CN104765075A - Dual-optical-path testing device for light speed limited effect in absolute gravimeter - Google Patents
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Abstract
本发明公开了一种绝对重力仪中光速有限效应的双光路测试装置，包括：隔振平台、支撑结构、第一激光干涉仪、第一参考棱镜、落体真空腔、对顶双棱镜形成的落体结构、第二激光干涉仪、第二参考棱镜；其中第一参考棱镜和第二参考棱镜刚性连接，即它们的运动完全一致；当对顶双棱镜形成的落体在落体真空腔中自由下落时，会在第一激光干涉仪和第二激光干涉仪中分别形成干涉信号，通过探测器分别探测两套激光干涉仪的干涉信号，由于光速有限效应在两套干涉仪中的作用效果是相反的，而重力加速度、振动噪声和其他噪声等对两套激光干涉仪的作用效果是相同的，是共模信号，因此通过数据处理实现两套激光干涉仪信号的差分测量，就可以直接测量绝对重力仪中光速有限效应的大小。
The invention discloses a dual optical path test device for the finite effect of light velocity in an absolute gravimeter, comprising: a vibration isolation platform, a support structure, a first laser interferometer, a first reference prism, a falling body vacuum cavity, and a falling body formed by a pair of double prisms on top structure, the second laser interferometer, and the second reference prism; wherein the first reference prism and the second reference prism are rigidly connected, that is, their movements are completely consistent; when the falling body formed by the pair of top double prisms falls freely in the falling body vacuum chamber, Interference signals will be formed in the first laser interferometer and the second laser interferometer respectively, and the interference signals of the two sets of laser interferometers will be respectively detected by the detector. Due to the finite speed of light effect in the two sets of interferometers, the effect is opposite. The effects of gravitational acceleration, vibration noise and other noise on the two sets of laser interferometers are the same, and they are common-mode signals. Therefore, the differential measurement of the two sets of laser interferometer signals can be directly measured through data processing. The magnitude of the finite effect of the speed of light in .
Description
技术领域technical field
本发明属于绝对重力仪技术领域，更具体地，涉及一种绝对重力仪中光速有限效应的双光路测试装置。The invention belongs to the technical field of absolute gravimeters, and more particularly relates to a dual optical path testing device for the finite effect of light velocity in absolute gravimeters.
背景技术Background technique
绝对重力仪的测量不确定度由两部分误差共同决定：测量中的随机误差和仪器本身的系统误差。其中大部分的误差源都能够被很好地独立分析、计算和测量，从而获得较为准确的不确定度。但是，有一些误差源至今只能通过理论方法进行计算分析，例如光速有限效应的影响，该项误差的大小可以达到十几μGal(1μGal＝10-8m/s2)的量级，并且很多科学家都对这一项误差进行了理论分析和计算，但是至今仍无法达成共识。The measurement uncertainty of an absolute gravimeter is determined by two parts of error: the random error in the measurement and the systematic error of the instrument itself. Most of these error sources can be independently analyzed, calculated and measured well, so as to obtain more accurate uncertainties. However, some error sources can only be calculated and analyzed by theoretical methods so far, such as the influence of the finite effect of the speed of light. Scientists have theoretically analyzed and calculated this error, but so far they have not been able to reach a consensus.
光速有限效应是由于激光传播速度有限(尽管很大)，激光束到达光电管产生干涉信号的时刻总是延迟于激光束从自由落体的角锥棱镜处反射的时刻，这种情况下，从干涉信号中提取的角锥棱镜的位置并不是该时刻角锥棱镜的真实位置，从而引起了绝对重力测量的误差。The finite effect of the speed of light is due to the limited propagation speed of the laser (although it is very large), the moment when the laser beam reaches the photocell to generate the interference signal is always delayed from the moment when the laser beam is reflected from the free-falling corner cube. In this case, from the interference The position of the corner cube extracted from the signal is not the true position of the corner cube at that moment, which causes an error in the absolute gravity measurement.
光速有限效应的修正的物理模型都是基于时间延迟和多普勒效应，可以将修正后的重力加速度g值表示为：其中k为修正系数，v0表示落体角锥棱镜的初始速度，g0表示被测量处的重力加速度，T表示落体一次所需要的总时间。理论上无论是基于时间延迟进行计算，还是基于多普勒效应进行计算，由于物理的本质都是光速有限引起的物理效应，该修正系数只可能得到唯一的数值。但是基于时间延迟的方法进行计算时，修正系数k＝3；而基于多普勒效应的方法进行计算时，修正系数k＝2。对于FG5绝对重力仪(美国Micro-g LaCoste公司生产和制造，该公司是目前唯一生产商用绝对重力仪的公司)，其落体距离约为20cm，实际用于数据拟合的落体总时间约为T＝0.17s，初速度约为v0＝0.4m/s，则当修正系数k＝3时，光速有限效应的修正约为12μGal；而当修正系数k＝2时，该修正的大小约为8μGal。修正系数的不同可以产生4μGal的系统误差，由于重力加速度g值的真值未知，修正系数的多少将直接影响重力加速度g值的测量结果。The corrected physical models of the finite effect of the speed of light are all based on the time delay and the Doppler effect, and the corrected gravitational acceleration g value can be expressed as: Among them, k is the correction coefficient, v 0 represents the initial velocity of the falling cube corner cube, g 0 represents the gravitational acceleration of the measured place, and T represents the total time required for one fall. In theory, whether the calculation is based on time delay or the Doppler effect, since the essence of physics is the physical effect caused by the limited speed of light, the correction coefficient can only obtain a unique value. However, when the calculation is performed based on the time delay method, the correction coefficient k=3; and when the calculation is performed based on the Doppler effect, the correction coefficient k=2. For the FG5 absolute gravimeter (produced and manufactured by Micro-g LaCoste in the United States, which is currently the only company that produces commercial absolute gravimeters), the falling distance is about 20cm, and the total falling time actually used for data fitting is about T =0.17s, the initial velocity is about v 0 =0.4m/s, then when the correction factor k=3, the correction of the finite effect of light speed is about 12μGal; and when the correction factor k=2, the size of the correction is about 8μGal . The difference in the correction coefficient can produce a systematic error of 4μGal. Since the true value of the g-value of the acceleration of gravity is unknown, the amount of the correction coefficient will directly affect the measurement result of the g-value of the acceleration of gravity.
科学家们试图利用FG5X绝对重力仪进行实验测量光速有限效应的影响，试图证明修正系数并不是过去一直认为的k＝3，而应该修正为k＝2。该实验的最大难点是仪器的各种噪声都会进入最后的数据，从实验数据中判断和扣除其他各项误差。但是科学家们对该实验的数据分析和误差扣除目前还存在一些争议，并不认为该实验确定了光速有限效应的影响多少，也就并没有彻底解决对于该修正系数的争议。Scientists tried to use the FG5X absolute gravimeter to conduct experiments to measure the influence of the finite effect of the speed of light, and tried to prove that the correction factor should be corrected to k=2 instead of k=3 as always thought in the past. The biggest difficulty of this experiment is that various noises of the instrument will enter the final data, and other errors are judged and deducted from the experimental data. However, there are still some controversies about the data analysis and error deduction of the experiment. They do not think that the experiment has determined the influence of the finite effect of the speed of light, and the controversy over the correction coefficient has not been completely resolved.
发明内容Contents of the invention
针对现有测试装置和实验手段的不足和该科学问题的重要性，本发明提供一种绝对重力仪中光速有限效应的双光路测试装置，通过该测试装置能够直接测量绝对重力仪中光速有限效应的影响，从而解决上述关于修正系数的争议。Aiming at the deficiency of existing test devices and experimental means and the importance of this scientific problem, the present invention provides a dual optical path test device for the finite effect of light velocity in an absolute gravimeter, through which the finite effect of light speed in an absolute gravimeter can be directly measured , so as to solve the above-mentioned controversy about the correction coefficient.
光程差在通常落体式绝对重力仪中都随着角锥棱镜的下落而减小，这是因为落体相对于参考棱镜的距离在减小。如果将落体替换为固连的两个对顶的角锥棱镜，即落体具有平行的上、下两个反射面，并在落体的上方增加一套激光干涉仪。这样，在落体的下落过程中，上方干涉仪中的光程差将随着落体的下落而增大。在这种情况下，两套干涉仪对应的干涉信号中，光速有限效应的符号相反，而重力加速度、地面振动和仪器的其他误差等都是共模项，从而通过差分测量的方式能够对光速有限效应进行直接的实验测量。基于以上陈述，本发明通过搭建一套创新的双光路系统，利用对顶的角锥棱镜作为落体，在其上方和下方分别构建一套激光干涉仪，利用这种双光路系统的两个干涉仪输出信号的差分来直接测量光速有限效应的影响，解决国际上关于这一问题的争议。The optical path difference decreases with the fall of the corner cube in the general falling body absolute gravimeter, because the distance of the falling body relative to the reference prism is decreasing. If the falling body is replaced by two fixed-connected corner cubes, that is, the falling body has two parallel upper and lower reflective surfaces, and a set of laser interferometers is added above the falling body. In this way, during the falling process of the falling object, the optical path difference in the upper interferometer will increase with the falling of the falling object. In this case, in the interference signals corresponding to the two sets of interferometers, the sign of the finite effect of the speed of light is opposite, while the acceleration of gravity, ground vibration and other errors of the instrument are all common-mode items, so that the speed of light can be measured by means of differential measurement. Finite effects are directly experimentally measured. Based on the above statements, the present invention builds a set of innovative dual-optical path system, uses the corner cube on the top as a falling body, and builds a set of laser interferometers above and below it respectively, and utilizes the two interferometers of this dual-optical path system The difference of the output signal is used to directly measure the influence of the finite effect of the speed of light, and to solve the international controversy on this issue.
本发明提供了一种基于双光路的绝对重力仪中光速有限效应的测试装置，包括：隔振平台、位于隔振平台上方的支撑结构、位于所述支撑结构上方的第一激光干涉仪、位于所述第一激光干涉仪的下方的第一参考棱镜、位于所述第一激光干涉仪上方的落体真空腔、位于所述落体真空腔中间的对顶双棱镜形成的落体以及相应的落体机械结构、位于所述落体真空腔上方的第二激光干涉仪、位于所述第二激光干涉仪上方的第二参考棱镜；第一参考棱镜、第一激光干涉仪和双棱镜的下反射面组成第一套完整的激光干涉光路系统；所述第二参考棱镜、第二激光干涉仪和双棱镜的上反射面组成第二套完整的激光干涉光路系统。当对顶双棱镜形成的落体在落体真空腔中自由下落时，会在第一激光干涉仪和第二激光干涉仪中分别形成干涉信号，通过探测器分别探测两套激光干涉仪的干涉信号，通过数据处理实现两套干涉仪信号的差分测量，由于光速有限效应在两套干涉仪中的作用效果是相反的，而重力加速度、振动噪声和其他噪声等对两套激光干涉仪的作用效果是相同的，是共模信号，因此通过这种差分测量就可以直接测量绝对重力仪中光速有限效应的大小。The invention provides a test device for the finite speed of light effect in an absolute gravimeter based on dual optical paths, comprising: a vibration isolation platform, a support structure located above the vibration isolation platform, a first laser interferometer located above the support structure, a The first reference prism below the first laser interferometer, the falling body vacuum chamber above the first laser interferometer, the falling body formed by the paired double prism in the middle of the falling body vacuum chamber, and the corresponding falling body mechanical structure , the second laser interferometer positioned above the falling body vacuum chamber, the second reference prism positioned above the second laser interferometer; the first reference prism, the first laser interferometer and the lower reflective surface of the double prism form the first A complete laser interference optical path system; the second reference prism, the second laser interferometer and the upper reflection surface of the double prism form a second complete laser interference optical path system. When the falling body formed by the double prism on the top falls freely in the falling body vacuum chamber, interference signals will be formed in the first laser interferometer and the second laser interferometer respectively, and the interference signals of the two sets of laser interferometers will be detected by the detector respectively. The differential measurement of the two sets of interferometer signals is realized through data processing. Due to the finite effect of light velocity, the effects of the two sets of interferometers are opposite, while the effects of gravitational acceleration, vibration noise and other noise on the two sets of laser interferometers are The same is a common-mode signal, so the size of the finite effect of the speed of light in the absolute gravimeter can be directly measured through this differential measurement.
更进一步地，所述隔振平台为超长周期的低频隔振系统，该隔振系统的谐振周期通常需要达到15s以上，由于绝对重力仪对低频敏感，而地脉动在1/6Hz附近存在一个峰，因此需要增加超长周期的低频隔振系统来隔离地脉动的影响。Furthermore, the vibration isolation platform is an ultra-long-period low-frequency vibration isolation system, and the resonance period of the vibration isolation system usually needs to reach more than 15s. Since the absolute gravimeter is sensitive to low frequencies, and the ground pulsation exists around 1/6Hz peak, so it is necessary to add an ultra-long period low-frequency vibration isolation system to isolate the impact of ground pulsations.
更进一步地，所述的第一激光干涉仪和第二激光干涉仪的结构应该尽可能对称，从而提高共模抑制。Furthermore, the structures of the first laser interferometer and the second laser interferometer should be as symmetrical as possible, so as to improve common mode suppression.
更进一步地，所述第一参考棱镜与第二参考棱镜应该固连，这样保证两个参考棱镜受到的地脉动和外部振动是相同的，从而进行共模抑制。Furthermore, the first reference prism and the second reference prism should be fixedly connected, so as to ensure that the ground pulsation and external vibrations experienced by the two reference prisms are the same, so as to perform common mode suppression.
本发明在普通落体式绝对重力仪的基础上，将落体更改为两个对顶放置的角锥棱镜，并在该落体的上反射面的上方增加一套激光干涉仪和相应的参考棱镜，并且保证两个参考棱镜固连。当落体在真空腔中进行自由下落时，光速有限效应在两套激光干涉仪中的作用效果是相反的，而重力加速度、外部振动和其他噪声等在两套干涉仪中的作用效果相同，是共模项，因此可以通过两套干涉仪的信号的差分对绝对重力仪中光速有限效应进行直接测量，解决国际上关于这一问题的争议。In the present invention, on the basis of an ordinary falling body type absolute gravimeter, the falling body is changed into two corner cube prisms placed on top, and a set of laser interferometer and corresponding reference prism are added above the upper reflecting surface of the falling body, and Make sure that the two reference prisms are firmly attached. When the falling object falls freely in the vacuum cavity, the effects of the finite speed of light in the two sets of laser interferometers are opposite, while the effects of gravitational acceleration, external vibration and other noises in the two sets of interferometers are the same. Therefore, the finite effect of the speed of light in the absolute gravimeter can be directly measured by the difference of the signals of the two sets of interferometers, and the international controversy on this issue can be resolved.
本发明还提供了一种基于双光路的绝对重力仪中光速有限效应的测试方法，包括下述步骤：The present invention also provides a method for testing the finite effect of the speed of light in an absolute gravimeter based on dual optical paths, comprising the following steps:
(1)利用两个对顶的角锥棱镜固连形成一个落体结构，并且在落体上反射面的上方增加一套激光干涉仪，并且使两套激光干涉仪的参考棱镜固连，形成双光路系统；(1) Use two opposite corner cube prisms to form a falling body structure, and add a set of laser interferometers above the reflecting surface of the falling body, and connect the reference prisms of the two sets of laser interferometers to form a double optical path system;
(2)落体在真空腔中自由下落时，两套激光干涉仪分别采集和记录干涉信号，将两套激光干涉仪的干涉信号进行相应的数据处理差分后即可得到光速有限效应影响的大小。(2) When the falling object falls freely in the vacuum cavity, two sets of laser interferometers collect and record the interference signals respectively, and after corresponding data processing and difference of the interference signals of the two sets of laser interferometers, the magnitude of the influence of the finite speed of light effect can be obtained.
更进一步地，对第一激光干涉仪进行计算得到的光速有限效应修正后的重力加速度为对第二激光干涉仪进行计算得到的光速有限效应修正后的重力加速度为通过对比两套激光干涉仪计算得到的光速有限效应修正后的重力加速度结果可以发现，光速有限效应在两套激光干涉仪中的作用效果是相反的，而重力加速度、外部振动和其他的误差对于两套干涉仪的作用效果却是相同的，所以通过两套激光干涉仪的干涉信号的差分即可实现光速有限效应的直接测量。Furthermore, the gravitational acceleration corrected by the finite effect of the speed of light obtained by calculating the first laser interferometer is The gravitational acceleration corrected by the finite effect of the speed of light obtained by calculating the second laser interferometer is By comparing the gravitational acceleration results corrected by the finite effect of light speed calculated by the two sets of laser interferometers, it can be found that the effect of the finite effect of light speed in the two sets of laser interferometers is opposite, and the acceleration of gravity, external vibration and other errors have a significant impact on the The effects of the two sets of interferometers are the same, so the direct measurement of the finite effect of the speed of light can be realized through the difference of the interference signals of the two sets of laser interferometers.
本发明提供了一种基于双光路的绝对重力仪中光速有限效应的测试装置和测试方法。由于在一般的落体型绝对重力仪中，光速有限效应是和其他各项噪声共同被采集和处理的，对其进行测试的最大难点是仪器的各种噪声都会进入最后的数据，从实验数据中判断和扣除其他各项误差。本发明在普通落体型绝对重力仪的基础上，利用对顶的两个角锥棱镜固连作为一个整体落体，并且在该落体上反射面的上方增加一套激光干涉仪，同时使两套激光干涉仪中的参考棱镜固连。在这种配置下，当落体自由下落的过程中，光速有限效应在两套激光干涉仪中的作用效果是相反的，而重力加速度、外部振动和其他误差等在两套干涉仪中的作用效果是共模项，因此可以通过两套激光干涉仪的干涉信号的差分直接测量光速有限效应在绝对重力仪中的影响大小。The invention provides a test device and a test method for the finite effect of light speed in an absolute gravimeter based on double light paths. Since in a general falling-type absolute gravimeter, the finite effect of light velocity is collected and processed together with other noises, the biggest difficulty in testing it is that various noises of the instrument will enter the final data, from the experimental data Judging and deducting other errors. On the basis of the ordinary falling body type absolute gravimeter, the present invention utilizes two corner cube prisms on the top to be fixedly connected as a whole falling body, and a set of laser interferometer is added above the reflecting surface of the falling body to make the two sets of laser The reference prism in the interferometer is fixed. Under this configuration, when the falling object falls freely, the effects of the finite speed of light in the two sets of laser interferometers are opposite, while the effects of gravity acceleration, external vibration and other errors in the two sets of interferometers is a common mode item, so the influence of the finite effect of light speed in the absolute gravimeter can be directly measured through the difference of the interference signals of two sets of laser interferometers.
总体而言，通过本发明所构思的以上技术方案与现有技术相比，本发明通过将落体更改为两个对顶放置的角锥棱镜，并在落体上反射面的上方增加一套激光干涉仪，同时使两套激光干涉仪的参考棱镜固连，通过两套激光干涉仪的干涉信号的差分能够实现对光速有限效应在绝对重力仪中的影响大小进行直接测量。该测试装置和测试方法将外部振动和其他误差等难以扣除的误差直接转换为共模项，利用差分的手段直接扣除，使得实验数据便于分析和解释。Generally speaking, compared with the prior art, the above technical solution conceived by the present invention is that the present invention changes the falling body to two corner cubes placed on top, and adds a set of laser interference above the upper reflecting surface of the falling body. At the same time, the reference prisms of the two sets of laser interferometers are fixedly connected, and the difference of the interference signals of the two sets of laser interferometers can realize the direct measurement of the influence of the finite effect of light speed in the absolute gravimeter. The test device and test method directly convert the errors that are difficult to deduct, such as external vibration and other errors, into common mode items, and directly subtract them by means of difference, so that the experimental data is convenient for analysis and interpretation.
附图说明Description of drawings
图1是本发明的双光路系统结构原理示意图；Fig. 1 is a schematic diagram of the structural principle of the dual optical path system of the present invention;
图2是本发明的双光路形成的两套激光干涉仪的光路示意图。Fig. 2 is a schematic diagram of the optical paths of two sets of laser interferometers formed by the dual optical paths of the present invention.
在所有附图中，相同的附图标记用来表示相同的元件或结构，其中：Throughout the drawings, the same reference numerals are used to designate the same elements or structures, wherein:
1为超长周期低频隔振平台、2为支撑结构、3为第一激光干涉仪、4为第一参考棱镜、5为落体真空腔、6为落体结构、7为第二激光干涉仪、8为第二参考棱镜、9为加速度计、10为主动反馈控制系统、11为稳频激光器、12为第一探测器、13为第二探测器。1 is the ultra-long period low-frequency vibration isolation platform, 2 is the supporting structure, 3 is the first laser interferometer, 4 is the first reference prism, 5 is the falling vacuum cavity, 6 is the falling structure, 7 is the second laser interferometer, 8 1 is the second reference prism, 9 is the accelerometer, 10 is the active feedback control system, 11 is the frequency-stabilized laser, 12 is the first detector, 13 is the second detector.
具体实施方式Detailed ways
为了使本发明的目的、技术方案及优点更加清楚明白，以下结合附图及实施例，对本发明进行进一步详细说明。应当理解，此处所描述的具体实施例仅用以解释本发明，并不用于限定本发明。In order to make the object, technical solution and advantages of the present invention clearer, the present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described here are only used to explain the present invention, not to limit the present invention.
图1示出了本发明实施例提供的绝对重力仪中光速有限效应的双光路测试装置的原理结构图，为了便于说明，仅示出了与本发明实施例相关的部分，详述如下：Fig. 1 shows the principle structure diagram of the dual optical path test device of the finite effect of light velocity in the absolute gravimeter provided by the embodiment of the present invention. For the convenience of explanation, only the parts related to the embodiment of the present invention are shown, and the details are as follows:
绝对重力仪中光速有限效应的双光路测试装置包括：超长周期低频隔振平台1、位于隔振平台1上方的支撑结构2、位于所述支撑结构2上方的第一激光干涉仪3、位于所述第一激光干涉仪3的下方的第一参考棱镜4、位于所述第一激光干涉仪3上方的落体真空腔5、位于所述落体真空腔5中间的落体结构6、位于所述落体真空腔5上方的第二激光干涉仪7、位于所述第二激光干涉仪7上方的第二参考棱镜8；所述第一参考棱镜4、第一激光干涉仪3和落体结构6的下反射面组成第一套完整的激光干涉光路系统；所述第二参考棱镜8、第二激光干涉仪7和落体结构6的上反射面组成第二套完整的激光干涉光路系统。当落体结构6在落体真空腔5中自由下落时，会在第一激光干涉仪3和第二激光干涉仪7中分别形成干涉信号，通过第一探测器12、第二探测器13分别探测两套激光干涉仪的干涉信号，通过数据处理实现两套干涉仪信号的差分测量，由于光速有限效应在两套干涉仪中的作用效果是相反的，而重力加速度、振动噪声和其他噪声等对两套干涉仪的作用效果是相同的，是共模信号，因此通过这种差分测量就可以直接测量绝对重力仪中的光速有限效应的大小。The dual optical path test device for the finite effect of light speed in an absolute gravimeter includes: an ultra-long-period low-frequency vibration isolation platform 1, a support structure 2 located above the vibration isolation platform 1, a first laser interferometer 3 located above the support structure 2, and a The first reference prism 4 below the first laser interferometer 3, the falling body vacuum chamber 5 above the first laser interferometer 3, the falling body structure 6 in the middle of the falling body vacuum chamber 5, and the falling body The second laser interferometer 7 above the vacuum chamber 5, the second reference prism 8 above the second laser interferometer 7; the first reference prism 4, the first laser interferometer 3 and the lower reflection of the falling structure 6 The surface forms the first complete laser interference optical path system; the second reference prism 8, the second laser interferometer 7 and the upper reflection surface of the falling structure 6 form the second complete laser interference optical path system. When the falling structure 6 falls freely in the falling vacuum chamber 5, interference signals will be formed in the first laser interferometer 3 and the second laser interferometer 7 respectively, and the first detector 12 and the second detector 13 will detect the two laser interferometers respectively. The interference signals of two sets of laser interferometers are realized through data processing to realize the differential measurement of the signals of the two sets of interferometers. Due to the finite effect of light speed, the effects of the two sets of interferometers are opposite, and the acceleration of gravity, vibration noise and other noises affect the two sets of interferometers. The effects of the sets of interferometers are the same, and they are common-mode signals, so the size of the finite effect of the speed of light in the absolute gravimeter can be directly measured through this differential measurement.
在本发明实施例中，落体结构6由两个落体棱镜固连组成，两个落体棱镜均为角锥棱镜且对顶角设置，落体结构6具有平行的上、下两个反射面，落体结构6的上反射面与第二激光干涉仪7相对，落体结构6的下反射面与第一激光干涉仪3相对。In the embodiment of the present invention, the falling body structure 6 is composed of two falling body prisms, both of which are corner cube prisms and arranged at opposite corners. The upper reflective surface of 6 is opposite to the second laser interferometer 7 , and the lower reflective surface of the drop structure 6 is opposite to the first laser interferometer 3 .
在本发明实施例中，隔振平台1可以为超长周期(15s以上)的低频隔振系统，其中加速度计9探测隔振平台1上的振动加速度，主动反馈补偿系统10根据加速度计9的输出施加适当的磁反馈力补偿隔振平台的运动，从而实现隔振系统的谐振周期达到15s以上。由于绝对重力仪对低频敏感，而地脉动在1/6Hz附近存在一个峰，因此需要增加超长周期的低频隔振系统来隔离地脉动的影响。In the embodiment of the present invention, the vibration isolation platform 1 can be a low-frequency vibration isolation system with an ultra-long period (more than 15s), wherein the accelerometer 9 detects the vibration acceleration on the vibration isolation platform 1, and the active feedback compensation system 10 according to the vibration acceleration of the accelerometer 9 The output applies an appropriate magnetic feedback force to compensate the movement of the vibration isolation platform, so that the resonance period of the vibration isolation system can reach more than 15s. Since the absolute gravimeter is sensitive to low frequencies, and the ground pulsation has a peak near 1/6Hz, it is necessary to add an ultra-long period low-frequency vibration isolation system to isolate the influence of the ground pulsation.
在本发明实施例中，第一激光干涉仪3和第二激光干涉仪7的结构应该尽可能对称，从而提高共模抑制。In the embodiment of the present invention, the structures of the first laser interferometer 3 and the second laser interferometer 7 should be as symmetrical as possible, so as to improve common mode suppression.
在本发明实施例中，第一参考棱镜4与第二参考棱镜8应该刚性连接，使得第一参考棱镜4与第二参考棱镜8的运动完全一致；这样保证两个参考棱镜受到的地脉动和外部振动是相同的，从而进行共模抑制。作为本发明的一个实施例，第一参考棱镜4和第二参考棱镜8可以通过支撑架实现固定刚性连接。作为本发明的另一个实施例，可以将第一参考棱镜4、第一激光干涉仪3、落体真空腔5、第二激光干涉仪7与第二参考棱镜8固定连接，保证第一参考棱镜4与第二参考棱镜8的运动完全一致。In the embodiment of the present invention, the first reference prism 4 and the second reference prism 8 should be rigidly connected, so that the motions of the first reference prism 4 and the second reference prism 8 are completely consistent; thus ensuring that the two reference prisms are subject to ground pulsation and External vibrations are the same, resulting in common-mode rejection. As an embodiment of the present invention, the first reference prism 4 and the second reference prism 8 can be fixed and rigidly connected through a support frame. As another embodiment of the present invention, the first reference prism 4, the first laser interferometer 3, the falling vacuum chamber 5, the second laser interferometer 7 and the second reference prism 8 can be fixedly connected to ensure that the first reference prism 4 It is completely consistent with the movement of the second reference prism 8 .
在本发明实施例中，落体真空腔5包括真空腔和落体的辅助机械结构，由于该落体真空腔5的结构属于现有技术，在此不再赘述。In the embodiment of the present invention, the falling body vacuum chamber 5 includes a vacuum chamber and an auxiliary mechanical structure for the falling body. Since the structure of the falling body vacuum chamber 5 belongs to the prior art, it will not be repeated here.
图2示出了本发明实施例中双光路形成的两套激光干涉仪的光路结构示意图，稳频激光器11发出的激光经过分束镜后分别入射到两套激光干涉仪中，对于第一激光干涉仪3，入射的激光经过分束镜分成两束，一束经过落体结构6的下反射面到第一参考棱镜4后，再经过反射镜与另一束激光形成干涉条纹，并被第一探测器12检测；对于第二激光干涉仪7，入射的激光经过分束镜分成两束，一束经过落体结构6的上反射面到第二参考棱镜8后，再经过反射镜与另一束激光形成干涉条纹，并被第二探测器13检测。具体的光路可以不同，图2仅给出一种可能的光路示意图。Fig. 2 shows the schematic diagram of the optical path structure of two sets of laser interferometers formed by dual optical paths in the embodiment of the present invention. The laser light emitted by the frequency-stabilized laser 11 is respectively incident on the two sets of laser interferometers after passing through the beam splitter. For the first laser In the interferometer 3, the incident laser light is divided into two beams through the beam splitter, one beam passes through the lower reflection surface of the falling structure 6 to the first reference prism 4, and then passes through the mirror to form interference fringes with the other beam of laser light, and is captured by the first The detector 12 detects; for the second laser interferometer 7, the incident laser light is divided into two beams through a beam splitter, one beam passes through the upper reflection surface of the falling body structure 6 to the second reference prism 8, and then passes through the reflector and the other beam The laser light forms interference fringes, which are detected by the second detector 13 . The specific optical path may be different, and FIG. 2 only shows a schematic diagram of a possible optical path.
本发明在普通落体式绝对重力仪的基础上，将落体更改为两个对顶放置的角锥棱镜，并在该落体的上反射面的上方增加一套激光干涉仪和相应的参考棱镜，并且保证两个参考棱镜固连。当落体在真空腔中进行自由下落时，两套干涉仪都会对该落体的运动进行测量，其中光速有限效应在两套激光干涉仪中的作用效果是相反的，而重力加速度、外部振动和其他噪声等在两套干涉仪中的作用效果相同，是共模项，因此可以通过两套干涉仪的信号的差分对绝对重力仪中光速有限效应进行直接测量，解决国际上关于这一问题的争议。In the present invention, on the basis of an ordinary falling body type absolute gravimeter, the falling body is changed into two corner cube prisms placed on top, and a set of laser interferometer and corresponding reference prism are added above the upper reflecting surface of the falling body, and Make sure that the two reference prisms are firmly attached. When the falling object falls freely in the vacuum cavity, both sets of interferometers will measure the motion of the falling object, and the effect of the finite speed of light in the two sets of laser interferometers is opposite, while the acceleration of gravity, external vibration and other Noise and other effects in the two sets of interferometers are the same, and they are common mode items. Therefore, the finite effect of the speed of light in the absolute gravimeter can be directly measured through the signal difference of the two sets of interferometers, and the international dispute on this issue can be resolved. .
本发明还提供了一种基于双光路的绝对重力仪中光速有限效应的测试方法，包括下述步骤：The present invention also provides a method for testing the finite effect of the speed of light in an absolute gravimeter based on dual optical paths, comprising the following steps:
(1)利用两个对顶的角锥棱镜固连形成一个落体结构6，并且在落体上反射面的上方增加一套激光干涉仪7，并且使两套激光干涉仪的参考棱镜4、8固连，形成双光路系统；(1) Utilize two corner cube prisms on the top to be fixedly connected to form a falling body structure 6, and add a set of laser interferometer 7 above the reflecting surface on the falling body, and make the reference prisms 4, 8 of the two sets of laser interferometers fixed Connected to form a dual optical path system;
(2)落体6在真空腔5中自由下落时，两套激光干涉仪3、7分别采集和记录干涉信号，将两套激光干涉仪的干涉信号进行相应的数据处理差分后即可得到光速有限效应影响的大小。(2) When the falling body 6 falls freely in the vacuum cavity 5, the two sets of laser interferometers 3 and 7 collect and record the interference signals respectively, and after performing corresponding data processing and difference on the interference signals of the two sets of laser interferometers, the finite speed of light can be obtained. The size of the effect.
更进一步地，对第一激光干涉仪进行计算得到的光速有限效应修正后的重力加速度为对第二激光干涉仪进行计算得到的光速有限效应修正后的重力加速度为通过对比两套激光干涉仪计算得到的光速有限效应修正后的重力加速度结果可以发现，光速有限效应在两套激光干涉仪中的作用效果是相反的，而重力加速度、外部振动和其他的误差对于两套激光干涉仪的作用效果却是相同的，所以通过两套激光干涉仪的干涉信号的差分即可实现光速有限效应的直接测量。Furthermore, the gravitational acceleration corrected by the finite effect of the speed of light obtained by calculating the first laser interferometer is The gravitational acceleration corrected by the finite effect of the speed of light obtained by calculating the second laser interferometer is By comparing the gravitational acceleration results corrected by the finite effect of light speed calculated by the two sets of laser interferometers, it can be found that the effect of the finite effect of light speed in the two sets of laser interferometers is opposite, and the acceleration of gravity, external vibration and other errors have a significant impact on the The effect of the two sets of laser interferometers is the same, so the direct measurement of the finite effect of the speed of light can be realized through the difference of the interference signals of the two sets of laser interferometers.
本领域的技术人员容易理解，以上所述仅为本发明的较佳实施例而已，并不用以限制本发明，凡在本发明的精神和原则之内所作的任何修改、等同替换和改进等，均应包含在本发明的保护范围之内。It is easy for those skilled in the art to understand that the above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present invention, All should be included within the protection scope of the present invention.
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| CN115032706A (en) * | 2022-06-07 | 2022-09-09 | 浙江法拉第激光科技有限公司 | Absolute gravimeter based on Michelson laser |
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| CN118795562A (en) * | 2024-06-19 | 2024-10-18 | 中国计量科学研究院 | Absolute gravimeter falling body and trailer separation distance measurement system and measurement method |
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