JPS60100775A - Removal system for radar interference - Google Patents

Abstract

PURPOSE:To remove an interference signal which has the same stagger ratio and an equal mean repetitive frequency by selecting the repetition order of stagger triggers optionally, and extracting only receive signals synchronizing with the trigger of this system. CONSTITUTION:A stagger trigger generating circuit 1 includes stagger trigger generating circuits which differ in the repetition order of stagger triggers as many as permutations corresponding to the maximum trigger number, and one of them is selected by a stagger selecting circuit 2; and a receiver 6 incorporates an interference removing circuit 61 and an interference removing circuit by-pass switch 62. The output of the circuit 2 is sent to a transmitter 3, whose high-frequency wave signal is radiated from an antenna 5 through a circulator 4 to acquire and send a target signal and an interference signal to the receiver 6. Consequently, the stagger repetition order different from the stagger repetition period of the interference signal is selected by the circuit 2.

Description

[Detailed description of the invention] The present invention relates to a mutual interference removal method for radar equipment.

Conventionally, when removing interference in a sensor device, by taking the correlation between several pulses, only correlated signals can be removed from all targets.
No. 5 is output, and a method is adopted in which signals that cannot be out of phase are treated as interference signals and removed.

Figure 1 (al) shows an example of a triple stagger in which the period of the interference wave is increased by one value To, and the transmission trigger consists of periods 'r!, T, and Ts. The target signal is constant in each trigger period. However, the interference signal Ig is “21” in each trigger period.
Since the positions of F and t4 are changed, the correlation between the pulses cannot be established and the pulses are removed as interference signals.

However, as shown in FIG. 1Fb), when the interference signal has the same staggered period T1#T2 and Tsk, the position of the interference signal has the same value 1. Get what you need. In this case, there is a drawback that the interference 1g cannot be removed because the correlation between the pulses is lost.

The invention provides a radar interference removal method that solves the above disadvantages by making it possible to select the repetition order of the staggered trigger.In other words, the invention provides a circuit in which the repetition order of the staggered trigger can be arbitrarily selected. And a conventional interference cancellation circuit? In combination, FIG. 2 shows an embodiment of a particularly uninvented system characterized in that the interference removal function is effective even for interference signals having the same stagger ratio and the same average repetition frequency V. This will be explained with reference to ・A staggered trigger is generated by a staggered trigger generation circuit l. Inside the staggered trigger generation circuit, there are staggered trigger generation circuits with different repetition orders of staggered triggers.

As many permutations as the maximum number of staggers are prepared. In the case of a triple stagger, which is unusual, a maximum of six circuits are prepared.

One of the outputs of the staggered trigger generation circuit 1 is selected by a staggered selection circuit 2 and sent to a transmitting device 3 and a receiving device 6. The high-frequency signal having a staggered period generated by the transmitter 13 is radiated into the air from the antenna 5 via the circulator 4 . The target signal and the interference signal 1g are captured by the antenna 5 and sent to the receiving device 6 via the circulator 4.

An interference removal circuit 61 and a switch for bypassing the interference removal circuit, Chiro 2, are prepared inside the interference removal circuit 6. In Fig. 3, the staggered repetition period of the interference signal is T1 m T2.
and 7 for l1ls. At this time, the staggered selection circuit 2 in FIG. 2 sends 1. to ↓9 in FIG. ■Signal'
It becomes possible to set the staggered repetition order other than kTx*'I', , Ts. As a result, the position of the interference signal jtK changes, and it becomes possible to eliminate the interference signal sound by the interference cancellation circuit.

In Fig. 3, the interference signal 1d still exists at the same position as +HJ, so the interference cancellation circuit using 2-pulse correlation cannot completely remove all the interference signals, but if the 3-pulse correlation circuit is used, it can be completely removed - As explained above, by combining all the circuits that can arbitrarily select the repetition order of staggered triggers and all the interference removal circuits, it is possible to eliminate interference 1 with the same stagger ratio and the same average repetition frequency. It also has the effect of completely removing interference from the sea signals.

[Brief explanation of the drawing]

Figures 1 (a) and (b) show the interference signal position k I3'l when the interference signal has the same repetition period and staggered period.
FIG. 2 is a block diagram showing the complete configuration of an embodiment of the present invention, and FIG. 3 is a diagram illustrating the positions of a target signal and an interference signal in an embodiment of the present invention. 1... Staggered trigger generation circuit, 2...
Stagger selection circuit, 3... Send'+M device, 4...
... Circulator, 5 ... Antenna, 6.
...Receiving device, 61...Interference removal circuit,
62...Interference removal circuit bypass switch. (a) (b+ 1st so° j #2 Fig.

Claims (1)

[Claims] A radar interference cancellation method characterized in that interference waves are removed by means for arbitrarily selecting the repeating order of IJ and interference removal means for extracting only received signals synchronized with its own trigger.