CN101188456A - A performance tracking and testing method for space optical communication system - Google Patents

Abstract

The invention discloses a spatial optical communication system tracking performance testing method which is an improvement of the testing and optimization method for spatial optical communication tracking performance to resolve the prior problems that the existing spatial optical communication tracking method has the singularity of the tracking test performance and cannot carry the comparison and optimization analysis on a plurality of parameters and strategies. The method of the invention is formed by the following steps: firstly, a needy link is set and two satellite original states are set; secondly, the two relative satellite positions and postures of the needy link and the real-time mobile data are preset in a main control device; thirdly, a testing device and a tested terminal cooperate with each other to carry the testing; fourthly, an initial link is established; fifthly, a plurality of the tracking strategies, the tracking beam apical angle, the detection viewing area, the detection frame rate and the received signal-to-disturbance ratio combination are set; sixthly, the beacon optical tracking tests are carried out and the tested results are kept; lastly, the tested results are analyzed and compared to choose the best tracking strategy and the best tracking parameter configuration.

Description

Performance tracking and testing method for space optical communication system

Technical field

The present invention relates to a kind of to the test of space optical communication tracking performance and the improvement of optimization method.

Background technology

The pencil tracing performance is one of key technical index of space optical communication terminal, existing method of testing is: LASER Light Source and imaging optical system simulation tracing beacon beam are set and follow the tracks of pick-up probe, the unit performance test of in the laboratory, following the tracks of, publication number is that the patent of invention of CN101072071 discloses a kind of space optical communication terminal scanning tracking performance method of testing, but there is following shortcoming in this method:

(1), be subjected to the restriction of analogue means characteristic, can only test the tracking performance of terminal at transmitting and receiving the parameter situation, and tracking accuracy and tracking stability are relatively poor;

(2), do not possess complete termination function, can't cooperate test such as the system index that carries out the composite shaft tracking with dut terminal;

(3), can't test parameters such as tracking beacon light beam divergence angle, the tracking ken and tracking frame frequency changes the influence of tracking and the contrast optimization analysis of strategy.

Summary of the invention

The present invention is for solving can only the tracking performance of terminal being tested at transmitting and receiving the parameter situation of existing space optical communication system tracking existence, and tracking accuracy and tracking stability are relatively poor, can't cooperate test such as the system index that carries out the composite shaft tracking with dut terminal, can't test tracking beacon light beam divergence angle, follow the tracks of the problem that parameters variations such as the ken and tracking frame frequency are analyzed the influence and the tactful contrast optimization of tracking, propose a kind of space optical communication system tracking performance test optimization analytical method.Method of the present invention is realized by following steps:

Step 1, setting need the relative position and the attitude of two satellites of link, and the real-time relative position of a period of time and the delta data of attitude;

Step 2, the relative position of two satellites that need link of setting in the step 1 and the delta data of the real-time relative position of attitude and a period of time and attitude are preset in the master control set 4;

Step 3, signal receiving device 2 and smart collimation device 3 all are fixed on the thick collimation device 1 to change the direction of optical axis with it, described thick collimation device 1 can be done and rotate in the horizontal plane and the pitch orientation rotation, and the optical axis of signal receiving device 2 and smart collimation device 3 is parallel to each other, three input/output terminals of master control set 4 are connected with thick collimation device 1, signal receiving device 2 and the input/output terminal of smart collimation device 3 respectively, thick collimation device 1, signal receiving device 2, smart collimation device 3 and the master control set 4 common tracking equipment A that form;

Step 4, rotate by the thick collimation device 1 of master control set 4 controls, the beacon beam of 2 pairs of dut terminal B emissions of signal receiving device is scanned, when scanning the beacon beam of dut terminal B emission, signal receiving device 2 stops scanning, and by smart collimation device 3 to dut terminal B emission beacon beam, set up initial link circuit, follow according to the delta data of the relative position of two default in the master control set 4 satellites and the real-time relative position of attitude and a period of time and attitude then and take aim at, and record compensates relative motion between two stars according to the default real-time relative position and the delta data of attitude then with the result who takes aim at, Satellite Attitude Movement and satellite platform vibration are to the influence of link;

Step 5, the scanning principle of following the tracks of according to single-direction tracing, bi-directional tracking, open-loop tracking and closed loop on master control set 4, set respectively multiple tracking mode, beacon beam beam divergence angle, survey the ken, survey frame frequency and receive the combination of signal to noise ratio;

Step 6, master control set 4 control signal receiving systems 2 are passed in the scanning of setting according to step 5 in principle and smart collimation device 3 carries out repeatedly beacon beam tracking and testing and logging test results;

Step 7, basis are to the adaptability of satellite platform and the time principle of stable maintenance link, the test result that step 6 is obtained carry out the combination of tracking strategy, terminal parameter and selection, finally realize terminal and chain-circuit system tracking performance analysis relatively, according to the test result of the stability that keeps tracking time, select the setting of optimal tracking strategy and tracking parameter.

The invention has the beneficial effects as follows: can test tracking accuracy and tracking stability under the different satellite platform control precisions, test tracking beacon light beam divergence angle, the tracking ken and tracking frame frequency change the influence to following the tracks of; Can test the tracking performance of terminal transmitting and receiving the parameter situation simultaneously; Can cooperate test such as the system index that carries out the composite shaft tracking with dut terminal; And the contrast optimization that can carry out multiple parameter and strategy is analyzed.

Description of drawings

Fig. 1 is an overall structure schematic diagram of finishing the required device of the inventive method.

Embodiment

Embodiment one: present embodiment is described in conjunction with Fig. 1.

The method of present embodiment is realized by following steps:

Step 1, setting need the relative position and the attitude of two satellites of link, and the real-time relative position of a period of time and the delta data of attitude;

Step 2, the relative position of two satellites that need link of setting in the step 1 and the delta data of the real-time relative position of attitude and a period of time and attitude are preset in the master control set 4;

Step 3, the rotation axis of signal receiving device 2 and smart collimation device 3 all is fixed on the thick collimation device 1 to change the angle of optical axis with it, and the optical axis of signal receiving device 2 and smart collimation device 3 is parallel to each other, three input/output terminals of master control set 4 are connected with thick collimation device 1, signal receiving device 2 and the input/output terminal of smart collimation device 3 respectively, thick collimation device 1, signal receiving device 2, smart collimation device 3 and the master control set 4 common tracking equipment A that form;

Step 4, rotate by the thick collimation device 1 of master control set 4 controls, the beacon beam of 2 pairs of dut terminal B emissions of signal receiving device is scanned, when scanning the beacon beam of dut terminal B emission, signal receiving device 2 stops scanning, and by smart collimation device 3 to dut terminal B emission beacon beam, set up initial link circuit, follow according to the delta data of the relative position of two default in the master control set 4 satellites and the real-time relative position of attitude and a period of time and attitude then and take aim at, and record compensates relative motion between two stars according to the default real-time relative position and the delta data of attitude then with the result who takes aim at, Satellite Attitude Movement and satellite platform vibration are to the influence of link;

Step 5, the scanning principle of following the tracks of according to single-direction tracing, bi-directional tracking, open-loop tracking and closed loop on master control set 4, set respectively multiple tracking mode, beacon beam beam divergence angle, survey the ken, survey frame frequency and receive the combination of signal to noise ratio;

Step 6, master control set 4 control signal receiving systems 2 are passed in the scanning of setting according to step 5 in principle and smart collimation device 3 carries out repeatedly beacon beam tracking and testing and logging test results;

Step 7, basis are to the adaptability of satellite platform and the time principle of stable maintenance link, the test result that step 6 is obtained carry out the combination of tracking strategy, terminal parameter and selection, finally realize terminal and chain-circuit system tracking performance analysis relatively, according to the test result of the stability that keeps tracking time, select the setting of optimal tracking strategy and tracking parameter.

Described thick collimation device 1 can adopt MS650 absolute type code-disc and torque motor to realize; Described signal receiving device 2 is made up of optical antenna, imaging optical path and imaging detector, optical antenna and imaging optical path are general imaging system, antenna aperture 100～300mm, imaging detector requires big face battle array cmos detector, the pixel number is greater than 100 * 100, and surveying the ken is that 0.2～2mrad is adjustable, and unit pixel search angle resolution is 10 μ rad, it is adjustable to survey frame frequency 20～1kHz, the 622f type CCD that can adopt German Basler company to produce; Described smart collimation device 3 is by optical antenna, the shaping light path, deflecting mirror and laser constitution, laser is for realizing the maximum 20W high power semiconductor lasers of output continuously, the NE-C3720-F4 type laser that can adopt French Thales company to produce, optical antenna and shaping light path are for pressing the general optical system of laser output parameter design, by adjusting the position of laser light-emitting area at optical axis direction, can realize that beam divergence angle is that 0.03～1mrad is adjustable, deflecting mirror can be realized X and the deflection of Y two dimension angular, scope is ± 2.5mrad, gamut repeatable accuracy ± 2 μ rad, the piezoelectricity galvanometer beat platform S-330.2SL type deflecting mirror that can adopt German PI company to produce; Described master controller 4 can adopt general circuit design method to realize, can control thick collimation device 1 by the two-way drive circuit, the revolving table position feedback signal realizes aiming on a large scale by the encoding process circuit, digital signal by the output of digital signal processing circuit treated side array detector, by two-way drive circuit control deflecting mirror angle feedback signal by A the D treatment circuit realize the high accuracy aiming, adjust the input current of laser in the smart collimation device 3 or attenuator is installed, adjust the transmitting power of smart collimation device 3 within the specific limits.

Following principle: after the link establishment, need the terminal of two links to carry out mutually with taking aim to compensate relative motion between two stars, Satellite Attitude Movement and satellite platform vibration influence to link.With the factors such as size of taking aim at beam divergence angle, the tracking of laser inter-satellite link can be divided into following three kinds of modes in theory according to satellite orbit predictions precision, platform attitude control accuracy, platform vibration situation and terminal:

(1) two-way open loop pencil tracing; During two-way open loop pencil tracing, two link terminals are all aimed at mutually according to the track and the attitude parameter of satellite.This mode is lower with taking aim at performance requirement for terminal, but survey rail and survey appearance precision, the frequency of satellite platform all had high requirement.

(2) unidirectional closed loop pencil tracing; During unidirectional closed loop pencil tracing, link terminal carries out open loop according to the track of satellite and attitude parameter to be aimed at, and another link terminal carries out closed loop aiming control according to the light signal angular deviation that receives.This mode is lower with taking aim at performance requirement for open loop aiming terminal, but survey rail and survey appearance precision, the frequency of its place satellite platform all had high requirement.Higher for closed loop aiming terminal with taking aim at performance requirement.

(3) two-way closed loop pencil tracing; During two-way closed loop pencil tracing, two link terminals all carry out closed loop according to the light signal angular deviation that receives and aim at control mutually.This kind mode is higher with taking aim at performance requirement for terminal, and is higher to the adaptability of satellite platform.

Two-way closed loop pencil tracing is called for short bi-directional tracking, is the process that one two terminal is aimed at simultaneously mutually, and the pointing accuracy that two ends all will produce a sighting angle error and an end will influence the error of the other end.Therefore, the sighting angle error on two terminals is beam Propagation time-delay and collimating fault at statistical joint random variable.Its basic principle is: with θ _V0(t) and θ _H0(t) angular direction of two terminal Heavens of expression linear light door screen line of centres is with θ _v(t) and θ _h(t) the signal beams angular direction of expression transmitting terminal emission, with two intersatellite distances of link of ρ (t) expression, subscript v and h represent two angular direction of pitching and orientation respectively.If in the laser inter-satellite link process is the basic mode Gaussian with taking aim at beacon light beam.When the z direction of principal axis is propagated, the intensity distribution function in the transmission cross section is

$I(x,y,z)=\frac{C_0^2}{w^2\left(z\right)}\exp [-\frac{2(x^2+y^2)}{w^2\left(z\right)}]$

C in the formula ₀Be invariant, ω (z) is and propagates axis and intersect at spot radius on the Gaussian beam equiphase surface that z orders.The collimating fault in level and pitch orientation of transmitting terminal is

$\left\{\begin{array}{c}{\mathrm{\Ψ}}_v\left(t\right)={\mathrm{\θ}}_v\left(t\right)-{\mathrm{\θ}}_{v0}\left(t\right)\\ {\mathrm{\Ψ}}_h\left(t\right)={\mathrm{\θ}}_h\left(t\right)-{\mathrm{\θ}}_{h0}\left(t\right)\end{array}\right.$

Collimating fault can be carried out small angle approximation usually in the microradian magnitude:

$I({\mathrm{\Ψ}}_e,\mathrm{\ρ})=\frac{4C_0^2}{{\mathrm{\ρ}}^2{\mathrm{\θ}}_b^2}\exp (-\frac{8{\mathrm{\Ψ}}_e^2}{{\mathrm{\θ}}_b^2})$

Wherein,

${\mathrm{\Ψ}}_e=\sqrt{{\mathrm{\Ψ}}_v^2+{\mathrm{\Ψ}}_h^2}$

For radially following of transmitting terminal taken aim at error.The luminous power that receiving terminal receives is

$P_r=\underset{A_r}{\∫}\∫I({\mathrm{\Ψ}}_e,\mathrm{\ρ})d{\mathrm{\θ}}_{v}d{\mathrm{\θ}}_h$

A wherein _rEffective area for the reception antenna bore.Because link range is far away, at the area of receiving terminal place hot spot much larger than A _r, can be similar to and think that light intensity magnitude is constant in integral area, so

$P_r\≈\frac{4C_0^2{A}_0}{{\mathrm{\ρ}}^2{\mathrm{\θ}}_b^2}\exp (-\frac{8{\mathrm{\Ψ}}_e^2}{{\mathrm{\θ}}_b^2})$

Power P _rVariation be directly connected to taking aim at signal to noise ratio on the detector, angle measurement accuracy also will be affected.According to noise equivalent angle (Noise Equivalent Angle) notion

${\mathrm{\θ}}_{\mathrm{NEA}}\left({\mathrm{\Ψ}}_e\right)=C_1\frac{(P_b+P_n)}{P_r{\mathrm{\τ}}_r}$

P _bBe background noise, P _nBe detector noise, τ _rBe the attenuation coefficient of receiving optics, C ₁Relevant with the angle measurement algorithm and the detection threshold of system.Can get

${\mathrm{\θ}}_{\mathrm{NEA}}\left({\mathrm{\Ψ}}_e\right)={\mathrm{\θ}}_{\mathrm{NEA}}\left(0\right)\exp \left(\frac{8{\mathrm{\Ψ}}_e^2}{{\mathrm{\θ}}_b^2}\right)$

${\mathrm{\θ}}_{\mathrm{NEA}}\left(0\right)=\frac{C_1(P_b+P_n){\mathrm{\ρ}}^2{\mathrm{\θ}}_b^2}{4{\mathrm{\τ}}_r{C}_0^2{A}_0}$

θ wherein _NEA(0) for distant terminal is 0 o'clock noise equivalent angle with taking aim at error, main relevant with the characteristic of sighting device and space environment.

Embodiment two: the difference of present embodiment and embodiment one is that the scope of the beam divergence angle of the beacon beam described in the step 5 is 30 differential of the arcs～1 milli arc, and the scope of the detection ken in the detection mode is that the scope of 50 differential of the arcs～1 milli arc, detection frame frequency is 50Hz～1kHz.

Claims (1)

1. performance tracking and testing method for space optical communication system is characterized in that method of the present invention is realized by following steps:

Step 1, setting need the relative position and the attitude of two satellites of link, and the real-time relative position of a period of time and the delta data of attitude;

Step 2, the relative position of two satellites that need link of setting in the step 1 and the delta data of the real-time relative position of attitude and a period of time and attitude are preset in the master control set 4;

Step 3, the rotation axis of signal receiving device (2) and smart collimation device (3) all is fixed on thick collimation device (1) goes up to change the angle of optical axis with it, and the optical axis of signal receiving device (2) and smart collimation device (3) is parallel to each other, three input/output terminals of master control set (4) are connected with thick collimation device (1), signal receiving device (2) and the input/output terminal of smart collimation device (3) respectively, and thick collimation device (1), signal receiving device (2), smart collimation device (3) and master control set (4) are formed tracking equipment (A) jointly;

Step 4, controlling thick collimation device (1) by master control set (4) rotates, signal receiving device (2) is scanned the beacon beam of dut terminal (B) emission, when scanning the beacon beam of dut terminal (B) emission, signal receiving device (2) stops scanning, and by smart collimation device (3) to dut terminal (B) emission beacon beam, set up initial link circuit, follow according to the delta data of the relative position of two default in the master control set (4) satellites and the real-time relative position of attitude and a period of time and attitude then and take aim at, and record compensates relative motion between two stars according to the default real-time relative position and the delta data of attitude then with the result who takes aim at, Satellite Attitude Movement and satellite platform vibration are to the influence of link;

Step 5, the scanning principle of following the tracks of according to single-direction tracing, bi-directional tracking, open-loop tracking and closed loop go up beam divergence angle, the detection ken, the detection frame frequency of setting multiple tracking strategy, beacon beam and the combination that receives signal to noise ratio at master control set (4) respectively;

Step 6, master control set (4) control signal receiving system (2) is passed in the scanning of setting according to step 5 in principle and smart collimation device (3) carries out repeatedly beacon beam tracking and testing and logging test results;

Step 7, basis are to the adaptability of satellite platform and the time principle of stable maintenance link, the test result that step 6 is obtained carry out the combination of tracking strategy, terminal parameter and selection, finally realize terminal and chain-circuit system tracking performance analysis relatively, according to the test result of the stability that keeps tracking time, select the setting of optimal tracking strategy and tracking parameter.