CN104215981A - Adaptive tracking method for receiver in high-dynamic environment - Google Patents

Abstract

The invention discloses an adaptive tracking method for a receiver in a high-dynamic environment. According to the adaptive tracking method, bandwidths of loop filters for a frequency-locked loop, a phase-locked loop and an auxiliary phase-locked loop of the frequency-locked loop are adjusted by detecting the dynamic property and the signal-to-noise property of tracking signals of the receiver in real time, so that optimum values of the bandwidths are kept; meanwhile, a dynamic application range of a tracking loop is widened by adjusting an auxiliary coefficient of the auxiliary phase-locked loop of the frequency-locked loop, so that stability of the tracking loop in the high-dynamic environment is improved. The adaptive tracking method for the receiver in the high-dynamic environment has the advantages that the adaptive tracking method is capable of enabling the receiver to adjust own parameters timely in a dynamic change environment, errors of tracking satellite navigation signals are kept within a small range, and the shortcomings of large tracking errors and proneness to lock loss of the receiver in the prior art are overcome.

Description

Adaptive tracking method under a kind of receiver high dynamic environment

Technical field

The present invention relates to satellite communication receiver, particularly relate to adaptive tracking method under a kind of receiver high dynamic environment.

Background technology

Beidou satellite navigation system (hereinafter referred to as BD) is that China independently builds, independent operating, and the GPS (Global Position System) shared with other satellite navigation system compatibilities of the world.By 5 geostationary orbit (GEO) satellites, circle Earth's orbit (MEO) satellite and 3 inclination geostationary orbit (IGSO) satellites form in 27.Current Beidou satellite navigation system has succeeded in sending up 16 satellites, defines regional service ability, provides the services such as passive location, navigation and time service towards China and periphery most area.

BD satellite-signal has B1, B2 and B3 tri-frequencies, and wherein B1 and B2 is two civil signal.B1 and B2 signal is made up of on carrier wave " ranging code+navigation message " orthogonal modulation of I, Q two branch roads.

The base band signal process of BD receiver mainly comprise catch, follow the tracks of, the synchronous step such as (frame synchronization and bit synchronization) and navigation calculation.Carrier signal, after the carrier signal being received corresponding frequency by antenna, is become digital intermediate frequency signal through down coversion and analog to digital conversion, is supplied to trapping module by BD receiver.Trapping module obtains the carrier frequency of all visible satellites and the coarse value of ranging code phase place by reproduction intermediate frequency carrier and ranging code and the parameter that adjusts them.The phase place of information to the carrier frequency of visible satellite and ranging code that track loop obtains based on trapping module carries out further accurately measuring.When track loop success locking satellite signal, just can carry out bit synchronization, and frame synchronization operation, the textual information that last basis obtains carries out position, speed, time (PVT) resolves.

In BD receiver, track loop is by carrying out accurate tracking to the carrier frequency of BD signal and ranging code phase place, and obtain pseudo-range information according to the ranging code phase place that code tracking loop is measured, from in-phase branch, demodulate navigation message information, thus provide required pseudorange and telegraph text data for navigation calculation.Therefore, the pseudorange accuracy measured of track loop and navigation message demodulation quality directly determine the positioning precision of BD receiver.

In track loop, the performance of loop filter decides the performance of track loop, and determines exponent number and the noise bandwidth of the mainly loop filter of loop filter performance.High exponent number can follow the tracks of the Dynamic Signal of high order.Narrow noise bandwidth contributes to noise in filtering loop, improves the tracking accuracy of loop.Wide noise bandwidth following range is comparatively large, is applicable to following the tracks of dynamically higher signal, but also can increases the noise in loop simultaneously.At present, existing BD receiver tracking loop circuit at least comprises FLL, phaselocked loop and FLL and assists one in phaselocked loop, its exponent number and loop bandwidth set already, limit the dynamic scope of application of loop, under high dynamic environment, tracking error is easily caused to strengthen, the even phenomenon of loop losing lock.Particular problem is as follows:

1) although phaselocked loop is less to carrier tracking error, dynamic property is poor, follows the tracks of carrier phase difficulty comparatively greatly, easy losing lock under high dynamic environment;

2) although FLL has larger following range to Dynamic Signal, tracking error is larger;

3) although FLL assists phaselocked loop can improve the dynamic property of track loop to a certain extent, its fixing initial loop bandwidth limits the ability of loop dynamics and anti-noise jamming.And although can tracking signal preferably based on the track loop of Kalman Filter Technology, its complexity be high, and software simulating cost is high.

Summary of the invention

For the problems referred to above, the present invention proposes adaptive tracking method under a kind of new receiver high dynamic environment, it comprises the following steps:

The intermediate frequency carrier frequency that S100, basis are caught and ranging code phase place, initialization carrier generator and ranging code generator produce the correlation parameter of signal;

S200, the signal pair frequency carrier wave digital signal utilizing carrier generator and ranging code generator to produce carry out carrier wave stripping and ranging code stripping, extract baseband digital signal;

S300, baseband digital signal carried out to phase demodulation, frequency discrimination and carrier-to-noise ratio and calculate;

S400, according to phase demodulation, frequency discrimination and carrier-to-noise ratio result of calculation, ask for according to the mathe-matical map relation preset the auxiliary coefficient that new frequency-locked loop bandwidth sum phase-locked loop bandwidth and FLL assist phaselocked loop;

S500, the auxiliary coefficient of phaselocked loop is assisted to reset the bandwidth of loop filter according to new frequency-locked loop bandwidth sum phase-locked loop bandwidth and FLL;

S600, according to the Output rusults of loop filter adjustment carrier generator and ranging code generator, return step S200.

According to embodiments of the invention, in above-mentioned steps S100, described correlation parameter comprises the phase increment control word of carrier generator and the initial phase of ranging code generator;

Can the phase increment control word △ P of initialization carrier generator according to the following formula _f:

$\mathrm{\Δ}{P}_f=\frac{2^M\·f_{\mathrm{carr}}}{f_{\mathrm{clk}}}$

In formula, M is the word length of the phase accumulator of carrier generator, f _clkfor the clock of carrier generator, f _carrfor the intermediate frequency carrier frequency values of catching;

Can the initial phase C of initialization ranging code generator according to the following formula _pha0:

C _pha0＝C _pha

In formula, C _phafor the ranging code phase value of catching.

According to embodiments of the invention, in above-mentioned steps S300, described phase demodulation comprises yard ring phase demodulation and carrier wave ring phase demodulation, and described frequency discrimination comprises carrier wave ring frequency discrimination.

According to embodiments of the invention, preferably, in above-mentioned steps S300, first can carry out integration to baseband digital signal and add up, and then the calculating of phase demodulation, frequency discrimination and carrier-to-noise ratio is carried out to integration accumulation result.

According to embodiments of the invention, in above-mentioned steps S400, described mathe-matical map relation comprises time interval T _kthe average of interior carrier-to-noise ratio result of calculation is as the carrier-to-noise ratio of the tracked satellite-signal of t

${\stackrel{\‾}{\mathrm{CNR}}}_t=\frac{1}{K}\underset{k=0}{\overset{K}{\mathrm{\Σ}}}\mathrm{CNR}\left(k\right)$

In formula, CNR (k) is a kth carrier-to-noise ratio result of calculation, and K is moment t-T _kto the number of carrier-to-noise ratio result of calculation between moment t.

According to embodiments of the invention, in above-mentioned steps S400, described mathe-matical map relation comprises the loop bandwidth Bf calculating new i rank FLL according to following formula _i':

${{\mathrm{Bf}}_i}^{\′}=\sqrt[2i+1]{\frac{{\mathrm{\π}}^2{T}^2\·{\stackrel{\‾}{\mathrm{CNR}}}_t\·{\left(V^{(i+1)}\right)}^2\·{\left({\mathrm{\λ}}_i\right)}^{2i}}{9F\·(1+\frac{1}{T\·{\stackrel{\‾}{\mathrm{CNR}}}_t})}}$

In formula, i represents FLL exponent number, V ⁽ⁱ⁺¹⁾represent the i+1 order derivative of receiver bearer rate, λ _ifor the scale-up factor of i rank FLL loop bandwidth and characteristic frequency, for the carrier-to-noise ratio of the tracked satellite-signal of t, T is integration accumulation interval, and F is one and carrier-to-noise ratio relevant parameter.

According to embodiments of the invention, in above-mentioned steps S400, described mathe-matical map relation comprises the loop bandwidth Bp calculating new j rank phaselocked loop according to following formula _j':

$B{p_j}^{\′}=\sqrt[2j+1]{\frac{4{\stackrel{\‾}{\mathrm{CNR}}}_t\·{\left({\mathrm{\μ}}_j\right)}^{2j}\·{\left(V^{\left(j\right)}\right)}^2}{9(1+\frac{1}{2T\·{\stackrel{\‾}{\mathrm{CNR}}}_t})}}$

In formula, j represents phaselocked loop exponent number, V ^(j)represent the j order derivative of receiver bearer rate, μ _jfor the scale-up factor of j rank PLL loop bandwidth and characteristic frequency, for the carrier-to-noise ratio of the tracked satellite-signal of t, T is integration accumulation interval.

According to embodiments of the invention, in above-mentioned steps S500, described mathe-matical map relation comprises:

Calculate the sighting distance acceleration a of receiver carrier t _twith sighting distance acceleration a _t';

$a_t=\frac{1}{K}\underset{k=0}{\overset{K}{\mathrm{\Σ}}}{f}_e\left(k\right)\·(B{f}_i/{\mathrm{\λ}}_i),{a_t}^{\′}=\frac{1}{K}\underset{k=0}{\overset{K}{\mathrm{\Σ}}}{f}_e\left(k\right)\·{(B{f}_i/{\mathrm{\λ}}_i)}^2$

In formula, f _ek () is a kth carrier wave ring frequency discrimination result, K is moment t-T _kto the number of the carrier wave ring frequency discrimination result exported between moment t, λ _ifor the scale-up factor of i rank FLL loop bandwidth and characteristic frequency, Bf _ifor the loop bandwidth that i rank FLL is current;

If sighting distance acceleration and sighting distance acceleration are all less than corresponding threshold value, the auxiliary coefficient α >1 that FLL assists phaselocked loop is set, 0< β <1;

If sighting distance acceleration is greater than corresponding threshold value and sighting distance acceleration is less than corresponding threshold value, the auxiliary coefficient 0< α <1 that FLL assists phaselocked loop is set, β >1;

If sighting distance acceleration and sighting distance acceleration are all greater than corresponding threshold value, the auxiliary coefficient 0< α <0.5 that FLL assists phaselocked loop is set, β >1.

According to embodiments of the invention, further, in above-mentioned steps S500, described loop filter comprises FLL, phaselocked loop and FLL and assists cycle of phase-locked loop ring wave filter and Loop filter, according to the loop bandwidth of new FLL, the loop bandwidth of phaselocked loop, and the product of identified result that auxiliary coefficient α and carrier wave ring phase detector export, the product of the frequency discrimination result that auxiliary coefficient β and carrier wave ring frequency discriminator export resets the bandwidth that FLL, phaselocked loop and FLL assist cycle of phase-locked loop ring wave filter.

According to embodiments of the invention, further, further, in above-mentioned steps S600, the Output rusults of cycle of phase-locked loop ring wave filter is assisted according to FLL, carrier generator adjustment produces the correlation parameter of signal, and according to filtered code ring identified result, the adjustment of ranging code generator produces the correlation parameter of signal.

Compared with prior art, the technical scheme that the present invention proposes has the following advantages:

1, dynamic perfromance and noise characteristic by detecting receiver in real time carry out the bandwidth of adjustment loop, make track loop can under the environment of dynamic change, especially the bandwidth of timely adjustment loop wave filter under the environment of high dynamic change, make it keep optimal value, tracking error is remained in less scope.

2, assist the auxiliary coefficient of phaselocked loop to increase the dynamically adapting scope of track loop further by adjustment FLL, thus enhance track loop under the environment of dynamic change, the stability especially under the environment of high dynamic change.

3, the present invention proposes technical scheme to overcome in prior art receiver tracking error under high dynamic environment large, the shortcoming of loss of lock easily occurs, and complexity is low, can realize easily by software.

Other features and advantages of the present invention will be set forth in the following description, and partly become apparent from instructions, or understand by implementing the present invention.Object of the present invention and other advantages realize by structure specifically noted in instructions, claims and accompanying drawing and obtain.

Accompanying drawing explanation

Accompanying drawing is used to provide a further understanding of the present invention, and forms a part for instructions, with embodiments of the invention jointly for explaining the present invention, is not construed as limiting the invention.In the accompanying drawings:

Fig. 1 is the structured flowchart of the track loop of the BD receiver adopted in the embodiment of the present invention;

Fig. 2 is the implementing procedure figure of the adaptive tracking method of BD receiver in the embodiment of the present invention.

Embodiment

Below in conjunction with drawings and Examples, technical scheme of the present invention is described in detail.

Fig. 1 shows the structured flowchart of the track loop of the BD receiver adopted in the embodiment of the present invention.Wherein, carrier wave NCO and code ring NCO represents carrier generator and ranging code generator respectively, is digital controlled oscillator.FLL assists PLL loop ring wave filter to be the abbreviation that FLL assists cycle of phase-locked loop ring wave filter.

This BD receiver, can by the control errors of tracking satellite navigation signal in less scope according to the process flow diagram work shown in Fig. 2.

The intermediate frequency carrier frequency that S100, basis are caught and ranging code phase place, initialization carrier generator and ranging code generator produce the correlation parameter of signal.Particular content is as follows.

After BD receiver to receive the carrier signal of corresponding frequency by antenna, through down coversion and analog to digital conversion, carrier signal is become digital intermediate frequency signal, be supplied to trapping module.Trapping module reproduction intermediate frequency carrier and ranging code, obtain intermediate frequency carrier frequency f _carrwith the coarse value C of ranging code phase place _pha.

According to the intermediate frequency carrier frequency values f obtained _carrwith ranging code phase value C _pha, initialization carrier generator and ranging code generator produce the correlation parameter of signal.In the present embodiment, these correlation parameters comprise the phase increment control word △ P of carrier generator _f, and the initial phase C of ranging code generator _pha0.Wherein:

$\mathrm{\&Delta;}{P}_f=\frac{2^M\&CenterDot;f_{\mathrm{carr}}}{f_{\mathrm{clk}}}$ C _pha0＝C _pha

Wherein, M is the word length of the phase accumulator of carrier generator, f _clkfor the clock of carrier generator.

S200, the signal pair frequency digital signal utilizing carrier generator and ranging code generator to produce carry out carrier wave stripping and ranging code stripping, extract baseband digital signal.Particular content is as follows.

Carrier generator and ranging code generator produce corresponding signal respectively and carry out carrier wave stripping and ranging code stripping to the digital intermediate frequency signal obtained through analog to digital conversion, thus obtain following six road baseband digital signals:

Advanced code i _e(n) q _e(n) orthogonal two-way;

Instantaneous code i _p(n) q _p(n) orthogonal two-way;

Delayed code i _l(n) q _l(n) orthogonal two-way;

Wherein n=0,1,2 ... for sampled point sequence number.

S300, carries out phase demodulation, frequency discrimination and carrier-to-noise ratio to baseband digital signal and calculates.Particular content is as follows.

In embodiments of the present invention, preferably, also integration is carried out to above-mentioned six roadbed band signals and adds up, obtain following six road low speed base band datas:

$I_E\left(k\right)=\underset{n=\mathrm{kN}}{\overset{(k+1)N-1}{\mathrm{\&Sigma;}}}{i}_E\left(n\right),Q_E\left(k\right)=\underset{n=\mathrm{kN}}{\overset{(k+1)N-1}{\mathrm{\&Sigma;}}}{q}_E\left(n\right),$

$I_P\left(k\right)=\underset{n=\mathrm{kN}}{\overset{(k+1)N-1}{\mathrm{\&Sigma;}}}{i}_P\left(n\right),Q_P\left(k\right)=\underset{n=\mathrm{kN}}{\overset{(k+1)N-1}{\mathrm{\&Sigma;}}}{q}_P\left(n\right),$

$I_L\left(k\right)=\underset{n=\mathrm{kN}}{\overset{(k+1)N-1}{\mathrm{\&Sigma;}}}{i}_L\left(n\right),Q_L\left(k\right)=\underset{n=\mathrm{kN}}{\overset{(k+1)N-1}{\mathrm{\&Sigma;}}}{q}_L\left(n\right),$

Wherein, k=0,1,2 ... for cumulative rear data point sequence number, T is integration accumulation interval, and N is original intermediate frequency data sampled point number in time T.

Then six road low speed base band datas are inputed to a yard ring phase detector, carrier wave ring phase detector, carrier wave ring frequency discriminator and carrier-to-noise ratio computing unit, carry out corresponding phase demodulation, frequency discrimination and carrier-to-noise ratio and calculate (as shown in Figure 1).Wherein, the identified result that code ring phase detector exports is designated as φ _ek (), the identified result that carrier wave ring phase detector exports is designated as θ _ek (), the frequency discrimination result that carrier wave ring frequency discriminator exports is designated as f _ek (), the result of calculation that carrier-to-noise ratio computing unit exports is designated as CNR (k).

Should be understood that, in the present embodiment, carry out integration add up to baseband digital signal, then cumulative to integration result is carried out phase demodulation, frequency discrimination and carrier-to-noise ratio and is calculated, and is to reduce noise further.But this does not get rid of, directly baseband digital signal is carried out to the feasibility of phase demodulation, frequency discrimination and carrier-to-noise ratio calculating.

S400, according to phase demodulation, frequency discrimination and carrier-to-noise ratio result of calculation, ask for according to the mathe-matical map relation preset the auxiliary coefficient that new frequency-locked loop bandwidth sum phase-locked loop bandwidth and FLL assist phaselocked loop.Particular content is as follows.

In the present embodiment, preferred acquisition time interval T _kthe result that interior carrier-to-noise ratio computing unit exports, gets the carrier-to-noise ratio of its average as the tracked satellite-signal of t

${\stackrel{\&OverBar;}{\mathrm{CNR}}}_t=\frac{1}{K}\underset{k=0}{\overset{K}{\mathrm{\&Sigma;}}}\mathrm{CNR}\left(k\right)$

Wherein, CNR (k) is a kth carrier-to-noise ratio result of calculation, and K is moment t-T _kto the number of the result that carrier-to-noise ratio computing unit between moment t exports.

The loop bandwidth Bf of new (i.e. subsequent time) i rank FLL is calculated according to following formula _i':

${{\mathrm{Bf}}_i}^{\&prime;}=\sqrt[2i+1]{\frac{{\mathrm{\&pi;}}^2{T}^2\&CenterDot;{\stackrel{\&OverBar;}{\mathrm{CNR}}}_t\&CenterDot;{\left(V^{(i+1)}\right)}^2\&CenterDot;{\left({\mathrm{\&lambda;}}_i\right)}^{2i}}{9F\&CenterDot;(1+\frac{1}{T\&CenterDot;{\stackrel{\&OverBar;}{\mathrm{CNR}}}_t})}}$

Wherein, i represents FLL exponent number, V ⁽ⁱ⁺¹⁾represent the i+1 order derivative of receiver bearer rate, λ _ifor the scale-up factor of i rank FLL loop bandwidth and characteristic frequency, T is integration accumulation interval.F be one with the carrier-to-noise ratio of tracked satellite-signal relevant parameter, works as carrier-to-noise ratio when being greater than given threshold value, F gets 1, works as carrier-to-noise ratio when being less than given threshold value, F gets 2.

The loop bandwidth Bp of new (i.e. subsequent time) j rank phaselocked loop is calculated according to following formula _j':

$B{p_j}^{\&prime;}=\sqrt[2j+1]{\frac{4{\stackrel{\&OverBar;}{\mathrm{CNR}}}_t\&CenterDot;{\left({\mathrm{\&mu;}}_j\right)}^{2j}\&CenterDot;{\left(V^{\left(j\right)}\right)}^2}{9(1+\frac{1}{2T\&CenterDot;{\stackrel{\&OverBar;}{\mathrm{CNR}}}_t})}}$

Wherein, j represents phaselocked loop exponent number, V ^(j)represent the j order derivative of receiver bearer rate, μ _jfor the scale-up factor of j rank PLL loop bandwidth and characteristic frequency, T is integration accumulation interval.

Based on the frequency discrimination result f that frequency discriminator exports _ek (), calculates the sighting distance dynamic value of receiver carrier t, also namely calculate sighting distance acceleration a _twith sighting distance acceleration a _t':

$a_t=\frac{1}{K}\underset{k=0}{\overset{K}{\mathrm{\&Sigma;}}}{f}_e\left(k\right)\&CenterDot;(B{f}_i/{\mathrm{\&lambda;}}_i),{a_t}^{\&prime;}=\frac{1}{K}\underset{k=0}{\overset{K}{\mathrm{\&Sigma;}}}{f}_e\left(k\right)\&CenterDot;{(B{f}_i/{\mathrm{\&lambda;}}_i)}^2$

Wherein, f _ek () is a kth frequency discrimination result, K is moment t-T _kto the number exporting frequency discrimination result between moment t; Bf _ifor the loop bandwidth of current time i rank FLL.

In the present embodiment, FLL assists auxiliary coefficient α and β of phaselocked loop according to sighting distance acceleration a _twith sighting distance acceleration a _t' size, reset according to following mechanism:

The threshold value supposed sighting distance given and accelerate with the threshold value of sighting distance acceleration

When time, auxiliary coefficient value α >1,0< β <1;

When time, auxiliary coefficient value 0< α <1, β >1;

When time, auxiliary coefficient value 0< α <0.5, β >1.

S500, the auxiliary coefficient of phaselocked loop is assisted to reset the bandwidth of loop filter according to new frequency-locked loop bandwidth sum phase-locked loop bandwidth and FLL.Particular content is as follows:

According to the loop bandwidth Bf of new FLL _i', the loop bandwidth Bp of new phaselocked loop _j', and the identified result θ that new auxiliary coefficient α and carrier wave ring phase detector export _ethe product of (k), the frequency discrimination result f that new auxiliary coefficient β and carrier wave ring frequency discriminator export _ek the product of () resets the bandwidth that FLL, phaselocked loop and FLL assist cycle of phase-locked loop ring wave filter.

S600, according to the Output rusults of loop filter adjustment carrier generator and ranging code generator, return step S200.

Particularly, as shown in Figure 1, assist the Output rusults of cycle of phase-locked loop ring wave filter according to FLL, carrier generator adjustment produces the correlation parameter of signal, and produces new signal accordingly, and the carrier wave carrying out a new round is peeled off; Simultaneously according to the Output rusults of Loop filter (also i.e. filtered identified result φ _e(k)), the adjustment of ranging code generator produces the correlation parameter of signal, and produces new signal accordingly, and the ranging code carrying out a new round is peeled off.

Adjusted by this iterative cycles, the error of tracking satellite navigation signal remains in less scope by BD receiver, achieves the accurate measurement of carrier frequency to satellite and ranging code phase place.

The tracking that the present invention proposes, residing for detection receiver, the dynamic perfromance of environment and the noisiness of signal adjust the bandwidth of track loop loop filter and the auxiliary coefficient of FLL and phaselocked loop in real time, track loop is made to adjust inherent parameters in time under the environment of dynamic change, tracking error is remained in less scope, also increase the dynamically adapting scope of track loop simultaneously, improve the stability of track loop, solve the problem that existing BD receiver track loop error under high dynamic environment is large, losing lock easily occurs.In addition, the mathe-matical map relation set in above-described embodiment can by writing corresponding software simulating in the original central control unit of receiver, and without the need to increasing extra cost, implementation complexity is low.

Last it is noted that above each embodiment is only in order to illustrate technical scheme of the present invention, be not intended to limit; Although with reference to foregoing embodiments to invention has been detailed description, those of ordinary skill in the art is to be understood that: it still can be modified to the technical scheme described in foregoing embodiments, or carries out equivalent replacement to wherein some or all of technical characteristic; And these amendments or replacement, do not make the essence of appropriate technical solution depart from the scope of various embodiments of the present invention technical scheme.

Claims (10)

1. an adaptive tracking method under receiver high dynamic environment, comprises the following steps:

The intermediate frequency carrier frequency that S100, basis are caught and ranging code phase place, initialization carrier generator and ranging code generator produce the correlation parameter of signal;

S200, the signal pair frequency carrier wave digital signal utilizing carrier generator and ranging code generator to produce carry out carrier wave stripping and ranging code stripping, extract baseband digital signal;

S300, baseband digital signal carried out to phase demodulation, frequency discrimination and carrier-to-noise ratio and calculate;

S400, according to phase demodulation, frequency discrimination and carrier-to-noise ratio result of calculation, ask for according to the mathe-matical map relation preset the auxiliary coefficient that new frequency-locked loop bandwidth sum phase-locked loop bandwidth and FLL assist phaselocked loop;

S500, the auxiliary coefficient of phaselocked loop is assisted to reset the bandwidth of loop filter according to new frequency-locked loop bandwidth sum phase-locked loop bandwidth and FLL;

S600, according to the Output rusults of loop filter adjustment carrier generator and ranging code generator, return step S200.

2. adaptive tracking method as claimed in claim 1, is characterized in that:

In step S100, described correlation parameter comprises the phase increment control word of carrier generator and the initial phase of ranging code generator;

The phase increment control word △ P of initialization carrier generator according to the following formula _f:

$\mathrm{\&Delta;}{P}_f=\frac{2^M\&CenterDot;f_{\mathrm{carr}}}{f_{\mathrm{clk}}}$

Wherein, M is the word length of the phase accumulator of carrier generator, f _clkfor the clock of carrier generator, f _carrfor the intermediate frequency carrier frequency values of catching;

The initial phase C of initialization ranging code generator according to the following formula _pha0:

C _pha0＝C _pha

Wherein, C _phafor the ranging code phase value of catching.

3. adaptive tracking method as claimed in claim 1, is characterized in that:

In step S300, described phase demodulation comprises yard ring phase demodulation and carrier wave ring phase demodulation, and described frequency discrimination comprises carrier wave ring frequency discrimination.

4. the adaptive tracking method as described in claims 1 to 3 any one, is characterized in that:

Further, in step S300, first integration is carried out to baseband digital signal and add up, and then the calculating of phase demodulation, frequency discrimination and carrier-to-noise ratio is carried out to integration accumulation result.

5. adaptive tracking method as claimed in claim 4, it is characterized in that, in step S400, described mathe-matical map relation comprises time interval T _kthe average of interior carrier-to-noise ratio result of calculation is as the carrier-to-noise ratio of the tracked satellite-signal of t

${\stackrel{\&OverBar;}{\mathrm{CNR}}}_t=\frac{1}{K}\underset{k=0}{\overset{K}{\mathrm{\&Sigma;}}}\mathrm{CNR}\left(k\right)$

Wherein, CNR (k) is a kth carrier-to-noise ratio result of calculation, and K is moment t-T _kto the number of carrier-to-noise ratio result of calculation between moment t.

6. adaptive tracking method as claimed in claim 4, it is characterized in that, in step S400, described mathe-matical map relation comprises the loop bandwidth Bf calculating new i rank FLL according to following formula _i':

${{\mathrm{Bf}}_i}^{\&prime;}=\sqrt[2i+1]{\frac{{\mathrm{\&pi;}}^2{T}^2\&CenterDot;{\stackrel{\&OverBar;}{\mathrm{CNR}}}_t\&CenterDot;{\left(V^{(i+1)}\right)}^2\&CenterDot;{\left({\mathrm{\&lambda;}}_i\right)}^{2i}}{9F\&CenterDot;(1+\frac{1}{T\&CenterDot;{\stackrel{\&OverBar;}{\mathrm{CNR}}}_t})}}$

Wherein, i represents FLL exponent number, V ⁽ⁱ⁺¹⁾represent the i+1 order derivative of receiver bearer rate, λ _ifor the scale-up factor of i rank FLL loop bandwidth and characteristic frequency, for the carrier-to-noise ratio of the tracked satellite-signal of t, T is integration accumulation interval, and F is one and carrier-to-noise ratio relevant parameter.

7. adaptive tracking method as claimed in claim 4, it is characterized in that, in step S400, described mathe-matical map relation comprises the loop bandwidth Bp calculating new j rank phaselocked loop according to following formula _j':

$B{p_j}^{\&prime;}=\sqrt[2j+1]{\frac{4{\stackrel{\&OverBar;}{\mathrm{CNR}}}_t\&CenterDot;{\left({\mathrm{\&mu;}}_j\right)}^{2j}\&CenterDot;{\left(V^{\left(j\right)}\right)}^2}{9(1+\frac{1}{2T\&CenterDot;{\stackrel{\&OverBar;}{\mathrm{CNR}}}_t})}}$

Wherein, j represents phaselocked loop exponent number, V ^(j)represent the j order derivative of receiver bearer rate, μ _jfor the scale-up factor of j rank PLL loop bandwidth and characteristic frequency, for the carrier-to-noise ratio of the tracked satellite-signal of t, T is integration accumulation interval.

8. adaptive tracking method as claimed in claim 4, it is characterized in that, in step S500, described mathe-matical map relation comprises:

Calculate the sighting distance acceleration a of receiver carrier t _twith sighting distance acceleration a _t';

$a_t=\frac{1}{K}\underset{k=0}{\overset{K}{\mathrm{\&Sigma;}}}{f}_e\left(k\right)\&CenterDot;(B{f}_i/{\mathrm{\&lambda;}}_i),{a_t}^{\&prime;}=\frac{1}{K}\underset{k=0}{\overset{K}{\mathrm{\&Sigma;}}}{f}_e\left(k\right)\&CenterDot;{(B{f}_i/{\mathrm{\&lambda;}}_i)}^2$

Wherein, f _ek () is a kth carrier wave ring frequency discrimination result, K is moment t-T _kto the number of the carrier wave ring frequency discrimination result exported between moment t, λ _ifor the scale-up factor of i rank FLL loop bandwidth and characteristic frequency, Bf _ifor the loop bandwidth of current time i rank FLL;

If sighting distance acceleration and sighting distance acceleration are all less than corresponding threshold value, the auxiliary coefficient α >1 that FLL assists phaselocked loop is set, 0< β <1;

If sighting distance acceleration is greater than corresponding threshold value and sighting distance acceleration is less than corresponding threshold value, the auxiliary coefficient 0< α <1 that FLL assists phaselocked loop is set, β >1;

If sighting distance acceleration and sighting distance acceleration are all greater than corresponding threshold value, the auxiliary coefficient 0< α <0.5 that FLL assists phaselocked loop is set, β >1.

9. the adaptive tracking method as described in claims 1 to 3 any one, is characterized in that:

Further, in step S500, described loop filter comprises FLL, phaselocked loop and FLL and assists cycle of phase-locked loop ring wave filter and Loop filter, according to the loop bandwidth of new FLL, the loop bandwidth of phaselocked loop, and the product of identified result that auxiliary coefficient α and carrier wave ring phase detector export, the product of the frequency discrimination result that auxiliary coefficient β and carrier wave ring frequency discriminator export resets the bandwidth that FLL, phaselocked loop and FLL assist cycle of phase-locked loop ring wave filter.

10. the adaptive tracking method as described in claims 1 to 3 any one, is characterized in that:

Further, in step S600, assist the Output rusults of cycle of phase-locked loop ring wave filter according to FLL, carrier generator adjustment produces the correlation parameter of signal, and according to filtered code ring identified result, the adjustment of ranging code generator produces the correlation parameter of signal.