• DOI:10.1103/PhysRevD.103.123027
• Corpus ID: 218516865

Clock-jitter reduction in LISA time-delay interferometry combinations

@article{Hartwig2021ClockjitterRI,
  title={Clock-jitter reduction in LISA time-delay interferometry combinations},
  author={Olaf Hartwig and Jean-Baptiste Bayle},
  journal={Physical Review D},
  year={2021}
}

• Olaf Hartwig, Jean-Baptiste Bayle
• Published 5 May 2020
• Physics
• Physical Review D

The Laser Interferometer Space Antenna (LISA) is a European Space Agency mission that aims to measure gravitational waves in the millihertz range. The three-spacecraft constellation form a nearly-equilateral triangle, which experiences flexing along its orbit around the Sun. These time-varying and unequal armlengths require to process measurements with Time-Delay Interferometry (TDI) to synthesize a virtual equal-arm interferometer, and reduce the otherwise-overwhelming laser frequency noise. Algorithms compatible with such TDI combinations have recently been proposed in order to suppress the phase fluctuations of the onboard ultra-stable oscillators (USO) used as reference clocks. In this paper, we present a method to compute improved algorithms, which provide exact cancellation of the USO noise for a large class of TDI combinations, even for time-varying armlengths, if we neglect Doppler effects. We account for errors present in the sideband signals used in the algorithm, and include a new step to reduce it. We propose analytic models for the power spectral densities of residual noises, including residual clock noise due to the filters used on board to downsample data before telemetry. We present the results of simulations, which include realistic USO noise. We show that our model agrees very well with the simulated data, and that our algorithms are able to reduce clock jitter well below other noises, and the mission requirements.