CN105445760A - Satellite navigation single-antenna broadband interference prevention method - Google Patents

Abstract

The invention belongs to the technical field of satellite navigation, and specifically relates to a satellite navigation single-antenna broadband interference prevention method. The method comprises the following steps: 1, receiving a satellite signal through employing an N-element polarized sensitive vector array antenna, and obtaining an output x(t) of the N-element polarized sensitive vector array; 2, synthesizing the output through employing a beam former. The method employs polarized antenna array elements to receive the satellite signal, synthesizes the multiple outputs of the array elements through the reasonable arrangement of a weight vector, finally achieves a purpose of inhibiting broadband interference, and is high in usability.

Description

A kind of anti-broadband interference method of satellite navigation single antenna

Technical field

The invention belongs to technical field of satellite navigation, be specifically related to a kind of anti-broadband interference method of satellite navigation single antenna.

Background technology

In the design of some aircraft, in order to improve overall performance, requiring the satellite receiver as navigation arrangement to take up room little as far as possible, requiring that again receiver has higher antijamming capability simultaneously.Therefore, make when not affecting antenna performance antenna miniaturization become in Antenna Design as far as possible and need the key factor of consideration.

The method of the anti-broadband interference ability of acquisition prevailing for the time being in force uses array antenna, utilizes the steering vector of array antenna received undesired signal and satellite-signal upwards to form zero in interference and fall into thus reach the object suppressing interference.But while possessing antijamming capability, taking up room of conventional antenna array also increases much.

Polarized array refers to that polarization sensitive array element places the array system formed in space by certain way, polarization sensitive array element is utilized to obtain the polarization information of spatial electromagnetic signal, polarization information shows as the polarization characteristic between array element pairwise orthogonal POLARIZATION CHANNEL, and utilize array geometry structure to carry out the spatial information (si) of Space domain sampling acquisition spatial electromagnetic signal simultaneously, show as the spatial phase delay between adjacent array element.Therefore polarized array both can obtain the space angle of arrival information of signal, can obtain again the polarization information of signal.

Generic array only has spatial domain filter capacity, and polarized array not only can utilize the difference of wanted signal and the undesired signal space angle of arrival at airspace filter, but also the difference of its polarized state can be utilized in polarizing field filtering.Therefore polarized array has stronger suppression interference than generic array, strengthens the ability of signal.And when requiring to possess identical antijamming capability, polarized antenna arrays takes up room and can greatly reduce, meet the requirement of miniaturization completely.

Summary of the invention

The technical issues that need to address of the present invention are: a kind of method providing suppression broadband interference of polarized array single antenna.

Technical scheme of the present invention is as described below:

A kind of anti-broadband interference method of satellite navigation single antenna, comprises the following steps:

Step 1, use N unit polarization sensitive vector array antenna receiving satellite signal, and obtain output x (t) of N unit polarization sensitive vector array;

x(t)＝[x ₁(t),x ₂(t),…,x _N(t)]

Wherein, x _kt () is the output signal of a kth array element, k=1,2 ..., N;

The synthesis of step 2, Beam-former exports

The concrete formula that Beam-former synthesis exports is:

y(t)＝w ^Hx(t)

Wherein, the output that y (t) is Beam-former, w is weight vector.

Preferably, the computing method of weight vector w are:

$w=\stackrel{\↔}{P_{\max }}\left\{{R_{i+n}}^{-1}{R}_d\right\}$

Wherein, representing matrix main proper vector corresponding to eigenvalue of maximum; for desired signal components array output covariance matrix; for the power of wanted signal; s ^dt () is wanted signal; for expecting signal guide vector, provided by external unit; R _i+n=E{x ⁱ⁺ⁿ(t) [x ⁱ⁺ⁿ(t)] ^hit is interference plus noise component arrays output covariance matrix.

Preferably, the computing method of weight vector w are:

Wherein, for expecting signal guide vector, R _xxfor the autocorrelation matrix of x (t).

Preferably, the computing method of weight vector w are:

$w={R_{xx}}^{-1}{r}_{xd}$

Wherein, R _xxfor the autocorrelation matrix of x (t), r _xdfor the first polarization sensitive vector array of reference signal d (t) and N exports the cross-correlation matrix of x (t).

Preferably, described N=2, choose polarization sensitive vector array wherein arbitrary array element output as with reference to signal d (t).

Beneficial effect of the present invention is:

The present invention uses poliarizing antenna array element receiving satellite signal, by reasonably arranging weight vector, is synthesized by the multiple-channel output of array element, finally reaches the object suppressing broadband interference, has very strong ease for use.

Accompanying drawing explanation

Fig. 1 is single antenna anti-interference satellite receiver overall design block diagram the general frame;

Fig. 2 is dual polarized antenna Anti-interference algorithm block diagram;

Fig. 3 is the actual 80dB Big Dipper 2 broadband interference spectrogram;

Fig. 4 is spectrogram after the anti-broadband interference of single antenna suppresses.

Embodiment

Below in conjunction with drawings and Examples, the anti-broadband interference method of a kind of satellite navigation single antenna of the present invention is described in detail.

Consider a N unit polarization sensitive vector array, the output signal of its kth array element can be write as

In formula, k=1,2 ..., N, M are the numbers of undesired signal, p=1,2 ..., M, s ^dt () is wanted signal, s _p ⁱt () is p undesired signal, a _kcoefficient, wanted signal s ^dthe gain of (t), p interference s _p ⁱthe gain of (t), n _kt () is the additivity circle noise in a kth array element.Assuming that wanted signal s ^d(t), interference s _p ⁱ(t) and additivity circle noise n _kt () be statistical iteration each other.Then array measurement vector has form below:

In formula, a=[a ₁, a ₂..., a _n] ^t, for expecting signal guide vector, directly can obtain from external unit. be the steering vector of p interference, A is sequency spectrum matrix, s (t)=[s ^d(t), s ₁ ⁱ(t) ..., s _m ⁱ(t)] ^t, s ⁱ(t)=[s ₁ ⁱ(t), s ₂ ⁱ(t) ..., s _m ⁱ(t)] ^t.

If note w=is [w ₁, w ₂..., w _n] ^tfor the weight vector of the anti-interference Beam-former of polarizing field, then the output of Beam-former is y (t)=w ^hx (t).By appropriate design weight vector w, the interference in Beam-former and noise contribution can be made to be fully suppressed, retain interested wanted signal composition simultaneously.

Several Beam-former is as follows:

1. maximum output Signal to Interference plus Noise Ratio Beam-former (MSINR)

Export the main performance index that Signal to Interference plus Noise Ratio is Beam-former (SINR), and make output SINR maximization be the most basic design criteria of adding up optimal beam forming device.

Wherein, σ _d ²=E{|s ^d(t) | ²be the power of wanted signal, for desired signal components array output covariance matrix, R _i+n=E{x ⁱ⁺ⁿ(t) [x ⁱ⁺ⁿ(t)] ^hit is interference plus noise component arrays output covariance matrix.

Then quadratic constraints maximizes power criterion is:

maxw ^HR _dws.t.w ^HR _i+nw＝1

Utilize method of Lagrange multipliers, the optimum weight vector that can obtain maximum output SINR statistics optimal beam forming device is:

$w=\stackrel{\↔}{P_{\max }}\left\{{R_{i+n}}^{-1}{R}_d\right\}$

Wherein, representing matrix R _i+n ^-1r _dmain proper vector corresponding to eigenvalue of maximum.

2. the undistorted respective beam shaper (MVDR) of minimum variance

Minimum variance is undistorted, and respective beam shaper designs by following criterion:

minw ^HR _xxw

If wanted signal steering vector can be obtained and array output covariance matrix R _xx=E{x (t) x ^h(t) }, the solution utilizing method of Lagrange multipliers can obtain w is

3. based on the least mean-square error Beam-former (MMSE) of reference signal

Called reference signal method refers to according to minimum mean square error criterion design Beam-former below:

w＝argming(w)＝E{|d(t)-w ^H(t)| ²}

Wherein d (t) is reference signal.

According to Newton iteration optimization method, its optimum solution is

w＝R _xx ^-1r _xd

Above-mentioned three kinds of Beam-formers, to choose any one kind of them the suppression that can realize broadband interference according to actual conditions.

In the present embodiment, employ binary polarization sensitive vector array antenna as shown in Figure 1, adopt the least mean-square error Beam-former of reference signal, as shown in Figure 2, interference number is 1 to the algorithm block diagram of this Beam-former.Using I road polarization information as reference signal, Q road polarization information, as input signal, is expect with reference signal, exports pooling information after carrying out auto adapted filtering process to input signal.Fig. 3 and Fig. 4 give utilize based on before and after the least mean-square error Beam-former of reference signal to the Big Dipper 2 broadband interference 80dB pre-process and post-process Contrast on effect, Fig. 3 is actual 80dB Big Dipper broadband interference spectrogram, Fig. 4 carries out suppressing rear spectrogram for utilizing single antenna anti-broadband interference method, and in visible band, the basic filtering of interference is clean.

Claims (5)

1. the anti-broadband interference method of satellite navigation single antenna, is characterized in that: comprise the following steps:

Step 1, use N unit polarization sensitive vector array antenna receiving satellite signal, and obtain output x (t) of N unit polarization sensitive vector array;

x(t)＝[x ₁(t),x ₂(t),…,x _N(t)]

Wherein, x _kt () is the output signal of a kth array element, k=1,2 ..., N;

The synthesis of step 2, Beam-former exports

The concrete formula that Beam-former synthesis exports is:

y(t)＝w ^Hx(t)

Wherein, the output that y (t) is Beam-former, w is weight vector.

2. the anti-broadband interference method of satellite navigation single antenna as claimed in claim 1, is characterized in that:

The computing method of weight vector w are:

Wherein, representing matrix main proper vector corresponding to eigenvalue of maximum; for desired signal components array output covariance matrix; for the power of wanted signal; s ^dt () is wanted signal; for expecting signal guide vector, provided by external unit; R _i+n=E{x ⁱ⁺ⁿ(t) [x ⁱ⁺ⁿ(t)] ^hit is interference plus noise component arrays output covariance matrix.

3. the anti-broadband interference method of satellite navigation single antenna as claimed in claim 1, is characterized in that:

The computing method of weight vector w are:

Wherein, for expecting signal guide vector, R _xxfor the autocorrelation matrix of x (t).

4. the anti-broadband interference method of satellite navigation single antenna as claimed in claim 1, is characterized in that: the computing method of weight vector w are:

w＝R _xx ^-1r _xd

Wherein, R _xxfor the autocorrelation matrix of x (t), r _xdfor the first polarization sensitive vector array of reference signal d (t) and N exports the cross-correlation matrix of x (t).

5. the anti-broadband interference method of satellite navigation single antenna as claimed in claim 4, is characterized in that: described N=2, chooses the output of polarization sensitive vector array wherein arbitrary array element as with reference to signal d (t).