This article examines synchronization methods for multi-detector phased systems that integrate spatially distributed transmit–receive nodes into a single coherent structure. The study's primary aim is to determine the technical requirements for temporal, frequency, and phase alignment of the elements, and to analyze the hardware and algorithmic means for achieving them. The relevance of this work is driven by the rapid development of phased arrays and distributed radar and astronomical systems, where even tens of picoseconds of desynchronization lead to significant loss of coherent gain and degradation of spatial resolution. Contemporary network protocols such as IEEE 1588 provide only microsecond-level accuracy, which is insufficient for the often-required budgets on the order of tens of picoseconds; therefore, a multi-level architecture is necessary, combining highly stable reference oscillators, zero-delay hardware buffers, deterministic data-transfer interfaces, and digital correction algorithms. The novelty of this research lies in the comprehensive comparison and integration of four classes of solutions: a distributed clock tree with LVDS and fiber-optic lines and zero-delay PLL buffers; deterministic SYSREF frame distribution according to JESD204B/C; bidirectional microwave wireless exchange with pilot-tone synchronization; and digital corrections via cross-correlation and Kalman-consensus algorithms to compensate residual drifts. A methodology for budgeting phase slip—accounting for source jitter, port trace dispersion, and network delays—is presented, enabling early identification and elimination of design bottlenecks. The key conclusion demonstrates the effectiveness of the multi-level scheme: an external hardware-network loop provides coarse phase alignment and frequency stability at the level of single to tens of picoseconds. In contrast, the internal digital loop maintains instantaneous coherence with phase errors of only a few degrees, even when nodes are separated by hundreds of meters or during GNSS outages. Systematic summation of contributions from jitter, trace skew, and network delays guarantees ≥ 90% coherent gain and the specified dynamic range. This article will be helpful to engineers developing phased antenna arrays, distributed radar, and interferometric systems, as well as researchers in precise frequency–time distribution.