The effect of IMU inaccuracies on airborne SAR imaging

Error analysis of SAR motion compensation

“…nref R and m R are the distance between the reference position of the target and the APC position with respect to nominal and measured track. During the MOCO, a linear nominal track should be fitted from the measured track first, and then with the usual narrow-beam approximation the phase error given by (1) is compensated [3,5,6,7]. where λ is the radar wavelength and η is the azimuth time measured in flight direction.…”

“…Compare (1) with (2), the residual phase error in radar signals after MOCO can be described as [3] can be estimated from the performance parameters of IMU/GPS. A general method to estimate measured error of the track resulting from IMU/GPS inaccuracies is given in [3], and the experiment results in [3] indicate that under the performance level of measurement instruments such as POS AV510, the residual uncompensated errors due to IMU/GPS inaccuracies during SAR MOCO are usually very small and can be ignored.…”

“…A general method to estimate measured error of the track resulting from IMU/GPS inaccuracies is given in [3], and the experiment results in [3] indicate that under the performance level of measurement instruments such as POS AV510, the residual uncompensated errors due to IMU/GPS inaccuracies during SAR MOCO are usually very small and can be ignored. So we can write…”

“…In airborne synthetic aperture radar (SAR) systems, deviation of the trace from the nominal straight flight often occurs due to atmospheric turbulence and aircraft manoeuvres [1][2][3]. Therefore, inertial measurement unit (IMU) and global positioning system (GPS) are used onboard to measure the motion parameters [3,4], with which the motion compensation (MOCO) stage can be carried out.…”

“…Therefore, inertial measurement unit (IMU) and global positioning system (GPS) are used onboard to measure the motion parameters [3,4], with which the motion compensation (MOCO) stage can be carried out. However, the measurement instrument inaccuracies may cause residual uncompensated motion errors which may degrade SAR images.…”