Signal processing device, signal processing method, computer readable media storing signal processing program and radar apparatus
A signal processing device is provided. The device includes a signal input unit for receiving reception signals obtained from transmission signals reflecting on one or more objects, a pulse compressor for pulse compressing the reception signals, an interference detector for detecting a reception signal caused by interference, from the pulse-compressed reception signals, a signal level controlling module for controlling a level of the detected reception signal, and an interpolation processing module for interpolating the level-controlled reception signal in an azimuth direction.
1. A signal processing device, comprising:
a signal input unit configured to receive reception signals obtained from transmission signals reflecting on one or more objects;
a pulse compressor configured to pulse compress the reception signals;
an interference detector configured to detect a reception signal caused by interference, from the pulse-compressed reception signals;
a signal level controller configured to control a level of the detected reception signal; and
an interpolation processing module configured to interpolate the level-controlled reception signal in an azimuth direction.
2. The device of claim 1 , wherein the interpolation processing module interpolates the level-controlled reception signal in the azimuth direction by integrating the level-controlled reception signals.
3. The device of claim 1 , wherein the interference detector also detects a signal caused by interference before the pulse compression, from the reception signals inputted into the signal input unit, and
the signal level controller controls the level of the reception signal detected by the interference detection before the pulse compression.
4. The device of claim 1 , wherein the interference detector includes:
a level change detecting module configured to detect a level change between the reception signals from sampling locations close to each other where the distances from an antenna are substantially the same but the azimuths from the antenna are different, the antenna receiving the reception signals;
a pattern output module configured to compare the level change with a predetermined reference pattern and outputting a level change pattern; and
an interference determining module configured to determine the interference based on at least two of the level change patterns.
5. The device of claim 4 , wherein the pattern output module compares the level change of the reception signals from adjacent sampling locations with the predetermined reference pattern.
6. The device of claim 4 , wherein the pattern output module classifies the pattern into one of a first pattern in which the level change exceeds a first threshold, a second pattern in which the level change is below a second threshold, and a third pattern in which the level change applies to neither the first pattern nor the second pattern.
7. The device of claim 6 , wherein the interference determining module outputs an identified signal indicating interference when the pattern changes from the first pattern to the second pattern.
8. The device of claim 6 , wherein the interference determining module outputs an identified signal indicating interference when the pattern changes from the first pattern to the third pattern.
9. The device of claim 6 , wherein the interference determining module outputs an identified signal indicating interference when the pattern changes from the third pattern to the second pattern.
10. The device of claim 4 , wherein the level change is based on a difference value between the levels of the reception signals adjacent to each other in the azimuth direction.
11. The device of claim 6 , wherein the interference determining module outputs an identified signal indicating interference when the third pattern following the first pattern and a group of at least two of the third patterns exist continuously.
12. The device of claim 6 , wherein the interference determining module outputs an identified signal indicating interference when a group of at least two of the third patterns exist continuously and the second pattern following the third pattern exists.
13. The device of claim 6 , wherein the interference determining module outputs an identified signal indicating interference when a group of at least two of the first patterns continuously exist.
14. The device of claim 6 , wherein the interference determining module outputs an identified signal indicating interference when a group of at least two of the second patterns continuously exists.
15. The device of claim 1 , wherein the level change detector averages the level changes in the distance direction, and
the pattern output module compares the averaged level change with the level change pattern.
16. The device of claim 1 , wherein the level change detector further detects a level change between the reception signals from locations close to each other where the azimuths from an antenna are substantially the same but the distances from the antenna are different, the antenna receiving the reception signals, and
the pattern output module outputs the most frequent level change pattern within a predetermined distance range as the level change pattern for the azimuth and the distance.
17. The device of claim 1 , wherein the level change detector further detects a level change between the reception signals from locations close to each other where the azimuths from an antenna are substantially the same but the distances from the antenna are different, the antenna receiving the reception signals, and
the interference determining module further determines interference based on a plurality of level change patterns close to each other in the distance direction.
18. The device of claim 1 , wherein the signal level controlling module performs zero conversion on the level of the reception signal caused by interference.
19. A radar apparatus, comprising:
an antenna for discharging transmission signals using electromagnetic waves respectively in each azimuth, and configured to receive signals obtained by reflecting on one or more objects;
a pulse compressor configured to pulse compress the reception signals;
an interference detector configured to detect a signal caused by interference from the pulse-compressed reception signals;
a signal level controller configured to control a level of the reception signal caused by interference that is detected by the interference detector; and
an interpolation processing module configured to interpolate the level-controlled reception signal in an azimuth direction.