front-end, the synchronizing clock signals needed for data acquisition module and chirped excitation letter Number；

Data processing and terminal display system are made of data processing module and terminal display module, are completed water and are floated each information of plant Online real-time measuring and calculating and display.

2. water according to claim 1 floats plant radar sensing system, which is characterized in that the antenna system is using transmitting-receiving The planar array antenna system split, antenna form horizontal narrow lobe, the pattern characteristics of vertical width lobe.

3. water according to claim 2 floats plant radar sensing system, which is characterized in that the planar array antenna system It is planar waveguide array antenna, using the structure of submatrix block design, working frequency is K-band, and f0 ± 150MHz, f0 take 24GHz。

4. water according to claim 3 floats plant radar sensing system, which is characterized in that the antenna gain >=30dB, Lobe width level≤1 °, vertical≤5 °, horizontal, vertical minor level≤- 20dB；Standing wave requires VSWR≤1.6, polarization mode For vertical polarization, isolation between transmitting and receiving antenna >=80dB；Beam position deviation electric axis in frequency band is directed toward deviation and meets≤0.2 °.

5. water according to claim 1 floats plant radar sensing system, which is characterized in that the three-level frequency mixer includes the Level-one frequency mixer, second level frequency mixer, third level frequency mixer；

The rf excitation signal enters first order frequency mixer through limiter, low-noise amplifier, filter and is mixed to obtain The first intermediate-freuqncy signal of 7.75GHz bandwidth 300MHz；

The filtered device of first intermediate-freuqncy signal, amplifier enter second level frequency mixer and obtain the second intermediate frequency of 750MHz bandwidth 500KHz Signal；

Second intermediate-freuqncy signal obtains 70MHz bandwidth after filtered device, amplifier, numerical-control attenuator into third level frequency mixer The third intermediate-freuqncy signal of 5MHz；

The filtered amplifier of third intermediate-freuqncy signal, numerical-control attenuator, low-pass filter output.

6. water according to claim 5 floats plant radar sensing system, which is characterized in that the anti-aliasing filter is main For preventing noise aliasing when ADC bandpass samplings, parameter from being：Centre frequency F0=70MHz；BW-1dB=3~ 5MHz；BW-40dB<40MHz；BW-80dB<70MHz.

7. water according to claim 6 floats plant radar sensing system, which is characterized in that the FPGA is by ADC hits According to three-level decimation filter is entered after Digital Down Convert, 2 times of extractions, 5 times of extractions, 5 times of extractions are followed successively by, 2MHz is equivalent to Sample rate, set form is then packed the data to after a high-pass filter and is sent to Ethernet transmission module.

8. water according to claim 7 floats plant radar sensing system, which is characterized in that the clock reference circuit is by perseverance Warm crystal oscillator generates 100MHz signals, does comb spectrum driving source to the sources 12G all the way through the output of two power splitters of ADP-2-1W, passes through all the way Tetra- road power splitters of SCA-4-10 are supplied respectively to 3.5GHz, CRO phase locked sources；LTC6946-2 outputs receive three local oscillation signal 820MHz； Transmitting pumping signal 750MHz is exported through LTC6946-1；Through amplifier export 13dBm signals for signal processor when acquisition when Clock.

9. water according to claim 8 floats plant radar sensing system, which is characterized in that the Waveform generating circuit work It is as follows：

Generation to be mixed after, amplification filtered with comb spectrum generation 12G signals latter by CRO phase-locked loop circuits generation 3.5GHz signals Local oscillation signal, a local oscillation signal is filtered, amplification, for transmission channel and receiving module does a local oscillator after work(point；

Frequency sweep local oscillator divides two-way to do local oscillation signal through amplification, frequency multiplication, filtering generation 7GHz all the way by 3.5G；It is done all the way to AD9914 Clock, generates 600~900MHz signals, and two kinds of signals are logical for emitting through filtering, amplification, work(point after the mixing of HMC558 frequency mixers Road and output do two local oscillators to receiving module.

10. water according to claim 9 floats plant radar sensing system, which is characterized in that the transmission channel is by frequency Synthesizer generates 750MHz and is mixed with 7.6~7.9GHz of frequency sweep local vibration source, mixed with a local oscillator 15.5GHz after filtered amplification Frequently, 23.85~24.15GHz signals are exported, are exported through isolator by filtering mixing, amplification.

11. floating plant radar sensing system according to claim 1-10 any one of them water, which is characterized in that the items of system Performance indicator is as follows：

1) it encourages：24GHz ± 50MHz, power：1~1.3W, phase noise：L (1K)≤- 103dBc/Hz, L (100K)≤- 113dBc/Hz；

2) local oscillator：15.5GHz, power：13dBm ± 1dBm, phase noise：L (1K)≤- 108dBc/Hz, L (100K)≤- 118dBc/Hz；

3) two local oscillator：7.75GHZ, power：10dBm±1dBm；Phase noise：Better than a local oscillator；

4) three local oscillator：820MHz, power：10dBm ± 1dBm, phase noise：Better than two local oscillators；

5) clock：100MHz, power：13 ± 0.5dBm,

Phase noise：L (1K)≤- 140dBc/Hz, L (100K)≤- 150dBc/Hz；Wherein 1K indicates offset signal 1KHz, i.e., Measured signal 100MHz deviates the intensity of phase noise at frequency point 1kHz, and 100K indicates the meaning, and principle is identical therewith；

6) amplitude coincidence in swept-frequency signal frequency modulation band bandwidth：≤1dB；

7) clutter is exported：Excitation >=60dBc, one local oscillator >=70dBc, two local oscillators >=70dBc, three local oscillators >=70dBc, clock >= 70dBc

8) harmonics restraint：Excitation >=55dBc, one local oscillator >=60dBc, two local oscillators >=60dBc, three local oscillators >=60dBc, clock >= 60dBc

9) power fluctuation：≤0.5dB

10) power consumption：≤30W；

11) it puts and alternately exports each 1s, linear frequency modulation time 1ms, modulating bandwidth 300MHz with linear modulation frequently, fm linearity≤ 2/1000。

12. water according to claim 11 floats plant radar sensing system, which is characterized in that the data processing module profit With the difference in river and water plant albedo, the water plant of floating on water is detected.Measure section is flowed through by measuring Water plant distribution situation, and movement speed under the section carry out the area of COMPREHENSIVE CALCULATING water plant.

13. water according to claim 12 floats plant radar sensing system, which is characterized in that the data processing module pair The linear frequency modulation continuous wave signal processing method of 1S is as follows：

Linear frequency modulation continuous wave signal realizes the area measurement of floater, and measuring section by broadband signal ties up each distance The echo strength of point, is detected in frequency domain, and the face of water plant is determined by the way that whether there is or not the variations of the echo strength of water plant Product；

The continuously linear frequency modulation continuous wave signal of 1000 1ms of hair, handles the data of the data and 1000ms of 1ms；

S01：Under normal operation, one piece of water surface for floating plant without water is looked for, each resolution cell in azimuth beamwidth is measured The reflected intensity of water, as detection benchmark threshold value；

S02：The echo-signal of 1ms is detected, the value obtained using in S01 as benchmark thresholding, according to actual conditions into Row adjustment, judges that each resolution cell has anhydrous floating plant；

S03：The intensity value for preserving each range points makes label to the range points for having water to float plant.

14. water according to claim 13 floats plant radar sensing system, which is characterized in that the data processing module pair The point frequency continuous wave signal processing method of 1s is as follows：

S11：Power spectral density is asked to gathered data；

S12：It respectively takes the data of 1kHz to carry out Threshold detection in intermediate frequency 500KHz or so, thinks there is target more than thresholding, normally In the case of, general water speed is less than 0.1m/s, f_d=2v/ λ, therefore maximum doppler frequency is about 16Hz, consideration has wind etc. abnormal In the case of there are surplus both sides, and 1KHz, the detection benchmark threshold value that threshold value is obtained using in S01 respectively to be taken to be finely adjusted as benchmark.

S13：Target velocity is found out according to detection frequency.

15. water according to claim 14 floats plant radar sensing system, which is characterized in that the data processing module pair Target area calculates as follows：River width divides for 0.6 meter by 50 meters of calculating, by Range resolution unit, 1 ° of orientation velocity of wave width, then orientation About 0.8 meter of farthest distance in wave beam；Its calculation formula is as follows

R=river width；

θ=azimuth beamwidth；

Then at different distance, orientation width=2Rtan (θ/2) of azimuth beam covering；

S21：Target area is smaller

When the area of target is less than or equal to the area of a Range resolution unit, the echo strength measured at this time is to change relatively suddenly Bell-shaped curve, the flow measured at this time time dimension target length L in the same direction₂For：

Wherein：2 represent time of measuring interval 2 seconds, v_iIt represents water velocity=water that each time of measuring interval is found out and floats plant survey Speed/sin θ is measured, n representatives continuously the time interval number of target occur, and d is a fixed value, refer to section dimension different distance list Lateral distance in the corresponding azimuth beamwidth of member point；

The range cell occurred according to target, you can find out the length L of object section dimension₁=measure section dimension length * cos θ；

Then area：S=L₁×L₂

S22：Target area is larger

For the target that time and range cell are all continuously occurred as a big target, the echo strength variation measured at this time is similar Bandpass filter, both sides variation is steeper, and centre is shallower, the then time dimension target length L in the same direction with flow₂For：

L₂=2 × v_i

Wherein：2 represent time of measuring interval 2 seconds, v_iRepresent the water velocity that each time of measuring interval is found out.

The range cell occurred according to target, you can find out the length L of target range dimension₁=section dimension length * cos θ are measured, such as The object section dimension range cell that fruit is surveyed is discontinuous, thenN, which refers to, measures the range cell that section dimension has water to float plant Number；

The water that then each time interval is measured floats plant area：S_i=L₁×L₂

Then target area is：

N, which is represented, continuously there is the time interval number of target, and d' refers to the orientation corresponding to object section dimension different distance unit spot The maximum value of lateral distance in beam angle, v' refer to current goal last time detection speed, m refer to that area computes repeatedly when Between be spaced number, S' refers to computes repeatedly area by what the water in beam angle floated plant, is provided per half an hour and flows through measurement One gross area in section simultaneously preserves result.

16. water according to claim 15 floats plant radar sensing system, which is characterized in that the data processing module is also It is specific as follows including calculating data transmission, processing, storage and display time：

For data by the time of cable incoming data buffer area, input signal is 16bit floating numbers, the total 2M sampling of 1S after A/D Point, therefore the data volume of required transmission is 32Mbit；

Data transmission is quasi- to use 10,000,000,000 nets, and the transmission rate of 10,000,000,000 nets is 10000Mb/s, if network transmission efficiency is 50%, is passed The data of defeated 32Mb need to take 6.4ms；

Hard disk is write data into, computer hard disc memory rate 20MB/s deposits 2M point 16bit data and needs 200ms, is read from hard disk Data are to memory, computer hard disc reading rate 30MB/s, read 2M point 16bit data and need 140ms, CPU, PCI-E are stored to from interior The transmission rate of bus is 8Gb/s, and the data of 32Mb are 4ms from the interior time for being stored to CPU；

CPU carries out FFT processing to data and Threshold detection needs 600ms, display to be shown simultaneously using 1s data, and required time is 50ms, therefore the linear FM signal processing time of 1s is about 1 second.

Followed by the point-frequency signal of 1s, we only take wherein a bit of data processing, and it is about 200ms to ask speed, time；

Therefore the point frequency continuous wave processing time of the linear FM signal+1s of 1s is about 1200ms, so between the repetition time of 2s Every that can complete to handle, data will not be lost.