Displaced phase center antenna (DPCA) and along-track interferometry (ATI) are the two popular techniques used to determine synthetic aperture radar-ground moving target indication fields, and studies have shown that the combinations of these techniques can improve the target detection performance. However, a crucial problem is how to combine the two techniques, which requires a complete analysis and comparison of the individual techniques. Generally, it is well known that the performances of these techniques are closely related to clutter and noise. A detailed comparison of the detection performance of ATI and DPCA is presented, together with an assessment developed by theoretical analysis and simulations. The results show that the ATI is limited mainly by the clutter and noise, while DPCA is limited mainly by channel imbalance and noise. The ATI’s main drawback is its high false alarm rate, and DPCA is more sensitive to the channel imbalance. In most cases, DPCA is better than ATI, but for a high clutter-to-noise ratio, low signal-to-clutter power ratio, and channel imbalance, ATI has a better performance than DPCA. The real data experiments verify the theoretical findings. Meanwhile, the effects of target radial velocity, incidence angle, transmission bandwidth, and terrain type on the performance of the two detection approaches are also investigated.