Multi-baseline/multi-frequency-band interference phase unwrapping frequency domain quick algorithm

Abstract

The invention provides a multi-baseline / multi-frequency-band phase unwrapping frequency domain quick algorithm. The technical scheme includes that firstly, calculating phase gradient values in the horizontal and vertical directions according to interference phase observed values of an interference phase diagram, and calculating phase gradient values on the border of a phase gradient diagram according to time domain irrotational conditions; secondly, subjecting the phase gradient values to Fourier transform to obtain a frequency domain function of the phase gradient values, and calculating a Fourier coefficient approximate value meeting the irrotational conditions under the condition that the quadratic sum of the weighted sum of and the difference between the frequency domain function of phase gradient estimated values and a frequency domain function of each baseline / each frequency band phase gradient values; thirdly, subjecting the Fourier coefficient approximate value to Fourier transform to obtain a phase gradient estimated value meeting the phase irrotational conditions; and fourthly, integrating the obtained phase gradient estimated value meeting the phase irrotational conditions to obtain a phase unwrapping value. Calculation amount of the phase unwrapping algorithm is reduced while precision is unaffected.

Description

technical field [0001] The invention belongs to the intersecting technical field of remote sensing and signal processing, in particular to a frequency-domain fast method for interferometric phase unwrapping under multi-baseline / multi-frequency band conditions by using interferometric synthetic aperture radar. Background technique [0002] All the process of restoring the phase from the main value or the phase difference value to the real value are collectively called phase unwrapping. In addition to the application of interferometric synthetic aperture radar, phase unwrapping is widely used in synthetic aperture sonar, adaptive optics, nuclear magnetic resonance, seismic processing, etc. have important applications. Using multiple interferometric synthetic aperture radars to form multi-baseline or multi-band interference can improve the performance of phase unwrapping. [0003] The present invention takes the application of interferometric synthetic aperture radar as an exa...

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Problems solved by technology

[0004] At present, the multi-baseline / multi-band phase unwrapping methods mainly include: Chinese remainder law method, projection method and linear combination method, iterative method, time domain least square method, Kalman filter method, maximum likelihood method, maximum a posteriori method, space- Image domain joint subspace orthogonal projection method and network flow method, among which the basic idea of ​​multi-baseline / multi-band time-domain least squares method is to minimize the sum of squares of the difference between the estimated value of phase gradient and the weighted sum of multiple phase gradient values, It is equivalent to solving the Poisson equation with Newman boundary. The essence of this method is to average the errors. It is very robust but not efficient

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