Steganographic synchronization signals (sometimes termed “orientation signals,” “marker signals,” reference signals,” “grid signals,” “calibration signals,” etc.) are sometimes included with digital watermarking signals to aid in correct decoding of the object thereby marked (e.g., a digital image file, audio clip, document, etc.). Digital watermark detection systems sometimes fail if the object encompasses several separately-watermarked components (e.g., a scanned magazine page with several different images, or photocopy data resulting from scanning while several documents are on the photocopier platen). Each component may include its own synchronization signal, confusing the detection system. In accordance with certain embodiments, this problem is addressed by a proximity-based approach, and/or a multiple grid-based approach. In accordance with other embodiments, the synchronization signal can—itself—convey watermark information, so it serves both a synchronization and a payload-conveyance function.