The Application of Coherent Local Time for Optical Time Transfer and the Quantification of Systematic Errors in Satellite Laser Ranging

Kodet, Jan

doi:10.1007/s11214-017-0457-2

Cited by 19 publications

(6 citation statements)

References 20 publications

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“…It manifests as an elevation-dependent variation of the SLR residuals and thus can lead to corrupting the determination of station heights. The effect is all the more pronounced as the SLR stations do not (or cannot because of the signature effect) control strictly the variable intensity in their laser returns when tracking at different elevation angles (e.g., atmospheric attenuation or telescope/laser pointing may introduce variable return signal strengths between the zenith and low-elevation observations (Schreiber and Kodet 2017)). This is illustrated in Fig.…”

Section: Resultsmentioning

confidence: 99%

Self-consistent determination of the Earth’s GM, geocenter motion and figure axis orientation

Couhert

Bizouard

Mercier

et al. 2020

J Geod

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The very low-degree Earth's gravity coefficients, associated with the largest-scale mass redistribution in the Earth's fluid envelope (atmosphere, oceans and continental hydrology), are the most poorly known. In particular, the first three degree geopotential terms are important, as they relate to intrinsic Earth's mass references: gravitational coefficient (G M) of the Earth (degree 0), geocenter motion (degree 1), Earth's figure axis orientation (degree 2). This paper presents a self-consistent determination of these three properties of the Earth. The main objective is to deal with the remaining sources of altimetry satellite orbit uncertainties affecting the fundamental record of sea surface height measurements. The analysis identifies the modeling errors, which should be mitigated when estimating the geocenter coordinates from Satellite Laser Ranging (SLR) observations. The long-term behavior of the degree-0 and -2 spherical harmonics is also observed over the 34-year period 1984-2017 from the long-time history of satellite laser tracking to geodetic spherical satellites. From the analysis of the evolution of these two coefficients, constraints regarding the Earth's rheology and uncertainties in the value of G M could be inferred. Overall, the influence of the orbit characteristics, SLR station ranging/position biases and satellite signature effects, measurement modeling errors (tropospheric corrections, non-tidal deformations) are also discussed.

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Section: Resultsmentioning

confidence: 99%

Self-consistent determination of the Earth’s GM, geocenter motion and figure axis orientation

Couhert

Bizouard

Mercier

et al. 2020

J Geod

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“…The optical comb is understood as an optical timing ruler, and the range measurement must be realized against this ruler. The timing stability between the two endpoints of the timing signal distribution is not greater than 1 mm (or three ps) peak to peak [3]. Each link ends up with an optical-to-electrical converter.…”

Section: Drift-free Optical Timing Systemmentioning

confidence: 99%

Satellite range finding by photon counting against optical time ruler

Kodet¹,

Eckl

2023

Quantum Optics and Photon Counting 2023

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This work focused on two primary error sources limiting Satellite Laser Ranging accuracy. The detection delay instability spoils ranging data concerning long-term stability. This results in the impossibility of distinguishing if the error has an origin during calibration or ranging; both errors limit the SLR product quality. Another error source arises from threshold detection, where no information about signal amplitude is available for individual laser signal returns. In this contribution, we will introduce a new ranging strategy, where we time-tag photons of interest against so-called clock photons. They are accurately synchronized to a stable atomic clock and generate equidistantly well-defined time intervals as an optical ruler. The clock photons propagate through the same detection chain as ranging photons and effectively remove and calibrate all variable electrical delays during the detection process. In this detection scenario, the biggest drawback may be the increase in noise since the detector noise is added twice. However, the clock photons can be averaged effectively; therefore, the additive clock detection jitter is suppressed. Since the detector response is sampled using 20 GSPS, it allows us to reconstruct a detector response envelope and consequently remove any amplitude to timing modulation from ranging data. Here we will outline the measurement concept and discuss laboratory tests and range measurements obtained from satellite echos.

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“…Laser ranging accuracy can reach sub-centimeters by satellite laser ranging (SLR), and it is widely used in determining the satellite attitude, high-precision time comparison, precision orbit setting, relativity verification, and other fields [1][2][3][4][5]. The emission optical path of the laser in the coaxial telescope laser ranging system would be the same as the monitoring optical path for the satellites, and also, the optical system of the return laser echoes through the same as the structure.…”

Section: Introductionmentioning

confidence: 99%

An aperture of 21 cm telescope with polarized coaxial for satellite laser ranging

Long

Deng²,

Zhang³

et al. 2023

Front. Phys.

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With the development of aerospace and space scientific research, satellite laser ranging (SLR) has put forward higher requirements for response speed, data density, and measurement accuracy. In coaxial common optical path laser ranging, the emitted laser and the received laser echoes pass through the same optical system. Due to the reversibility of the optical path, the laser emission, monitoring, and laser echoes’ optical path all pass through the same optical system structure, and the response speed and ranging ability of the laser ranging system have been greatly improved. Based on the SLR system of the Shanghai Astronomical Observatory (SHAO), the laser transmitting telescope with an aperture of 21 cm was used to build a polarized coaxial SLR system. It uses a picosecond pulsed laser with a pulse repetition frequency of 2 kHz and a single-pulse energy of 2 mJ. Also, a 4f system was applied to shrink the laser echo beam and filter out noise, the measurements of low-Earth orbit and long-distance high-orbit satellites were realized, and the ranging accuracy was ∼2 cm. As far as we know, this is currently the smallest aperture telescope for SLR globally, which is conducive to the miniaturization and integrated development of SLR systems.

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The Application of Coherent Local Time for Optical Time Transfer and the Quantification of Systematic Errors in Satellite Laser Ranging

Cited by 19 publications

References 20 publications

Self-consistent determination of the Earth’s GM, geocenter motion and figure axis orientation

Self-consistent determination of the Earth’s GM, geocenter motion and figure axis orientation

Satellite range finding by photon counting against optical time ruler

An aperture of 21 cm telescope with polarized coaxial for satellite laser ranging

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