CN103560873B - A kind of production method of distributed synchronization pulse - Google Patents

Abstract

The present invention relates to the production method of a kind of distributed synchronization pulse, belong to electronic communication and Radar Technology field.The method simple and flexible of the present invention, it is simple to adjust；For a 100M system clock, it is short that phase place adjusts the time, and will not take too many FPGA resource.

Description

A kind of production method of distributed synchronization pulse

Technical field

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

Background technology

Radar plays irreplaceable effect in the modern and following electronic warfare, but the monostatic radar of original transceiver is faced with four kinds of threats: electronic interferences, ultra-low altitude penetration, Stealth weapons, antiradiation missile etc..By comparison, double-basis or multi-static radar system change the working method that in the single base system of tradition, cell site T and receiving station R position is identical, T station and R station are split, there is stronger survival ability and higher detecting function, thus causing the attention of people, and it is rapidly developed further and extensive use.But this wherein important technical problem is exactly transmitting-receiving station time synchronization problem, radar to measure target range according to the echo received relative to the time delay launching signal, therefore must keep strict time synchronized between transmitting-receiving station, 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 quickly grows and is widely used in various communication system, 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 method that realizes of various pseudo-random code ranging is adopted to be essentially all equally.Produced a pseudo-random code sequence by earth station's pseudo-code generator to send to satellite, by being forwarded to earth station after satellite reception, the phase place of the pseudo-random code sequence being originally sent by phase comparator contrast and the pseudo-random code sequence received, is determined time delay according to phase contrast to such an extent as to tries to achieve distance.Wherein an important sources of range error is exactly that earth 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 to distance measurement value, thus improving range accuracy.

Summary of the invention

The invention aims to overcome the method that traditional approach produces lock-out pulse to be mostly confined to increase peripheral module, FPGA only plays control action wherein, this not only adds the complexity of system, and precision is difficult to below nanosecond under high-frequency clock, the present invention proposes the production method of a kind of distributed synchronization pulse.

The present invention is achieved by the following technical solutions.

A kind of production method of the distributed synchronization pulse of the present invention, first main website carries out after receiving extension station data catching, find range branch road PN synchronization and carrier synchronization processes, range finding branch road despreading obtains demodulating data and original ranging information, can carry out frame synchronization according to range finding branch road demodulating data and original ranging information and distance calculates；Extension station receiving terminal is first depending on the range finding branch road PN code of its bookbinding and carries out catching, finding range branch road PN synchronization and carrier synchronization processes, and range finding branch road obtains the demodulating data after phase ambiguity after frame synchronization, provides frame start position mark simultaneously.Range finding branch road demodulated output data and original ranging information, demodulating data includes the main website ranging information to extension station, two kinds of aggregation of data can obtain the extension station distance measurement value to main website, auxiliary main distance measurement value is on the one hand issued main website by branch road of finding range, be used on the one hand calculating and produce lock-out pulse time delay.Step is:

There are two paths of data in step one, main website, and a road is used for finding range, and a road is used for communicating, and arrive extension station through wireless channel after processing through volume of data such as spread spectrum, carrier modulation, up-conversions；

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

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

Step 4, main website, extension station enter steady statue with following the tracks of afterwards successfully catching, main website can obtain demodulating data and original ranging information by branch road despreading of finding range, including the extension station ranging information to main website in demodulating data, two kinds of aggregation of data can draw the main website ranging information to extension station；

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

Step 6, extension station receiving terminal after step 3 by major-minor range information with launch burst length information demodulate out, extension station be actually needed wait launch pulse delay time be main website launch the burst length deduct the propagation delay time owing to major-minor distance introduces.If extension station launches integer the clock cycle in burst length does not then need clock adjustment, otherwise also need to carry out following steps；

Step 7, set extension station launch time as Δ T_r=MT+ θ, wherein T is system clock cycle, M is integer, 0 < θ < T, M clock period time can lean on register count, and needing the DCM module calling FPGA to adjust extension station clock less than the θ part of a clock cycle, DCM be output as the about θ phase place of delayed extension station clock one shifts to clock；

Step 8, adjustment time are smaller than the register count time, so every time whether the rising edge detection counter value of phase shifting clock reaches M, if then launching pulse, otherwise continue waiting for；

The communication process of step 9, main website and extension station will repeat step 4 to step 8 always.

Namely the process of major-minor transmitting lock-out pulse is completed through above-mentioned nine steps.

Beneficial effect

The method simple and flexible of the present invention, it is simple to adjust；The minimum phase stepping that DCM can adjust is T/256, T is the clock cycle, and for a 100M system clock, pulse precision is up to 0.039ns；It is short that phase place adjusts the time, and will 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；

Detailed description of the invention

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

Embodiment

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

Step one: main website, extension station work on power, main website transmits information to extension station, data up-conversion is again being forwarded it to main website by extension station after acquiring pseudo code with pseudo-code tracing, forwarding data are carried out acquiring pseudo code and tracking by main website equally, such both sides enter steady statue, it is possible to achieve the instant transmitting-receiving of information.

Step 2: the spacing of two load can be learnt according to pseudo-code phase by main website, and it is transmitted to extension station in time, main website starts timing at master clock rising edge simultaneously, pulse is produced after 100ms, owing to two load are apart from short, it is contemplated that the light velocity is very big, so the propagation delay time of signal will not be oversize, it is taken as that main website distance in once sending extension station once reception process does not change, such extension station can deduct, after range information being detected, the propagation delay time brought due to distance on the basis of 100ms.

Assume distance d=500m

Then 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 calculates number of cycles M and Fractional θ, solves

M=7999866, θ=0.72

Step 3: extension station starts timer counting starts, while adjusting clock according to difference θ, according to formulaPhase modulation times N=14 can be calculated,

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

Claims (1)

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

There are two paths of data in step one, main website, and a road is used for finding range, and a road is used for communicating, and arrive extension station through wireless channel after processing through spread spectrum, carrier modulation, up-conversion volume of data；

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

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

Step 4, main website, extension station enter steady statue with following the tracks of afterwards successfully catching, main website obtains demodulating data and original ranging information by branch road despreading of finding range, including the extension station ranging information to main website in demodulating data, two kinds of aggregation of data can draw the main website ranging information to extension station；

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

Step 6, extension station receiving terminal after step 3 by major-minor range information with launch burst length information demodulate out, extension station be actually needed wait launch pulse delay time be main website launch the burst length deduct the propagation delay time owing to major-minor distance introduces；If extension station launches integer the clock cycle in burst length does not then need clock adjustment, otherwise also need to carry out following steps；

Step 7, set extension station launch time as Δ T_r=MT+ θ, wherein T is system clock cycle, M is integer, 0 < θ < T, M clock period time can lean on register count, and needs the DCM module calling FPGA to adjust extension station clock less than the θ part of a clock cycle, and the minimum phase stepping that DCM regulates is T/256, N is the phase modulation number of times of DCM, according to formulaCalculate N, and withFor DCM the delayed extension station time shift to clock；

Step 8, adjustment time are smaller than the register count time, so every time whether the rising edge detection counter value of phase shifting clock reaches M, if then launching pulse, otherwise continue waiting for；

The communication process of step 9, main website and extension station will repeat step 4 to step 8 always；

Namely the process of major-minor transmitting lock-out pulse is completed through above-mentioned nine steps.