CN106713197A - Airborne instrument landing system data processing method based on software radio - Google Patents

Abstract

The invention belongs to the field of airplane navigation communication design and relates to an airborne instrument landing system data processing method based on software radio. The method comprises the following steps: 1, an AM demodulation module processing two digital baseband signals of a same-phase component sequence XI(n) and an orthogonal component sequence XQ(n) so as to obtain envelope signals A(n); 2, dividing the A(n) signals into four signals, obtaining 90Hz signals (i.e., A(n) signals) by subjecting one signal to a 90Hz filter, obtaining 150Hz signals (i.e., Z(n) signals) by subjecting one signal to a 150Hz filter, obtaining voice signals by subjecting one signal to a 300-3000Hz filter, and obtaining DC components by subjecting one signal to a DC component estimation module; 3, performing amplitude measurement on the X(n) signals and the Z(n) signals, wherein the amplitude measurement is performed by intercepting last one tenth of sampling points of a signal sequence; 4, respectively multiplying the 90Hz signals and the 150Hz signals by a coefficient square root of 2 so as to obtain corresponding amplitude output X' of X(n) as amplitude of the 90Hz signals and corresponding amplitude output Z' of Z(n) as amplitude of the 150Hz signals; and 5, according to the X', Y and the Z', obtaining a difference of depth of modulation needed for instrument landing through calculation.

Description

A kind of airborne instrument landing system data processing method based on software radio

Technical field

The invention belongs to aircraft navigation communication scheme field, it is related to a kind of instrument on board landing system based on software radio System data processing method.

Background technology

Type aircraft navigation communication system is made up of various airborne radio installations, including VOR, VHF, ILS etc..Due to passing Unite wireless device design with hardware as core, unitary function and poor expandability, the equipment of difference in functionality need difference Hardware design, R＆D costs are high, and are difficult to extension upgrading.Numerous discrete nav-com installations, cause airborne equipment Volume weight and power consumption are larger, and lack versatility and flexibility, and airborne nav-com installation needs a kind of integrated, one badly The solution of change.

Integrative solution based on software and radio technique has upgrading easy to maintain, and autgmentability, flexibility is high, into This low, a series of feature such as lightweight.On the basis of unitized hardware platform has been built, various navigational communications functions The design focal point of realization has just turned to Software for Design by hardware design, is just become to succinct high by the design requirement of advanced circuit Imitate the requirement of algorithm.

The content of the invention

The present invention proposes a kind of airborne instrument landing system software processing method based on software radio, traditional Improvement is made that on the basis of instrument-landing-system modulation degree difference calculation method, the theory of software radio is fully combined And design philosophy, with succinct efficiently and accurately it is general the characteristics of.

A kind of airborne instrument landing system software processing method based on software radio of the present invention can use following skill Art scheme：

Including：

(1) AM demodulation modules are to in-phase component sequence X_I(n), quadrature component sequence X_QN () two-way digital baseband signal is carried out Treatment, obtains envelope signal A (n), and its treatment formula is：

The A (n) is envelope signal, contains 90Hz signals, 150Hz signals, voice signal and DC component；

(2) A (n) signals are divided into four tunnels, lead up to 90Hz wave filters, obtain 90Hz signals；Lead up to 150Hz filters Ripple device, obtains 150Hz signals；300~3000Hz wave filters are led up to, voice signal is obtained；DC component is led up to estimate Meter module obtains DC component；

If the 90Hz signals are X (n), DC component signal is Y, and 150Hz signals are Z (n)；

(3) amplitude measurement is carried out to X (n) signals and Z (n) signals, rear the 1/10 of amplitude measurement intercept signal sequence adopts Sampling point is carried out；

(4) signal and the signal of 150Hz for 90Hz is multiplied by respectivelyCoefficient enter line amplitude amplification, X (n) obtains Corresponding amplitude exports X ', is 90Hz signal amplitudes；Z (n) obtains corresponding amplitude output Z ', is the amplitude of 150Hz signals；

(5) according to X ', Y, Z ', the modulation degree needed for being calculated instrument landing according to below equation are poor：

DDM=(X '-Z ')/Y,

Modulation degree of the wherein DDM for needed for instrument-landing-system is poor.

The process of the extraction that A (n) carries out DC component into DC component estimation module includes in step (2)：

DC component estimation module carries out multiplying window to input signal A (n) first, and its computing formula is：

y_i=a_i* [1-cos (ω)], wherein, intermediate parameters

Wherein n is the element number of sequence A (n), a_iIt is i-th element of A (n), y_iIt is a_iIt is defeated after corresponding adding window Go out；If the y_i, i=1,2, the 3...n-1 sequences for being constituted are Y (n), and Y (n) is carried out to take mean operation, can obtain direct current Component signal Y.

Step (2) median filter design parameter is respectively：

90Hz wave filters：Type is Butterworth bandpass filter, and passband initial frequency is 80Hz, cut-off frequecy of passband 90Hz, filter order is 10；

150Hz wave filters：Type is Butterworth bandpass filter, and passband initial frequency is 140Hz, cut-off frequecy of passband 150Hz, filter order is 10；

300~3000Hz wave filters：Butterworth type is bandpass filter, and passband initial frequency is 300Hz, and passband cuts Only frequency 3000Hz, filter order is 3.

The advantage of the invention is that：Algorithm is simple, and module design has versatility, its AM demodulation modules, filter module The software that can be used for other navigation communication systems realizes that the method is general for localizer and glide-path localizer receive capabilities , do not influenceed by localizer is different with glide-path localizer modulation degree.The more traditional calculation method of the algorithm is efficient, the degree of accuracy It is high.

Brief description of the drawings

Fig. 1 is module composition schematic diagram of the invention.

Fig. 2 is that modulation degree of the invention resolves module frame chart.

Fig. 3 is the schematic diagram of the DC component estimating part that modulation degree difference resolves inside modules.

Specific embodiment

The present invention is described in further details below in conjunction with the accompanying drawings, a kind of instrument on board based on software radio lands Systems soft ware processing method, is on general software radio hardware platform, to be designed using reusable, modularized design thought For airborne instrument landing system course and the data processing method of glide-path localizer function.The method applies the device based on Fig. 1, Step is as follows：

(1) AM demodulation modules are to in-phase component sequence X_I(n), quadrature component sequence X_QN () two-way digital baseband signal is carried out Treatment, obtains envelope signal A (n), and its treatment formula is：

The A (n) is envelope signal, contains 90Hz signals, 150Hz signals, voice signal and DC component；

(2) A (n) signals are divided into four tunnels, respectively by 90Hz wave filters, 150Hz wave filters, 300~3000Hz filtering Device, DC component estimation module is processed；

The design of filter module is based on considered below：System, can be using unlimited impact to the phase of signal and insensitive Response filter, i.e. I IR digital filters, are designed using ripe Design of Analog Filter method, are adopted in the method With Butterworth filter, general software module is fabricated to, its exponent number and frequency parameter are adjustable；By theory analysis and experiment Checking, the design parameter that one group of test that this method is used works well is respectively：

90Hz wave filters：Type is bandpass filter, and passband initial frequency is 80Hz, cut-off frequecy of passband 90Hz, filtering Device exponent number is 10；

150Hz wave filters：Type is bandpass filter, and passband initial frequency is 140Hz, cut-off frequecy of passband 150Hz, filter Ripple device exponent number is 10；

300~3000Hz wave filters：Type is bandpass filter, and passband initial frequency is 300Hz, cut-off frequecy of passband 3000Hz, filter order is 3；

Butterworth filter method for designing is ripe, can be carried out using softwares such as Matlab when being designed with upper filter auxiliary Help, repeat no more.

90Hz signals needed for can obtaining the Processing Algorithm by above-mentioned wave filter, 150Hz signals, in addition, voice Signal for needed for localizer system, after filtering after exported as audio digital signals, the follow-up algorithm be not related to.If institute 90Hz signals are stated for X (n), DC component amplitude is Y, 150Hz signals are Z (n)；

(3) as shown in Fig. 2 having carried out amplitude measurement, amplitude measurement intercept signal sequence to X (n) signals and Z (n) signals Rear 1/10 sampled point carry out, so it is possible to prevente effectively from signal is by the mistake caused by the amplitude fading caused by wave filter Difference, can be using the sampling duration of 0.1s-1s in laboratory；

(4) in order to make up the amplitude loss produced in filtering, it is necessary to be amplified to signal.In the filtering of (2nd) step In device design, the cut-off frequecy of passband of the first two wave filter has been set to 90Hz and 150Hz by us, and such 90Hz and 150Hz believes Number amplitude fading to be 3dB, i.e. amplitude fading be originalTimes, therefore, the letter of signal and 150Hz for 90Hz Number it is multiplied by respectivelyCoefficient enter line amplitude amplification, to ensure that amplitude does not decay.Thus, to obtain corresponding amplitude defeated for X (n) Go out X ', be 90Hz signal amplitudes；Z (n) obtains corresponding amplitude output Z ', is the amplitude of 150Hz signals.

(5) A (n) carries out the process of the extraction of DC component into DC component estimation module as shown in figure 3, DC component Estimation module carries out multiplying window to input signal A (n) first, and its computing formula is：

y_i=a_i* [1-cos (ω)], wherein, intermediate parameters

Wherein n is the element number of sequence A (n), a_iIt is i-th element of A (n), y_iIt is a_iIt is defeated after corresponding adding window Go out.

Next signal is carried out to take mean operation, DC component output Y can be obtained.

Modulation degree of the wherein DDM for needed for instrument-landing-system is poor.

The method is general for localizer and glide-path localizer receive capabilities, is not adjusted by localizer and glide-path localizer The different influence of system.

A kind of airborne instrument landing system data processing method based on software radio, sets up with open hardware On the basis of general-purpose platform, using the thought with object-oriented, reusable, modular software module is built, realized succinct, high Effect is accurately calculated.

Methods described Computer Simulation checking is carried out into, the absolute error of the modulation degree difference data for obtaining is no more than 0.000004DDM；

Two-shipper antenna transmitting-receiving methods described administration carried out on Hardware Platform of Software Radio under laboratory environment is tested Card, modulation degree difference absolute error is not less than 0.001DDM.

Claims (3)

1. a kind of airborne instrument landing system software processing method based on software radio, it is characterised in that including：

(1) AM demodulation modules are to in-phase component sequence X_I(n), quadrature component sequence X_QAt (n) two-way digital baseband signal Reason, obtains envelope signal A (n), and its treatment formula is：

$A\left(A\right)=\sqrt{X_I{\left(n\right)}^2+X_Q{\left(n\right)}^2};$

The A (n) is envelope signal, contains 90Hz signals, 150Hz signals, voice signal and DC component；

(2) A (n) signals are divided into four tunnels, lead up to 90Hz wave filters, obtain 90Hz signals；Lead up to 150Hz filtering Device, obtains 150Hz signals；300~3000Hz wave filters are led up to, voice signal is obtained；Lead up to DC component estimation Module obtains DC component；

If the 90Hz signals are X (n), DC component signal is Y, and 150Hz signals are Z (n)；

(3) carry out amplitude measurement to X (n) signals and Z (n) signals, amplitude measurement intercept signal sequence rear 1/10 sampled point Carry out；

(4) signal and the signal of 150Hz for 90Hz is multiplied by respectivelyCoefficient enter line amplitude amplification, X (n) obtains corresponding Amplitude exports X ', is 90Hz signal amplitudes；Z (n) obtains corresponding amplitude output Z ', is the amplitude of 150Hz signals；

(5) according to X ', Y, Z ', the modulation degree needed for being calculated instrument landing according to below equation are poor：

DDM=(X '-Z ')/Y,

Modulation degree of the wherein DDM for needed for instrument-landing-system is poor.

2. a kind of airborne instrument landing system software processing method based on software radio as claimed in claim 1, it is special Levy and be, the process of the extraction that A (n) carries out DC component into DC component estimation module includes in step (2)：

DC component estimation module carries out multiplying window to input signal A (n) first, and its computing formula is：

y_i=a_i* [1-cos (ω)], wherein, intermediate parametersI=1,2,3...n-1,

Wherein n is the element number of sequence A (n), a_iIt is i-th element of A (n), y_iIt is a_iOutput after corresponding adding window；If The y_i, i=1,2, the 3...n-1 sequences for being constituted are Y (n), and Y (n) is carried out to take mean operation, can obtain DC component letter Number Y.

3. a kind of airborne instrument landing system software processing method based on software radio as claimed in claim 1, it is special Levy and be,

Step (2) median filter design parameter is respectively：

90Hz wave filters：Type be Butterworth bandpass filter, passband initial frequency be 80Hz, cut-off frequecy of passband 90Hz, Filter order is 10；

150Hz wave filters：Type is Butterworth bandpass filter, and passband initial frequency is 140Hz, cut-off frequecy of passband 150Hz, filter order is 10；

300~3000Hz wave filters：Butterworth type is bandpass filter, and passband initial frequency is 300Hz, passband cutoff frequency Rate 3000Hz, filter order is 3.