A method performed in a radar system for detecting targets comprising moving and stationary targets, the radar system being equipped with Synthetic Aperture Radar, SAR, onboard a SAR platform, said platform comprising navigation equipment for accurate determination of the position of the SAR platform, and transversing a stationary ground region and targets in the said ground region, in which the SAR platform obtains radar data by means of at least one antenna, the movement of the SAR platform during recording of the data being essentially rectilinear and uniform in an azimuth direction, and its velocity being significantly larger than those of the moving targets, the radar system further comprising a SAR processor recording the radar data and the position of the antenna or antennas for each transmitted radar pulse, wherein within synthetic sub-apertures, each sub-aperture covering a surveyed region being a part of the stationary ground region, radar data are: • successively merged in N iteration steps into SAR images of increasing resolution of the surveyed region and where • each iteration step consists of forming a new SAR image at a new iteration level by a linear combination of neighbouring SAR images in the previous iteration step, said method being characterized by that the linear combination comprises a relation of coordinates of target positions in said neighbouring SAR images such that related coordinates indicate the same target position at a given reference time for all targets having a specific relative velocity with respect to the moving SAR platform and a specific degree of acceleration in the direction orthogonal to the movement of the SAR platform, wherein • m iteration steps, m<N, are performed covering the surveyed region where data from one velocity computation at each iteration level using velocity increments Δ W l of a processing velocity W, and data from one acceleration computation for acceleration increments Δÿ l are used in a motion insensitive process continuously repeated over the surveyed region, wherein each cycle is defined as a loop A, for producing one SAR- image of the stationary ground points and the targets per iteration level and • N - m further iteration steps are performed for a selected patch being a part of the surveyed region, each iteration step using a target detection process at each iteration level with data from at least three computations, comprising at least one velocity computation with the velocity increments Δ W l and at least one acceleration computation with the acceleration increments Δ ÿ l for producing one SAR-image per combination of velocity and acceleration computation and for detecting targets and target tracks as well as calculating target parameters R,Φ, a processing velocity W and an acceleration ÿ in a direction perpendicular to the azimuth direction, the R,Φ, ÿ, W- parameters defining an R, Φ,ÿ,W -space for each target, and • in a target positioning process, the target position within the patch is calculated by determining the φ -parameter representative of a relative velocity of the target in relation to the moving SAR platform where each combination of velocity and acceleration computations represents an assumption of possible target parameters. • successively merged in N iteration steps into SAR images of increasing resolution of the surveyed region and where • each iteration step consists of forming a new SAR image at a new iteration level by a linear combination of neighbouring SAR images in the previous iteration step, • m iteration steps, m<N, are performed covering the surveyed region where data from one velocity computation at each iteration level using velocity increments Δ W l of a processing velocity W, and data from one acceleration computation for acceleration increments Δÿ l are used in a motion insensitive process continuously repeated over the surveyed region, wherein each cycle is defined as a loop A, for producing one SAR- image of the stationary ground points and the targets per iteration level and • N - m further iteration steps are performed for a selected patch being a part of the surveyed region, each iteration step using a target detection process at each iteration level with data from at least three computations, comprising at least one velocity computation with the velocity increments Δ W l and at least one acceleration computation with the acceleration increments Δ ÿ l for producing one SAR-image per combination of velocity and acceleration computation and for detecting targets and target tracks as well as calculating target parameters R,Φ, a processing velocity W and an acceleration ÿ in a direction perpendicular to the azimuth direction, the R,Φ, ÿ, W- parameters defining an R, Φ,ÿ,W -space for each target, and • in a target positioning process, the target position within the patch is calculated by determining the φ -parameter representative of a relative velocity of the target in relation to the moving SAR platform