Ambiguity Assessment and Mitigation Approaches for the TerraSAR-X Concurrent Imaging Technique

For TerraSAR-X the concurrent imaging technique enables the simultaneous acquisition of scenes in two different modes and over two disjoint areas. The acquisition scheme exploits the capability to toggle the antenna configuration from pulse to pulse. A direct consequence of this interleaved acquisition scheme is the necessity to increase the azimuth sampling rate. This in turn affects the ambiguity performance. The paper at hand analyzes the range and azimuth ambiguity performance of the concurrent imaging technique and describes approaches to mitigate the impact of ambiguities. Additionally, some experimental results are shown

Multiple PRI Technique for Concurrent Imaging Mode using TerraSAR-X

The concurrent imaging mode using TerraSAR-X is a technique that allows the acquisition of two images in a single flyover. It brings high versatility and can double the image output rate. These benefits are of great interest as there is a long revisit time for spaceborne SAR systems. One of the main drawbacks is the use of high pulse repetition frequencies (PRFs), which causes ambiguity issues and timing limitations. Therefore, knowing and improving the quality of the imaging mode is desired. This paper presents a quantitative analysis of its global availability. Moreover, a technique named multiple pulse repetition intervals (PRIs) is proposed to improve the coverage of the imaging mode while maintaining its ambiguity performance. Further simulations are presented, confirming the benefits of the technique, culminating in a vast global availability for the concurrent mode

Concurrent Imaging for TerraSAR-X: Wide-Area Imaging paired with High-Resolution Capabilities

The concurrent imaging technique enables parallel acquisitions with different beams or modes, e.g., a wide area Stripmap mode with a high resolution Spotlight mode. Such a concurrent Stripmap/Spotlight imaging technique is investigated for TerraSAR-X. This technique employs a pulse-topulse interleaving scheme to acquire two acquisitions - even of disjunctive areas - at the same time, offering products with different resolution and coverage portfolios. This capability is especially interesting for customers interested in an overview of a larger area but at the same time observing an area of interest with higher resolution, e.g., for infrastructure monitoring or reconnaissance applications. The basic concept, as well as the driving system parameters, are discussed in detail, together with a coverage analysis revealing the high availability rate of the mode combinations on a global scale. A processing approach reusing a substantial part of the existing infrastructure is described and exemplary acquisitions are shown, together with a detailed performance analysis with respect to resolution and ambiguities