Timedelay interferometric ranging for spaceborne gravitationalwave detectors
Abstract
Spaceborne interferometric gravitationalwave detectors, sensitive in the lowfrequency (mHz) band, will fly in the next decade. In these detectors, the spacecrafttospacecraft lighttravel times will necessarily be unequal and time varying, and (because of aberration) will have different values on up and downlinks. In such unequalarmlength interferometers, laserphase noise will be canceled by taking linear combinations of the laserphase observables measured between pairs of spacecraft, appropriately time shifted by the light propagation times along the corresponding arms. This procedure, known as timedelay interferometry (TDI), requires an accurate knowledge of the lighttime delays as functions of time. Here we propose a highaccuracy technique to estimate these time delays, and we study its use in the context of the Laser Interferometer Space Antenna (LISA) mission. We refer to this ranging technique, which relies on the TDI combinations themselves, as timedelay interferometric ranging (TDIR). For every TDI combination, we show that, by minimizing the rms power in that combination (averaged over integration times ∼10^{4} s) with respect to the timedelay parameters, we obtain estimates of the time delays accurate enough to cancel laser noise to a level well below the secondary noises. Thus TDIR allows the implementation of TDI without the use of dedicated interspacecraft ranging systems, with a potential simplification of the LISA design. In this paper we define the TDIR procedure formally, and we characterize its expected performance via simulations with the Synthetic LISA software package.
 Publication:

Physical Review D
 Pub Date:
 February 2005
 DOI:
 10.1103/PhysRevD.71.041101
 arXiv:
 arXiv:grqc/0410122
 Bibcode:
 2005PhRvD..71d1101T
 Keywords:

 04.80.Nn;
 07.60.Ly;
 95.55.Ym;
 Gravitational wave detectors and experiments;
 Interferometers;
 Gravitational radiation detectors;
 mass spectrometers;
 and other instrumentation and techniques;
 General Relativity and Quantum Cosmology
 EPrint:
 5 pages, 2 figures