Abstract: Systems and methods for estimating advertisement impressions needed for detecting sales lift are disclosed. In some embodiments, based on an impression estimation request received from a computing device, a disclosed system determines an item set including items proposed to be advertised with an advertising campaign, and a time period proposed for the advertising campaign. Based on at least one model and historical transaction data associated with the item set, control sales data in the time period is computed for the item set without the advertising campaign. Based on a trained model and additional data associated with the item set, the system computes a number of impressions needed to detect a target sales lift compared to the control sales data in the time period for the item set with the advertising campaign. Based on the number of impressions, the system generates and transmits estimated impression data to the computing device.

Abstract: A phase synchronization method includes: pulse widths of first and second phase synchronization signals and starting time of transmission of first and second phase synchronization signals are determined, wherein starting time is located between two successive moments when radar signals are transmitted; first spaceborne SAR is controlled to transmit first phase synchronization signal to second spaceborne SAR according to pulse width and starting time of first phase synchronization signal; second spaceborne SAR is controlled, according to pulse width and starting time of second phase synchronization signal, to transmit second phase synchronization signal to first spaceborne SAR; compensation phase is determined according to peak phases of first and second phase synchronization signals received by second and first spaceborne SARs respectively; and phase synchronization compensation is performed, according to compensation phase, on radar signals received by first spaceborne SAR and second spaceborne SAR.

Abstract: A phase synchronization method includes: pulse widths of first and second phase synchronization signals and starting time of transmission of first and second phase synchronization signals are determined, wherein starting time is located between two successive moments when radar signals are transmitted; first spaceborne SAR is controlled to transmit first phase synchronization signal to second spaceborne SAR according to pulse width and starting time of first phase synchronization signal; second spaceborne SAR is controlled, according to pulse width and starting time of second phase synchronization signal, to transmit second phase synchronization signal to first spaceborne SAR; compensation phase is determined according to peak phases of first and second phase synchronization signals received by second and first spaceborne SARs respectively; and phase synchronization compensation is performed, according to compensation phase, on radar signals received by first spaceborne SAR and second spaceborne SAR.