Radar apparatus for detection position information of a target by receiving reflection signals reflected by the target with a plurality of reception antennas
A radar apparatus includes a DBF process portion for grouping reception signals over plural channels into plural groups and performing DBF on each group, a summing portion for summing amplitudes or power of frequency components obtained by the DBF performed by the DBF process portion on each group, a peak detecting portion for detecting a peak frequency of a signal of the electric wave reflected by a target from results of the summation at the summing portion, a distance/speed calculating portion for calculating the distance and speed of the target based on the peak frequency, and an angle calculating portion for extracting a frequency component of the peak frequency detected by the peak detecting portion to calculate the angle of the electric wave reflected by the target. Thus, the amount of DBF calculation can be reduced, and a highly accurate positional information of the target can be obtained.
1. A radar apparatus comprising:
transmission means for transmitting an electric wave to a target;
reception means for obtaining reception signals over a plurality of channels from an electric wave reflected by said target;
digital beam forming means for grouping said reception signals over a plurality of channels into a plurality of groups and performing digital beam forming on each of said plurality of groups;
summing means for summing the amplitudes or power of frequency components obtained as a result of the digital beam forming performed on each of the plurality of groups by said digital beam forming means;
peak detection means for detecting a peak frequency of a signal of the electric wave reflected by the target from the result of the summation by said summing means;
distance/speed calculation means for calculating the distance and speed of the target based on the peak frequency obtained by said peak detection means; and
angle calculation means for extracting a frequency component of the peak frequency detected by said peak detection means to calculate the angle of the electric wave reflected by said target.
2. A radar apparatus according to claim 1 , wherein said angle calculation means performs ultra-resolution angle measurement such as multiple signal classification (MUSIC) to calculate the angle of the electric wave reflected by said target.
3. A radar apparatus according to claim 1 , wherein said angle calculation means performs mono-pulse angle measurement based on results of the digital beam forming to calculate the angle of the electric wave reflected by said target.
4. A radar apparatus according to claim 1 , wherein said digital beam forming means groups said reception signals over a plurality of channels into a plurality of groups such that a desired range of detection angles can be obtained after digital beam forming.
5. A radar apparatus according to claim 1 , wherein said target and reception means comprises an antenna array having a plurality of antenna elements, and
wherein when intervals between said plurality of antenna elements are partially unequal, said grouping into a plurality of groups is carried out such that antenna elements in a group obtained by the grouping are equally spaced.
6. A radar apparatus according to claim 1 , wherein said target and reception means comprises an antenna array having a plurality of antenna elements, and
wherein when the intervals between said plurality of antenna elements are unequal, said grouping into a plurality of groups is carried out such that antenna elements in a group obtained by the grouping are spaced as equally as possible.
7. A radar apparatus according to claim 1 , wherein
a plurality of said transmission means are provided in association with said reception means;
an electric wave is transmitted from each of the transmission means to said target on a time-division basis, whereby said reception means forms virtual reception channels; and
said digital beam forming means groups said virtual reception channels into each group consisting of actual reception channels.