Satellite vibration measurements with an autodyne CO_2 laser radar

Schultz, K.J.; Kocher, David G.; Daley, J. A.; Theriault, Joseph R.; Spinks, James M.; Fisher, Shalom

doi:10.1364/ao.33.002349

Cited by 18 publications

(10 citation statements)

References 1 publication

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Vibration signatures in orbit were obtained using a ground-based CO 2 laser radar while the retractable boom on a satellite was in motion. 8,9 Microvibration tests on the ARTEMIS spacecraft were conducted on the ground, and the in-orbit laser pointing was analyzed 10,11 using Monte Carlo simulation in 1997. A real in-orbit measurement of microvibrations was conducted by using laser communication equipment onboard the ETS-VI satellite.…”

Section: Introductionmentioning

confidence: 99%

In-orbit measurements of spacecraft microvibrations for satellite laser communication links

et al. 2010

View full text Add to dashboard Cite

Angular microvibrations of platform jitter on the optical interorbit communications engineering test satellite are measured in space during ground-to-satellite laser communication links. The microaccelerations are measured by the onboard accelerometers at a sampling rate of 2048 Hz. The angular microvibrations are estimated from the measured microaccelerations using the tracking characteristics of the laser communications terminal and the conversion factor on the basis of microvibration data obtained from ground-based tests. The power spectral density ͑PSD͒ of the satellite microvibrations is analyzed by using the fast Fourier transform analysis and the data length is examined according to the frequency resolution of the PSD. The in-orbit measurements of the PSDs are compared with those obtained from the ground test. The angular microvibrational base motion is estimated and a PSD up to 1024 Hz is additionally provided as a database of the real measurement results with previously obtained in-orbit measurements. The measured results will contribute to the angular jitter estimation and the design of a tracking control loop for space laser communication systems in the future.

show abstract

Section: Introductionmentioning

confidence: 99%

In-orbit measurements of spacecraft microvibrations for satellite laser communication links

et al. 2010

View full text Add to dashboard Cite

show abstract

“…The price of this time-frequency resolution is interference effects which, are reduced by window functions listed below. The Choi-Williams JTFT has been studied in particular [3][4][5]9 for laser radar applications. JTFT extrapolation from analog to digital signals, as in a computer, however, is not as straightforward 15 as one might think.…”

Section: Joint Time-frequency Transform Processingmentioning

confidence: 99%

“…In those studies the spectrogram (discussed in Sect. 2.4) estimator was found to be superior to frequency discriminators [1][2][3] (frequency to voltage converters), and the joint time-frequency transform (Choi-Williams only), discussed in Sect. 3, was found to be superior 1,3 -5,9 to the spectrogram approach.…”

Section: Introductionmentioning

confidence: 98%

See 1 more Smart Citation

Joint time-frequency transform processing for linear and sinusoidal FM coherent ladars

Youmans

2003

SPIE Proceedings

View full text Add to dashboard Cite

We examine the signal processing of both linear and sinusoidal frequency modulation (FM) coherent ladar returns from resolved and unresolved targets, which are spread in Doppler. The Doppler spread may be due to target spin, tumbling, or vibration as well as to the applied linear or sinusoidal-FM on the transmitted E-field. Monte Carlo realizations of the target surface random phasor reflector elements interact with the incident E-field producing laser speckle, and the speckled returns are analyzed in this study. The speckle signals are processed (1) using several spectrum (periodogram based) estimators, (2) the conventional "spectrogram" approach, and (3) ten joint time-frequency transforms (JTFT). We show that the Born-Jordan JTFT is superior to the other spectral estimators tested here in suppressing local oscillator laser noise and accurately estimating the target's spectrum for signal processing under speckle target return conditions pertaining to coherent laser radar. A new algorithm which sums particular pixels of the JTFT image is introduced and is shown to be much more robust in low CNR conditions than the JTFT maxima or JTFT centroid processing when utilizing the applied linear or sinusoidal-FM modulation waveform.

show abstract

“…Results of onboard measurements of the vibration spectra of communication satellites OLYMPUS and LANDSAT are specified in [9]- [12]. Results of measurements from the ground of satellite vibration spectra by laser radar are described in [13] and [14]. Chen and Gardner analyze the impact of random pointing and tracking errors on the design of coherent and incoherent optical intersatellite communication links.…”

Section: Introductionmentioning

confidence: 99%

Laser satellite communication network-vibration effect and possible solutions

1997

View full text Add to dashboard Cite

A number of serious consortiums develop satellite communication networks. The objective of these communication projects is to service personal communication users almost everywhere on earth. The intersatellite links in those projects use microwave radiation as the carrier. Free-space optical communication between satellites networked together can make possible high-speed communication between different places on earth. Some advantages of an optical communication system over a microwave communication system in free space are 1) smaller size and weight, 2) less transmitter power, 3) larger bandwidth, and 4) higher immunity to interference. The pointing from one satellite to another is a complicated problem due to the large distance between the satellite, the narrow beam divergence angle, and vibration of the pointing system. Such vibration of the transmitted beam in the receiver plane decreases the average received signal, which increases the bit error rate. In this paper, we review 1) the present status of satellite networks, 2) developing efforts of optical satellite communication around the world, 3) performance results of vibration effects on different kinds of optical communication satellite networks, and 4) seven approaches to overcome the problems caused by transmitter pointing vibration.

show abstract

Satellite vibration measurements with an autodyne CO_2 laser radar

Cited by 18 publications

References 1 publication

In-orbit measurements of spacecraft microvibrations for satellite laser communication links

In-orbit measurements of spacecraft microvibrations for satellite laser communication links

Joint time-frequency transform processing for linear and sinusoidal FM coherent ladars

Laser satellite communication network-vibration effect and possible solutions

Contact Info

Product

Resources

About