In this paper we propose an interference detection technique for detecting time varying jamming signals in spread spectrum communication systems. The technique is based on discrete polynomial phase transform (DPPT), where the jamming signal is synthesized from the modulated spread spectrum signal using the DPPT. The technique has shown good performance under low interference conditions with 2dB SJR, when correlation coefficient between the synthesized chirp signal and the reference chirp is 0.9. The computational complexity of the proposed technique is low compared to other techniques such as Hough-Radon transform. This interference detection technique can be applied for different interference excision methods in military and wireless communication applications.