CN103560873A - Method for generating distributed synchronous pulses - Google Patents

Abstract

The invention relates to a method for generating distributed synchronous pulses, and belongs to the technical field of electrocommunication and radars. The method is simple, flexible and convenient to adjust. For a 100M system clock, the phase adjustment time is short, and only a few FPGA resources are occupied.

Description

A kind of production method of distributed synchronization pulse

Technical field

The present invention relates to a kind of production method of distributed synchronization pulse, belong to electronic communication and Radar Technology field.

Background technology

Radar plays irreplaceable effect in modern and following electronic warfare, but the monostatic radar of original transceiver is faced with four kinds of threats: electronic jamming, ultra-low altitude penetration, stealthy weapon, antiradiation missile etc.By comparison, double-basis or multi-static radar system have changed the T of cell site and the identical working method in the R of receiving station position in traditional single base system, T station and R station are split, there is stronger survival ability and higher detecting function, thereby caused people's attention, and be further rapidly developed and extensive use.Yet this wherein an important technical problem be exactly transmitting-receiving station time synchronization problem, radar will carry out measurement target distance with respect to the time delay transmitting according to the echo receiving, therefore between transmitting-receiving station, must keep strict time synchronized, produce synchronous range finding pulse.The present invention just can solve the problem that transmitting-receiving station produces high precision lock-out pulse.

At present, spread spectrum develops rapidly and is widely used in various communication systems, and wherein, it is exactly an important application that satellite TT&C system utilizes pseudo noise code to find range.In satellite TT&C system, the implementation method that adopts various pseudo-random code rangings is all the same substantially.By ground station's pseudo-code generator, produce a pseudo-random code sequence and be sent to satellite, by being forwarded to ground station after satellite reception, by phase comparator, contrast the initial pseudo-random code sequence sending and the phase place of the pseudo-random code sequence that receives, according to phase difference, determine time delay to such an extent as to try to achieve distance.Wherein range error important sources is exactly that ground station's sending module is asynchronous with receiver module clock.The present invention can detect send-receive clock deviation in a system, and by this deviation compensation in distance measurement value, thereby improve range accuracy.

Summary of the invention

The object of the invention is to be mostly confined to increase peripheral module in order to overcome the method for traditional approach generation lock-out pulse, FPGA only plays control action therein, this has not only increased the complexity of system, and precision is difficult to accomplish that, below nanosecond, the present invention proposes a kind of production method of distributed synchronization pulse under high-frequency clock.

The present invention is achieved by the following technical solutions.

The production method of a kind of distributed synchronization pulse of the present invention, first main website catches, finds range branch road pseudo-code synchronously and carrier synchronization processes after receiving extension station data, the despreading of range finding branch road obtains demodulating data and original ranging information, according to range finding branch road demodulating data and original ranging information, can carry out frame synchronization and distance calculating; Branch road pseudo-code is caught, found range to extension station receiving terminal first synchronously and carrier synchronization processes according to the range finding branch road PN code of its bookbinding, and range finding branch road obtains the demodulating data after phase ambiguity after frame synchronization, provides frame start position sign simultaneously.Range finding branch road demodulated output data and original ranging information, in demodulating data, include the ranging information of main website to extension station, two kinds of aggregation of data can obtain the distance measurement value of extension station to main website, auxiliary main distance measurement value is issued to main website by range finding branch road on the one hand, be used for calculating on the one hand and produce lock-out pulse time of delay.Step is:

Step 1, main website have two paths of data ，Yi road for the ，Yi road of finding range for communication, through a series of data processings such as spread spectrums, carrier modulation, up-conversion, by wireless channel, arrive extension station;

Step 2, extension station receiving terminal are first to signal down-conversion, then utilize acquiring pseudo code and tracking technique by modulation demodulation out, baseband signal experiences equally the processes such as spread spectrum, carrier modulation, up-conversion range finding branch road and the communication leg information of main website transmission is transmitted to main website;

Step 3, main website receiving terminal equally will be to data down-conversions after receiving the forwarding data of extension station, utilize acquiring pseudo code and pseudo-code tracing to carry out carrier wave to signal and remove and pseudo-code removing, this data handling procedure is the same with the data handling procedure of extension station receiving terminal;

Step 4, main website, extension station successfully catch with follow the tracks of after enter stable state, main website can obtain demodulating data and original ranging information by the despreading of range finding branch road, in demodulating data, include the ranging information of extension station to main website, two kinds of aggregation of data can draw the ranging information of main website to extension station;

Step 5, main website can export distance measurement value to main website transmitting terminal after obtaining major-minor distance, send to extension station, in order to have assisted extension station to the range finding of main website and time synchronized by the bookbinding of range finding branch road information;

Step 6, extension station receiving terminal through after step 3 by major-minor range information and the demodulation of transmitted pulse temporal information out, the transmitted pulse time that be main website transmitted pulse time of delay of extension station actual needs wait deducts the propagation delay time of introducing due to major-minor distance.If an extension station transmitted pulse time integer clock cycle does not need clock adjustment, otherwise also need to carry out following steps;

Step 7 ,She extension station launch time is Δ T _r=MT+ θ, wherein T is system clock cycle, M is integer, 0< θ <T, M time clock cycle can be leaned on register counting, and the θ of a clock cycle of less than part need to be called the DCM module of FPGA and adjusts extension station clock, DCM is output as of the about θ phase place of hysteresis extension station clock and shifts to clock;

Step 8, adjustment time are smaller than register gate time, and whether each like this rising edge detection counter value at phase shifting clock reaches M, if transmitted pulse, otherwise continue to wait for;

The communication process of step 9, main website and extension station always repeating step four arrives step 8.

Through above-mentioned nine steps, completed the process of major-minor transmitting lock-out pulse.

Beneficial effect

Method simple and flexible of the present invention, is convenient to adjust; The minimum phase stepping that DCM can adjust is T/256, and T is the clock cycle, and for a 100M system clock, pulse precision can reach 0.039ns; It is short that phase place is adjusted the time, and can not take too many FPGA resource.

Accompanying drawing explanation

Fig. 1 is main website receiving end signal processing module schematic diagram in the present invention;

Fig. 2 is extension station receiving end signal processing module schematic diagram in the present invention;

Fig. 3 is lock-out pulse generation module schematic diagram in the embodiment of the present invention;

Embodiment

Below in conjunction with drawings and Examples, the present invention will be further described and detailed description.

Embodiment

Main website and extension station are distributed in respectively in two different load, two load distances can not surpass 1Km, and radial velocity is in 20m/s, two equipment adopt different clock sources, system clock is 80MHz, main website, extension station adopt and forward system, can utilize pseudo-code delay lock loop and carrier phase-locked loop to carry out precision ranging, now require main website, extension station to produce precise synchronization pulse every 100ms.

Step 1: main website, extension station work on power, main website transmits information to extension station, extension station is again transmitted to main website to data up-conversion after through acquiring pseudo code and pseudo-code tracing, main website carries out acquiring pseudo code and tracking equally to forwarding data, both sides enter stable state like this, can realize the instant of information and receive and dispatch.

Step 2: distance between two load can be learnt according to pseudo-code phase by main website, and be transmitted in time extension station, main website starts timing at main website rising edge clock simultaneously, after 100ms, produce pulse, because two load distances are short, consider that the light velocity is very large, so the propagation delay time of signal can be not oversize, therefore think that main website does not change once sending receiving course middle distance of extension station, extension station can deduct due to the propagation delay time apart from bringing after range information being detected on the basis of 100ms like this.

Suppose apart from d=500m

Propagation delay time $\mathrm{\&tau;}=\frac{500m}{c}=\frac{500m}{3\&times;{10}^{8}m/s}=1.\stackrel{\&CenterDot;}{6}\mathrm{us}$

Extension station needs time delay ${\mathrm{\&Delta;T}}_r=100\mathrm{ms}-1.\stackrel{\&CenterDot;}{6}\mathrm{us}=99998.\stackrel{\&CenterDot;}{3}4\mathrm{us}$

Clock cycle $T=\frac{1}{80\mathrm{MHz}}=12.5\mathrm{ns}$

By formula Δ T _r=MT+ θ computes integer cycle M and decimal cycle θ, solve

M=7999866，θ=0.72

Step 3: on one side starting timer, extension station starts counting, Yi Bian according to differing θ, adjust clock, according to formula

can calculate phase modulation times N=14,

At the FPGA of extension station intrinsic call DCM core, input clock is extension station system clock, after 14 phase places that move to right, output and the adjustment clock of main station system clock with frequency homophase, be enough in this process 1ms, whether reaches 7999866 afterwards in the rising edge detected register count value of adjusting clock, if arrive this value, export lock-out pulse, otherwise, continue to wait for.

Claims (1)

1. the production method of a distributed synchronization pulse, first main website catches, finds range branch road pseudo-code synchronously and carrier synchronization processes after receiving extension station data, the despreading of range finding branch road obtains demodulating data and original ranging information, according to range finding branch road demodulating data and original ranging information, can carry out frame synchronization and distance calculating; Branch road pseudo-code is caught, found range to extension station receiving terminal first synchronously and carrier synchronization processes according to the range finding branch road PN code of its bookbinding, and range finding branch road obtains the demodulating data after phase ambiguity after frame synchronization, provides frame start position sign simultaneously; Range finding branch road demodulated output data and original ranging information, in demodulating data, include the ranging information of main website to extension station, two kinds of aggregation of data can obtain the distance measurement value of extension station to main website, auxiliary main distance measurement value is issued to main website by range finding branch road on the one hand, be used for calculating on the one hand and produce lock-out pulse time of delay; It is characterized in that step is:

Step 1, main website have two paths of data ，Yi road for the ，Yi road of finding range for communication, through a series of data processings such as spread spectrums, carrier modulation, up-conversion, by wireless channel, arrive extension station;

Step 2, extension station receiving terminal are first to signal down-conversion, then utilize acquiring pseudo code and tracking technique by modulation demodulation out, baseband signal experiences equally the processes such as spread spectrum, carrier modulation, up-conversion range finding branch road and the communication leg information of main website transmission is transmitted to main website;

Step 3, main website receiving terminal equally will be to data down-conversions after receiving the forwarding data of extension station, utilize acquiring pseudo code and pseudo-code tracing to carry out carrier wave to signal and remove and pseudo-code removing, this data handling procedure is the same with the data handling procedure of extension station receiving terminal;

Step 4, main website, extension station successfully catch with follow the tracks of after enter stable state, main website can obtain demodulating data and original ranging information by the despreading of range finding branch road, in demodulating data, include the ranging information of extension station to main website, two kinds of aggregation of data can draw the ranging information of main website to extension station;

Step 5, main website can export distance measurement value to main website transmitting terminal after obtaining major-minor distance, send to extension station, in order to have assisted extension station to the range finding of main website and time synchronized by the bookbinding of range finding branch road information;

Step 6, extension station receiving terminal through after step 3 by major-minor range information and the demodulation of transmitted pulse temporal information out, the transmitted pulse time that be main website transmitted pulse time of delay of extension station actual needs wait deducts the propagation delay time of introducing due to major-minor distance; If an extension station transmitted pulse time integer clock cycle does not need clock adjustment, otherwise also need to carry out following steps;

Step 7 ,She extension station launch time is Δ T _r=MT+ θ, wherein T is system clock cycle, M is integer, 0< θ <T, M time clock cycle can be leaned on register counting, and the θ of a clock cycle of less than part need to be called the DCM module of FPGA and adjusts extension station clock, DCM is output as of the about θ phase place of hysteresis extension station clock and shifts to clock;

Step 8, adjustment time are smaller than register gate time, and whether each like this rising edge detection counter value at phase shifting clock reaches M, if transmitted pulse, otherwise continue to wait for;

The communication process of step 9, main website and extension station always repeating step four arrives step 8;

Through above-mentioned nine steps, completed the process of major-minor transmitting lock-out pulse.

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