Research On Wide Bandwidth Dual Swept Laser Ranging Technology

Swept-frequency interfero metry is an ideal large-scale abso lute distance measurement method.It has the advantages of high-precision,non-cooperative target measurement capabilit y and the absence of measurement blind spots.By increasing the sweep bandwidth,a high range reso lution can be obtained.And accuracy,and due to the use of heterodyne interferometry techno logy,can obtain higher measurement signal to no ise ratio.In this paper,the technique o f measuring the abso lute distance between two external cavit y lasers with swept frequency interference is studied.Two kinds of schemes are proposed to achieve stat ic measurement and dynamic measurement o f the target respect ively.The feasibilit y o f the two experimental schemes is verified by simulation.Finally,the experimental system is built.to verify its measurement accuracy and vibrat io n suppressio n effect.In the pre-simulat ion,this paper proposes a large-bandwidth reverse-chirp-synchronous sweep interferometric measurement with dual external cavit y tunable lasers to eliminate the dynamic error caused by the Doppler effect.Simultaneous correct ion of bi-direct ional sweeps based on signal mixing and other frequent interval resampling is proposed.The frequency non-linear solut ion so lves the problem that the non-linear non-uniformit y o f the sweep frequency o f the do uble external cavit y tunable laser is difficult to synchronize and correct,and realizes high-precisio n dynamic frequency sweep interfero metry.Simulated ranging analysis was performed on the vibrat ion target and the moving target respect ively to verify the effect iveness o f the above method.The accuracy of the proposed method was compared with that o f the exist ing method at different signal-to-noise ratios.The results show that the method proposed in this paper.There is a clear advantage in non-cooperat ive target measurement capabilit ies.For the moving target,this paper proposes a method to extract the phase o f the signal to co mplete the measurement o f the target displacement,and validates this so lut ion by simulating the moving target.When the late experimental system was set up,the synchronous triggering contro l so ftware o f the two lasers was programmed,and the frequency sweep contro l of the laser was completed.Through the analysis o f the experimental scheme,a double-cavit y swept frequency interference experimental optical pat h was designed.After the test,the optical path reached the experimental measurement requirements;The experimental system was set up and the stat ic measurement of the cooperat ion goal and the non-cooperat ive goal was co mpleted.The best reproducibilit y within the range of 1m o f the cooperat io n target was 0.80?m,and the repeatability of the metal rod at 5.7m and 10.9m was 8.4?m respectively.13.7?m;Through the dynamic measurement results of the vibrat ion target and uniform moving target,the 6?m vibration frequency 50 Hz target measurement accuracy is 0.23?m,and the 10mm/s uniform motion target measurement error is 0.0042mm/s.