Research on Continuous Wave Electromagnetic Effect in Swept Frequency Radar

Abstract

In order to establish the prediction model of radar equipment in multisource complex electromagnetic environment, the blocking effect and false alarm interference effect caused by single-frequency CW (continuous wave) electromagnetic interference on typical radar equipment are studied. Taking a certain sweep radar as the research object, the equivalent injection test of EMI (electromagnetic interference) is carried out. Based on the theory of radar front door coupling, the interference mechanism of EMI to radar receiver RF front end is revealed, and the variation law of blocking target and false alarm target level is analyzed. The results show that, under the single-frequency CW-EMI, the target echo level decreases with the increase of the interference field strength, and the false alarm level increases with the increase of the interference field strength. The blocking jamming sensitive bandwidth is about f 0 ± 200 MHz , and the false alarm jamming sensitive bandwidth is about f 0 ± 80 MHz .

Strong Electromagnetic Interference and Protection in UAVs

“…Front-door coupling refers to the entry of electromagnetic wave energy into the internal electronic system through signal channels such as antennas or sensors. This energy generates current that flows through the wiring, primarily along the cables, potentially leading to damage to the front-end equipment within the system [70]. Front-door protection involves implementing measures to reduce the coupling of electromagnetic energy from antennas and sensors or to limit its transmission into the system.…”

Test Evaluation Method for Second-order Intermodulation False Alarm Interference

“…From the previous analysis of radar EMI, it is known that the second-order intermodulation blocking signal is not obvious due to the stuttering phenomenon [19], while the SIFA shows a certain regularity. Secondly, under the existing conditions in the laboratory, the tested radar can get the complete single-frequency critical blocking interference sensitivity threshold, but not the single-frequency critical false alarm interference sensitivity threshold [20], based on this, the single-frequency blocking critical sensitivity threshold is used. Assuming that the single-frequency critical blocking EMI level and field strength corresponding to f0 are C 0 and E i0 (f i ), respectively, C 0 is only related to f 0 , and the change factors related to the interference frequency f i are included in the sensitivity coefficient B i (f i ), obtained [15]:…”

“…Whether the frequency equipment has good adaptability to the electromagnetic environment has become an important guarantee of battlefield intelligence reconnaissance, joint command and control [1]. Radar equipment has been widely used in military and civil fields with its advantages of the all-weather and real-time acquisition of target information [2]. Currently, more and more scientists and research laboratories are conducting research on the electromagnetic environmental effects of frequency equipment.…”

Generation Mechanism and Characteristic Analysis of Dual-Frequency Pseudo-Signal Interference of the Swept-Frequency Radar

“…e operating frequency is f0 ± 100 MHz (f0 is the center frequency), and the transmitting signal jumps in steps of 10 kHz/0.05 ms during a single detection cycle, with a maximum detection distance of 5000 m. e authors in [13] focused on the electromagnetic interference effect of in-band single-frequency continuous wave of the swept-frequency radar and described in detail the variation law of the true target echo level and false signal level when the tested radar equipment was interfered by in-band continuous wave. However, the detection target set in the [13] is only 4.5 m. In order to avoid the effect caused by too strong echo signals and make the test results universal, we added a 30 dB attenuator at the radar transmitting port and set the detection target to about 8.3 m. e full-band electromagnetic radiation interference effect test of the swept frequency continuous wave ranging radar was carried out. After the target echo signal is received by the tested radar, it is mixed and filtered and amplified and is collected as I/Q road data at the back-end.…”

“…Because the form of interference signal is similar to the form of the radar useful signal, the interference signal can form pseudo-signal interference in the radar display interface under the condition of weak interference field strength. When the interference field strength is strong, the pseudo-signal strength even exceeds the true echo signal strength, causing the radar to misjudge [13]. e authors in [14] pointed out that the single-frequency signal whose jamming frequency is located in the working frequency band of the radar can cause false alarm interference to the radar, but the target characteristics of the false alarm interference were not analyzed.…”