초록 ▼

A time needed until measurement values are obtained in a two-frequency continuous wave radar systems is reduced. An object detection system that emits transmission signals, as transmission waves, whose frequencies have been modulated successively into a plurality of stepped frequencies, and receives

A time needed until measurement values are obtained in a two-frequency continuous wave radar systems is reduced. An object detection system that emits transmission signals, as transmission waves, whose frequencies have been modulated successively into a plurality of stepped frequencies, and receives echoes of the transmission waves reflected from target objects, thereby calculating relative velocities of the target objects by frequency-analyzing reception signals obtained from the received echoes. The target object detection system includes: a frequency modulation component that repeatedly executes frequency-modulation processes to successively modulate the transmission signals into those of the stepped frequencies, within a minimum measurement time in which a desired velocity resolution is achieved; and a frequency-analysis component that frequency-analyzes throughout the repeated frequency-modulation processes the reception signals processed by the frequency-modulation component.

대표청구항 ▼

The invention claimed is: 1. A target object detection system for emitting, toward a target object, transmission signals as transmission waves, whose frequencies have been modulated successively into a plurality of stepped frequencies, and for receiving echoes of the transmission waves reflected fr

The invention claimed is: 1. A target object detection system for emitting, toward a target object, transmission signals as transmission waves, whose frequencies have been modulated successively into a plurality of stepped frequencies, and for receiving echoes of the transmission waves reflected from the target object, thereby to calculate a relative velocity of the target object by frequency-analyzing reception signals obtained from the echoes, the target object detection system comprising: a frequency-modulation unit that successively executes, within a measurement time derived from a desired velocity resolution, a plurality of times iterated frequency-modulation processes, where each of the frequency-modulation processes successively modulates the transmission signals into the stepped frequencies; and a frequency-analysis unit that frequency-analyzes, within said measurement time, for each of the stepped frequencies, throughout the plurality of frequency-modulation processes those signals, among the reception signals, corresponding to the identical stepped frequency in the frequency-modulation processes, wherein said measurement time is a minimum frequency modulation period required for the desired velocity resolution. 2. The target object detection system as recited in claim 1, wherein the frequency-analysis unit, by executing the frequency-analyzing throughout the plurality of frequency-modulation processes, generates a first frequency-analysis-result signal from reception signals corresponding to a first stepped frequency in the frequency-modulation processes, and, by executing the frequency-analyzing throughout the plurality of frequency-modulation processes, generates a second frequency-analysis-result signal from reception signals corresponding to a second stepped frequency different from the first stepped frequency, the target object detection system further comprising a distance-calculation unit that detects frequency components as a first peak frequency and a second peak frequency at which respective amplitude values of the first and the second frequency-analysis-result signals peak, and calculates a distance to the target object from the difference in signal phase between the detected first and second peak frequencies. 3. The target object detection system as recited in claim 1, wherein the frequency-analysis unit, by frequency-analyzing, throughout the plurality of frequency-modulation processes, reception signals corresponding to each of those stepped frequencies chosen from the plurality of stepped frequencies of the transmission signals modulated by the frequency-modulation unit, generates frequency-analysis-result signals from the reception signals, the target object detection system further comprising: a velocity-calculation unit that detects frequency components that give peak amplitude values of the frequency-analysis-result signals obtained from the reception signals corresponding to those stepped frequencies, and calculates from the frequency components a relative velocity of the target object; and a distance-calculation unit that calculates phase component shifts with respect to those stepped frequencies by frequency-analyzing throughout the plurality of stepped frequencies the frequency components detected by the velocity-calculation unit, and calculates a distance to the target object based on the phase component shifts. 4. The target object detection system as recited in claim 3, wherein the distance-calculation unit, by frequency-analyzing throughout the plurality of frequency-modulation processes with a super-resolution method, the frequency components detected by the velocity-calculation unit, calculates phase component shifts with respect to those stepped frequencies chosen from the plurality of stepped frequencies. 5. A target object detection method of emitting, toward a target object, transmission signals as transmission waves, whose frequencies have been modulated successively into a plurality of stepped frequencies, and of receiving echoes of the transmission waves reflected from the target object, thereby to calculate a relative velocity of the target object by frequency-analyzing reception signals obtained from the echoes, the target object detection method comprising: successively executing, within a measurement time derived from a desired velocity resolution, a plurality of times iterated frequency-modulation processes, each of the frequency-modulation processes successively modulating the transmission signals into the stepped frequencies; and frequency-analyzing, within said measurement time, for each of the stepped frequencies, throughout the plurality of frequency-modulation processes, those signals, among the reception signals, corresponding to the identical stepped frequency in the frequency-modulation processes, wherein said measurement time is a minimum frequency modulation period required for the desired velocity resolution. 6. The target object detection method as recited in claim 5, wherein executing the frequency-analyzing throughout the plurality of frequency-modulation processes includes generating a first frequency-analysis-result signal from reception signals corresponding to a first stepped frequency in the frequency-modulation processes; executing the frequency-analyzing throughout the plurality of frequency-modulation processes includes generating a second frequency-analysis-result signal from reception signals corresponding to a second stepped frequency different from the first stepped frequency; and wherein the method further comprises: detecting frequency components as a first peak frequency and a second peak frequency at which respective amplitude values of the first and the second frequency-analysis-result signals peak, and calculating a distance to the target object from the difference in signal phase between the detected first and second peak frequencies. 7. The target object detection system as recited in claim 5, wherein frequency-analyzing, throughout the plurality of frequency-modulation processes, reception signals corresponding to each of those stepped frequencies chosen from the plurality of stepped frequencies of the transmission signals modulated by the frequency-modulation processes includes generating frequency-analysis-result signals from the reception signals; and wherein the method further comprises: detecting frequency components that give peak amplitude values of the frequency-analysis-result signals obtained from the reception signals corresponding to those stepped frequencies, and calculating from the frequency components a relative velocity of the target object; and calculating phase component shifts with respect to those stepped frequencies by frequency-analyzing throughout the plurality of stepped frequencies the frequency components detected in said detecting frequency components step, and calculating a distance to the target object based on the phase component shifts. 8. The target object detection method as recited in claim 7, wherein calculating phase component shifts includes: frequency-analyzing, throughout the plurality of frequency-modulation processes, with a super-resolution method, the frequency components detected said detecting frequency components step; and calculating phase component shifts with respect to those stepped frequencies chosen from the plurality of stepped frequencies. 9. A target object detection device for emitting, toward a target object, transmission signals as transmission waves, whose frequencies have been modulated successively into a plurality of stepped frequencies, and for receiving echoes of the transmission waves reflected from the target object, thereby to calculate a relative velocity of the target object by frequency-analyzing reception signals obtained from the echoes, the target object detection device comprising: a frequency-modulation unit that successively executes, within a measurement time derived from a desired velocity resolution, a plurality of times, iterated frequency-modulation processes, where each iterated frequency-modulation process successively modulates the transmission signals into the stepped frequencies; and a frequency-analysis unit that frequency-analyzes, within said measurement time, for each of the stepped frequencies, throughout the plurality of frequency-modulation processes those signals, among the reception signals, corresponding to the identical stepped frequency in the frequency-modulation processes, wherein said measurement time is a minimum frequency modulation period required for the desired velocity resolution. 10. The target object detection device as recited in claim 9, wherein the frequency-analysis unit, by executing the frequency-analyzing throughout the plurality of frequency-modulation processes, generates a first frequency-analysis-result signal from reception signals corresponding to a first stepped frequency in the frequency-modulation processes, and, by executing the frequency-analyzing throughout the plurality of frequency-modulation processes, generates a second frequency-analysis-result signal from reception signals corresponding to a second stepped frequency different from the first stepped frequency, the target object detection system further comprising a distance-calculation unit that detects frequency components as a first peak frequency and a second peak frequency at which respective amplitude values of the first and the second frequency-analysis-result signals peak, and calculates a distance to the target object from the difference in signal phase between the detected first and second peak frequencies. 11. The target object detection device as recited in claim 9, wherein the frequency-analysis unit, by frequency-analyzing, throughout the plurality of frequency-modulation processes, reception signals corresponding to each of those stepped frequencies chosen from the plurality of stepped frequencies of the transmission signals modulated by the frequency-modulation unit, generates frequency-analysis-result signals from the reception signals, the target object detection system further comprising: a velocity-calculation unit that detects frequency components that give peak amplitude values of the frequency-analysis-result signals obtained from the reception signals corresponding to those stepped frequencies, and calculates from the frequency components a relative velocity of the target object; and a distance-calculation unit that calculates phase component shifts with respect to those stepped frequencies by frequency-analyzing throughout the plurality of stepped frequencies the frequency components detected by the velocity-calculation unit, and calculates a distance to the target object based on the phase component shifts. 12. The target object detection device as recited in claim 11, wherein the distance-calculation unit, by frequency-analyzing throughout the plurality of frequency-modulation processes with a super-resolution method, the frequency components detected by the velocity-calculation unit, calculates phase component shifts with respect to those stepped frequencies chosen from the plurality of stepped frequencies.