A kind of Planar integration type micro-wave height finding radar applied to unmanned plane
Technical field
The utility model relates to the range radar technical fields in microwave frequency band radar system, especially a kind of to be applied to nothing
Man-machine Planar integration type micro-wave height finding radar.
Background technique
Unmanned plane needs to follow the height of earth's surface to rise and fall and dynamically adjusts flying height in low-latitude flying operation process, with
Guarantee the safety of flight, this needs to ensure by the height measuring device of UAV flight by continuous elevation carrection.
Mainly there are several types of methods for existing drone height measurement:
1, it is surveyed by laser radar high
2, it is measured by air pressure high
3, pass through ultrasound height
4, it is surveyed by microwave radar high
For the 1st kind of method, high, such as " air force engineering college journal (natural science edition) " 2010 is surveyed by laser radar
Described in " the pulse laser height-finding system suitable for the unmanned plane hedgehopping " text delivered October, by continuous wave laser
Source carries out impulse modulation, emits laser pulse, and receive echo impulse, by comparing the time delay between transmitting-receiving pulse, pushes away
Calculate depth displacement.Unmanned plane is carried out by this method and surveys height, is exactly unable to whole day in the used time maximum limiting factor that actually begins
When all weather operations.It is well known that laser radar is typically all to work under conditions of illumination is weaker or night, if daytime is too
When sunlight shines strong, the solar irradiation of earth surface reflection may be also stronger, can generate biggish ambient noise to laser beam
Interference, influences measurement accuracy.In addition, laser is worn under the more meteorological condition of the airblrne particulates such as mist, heavily contaminated
Saturating power will be greatly reduced, and can not begin to use.Therefore, survey using laser radar that high there are certain deficiencies.
For the 2nd kind of method, high, such as " automation and instrument " periodical 2012 south China science and engineerings delivered are measured using air pressure
Described in " design and realization of unmanned helicopter elevation carrection " text that university's Li Hong brightness et al. is write, become using air pressure with height
The basic principle of change realizes elevation carrection in conjunction with high-order Kalman filtering using BMP085 barometer chip.This method exists
Main problem be: under different weather conditions, the relationship of air pressure and altitude shows variability, cause measurement error compared with
Greatly.
For the 3rd kind of method, ultrasound height, such as " aerospace measurement technology " periodical 2010 Inner Mongol works delivered are used
Sparetime university is learned described in " the ultrasonic wave low latitude height-finding system experimental study for small drone " text that Liu Bo et al. writes, and is based on
The aerial propagation reflections principle of ultrasonic wave combines carry out elevation carrection using ultrasonic wave module and microprocessor.The party
Method is similar with ultrasonic car-backing alarming device against colliding used on current most of automobiles, and structure is simple, low in cost.It is main
The disadvantage is that detection range is closer, practical maximum detectable range generally only has 10 meters or so, is poorly suitable for flying in complicated landform
Unmanned plane.
For the 4th kind of method, height is surveyed using microwave radar, as BJ University of Aeronautics & Astronautics Zhang Feng et al. 2015 deliver
" the single antenna LFMCW radar altimeter applied to unmanned plane is studied " described in a text, the system principle diagram given by this article
It is found that it uses the system schema of single antenna FM-CW laser ranging, in order to eliminate the leakage of transmission power brought by single antenna
The problem of barrage reception channel, introduces the circuit of vector cancellation.This method is the classics side of frequency modulated continuous wave radar ranging
One of method, its advantage is that the cost that can be reduced volume, but pay is needed using complicated vector cancellation electricity using single antenna
Road, and need objectively to increase cost using discrete circuits such as circulator, coupler, vector modulators, also exist in circuit
The advantage using single antenna bring reduction in bulk is counteracted to a certain extent.For small drone height finding radar, because
Closer for detection range, actually required antenna aperture can't be very big, so using single antenna and for using double antenna,
Bring comprehensive advantage is not obvious, instead because the introducing of vector cancellation circuit causes the increase of complexity and cost, this
It is unfavorable for the popularization and application of the product for civilian use.
The utility model patent of big et al. the application of Shanghai Radio Apparatus Inst. Wei Wei in 2014 is " a kind of for another example
The small-sized measuring height and distance device of 24GHz ", it also belongs to and carries out surveying height using microwave radar.From the description of claims as it can be seen that its
The thinking split using radio-frequency front-end and baseband processing circuitry, such as " microwave in this example described in its claims
Detect front-end module 10 and form a standalone module, signal processing composite module forms another standalone module ", after integrating,
Thickness reaches 20mm, and weight reaches 140g.Why this structure is used, is because the applicants have used Innosent
A kind of commercial radio frequency front-end module, causes integrated level lower.The structure type integrated using this three-dimensional encapsulation, for current
It is all unsuitable no matter on volume weight in the market for " big boundary " this kind of consumer level unmanned planes.
Existing UAV system height measuring device exist cannot round-the-clock round-the-clock work, be not easy to integrate, detection range
The deficiencies of limited.
Summary of the invention
Technical problem to be solved in the utility model is overcome the deficiencies in the prior art and provides and a kind of be applied to nobody
The Planar integration type micro-wave height finding radar of machine, the utility model proposes it is a kind of work in microwave frequency band, can be with round-the-clock whole day
The radar sensor of Shi Jinhang precise and stable elevation carrection, for the tracking of consumer level unmanned plane landform or avoidance.
The utility model uses following technical scheme to solve above-mentioned technical problem:
According to the utility model proposes a kind of Planar integration type micro-wave height finding radar applied to unmanned plane, including microwave
Substrate, the first substrate and the second substrate, the microwave substrate, the first substrate, the second substrate sequentially stack from top to bottom, microwave-based
The upper surface of piece is equipped with radio frequency receiving and transmitting front end, transmitting antenna, receiving antenna, first filter, second filter and mixing ring, the
The bottom of two substrates is equipped with frequency synthesizer, power management module, communication interface module and control processing circuit, wherein
Transmitting antenna, first filter, mixing ring, radio frequency receiving and transmitting front end are successively linked in sequence, receiving antenna, the second filtering
Device, radio frequency receiving and transmitting front end are successively linked in sequence, and control processing circuit, frequency synthesizer are connect with radio frequency receiving and transmitting front end respectively, electricity
Source control module is separately connected with communication interface module, control processing circuit, frequency synthesizer, radio frequency receiving and transmitting front end, at control
Reason circuit is separately connected with frequency synthesizer, communication interface module;
Frequency synthesizer for generating fast chirp swept-frequency signal, and be supplied to radio frequency receiving and transmitting front end for generate emit
Signal and the local oscillation signal for receiving down coversion;Radio frequency receiving and transmitting front end includes transmitting and reception both links, wherein transmitting link will
The fast chirp swept-frequency signal that frequency synthesizer provides amplifies the two paths of signals of output constant amplitude reverse phase after conditioning, two-way letter
Using filtering number after mixing ring carries out power combing, last emitted antenna output;Receiving antenna received signal
The receives link of input radio frequency receiving and transmitting front end after filtering, after low noise amplification and filtering, output to control processor into
Row processing;Power management module is used to supply for communication interface module, control processing circuit, frequency synthesizer, radio frequency receiving and transmitting front end
Electricity.
It is further excellent as a kind of Planar integration type micro-wave height finding radar applied to unmanned plane described in the utility model
Change scheme, radio frequency receiving and transmitting front end include voltage controlled oscillator, amplifier, coupler, low-noise amplifier and frequency mixer, voltage controlled oscillation
The input terminal of device and the output end of frequency synthesizer connect, and the output end of voltage controlled oscillator and the input terminal of amplifier connect, and put
The output end of big device and the input terminal of coupler connect, and the first output end of coupler is connect with mixing ring, and the second of coupler
The input terminal of the connection of the input terminal of output end and frequency mixer, second filter and low-noise amplifier connects, low-noise amplifier
Output end and the input terminal of frequency mixer connect, the output end of frequency mixer is connect with the input terminal for controlling processing circuit.
It is further excellent as a kind of Planar integration type micro-wave height finding radar applied to unmanned plane described in the utility model
Change scheme between microwave substrate and the first substrate equipped with microwave radio is equipped with power supply, number between the first substrate and the second substrate
Word and baseband analog.
It is further excellent as a kind of Planar integration type micro-wave height finding radar applied to unmanned plane described in the utility model
Change scheme, there are two differential transmission ports for radio frequency receiving and transmitting front end, by mixing ring for two differential transmissions of radio frequency receiving and transmitting front end
Port is converted into single port, and an extra receiving port is vacant.
It is further excellent as a kind of Planar integration type micro-wave height finding radar applied to unmanned plane described in the utility model
Change scheme, transmitting antenna is identical with receiving antenna, is all made of two-dimentional traveling-wave array antenna structure.
It is further excellent as a kind of Planar integration type micro-wave height finding radar applied to unmanned plane described in the utility model
Change scheme further includes host computer, and communication interface modules is connect by configuring interface with host computer, and host computer passes through the configuration interface
Carry out the running parameter configuration of radar.
It is further excellent as a kind of Planar integration type micro-wave height finding radar applied to unmanned plane described in the utility model
Change scheme, configuration interface are micro-USB.
It is further excellent as a kind of Planar integration type micro-wave height finding radar applied to unmanned plane described in the utility model
Change scheme, the interface transmitted using the micro- rectangle joint of 16 needles as external power supply, detection data.
It is further excellent as a kind of Planar integration type micro-wave height finding radar applied to unmanned plane described in the utility model
Change scheme, the first substrate and the second substrate are FR4 substrate.
The utility model compared with the prior art by using the above technical solution, has following technical effect that
(1) the utility model proposes a kind of elevation carrection radar sensor suitable for UAV flight, and based on swashing
The height measuring devices such as light, ultrasonic wave are different, the radar that the utility model is proposed can the round-the-clock steady operation of round-the-clock, and can visit
Ranging from dynamic range it is bigger;
(2) compared with general microwave height finding radar, the utility model proposes radar sensor use based on PCB's
Whole plane structure, the maximum gauge of the entire radar sensor including interface are only 5mm, and length and width are respectively 90mm, 80mm;
Because using PCB integration mode, entire radar does not need any Metal Packaging structure, weight 24g, and suitable unmanned plane is taken
It carries, and greatly reduces manufacturing cost;
(3) by using fast chirp radar waveform, Doppler frequency shift caused by unmanned plane rapid flight is reduced
Influence, avoid fuzzy distance solution, simplify signal processing flow;
(4) radar sensor proposed uses plane PCB construction form, all electricity such as antenna, radio frequency, base band, power supply
Road and device are integrated on one piece of pcb board, to meet compact and portable, convenient for the structural requirement with carrier aircraft platform intergration;
(5) can the work of round-the-clock round-the-clock, compact-sized, weight is light, ranging dynamic range is big, simple process, at
This UAV system height finding radar cheap, convenient for criticizing production.
Detailed description of the invention
Fig. 1 is the theory of constitution block diagram of radar sensor provided by the utility model;
Fig. 2 is the fast chirp transmitted waveform schematic diagram of radar sensor provided by the utility model;
Fig. 3 is the Radar Signal Processing flow diagram provided by the utility model based on Fast chirp system;
Fig. 4 is radar sensor board layer distributed architecture schematic diagram provided by the utility model;
Fig. 5 is one section of time-domain signal of radar sensor acquisition provided by the utility model;
Fig. 6 is radar sensor radar frequency domain analysis result provided by the utility model.
Appended drawing reference in figure is explained are as follows: 1- radio frequency receiving and transmitting front end, 2- transmitting antenna, 3- receiving antenna, 4- frequency synthesis
Device, 5- mixing ring, 6- control processing circuit, 7- power management module, 8- communication interface module, 9- transmitting antenna, receiving antenna
Place face, 10- radio frequency, 11- power supply-digitally-simulation ground, 12- intermediate frequency-base band-power circuit, 13- microwave substrate, 14-
FR4 substrate, 15- FR4 substrate, 101- voltage controlled oscillator, 102- amplifier, 103- low-noise amplifier, 104- frequency mixer.
Specific embodiment
The technical solution of the utility model is described in further detail with reference to the accompanying drawing:
This radar works in the 24GHz of one of international ISM band, and the frequency range is usually open to supervise for intelligent transportation
The civil fields such as control, automobile blind spot monitoring.
This radar works in autodyne frequency CW with frequency modulation system, and system block diagram is as shown in Fig. 1, mainly includes radio-frequency receiving-transmitting
Front end 1, transmitting antenna 2 and receiving antenna 3, mixing ring 5, control processing circuit 6, power management module 7, lead to frequency synthesizer 4
Communication interface module 8.Local oscillator is done by coupling part energy from transmitter from difference frequency system, does not need independent local vibration source, it can
To simplify radar arrangement, reduce cost.Continuous wave system can also realize the precision ranging of Larger Dynamic non-blind area.
This radar emission waveform sweeps transmitted waveform (fast chirp) using the zigzag of the big bandwidth of short cycle fastly, such as attached drawing
Shown in 2.Fast chirp waveform has the frequency sweep feature of big slope, frequency sweep cycle T generally in several ten mu sec order, with it is small tiltedly
The normal linear FM signal of rate is compared, and fast chirp has two big advantages when in use: (1) being gone oblique (de-chirp) processing
The doppler-frequency component that echo intermediate frequency later is included is far below apart from caused time delay frequency component, in this way at signal
There is no need to fuzzy distance solution and enough range accuracies are kept when reason, simplifies the process (2) of signal processing despite the use of
From the system of difference frequency, but the echo IF frequency after de-chirp processing can be far from zero intermediate frequency region, it is possible thereby to avoid electricity
The concentration zones of sub- device 1/f noise are conducive to simplify filtering, inhibit interference, to improve signal-to-noise ratio.
Basic signal processing flow is as shown in Fig. 3, and is described as follows:
(1) sample rate is used within a chirp periodfThe ADC of s carries out uniform time-domain sampling, sampling number M;Through
After crossing the sampling in continuous N number of period, the two-dimensional time-domain sampling dot matrix of M*N can be constructed;
(2) it carries out M point FFT to each column of two-dimensional time-domain sampling dot matrix to calculate, according to frequency domain peak value searching, Ke Yi
Target is found in corresponding range gate.After carrying out FFT calculating to N column data, the frequency domain Two-Dimensional Moment of new M*N point can be formed
Battle array.
(3) Two-dimensional FFT calculating is carried out to above-mentioned two-dimensional frequency matrix, the doppler information of target can be extracted, thus
The speed of related movement of target can be calculated.
This radar realizes radio frequency receiving and transmitting front end using mature industrialization monolithic integrated optical circuit, includes inside the integrated chip
One transmission channel and two receiving channels, built-in voltage controlled oscillator 101, amplifier 102, low-noise amplifier 103 and mixing
The functional circuits such as device 104.The structure that this radar is received using a hair one, by mixing ring 5 for two difference of radio frequency receiving and transmitting front end
Emission port is converted into single port, improves output power, and an extra receiving port is vacant.
This radar realizes frequency synthesizer using mature industrialization monolithic integrated optical circuit, is worked and is joined by reasonable disposition
Number, fast chirp voltage waveform needed for frequency synthesizer output can be made, and it is further provided to radio frequency front end chip, it controls
Make its internal voltage controlled oscillator output fast chirp swept-frequency signal.Frequency synthesizer is for exporting fast chirp voltage wave
Shape, and it is further provided to radio frequency receiving and transmitting front end, it controls the voltage controlled oscillator inside radio frequency receiving and transmitting front end and exports fast chirp
Swept-frequency signal is exported through amplifier, coupler transfer to transmitting antenna.
This radar uses four-sheet structure, as shown in Fig. 4, by receiving and transmitting front end and dual-mode antenna and mixes the radio-frequency parts such as ring
Parallel circuit is arranged in the same face of pcb board, from transmitting antenna, face 9 where receiving antenna down, with being followed successively by radio frequency 10, power supply-
Digitally-simulation ground 11, intermediate frequency-base band-power circuit 12.It does so and has the following advantages: (1) by radio frequency part and low frequency part
It is mutually isolated, it avoids interfering with each other;(2) it can directly be interconnected by microstrip line between dual-mode antenna and radio frequency chip, reliability
It is higher;If dual-mode antenna and radio frequency front end chip are located at the two sides of pcb board, gold can only be passed through between that day line and radio frequency chip
The interconnection of categoryization through-hole threading, loss and reliability are all not so good as microstrip line and directly interconnect.
This radar uses bistatic double antenna, and transmitting antenna 2 is identical with receiving antenna 3, using two-dimentional traveling wave battle array
Array antenna structure.
This radar using micro-USB as configuration interface, matched by the running parameter that the interface carries out radar by host computer
It sets.
The interface that this radar is transmitted using the micro- rectangle joint of 16 needles as external power supply, detection data.
Embodiment:
The present embodiment provides one work 24GHz frequency range, based on a thickness of 0.254mm RT/Rogers4350 and
The CW with frequency modulation height finding radar of the FR4 dielectric substrate of 0.6mm, technical indicator are as follows:
Working frequency range: 24.125 ± 0.25GHz;
Signal form: short cycle Gao Zhongying linear frequency modulation continuous wave (Fast chirp FMCW)
Transmission power: 13dBm
Antenna gain: 19dBi;
Beam angle: 14 °
Receiver noise factor: 18dB
Detection range: 1m -150m;
Survey high-resolution: 0.75m;
Altimetry precision: 0.1m
Data transfer rate: 100Hz
Equipment power dissipation: < 2.5W
External power supply: 5-30Vdc
Equipment dependability: MTBF > 5000h
Size: 90*80*5(long * wide * high, unit: mm)
Structure realization of the radar sensor that this example provides based on four layers of pcb board, as shown in Fig. 4.Dual-mode antenna is penetrated
Frequency front end and remaining microstrip circuit are located at first layer, this layer is supported by the RT/Rogers4350 microwave substrate 13 of 0.254mm;The
Two layers for microwave radio;Third layer is power supply, digitally and baseband analog;It is 0.6mm between the second layer and third layer
Thick FR4 substrate 14;4th layer is frequency synthesizer, power management, communication interface, control processing circuit, third layer and the 4th
It is supported between layer by the FR4 substrate 15 of 0.6mm thickness.
The material object of radar sensor: radio frequency receiving and transmitting front end 1(BGT24TRM12), transmitting antenna 2, receiving antenna 3 mixes ring
5, dual-mode antenna center spacing 41mm.It is isolated between dual-mode antenna using densely arranged plated-through hole, to inhibit possible
Existing surface wave crosstalk improves the isolation between dual-mode antenna.Intermediate-freuqncy signal caused by radio frequency receiving and transmitting front end 1 by close to
The plated-through hole of chip pin transits to the pcb board back side, acquires for the ADC of processor.
Frequency synthesizer 4(ADF4158), control processing circuit 6 be ARM chip (STM32F405), micro- rectangular interface, with
And micro-USB control interface.
The radar sensor provided using this example, in the case where field has carried out mobile condition for the survey of fixed target acquisition
The time domain waveform (two scan periods) that radar is recorded when being gradually distance from target is shown in examination, attached drawing 5, and attached drawing 6 is shown
Be corresponding frequency analysis as a result, from figure this it appears that in continuous two scan periods, since radar and target are deposited
The frequency shift (FS) caused by speed of related movement can easily calculate the distance and opposite fortune of target according to two frequency values
Dynamic speed.It, can be with according to the unmanned plane real-time flight data transmitted on airborne databus when being used in combination with unmanned aerial vehicle platform
Motion compensation is carried out, to obtain better range accuracy.
Above embodiments are only to illustrate the technical idea of the utility model, cannot limit the protection model of the utility model thus
Enclose, it is all according to the utility model proposes technical idea, any changes made on the basis of the technical scheme each falls within this reality
Within the scope of novel protected.