316 results about "Specific impulse" patented technology

The method serves to place a space vehicle, such as a satellite, on a target orbit such as the orbit adapted to normal operation of the space vehicle and starting from an elliptical initial orbit that is significantly different from, and in particular more eccentric than the target orbit. The space vehicle is caused to describe a spiral trajectory made up of a plurality of intermediate orbits while a set of high specific impulse thrusters mounted on the space vehicle are fired continuously and without interruption, thereby causing the spiral trajectory to vary so that on each successive revolution, at least during a first stage of the maneuver, perigee altitude increases, apogee altitude varies in a desired direction, and any difference in inclination between the intermediate orbit and the target orbit is decreased, after which, at least during a second stage of the maneuver, changes in perigee altitude and in apogee altitude are controlled individually in predetermined constant directions, while any difference in inclination between the intermediate orbit and the target orbit continues to be reduced until the apogee altitude, the perigee altitude, and the orbital inclination of an intermediate orbit of the space vehicle have substantially the values of the target orbit.

A method for processing a received, modulated pulse (i.e. waveform) that requires predictive deconvolution to resolve a scatterer from noise and other scatterers includes receiving a return signal; obtaining L+(2M−1)(N−1) samples y of the return signal, where y(l)={tilde over (x)}T(l) s+v(l); applying RMMSE estimation to each successive N samples to obtain initial impulse response estimates [{circumflex over (x)}1{−(M−1)(N−1)}, . . . , {circumflex over (x)}1{−1}, {circumflex over (x)}1 {0}, . . . , {circumflex over (x)}1{L−1}, . . . , {circumflex over (x)}1{L}, {circumflex over (x)}1{−1 +(M−1)(N−1)}]; computing power estimates {circumflex over (ρ)}1(l)=|{circumflex over (x)}1(l)|α for l=−(M−1)(N−1), . . . , L−1+(M−1)(N−1) and 0<α≦2; computing MMSE filters according to w(l)=ρ(l) (C(l)+R)−1s, where ρ(l)=E[|x(l)|α] is the power of x(l), for 0<α≦2, and R=E[v(l) vH(l)] is the noise covariance matrix; applying the MMSE filters to y to obtain [{circumflex over (x)}2{−(M−2)(N−1)}, . . . , {circumflex over (x)}2{−1}, {circumflex over (x)}2{0}, . . . , {circumflex over (x)}2{L−1}, {circumflex over (x)}2{L}, . . . , {circumflex over (x)}2{L−1+(M−2)(N−1)}]; and repeating (d)–(f) for subsequent reiterative stages until a desired length-L range window is reached, thereby resolving the scatterer from noise and other scatterers. The RMMSE predictive deconvolution approach provides high-fidelity impulse response estimation. The RMMSE estimator can reiteratively estimate the MMSE filter for each specific impulse response coefficient by mitigating the interference from neighboring coefficients that is a result of the temporal (i.e. spatial) extent of the transmitted waveform. The result is a robust estimator that adaptively eliminates the spatial ambiguities that occur when a fixed receiver filter is used.