CN104252000B - The quick compensating circuit of a kind of Doppler based on DDS and method - Google Patents

Abstract

The invention discloses the quick compensating circuit of a kind of Doppler based on DDS and method, the output of carrier tracking loop is connected with the input of frequency control word computing unit, the transmitting PN code clock frequency control word output of frequency control word computing unit is connected with an input of spectrum spreading circuit with PN code generator by PN code clock DDS successively, and another input of spectrum spreading circuit produces circuit with transmitting baseband and is connected; The IF carrier frequency control word output of frequency control word computing unit is connected with an input of BPSK modulation circuit by IF carrier DDS, and another input of BPSK modulation circuit is connected with the output of spectrum spreading circuit. The present invention utilizes the ability that the frequency of Direct Digital Frequency Synthesizers DDS is quick and precisely adjusted that the frequency deviation that transmits has been carried out in real time, compensated accurately, carry out Doppler effect correction to transmitting quickly and efficiently, solved the Problem of Failure that subscriber computer causes due to Doppler effect under high dynamic environment.

Description

The quick compensating circuit of a kind of Doppler based on DDS and method

Technical field

The present invention relates to the quick compensating circuit of a kind of Doppler based on DDS and method.

Background technology

Along with scientific and technical development, the application of navigation system is more and more extensive. Big Dipper RDSS subscriber computer is mainly realized big-dipper satelliteFast Acquisition, precision tracking, the synchronous demodulation of signal and the generation function that transmits, obtained applying comparatively widely at present.

The high dynamic subscriber's machine of Big Dipper RDSS refers to the Big Dipper RDSS subscriber computer being mounted on high speed carrier. Big Dipper RDSS is high dynamically to be usedFamily machine can produce Doppler effect in high dynamic movement process, if the frequency difference that Doppler effect brings has exceeded aeronautical satelliteRange of receiving, will cause subscriber computer normally to communicate with satellite.

For the Big Dipper RDSS subscriber computer of emission signal frequency not being revised, can under conventional stationary and low dynamic environmentNormally to work, but while applying on the high speed carrier of specific high-altitude, the frequency transmitting will make it due to Doppler effectFrequency difference exceedes the range of receiving of big-dipper satellite, causes the subscriber computer cannot proper communication, finally causes subscriber computer to lose efficacy.

In the time transmitting, most Big Dipper RDSS subscriber computers are not revised signal frequency, or adopt crystal oscillator frequencyThe mode of proofreading and correct is revised signal frequency. The north of carrying out emission signal frequency correction for the mode that adopts crystal oscillator frequency to proofread and correctBucket RDSS subscriber computer, because the mode that adopts counting is added up Doppler frequency deviation, Doppler adds up to exist and postpones, larger at accelerationDynamic environment under, due to exist proofread and correct time delay, also can make to launch the range of receiving that frequency difference exceedes big-dipper satellite, cause subscriber computerCannot proper communication. In addition, the quick compensating circuit of existing Doppler all adopts multiple crystal oscillators, realizes more complicated.

Summary of the invention

The object of the invention is to overcome the deficiencies in the prior art, provide a kind of novel Doppler based on DDS to compensate fast electricityRoad and method, utilize the ability that the frequency of Direct Digital Frequency Synthesizers DDS is quick and precisely adjusted to carry out reality to the frequency deviation that transmitsTime, accurately compensation, can carry out quickly and efficiently Doppler effect correction to transmitting, solve subscriber computer under high dynamic environmentThe Problem of Failure causing due to Doppler effect.

The object of the invention is to be achieved through the following technical solutions: the quick compensating circuit of a kind of Doppler based on DDS, itComprise:

Receive the carrier tracking loop of doppler information for Real-time Obtaining;

For calculating according to receiving doppler information the frequency control word meter of launching PN code clock and IF carrier frequency control wordCalculate unit;

For produce the PN code clock Direct Digital Frequency Synthesizers of transmitting PN code clock according to transmitting PN code clock frequency control word;

For produce the IF carrier Direct Digital Frequency Synthesizers of IF carrier according to IF carrier frequency control word;

The output of carrier tracking loop is connected with the input of frequency control word computing unit, the transmitting PN code of frequency control word computing unitClock frequency control word output is successively by one of PN code clock Direct Digital Frequency Synthesizers and PN code generator and spectrum spreading circuitInput connects, and another input of spectrum spreading circuit produces circuit with transmitting baseband and is connected; In frequency control word computing unitFrequently carrier frequency control word output is by an input of IF carrier Direct Digital Frequency Synthesizers and BPSK modulation circuitConnect, another input of BPSK modulation circuit is connected with the output of spectrum spreading circuit.

The output of described BPSK modulation circuit is successively by digital to analog converter, filter circuit, amplifying circuit, upconversion process electricityRoad and power amplification circuit are connected to transmitting antenna.

Doppler's fast-compensation method based on DDS, it comprises the following steps:

S1: adopt the crystal oscillator of high stability as frequency reference,, followed by carrier wave after receiver locking satellite signal according to this benchmarkTrack ring Real-time Obtaining receives doppler information;

S2: frequency control word computing unit calculates transmitting PN code clock and IF carrier FREQUENCY CONTROL according to receiving doppler informationWord;

S3: obtain digital intermediate frequency BPSK modulation signal, it comprises:

(1) PN code clock Direct Digital Frequency Synthesizers produces transmitting PN code clock, PN code according to transmitting PN code clock frequency control wordGenerator produces PN code based on this yard of clock, and the transmitting baseband that this PN code and transmitting baseband produce circuit generation carries out spread processing,After spread spectrum, export BPSK modulation circuit to and carry out BPSK modulation;

(2) IF carrier Direct Digital Frequency Synthesizers produces IF carrier according to IF carrier frequency control word, and IF carrier is defeatedGo out to BPSK modulation circuit and carry out BPSK modulation;

S4: digital intermediate frequency BPSK modulation signal is successively after digital-to-analogue conversion, filtering, amplification, up-conversion and power amplification are processedBe sent to transmitting antenna.

Further, IF carrier frequency control word FCW_{tran_carr}And transmitting PN code clock frequency control word FCW_pnComputational methodsAs follows:

${\mathrm{FCW}}_{\mathrm{tran}\_\mathrm{carr}}={\mathrm{FCW}}_{\mathrm{tran}\_\mathrm{carr}\_\mathrm{sd}}-\frac{f_{\mathrm{tran}\_\mathrm{carr}}\×f_{\mathrm{sys}\_\mathrm{loop}}}{f_{\mathrm{rev}\_\mathrm{carr}}\×f_{\mathrm{sys}\_\mathrm{tran}\_\mathrm{carr}}}\×({\mathrm{FCW}}_{\mathrm{loop}}-{\mathrm{FCW}}_{\mathrm{loop}\_\mathrm{sd}});$

${\mathrm{FCW}}_{\mathrm{pn}}={\mathrm{FCW}}_{\mathrm{pn}\_\mathrm{sd}}-\frac{f_{\mathrm{pn}}\×f_{\mathrm{sys}\_\mathrm{loop}}}{f_{\mathrm{rev}\_\mathrm{carr}}\×f_{\mathrm{sys}\_\mathrm{tran}\_\mathrm{pn}}}\×({\mathrm{FCW}}_{\mathrm{loop}}-{\mathrm{FCW}}_{\mathrm{loop}\_\mathrm{sd}});$

Wherein, FCW_{tran_carr_sd}The standard frequency control word of IF carrier Direct Digital Frequency Synthesizers when thering is no frequency deviation;

FCW_{pn_sd}The standard frequency control word of PN code clock Direct Digital Frequency Synthesizers when thering is no frequency deviation;

f_{tran_carr}For Big Dipper RDSS check-in signal carrier frequency;

f_pnFor Big Dipper RDSS check-in signal PN code frequency;

f_{rev_carr}For Big Dipper RDSS exit signal carrier frequency;

f_{sys_loop}For the system clock of reception carrier tracking loop carrier wave DDS;

f_{sys_tran_carr}For the system clock of transmitting carrier wave intermediate frequency DDS;

f_{sys_tran_pn}For the system clock of transmitter code clock DDS;

FCW_loopFor the frequency control word of reception carrier tracking loop carrier wave DDS after tracking signal;

FCW_{loop_sd}For there is no the standard frequency control word of reception carrier tracking loop carrier wave DDS of frequency deviation.

The invention has the beneficial effects as follows: utilize ability that the frequency of Direct Digital Frequency Synthesizers DDS quick and precisely adjusts to transmittingSignal frequency deviation has carried out in real time, compensation accurately, has carried out Doppler effect correction quickly and efficiently to transmitting, and has solved useThe Problem of Failure that family machine causes due to Doppler effect under high dynamic environment, has ensured the normal communication of subscriber computer, simultaneously toolThere is structure, realize the features such as simple, can be widely used in Aeronautics and Astronautics field, use this technology, can carry out Big Dipper locationCommunicate by letter with short message.

Brief description of the drawings

Fig. 1 is the structural representation of the quick compensating circuit of Doppler of the present invention.

Detailed description of the invention

Below in conjunction with accompanying drawing, technical scheme of the present invention is described in further detail, but protection scope of the present invention is not limited to following instituteState.

As shown in Figure 1, the quick compensating circuit of a kind of Doppler based on DDS, it comprises:

Receive the carrier tracking loop of doppler information for Real-time Obtaining;

For calculating according to receiving doppler information the frequency control word meter of launching PN code clock and IF carrier frequency control wordCalculate unit;

For produce the PN code clock Direct Digital Frequency Synthesizers of transmitting PN code clock according to transmitting PN code clock frequency control word;

For produce the IF carrier Direct Digital Frequency Synthesizers of IF carrier according to IF carrier frequency control word;

The output of carrier tracking loop is connected with the input of frequency control word computing unit, the transmitting PN code of frequency control word computing unitClock frequency control word output is successively by one of PN code clock Direct Digital Frequency Synthesizers and PN code generator and spectrum spreading circuitInput connects, and another input of spectrum spreading circuit produces circuit with transmitting baseband and is connected; In frequency control word computing unitFrequently carrier frequency control word output is by an input of IF carrier Direct Digital Frequency Synthesizers and BPSK modulation circuitConnect, another input of BPSK modulation circuit is connected with the output of spectrum spreading circuit.

The output of described BPSK modulation circuit is successively by digital to analog converter, filter circuit, amplifying circuit, upconversion process electricityRoad and power amplification circuit are connected to transmitting antenna.

Because transmitting of Big Dipper RDSS adopts Direct-Spread BPSK modulation, so revise emission signal frequency by two parts groupBecome: the one, revise the code clock frequency of launching PN code; The 2nd, revise the carrier frequency transmitting.

Doppler's fast-compensation method based on DDS, it comprises the following steps:

S1: adopt high stability crystal oscillator as frequency reference, according to this benchmark after receiver locking satellite signal, by carrier trackRing Real-time Obtaining receives doppler information;

S2: frequency control word computing unit calculates transmitting PN code clock and IF carrier FREQUENCY CONTROL according to receiving doppler informationWord;

S3: obtain digital intermediate frequency BPSK modulation signal, it comprises:

(1) PN code clock Direct Digital Frequency Synthesizers produces transmitting PN code clock, PN code according to transmitting PN code clock frequency control wordGenerator produces PN code based on this yard of clock, and the transmitting baseband that this PN code and transmitting baseband produce circuit generation carries out spread processing,After spread spectrum, export BPSK modulation circuit to and carry out BPSK modulation;

(2) IF carrier Direct Digital Frequency Synthesizers produces IF carrier according to IF carrier frequency control word, and IF carrier is defeatedGo out to BPSK modulation circuit and carry out BPSK modulation;

S4: digital intermediate frequency BPSK modulation signal is successively after digital-to-analogue conversion, filtering, amplification, up-conversion and power amplification are processedBe sent to transmitting antenna.

Further, IF carrier frequency control word FCW_{tran_carr}And transmitting PN code clock frequency control word FCW_pnComputational methodsAs follows:

${\mathrm{FCW}}_{\mathrm{tran}\_\mathrm{carr}}={\mathrm{FCW}}_{\mathrm{tran}\_\mathrm{carr}\_\mathrm{sd}}-\frac{f_{\mathrm{tran}\_\mathrm{carr}}\×f_{\mathrm{sys}\_\mathrm{loop}}}{f_{\mathrm{rev}\_\mathrm{carr}}\×f_{\mathrm{sys}\_\mathrm{tran}\_\mathrm{carr}}}\×({\mathrm{FCW}}_{\mathrm{loop}}-{\mathrm{FCW}}_{\mathrm{loop}\_\mathrm{sd}});$

${\mathrm{FCW}}_{\mathrm{pn}}={\mathrm{FCW}}_{\mathrm{pn}\_\mathrm{sd}}-\frac{f_{\mathrm{pn}}\×f_{\mathrm{sys}\_\mathrm{loop}}}{f_{\mathrm{rev}\_\mathrm{carr}}\×f_{\mathrm{sys}\_\mathrm{tran}\_\mathrm{pn}}}\×({\mathrm{FCW}}_{\mathrm{loop}}-{\mathrm{FCW}}_{\mathrm{loop}\_\mathrm{sd}});$

Wherein, FCW_{tran_carr_sd}The standard frequency control word of IF carrier Direct Digital Frequency Synthesizers when thering is no frequency deviation;

FCW_{pn_sd}The standard frequency control word of PN code clock Direct Digital Frequency Synthesizers when thering is no frequency deviation;

f_{tran_carr}For Big Dipper RDSS check-in signal carrier frequency;

f_pnFor Big Dipper RDSS check-in signal PN code frequency;

f_{rev_carr}For Big Dipper RDSS exit signal carrier frequency;

f_{sys_loop}For the system clock of reception carrier tracking loop carrier wave DDS;

f_{sys_tran_carr}For the system clock of transmitting carrier wave intermediate frequency DDS;

f_{sys_tran_pn}For the system clock of transmitter code clock DDS;

FCW_loopFor the frequency control word of reception carrier tracking loop carrier wave DDS after tracking signal;

FCW_{loop_sd}For there is no the standard frequency control word of reception carrier tracking loop carrier wave DDS of frequency deviation.

The above is only a preferred embodiment of the present invention, is to be understood that the present invention is not limited to disclosed shape hereinFormula, should not regard the eliminating to other embodiment as, and can be used for various other combinations, amendment and environment, and can be hereinIn described contemplated scope, change by technology or the knowledge of above-mentioned instruction or association area. And those skilled in the art carry outChange and variation do not depart from the spirit and scope of the present invention, all should be in the protection domain of claims of the present invention.

Claims (4)

1. the quick compensating circuit of the Doppler based on DDS, is characterized in that: it comprises:

Receive the carrier tracking loop of doppler information for Real-time Obtaining;

For calculating transmitting PN code clock frequency control word and IF carrier frequency according to receiving doppler informationThe frequency control word computing unit of control word;

For produce the PN code clock Direct Digital frequency of transmitting PN code clock according to transmitting PN code clock frequency control wordSynthesizer;

For produce the IF carrier Direct Digital frequency synthesis of IF carrier according to IF carrier frequency control wordDevice;

The output of carrier tracking loop is connected with the input of frequency control word computing unit, frequency control word computing unitTransmitting PN code clock frequency control word output successively by PN code clock Direct Digital Frequency Synthesizers and PN codeGenerator is connected with an input of spectrum spreading circuit, and another input of spectrum spreading circuit and transmitting baseband produceCircuit connects; The IF carrier frequency control word output of frequency control word computing unit is direct by IF carrierDigital frequency synthesizer is connected with an input of BPSK modulation circuit, and another of BPSK modulation circuit is defeatedEntering end is connected with the output of spectrum spreading circuit.

2. the quick compensating circuit of a kind of Doppler based on DDS according to claim 1, its feature existsIn: the output of described BPSK modulation circuit successively by digital to analog converter, filter circuit, amplifying circuit,Upconversion process circuit and power amplification circuit are connected to transmitting antenna.

3. the Doppler's fast-compensation method based on DDS, is characterized in that: it comprises the following steps:

S1: adopt the crystal oscillator of high stability as frequency reference, according to this benchmark after receiver locking satellite signal,Receive doppler information by carrier tracking loop Real-time Obtaining;

S2: frequency control word computing unit calculates the control of transmitting PN code clock frequency according to receiving doppler informationWord processed and IF carrier frequency control word;

S3: obtain digital intermediate frequency BPSK modulation signal, it comprises:

(1) PN code clock Direct Digital Frequency Synthesizers produces transmitting PN according to transmitting PN code clock frequency control wordCode clock, PN code generator produces PN code based on this yard of clock, and this PN code and transmitting baseband generation circuit produceTransmitting baseband carries out spread processing, exports BPSK modulation circuit to and carry out BPSK modulation after spread spectrum;

(2) IF carrier Direct Digital Frequency Synthesizers produces IF carrier according to IF carrier frequency control word,IF carrier exports BPSK modulation circuit to and carries out BPSK modulation;

S4: digital intermediate frequency BPSK modulation signal passes through digital-to-analogue conversion, filtering, amplification, up-conversion and merit successivelyRate is sent to transmitting antenna after amplifying processing.

4. a kind of Doppler's fast-compensation method based on DDS according to claim 3, its feature existsIn: described IF carrier frequency control word FCW_{tran_carr}And transmitting PN code clock frequency control word FCW_pn'sComputational methods are as follows:

${\mathrm{FCW}}_{tran\_carr}={\mathrm{FCW}}_{tran\_carr\_sd}-\frac{f_{tran\_carr}\×f_{sys\_loop}}{f_{rev\_carr}\×f_{sys\_tran\_carr}}\×({\mathrm{FCW}}_{loop}-{\mathrm{FCW}}_{loop\_sd});$

${\mathrm{FCW}}_{pn}={\mathrm{FCW}}_{pn\_sd}-\frac{f_{pn}\×f_{sys\_loop}}{f_{rev\_carr}\×f_{sys\_tran\_pn}}\×({\mathrm{FCW}}_{loop}-{\mathrm{FCW}}_{loop\_sd});$

Wherein, FCW_{tran_carr_sd}The standard frequency of IF carrier Direct Digital Frequency Synthesizers when thering is no frequency deviationControl word;

FCW_{pn_sd}The standard frequency control word of PN code clock Direct Digital Frequency Synthesizers when thering is no frequency deviation;

f_{tran_carr}For Big Dipper RDSS check-in signal carrier frequency;

f_pnFor Big Dipper RDSS check-in signal PN code frequency;

f_{rev_carr}For Big Dipper RDSS exit signal carrier frequency;

f_{sys_loop}For the system clock of reception carrier tracking loop carrier wave DDS;

f_{sys_tran_carr}For the system clock of transmitting carrier wave intermediate frequency DDS;

f_{sys_tran_pn}For the system clock of transmitter code clock DDS;

FCW_loopFor the frequency control word of reception carrier tracking loop carrier wave DDS after tracking signal;

FCW_{loop_sd}For there is no the standard frequency control word of reception carrier tracking loop carrier wave DDS of frequency deviation.