CN102769601A - Calibration system and method for amplitude-phase error of receiving channel of spaceborne DBF network - Google Patents

Abstract

The invention discloses a calibration system and method for the amplitude-phase error of a receiving channel of a spaceborne DBF (Digital Beam Forming) network. The system comprises a calibration signal generating module, a calibration signal transmitting module, a receiving channel and calibration interface module, and a calibration algorithm execution module, wherein the calibration algorithm execution module comprises an amplitude-phase error estimator and a calibration factor generator; the calibration signal generating module comprises an orthogonal pseudo random code block generator and a BPSK (Binary Phase Shift Keying) modulator; the calibration signal transmitting module comprises a digital up converter, a DA inverter, an analog up converter and a calibration feed source; the calibration signal generating module is connected with the calibration signal transmitting module; and the calibration algorithm execution module is connected with the receiving channel and calibration interface module. The system and the method provided by the invention have the advantages of strong real-time performance, high precision and high stability, and save satellite resources.

Description

Spaceborne digital beam forms network receive path amplitude phase error calibration system and method

Technical field

A kind of spaceborne DBF of the present invention (digital beam formation network) receive path amplitude phase error calibration system and method particularly relate to a kind of based on moving communication satellite load receive path calibration field.

Background technology

The moving communication satellite system is one and utilizes beam-forming technology to form a plurality of spot beams to carry out wide area and cover; Reach the enhanced rad gain; Support little terminal mobile communication business, become 245 spot beams like Thuraya star, the Imarsat4 satellite forms 228 spot beams.Satellite antenna is when long-term work; Its active device; Will be aging gradually like low noise amplifier, solid-state power amplifier, phase-shifter etc. with the increase of operating time; And causing the variation of signal amplitude and phase place in the different passages, this will impact the systematic function of multi-beam antenna, so must calibrate and compensate the active device of system.

The up link of moving communication satellite system adopts the reflecting surface multi-beam antenna to receive upward signal.Because the ground signal that multi-beam antenna receives arrives each channel amplitude and differs greatly, maximum reaches more than the 30dB, can't adopt ground signal as the calibration signal source.Consideration is provided with the calibration signal source on star; The calibration signal source is set on the star adopts wired calibration steps to calibrate usually; Method through each passage coupling being injected the calibration signal is calibrated; There is line method need increase a large amount of hardware devices, brings a large amount of burdens, take system valuable weight and power resource to on-board equipment.

Summary of the invention

Technical problem to be solved by this invention is: overcome the deficiency of prior art, the spaceborne DBF receive path amplitude phase error calibration system and the method for a kind of real-time, high accuracy, high stability is provided, can save resource on the star.

The present invention includes following technical scheme:

A kind of spaceborne digital beam forms the calibration system of network receive path amplitude phase error; Comprise calibrating signal generation module, calibrating signal transmitter module, receive path and calibration interface module and calibration algorithm Executive Module, said calibration algorithm Executive Module comprises amplitude phase error estimator and calibration factor generator; The calibrating signal generation module comprises orthogonal pseudo-random code character generator and BPSK modulator; The calibrating signal transmitter module comprises digital up converter, DA converter, simulation upconverter and calibration feed; The calibrating signal generation module links to each other with the calibrating signal transmitter module; The calibration algorithm Executive Module links to each other with receive path and calibration interface module.

Calibrating signal output coupler when calibrating signal output coupler and feed battle array were calibrated when receive path and calibration interface module comprised feed battle array calibration module, power device calibration module, power device calibration.

A kind of spaceborne digital beam forms the calibration steps of network receive path amplitude phase error, and said spaceborne digital beam forms the network receive path and comprises input feed battle array and power device,

The number that produces mutually orthogonal pseudorandom code character, pseudorandom code character through the calibrating signal generation module is consistent with the number of active lanes that needs calibration; And it is carried out BPSK modulate, thereby generate calibration signal source;

After calibration signal source is carried out Digital Up Convert, DA conversion, simulation up-conversion through the calibrating signal transmitter module, through calibration feed transmitting calibration signal;

Receive calibrating signal, the signal that receives handled the acquisition baseband signal through input feed battle array, and export to receive path and calibration interface module through power device;

Receive path and calibration interface module are passed to the calibration algorithm Executive Module with baseband signal;

Accomplish the passage amplitude phase error through the calibration algorithm Executive Module and estimate, and calculate the calibrate factor, the calibrate factor is passed to the calibration interface module, accomplish calibration through the calibration interface module.

Carry out following steps at the calibration algorithm Executive Module:

Judge whether it is calibration for the first time,

If then carrying out the feed calibration factor, calibration for the first time calculates; Then the feed calibration factor is transferred to feed battle array calibration module;

Then carry out the power device calibration factor if not calibration for the first time and calculate, then the power device calibration factor is transferred to the power device calibration module.

The present invention's advantage compared with prior art is:

(1) the present invention utilizes the calibrating signal of a plurality of orthogonal pseudo-random code characters as different passages; Adopt the orthogonal pseudo-random sign indicating number of formulating as calibrating signal to each passage, utilized the orthogonality of calibrating signal to eliminate the interference between the multiple signals, can estimate the amplitude phase error of a plurality of passages simultaneously, reduced the alignment time; Utilize the temporal correlation of calibrating signal, can improve the power after the calibrating signal receiving terminal is correlated with through the code length of control calibrating signal, making calibration system neither influence normal communication does not influence calibration performance yet.Because the mode that adopts sign indicating number to divide has stronger antijamming capability, can not receive normal communications signal and The noise simultaneously, guarantee the stability of calibration, adopt long sign indicating number can guarantee the precision of higher test.

(2) the present invention is injected into each passage to calibrating signal through wireless mode, can realize the calibration of a plurality of receive paths simultaneously; Thereby saved resource on the star.

(3) the present invention can be applied to the communications field of the employing DBF technology of communication satellite, investigation satellite and navigation satellite, also can be applicable to adopt the technical fields such as spaceborne radar of DBF technology.

Description of drawings

Fig. 1 is the composition sketch map of calibration system of the present invention;

Fig. 2 is the concrete composition frame chart of calibration system of the present invention;

Fig. 3 is the flow chart of calibration steps of the present invention.

Embodiment

The present invention proposes based on wireless receive path amplitude phase error calibration system and method, can realize calibration simultaneously for N receive path.Calibration system is formed as shown in Figure 1, comprises calibration algorithm Executive Module, calibrating signal generation module, receive path and calibration interface module and calibrating signal transmitter module.The calibrating signal that the calibrating signal generation module produces is handled through the calibrating signal transmitter module and the emission of process calibration feed.The calibration feed satisfies " far field " condition with input feed battle array; Be injected into each receive path to calibrating signal through input feed battle array; Require far to surpass antenna wavelength (d＞10* λ) apart from d between calibration feed and the input feed battle array, calibration feed signal reaches that to import the feed battle array be constant amplitude, equiphase plane wave.Through power device the signal that receives is handled the acquisition baseband signal, and export to receive path and calibration interface module; Through the calibration algorithm Executive Module calibration factor of each passage is estimated and obtained to the amplitude phase error of each receive path, compensate at numeric field, realize the calibration of DBF receive path amplitude-phase consistency through receive path and calibration interface module; The output of receive path and calibration interface module links to each other with DBF.

Principle of the present invention is: owing to inject calibrating signal through wireless mode, have the interference problem to normal signal, can address this problem through the orthogonal pseudo-random sign indicating number.

At first, calibrating signal is by N orthogonal pseudo-random coded signal s _k(l) form, k=1,2 ..., N; L=1,2 ..., L.L is a pseudo noise code length, can calculate good being stored in the memory in advance, and when calibration system was worked, N orthogonal pseudo-random coded signal got into N receive path simultaneously by the boresight antenna radiation; Each channel height is consistent in theory, has identical transfer function, but during real work, there are differences, and has different amplitude, phase response; The transfer function of each passage should be multiplied by each passage amplitude phase error { C again ₁, C ₂... .C _N.

If the transfer function of a certain receive path amplitude phase error C is h (t), the reception signal after then the pn sign indicating number passes through does

$r\left(t\right)=\mathrm{pn}\left(t\right)\⊗h\left(t\right)+N_{\mathrm{awgn}}\⊗h\left(t\right)---\left(1\right)$

R (t) is carried out the despreading computing, get final product

$x\left(t\right)=\mathrm{pn}\left(t\right)\⊗h\left(t\right)\⊗{\mathrm{pn}}^{*}\left(t\right)+N_{\mathrm{awgn}}\⊗h\left(t\right)\⊗{\mathrm{pn}}^{*}\left(t\right)---\left(2\right)$

To following formula,, then can obtain if utilize fft to ask convolution

X(nΔf)＝PN(nΔf)×H(nΔf)×PN ^*(nΔf)+Nawgn×H(nΔf)×PN ^*(nΔf)

＝|PN(nΔf)| ²×H(nΔf)+N _awgn×H(nΔf)×PN ^*(nΔf) (3)

Because N _AwgnBe additive white Gaussian noise, its average is 0, therefore can suppose N _Awgn* H (n Δ f) * PN ^*(n Δ f)=0.And, | PN (n Δ f) | ²=1.So can get

X(nΔf)＝H(nΔf) (4)

This shows; Obtain the signal x (t) after the despreading, can calculate the amplitude of receive path error | h (t) |, phase estimation

When normal communications signal y (t) imports since with orthogonal pseudo-random coded signal s _k(l) uncorrelated, during decorrelation, The calibration signal that normal communications signal y (t) can not have influence on band orthogonal pseudo-random sign indicating number carries out the channel error test.

As shown in Figure 2, the calibration algorithm Executive Module is made up of amplitude phase error estimator and calibration factor generator; The calibrating signal generation module is made up of orthogonal pseudo-random code character generator, BPSK (biphase phase shift keying) modulator; The calibrating signal transmitter module is made up of digital up converter, DA converter, simulation upconverter and calibration emission feed; Receive path and calibration interface module during by feed battle array calibration module 40, power device calibration module 41, power device calibration when calibrating signal output coupler 43 and the calibration of feed battle array calibrating signal output coupler 42 constitute.

Feed battle array calibration module 40 main calibration satellites are entered the orbit the back system owing to mismachining tolerance, the intrinsic channel error that can not change of system that mechanical factors such as antenna expansion departure cause.Begin operate as normal after satellite is entered the orbit, feed battle array calibration module 40 calibrated channel errors are accomplished the calibration back and are kept align mode constant.

System worked long hours after power device calibration module 41 main calibration satellites were entered the orbit, the channel error that the nonlinear change that power device produces causes, and this error can change along with the operating time.After satellite works long hours, power device calibration module 41 calibrated channel errors, align mode changes and changes along with channel error.

BPSK modulator in the calibrating signal generation module is connected with digital up converter in the calibrating signal transmitter module through the 1 pair of LVDS holding wire, transmits the calibration source signal; Power device when calibration calibrating signal output coupler 43 during with the calibration of input feed battle array calibrating signal output coupler 42 be connected with amplitude phase error estimator in the calibration algorithm Executive Module through 2 pairs of LVDS holding wires, transmit base band and calibrate and export signal; The calibration factor generator is connected the calibration factor table that transmission is made up of each calibrate factor with output feed battle array calibration module 40, power device calibration module 41 respectively through 2 pairs of RS422 holding wires.

The error estimation of amplitude phase error estimator is following in the calibration algorithm Executive Module:

(1) carry out despreading to the received signal, the signal that obtains after the despreading is following:

$x\left(t\right)=\mathrm{pn}\left(t\right)\⊗h\left(t\right)\⊗{\mathrm{pn}}^{*}\left(t\right)+N_{\mathrm{awgn}}\⊗h\left(t\right)\⊗{\mathrm{pn}}^{*}\left(t\right)$

(2) complex signal after the despreading being asked its amplitude and phase place, also is the amplitude phase error of passage, calculates as follows:

Δangle＝arctg(imag(x(t))/real(x(t)))

Δpow＝abs(x(t))

Wherein, imag representes to ask the imaginary part of plural number, and real representes to ask real, and arctg representes the tangent of negating, and abs representes to ask the mould value of plural number.

The error that the calibration factor generator is exported according to the amplitude phase error estimator generates the calibration factor of each passage, and this calibration factor is input to corresponding calibration module.

Calibration steps flow process of the present invention is as shown in Figure 3, specifically comprises the steps:

(1) the calibrating signal generation module produces mutually orthogonal pseudorandom code character and it is carried out the BPSK modulation as calibration signal source, and wherein the number of pseudorandom code character is consistent with the number of active lanes that needs calibration;

(2) the BPSK modulator is connected with digital up converter in the calibrating signal transmitter module through the 1 pair of LVDS holding wire, transmits the calibration source signal;

(3) the calibration source signal is through after Digital Up Convert, DA conversion, simulating up-conversion, through the calibrating signal after the calibration feed emission processing; The calibration feed satisfies far field condition with input feed battle array.

(4) receive calibrating signal, the signal that receives handled the acquisition baseband signal through input feed battle array, and export to receive path and calibration interface module through power device; Power device when calibration calibrating signal output coupler 43 during with the calibration of input feed battle array calibrating signal output coupler 42 be connected with amplitude phase error estimator in the calibration algorithm Executive Module through 2 pairs of LVDS holding wires, transmit base band and calibrate and export signal;

(5) the calibration algorithm Executive Module is accomplished the estimation of passage amplitude phase error, and calculates the calibration factor of each passage, and calibration factor is passed to feed battle array calibration module 40, the 41 completion calibrations of power device calibration module through RS422.Said calibration algorithm Executive Module need judge whether it is calibration for the first time; If calibration for the first time; Calibrating signal output coupler 42 transmission calibrating signal to amplitude phase error estimators carry out amplitude phase error calculating and feed battle array calibration factor then and calculate during then through the calibration of input feed battle array; Feed battle array calibration factor is transferred to feed battle array calibration module 40.If not calibration for the first time; Calibrating signal output coupler 43 transmission calibrating signal to amplitude phase error estimators during then through the power device calibration; Carry out amplitude phase error calculating and power device calibration factor then and calculate, the power device calibration factor that obtains is transferred to the power device calibration module.

After calibration process of the present invention was entered the orbit operate as normal from satellite, consistent continuing carried out.

The unspecified part of the present invention belongs to general knowledge as well known to those skilled in the art.

Claims (4)

1. a spaceborne digital beam forms the calibration system of network receive path amplitude phase error; Comprise calibrating signal generation module, calibrating signal transmitter module, receive path and calibration interface module and calibration algorithm Executive Module, it is characterized in that: said calibration algorithm Executive Module comprises amplitude phase error estimator and calibration factor generator; The calibrating signal generation module comprises orthogonal pseudo-random code character generator and BPSK modulator; The calibrating signal transmitter module comprises digital up converter, DA converter, simulation upconverter and calibration feed; The calibrating signal generation module links to each other with the calibrating signal transmitter module; The calibration algorithm Executive Module links to each other with receive path and calibration interface module.

2. calibration system as claimed in claim 1; It is characterized in that calibrating signal output coupler when calibrating signal output coupler and feed battle array were calibrated when receive path and calibration interface module comprised feed battle array calibration module, power device calibration module, power device calibration.

3. a spaceborne digital beam forms the calibration steps of network receive path amplitude phase error, and said spaceborne digital beam forms the network receive path and comprises input feed battle array and power device, it is characterized in that,

The number that produces mutually orthogonal pseudorandom code character, pseudorandom code character through the calibrating signal generation module is consistent with the number of active lanes that needs calibration; And it is carried out BPSK modulate, thereby generate calibration signal source;

After calibration signal source is carried out Digital Up Convert, DA conversion, simulation up-conversion through the calibrating signal transmitter module, through calibration feed transmitting calibration signal;

Receive calibrating signal, the signal that receives handled the acquisition baseband signal through input feed battle array, and export to receive path and calibration interface module through power device;

Receive path and calibration interface module are passed to the calibration algorithm Executive Module with baseband signal;

Accomplish the passage amplitude phase error through the calibration algorithm Executive Module and estimate, and calculate the calibrate factor, the calibrate factor is passed to the calibration interface module, accomplish calibration through the calibration interface module.

4. calibration steps as claimed in claim 3 is characterized in that, carries out following steps at the calibration algorithm Executive Module:

Judge whether it is calibration for the first time,

If then carrying out the feed calibration factor, calibration for the first time calculates; Then the feed calibration factor is transferred to feed battle array calibration module;

Then carry out the power device calibration factor if not calibration for the first time and calculate, then the power device calibration factor is transferred to the power device calibration module.

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