Two-frequency Doppler distance measuring apparatus and detection system having the apparatus
First Claim
1. A two-frequency Doppler distance measuring apparatus comprising:
- a first Doppler measuring device for producing a first Doppler signal from the transmission wave of a first frequency and the reflection wave thereof;
a second Doppler measuring device for producing a second Doppler signal from the transmission wave of a second frequency different from the first frequency and the reflection wave thereof;
an analogy determining device for determining whether the spectrum of the first Doppler signal and the spectrum of the second Doppler signal are analogous to each other or not; and
a distance calculation device for calculating the distance to a reflection object based on the first and second Doppler signals in the case where the spectra of the first and second Doppler signals are determined as analogous to each other.
1 Assignment
0 Petitions
Accused Products
Abstract
A technique is disclosed for accurate measurement of the distance and detection of an object such as a human body behaving in a complicated way and having a complicated reflection surface using the two-frequency Doppler method. Each of the two-frequency Doppler signals is subjected to the short time Fourier transform to produce a spectrum in a short time window. Based on restraints, it is determined whether the waveforms of the two spectra are analogous to each other or not, and only in the case where the waveforms are analogous, the Doppler signals of the particular time window are used for distance calculation. As a result, the Doppler signals having the phase information low in reliability are eliminated, and therefore high-accuracy distance measurement and object detection are possible.
31 Citations
14 Claims
-
1. A two-frequency Doppler distance measuring apparatus comprising:
-
a first Doppler measuring device for producing a first Doppler signal from the transmission wave of a first frequency and the reflection wave thereof;
a second Doppler measuring device for producing a second Doppler signal from the transmission wave of a second frequency different from the first frequency and the reflection wave thereof;
an analogy determining device for determining whether the spectrum of the first Doppler signal and the spectrum of the second Doppler signal are analogous to each other or not; and
a distance calculation device for calculating the distance to a reflection object based on the first and second Doppler signals in the case where the spectra of the first and second Doppler signals are determined as analogous to each other. - View Dependent Claims (2, 3, 4, 6, 7, 8, 9, 10, 11, 12, 13, 14)
-
-
5. A two-frequency Doppler distance measuring method comprising the steps of:
-
acquiring a first Doppler signal from the transmission wave of a first frequency and the reflection wave thereof;
acquiring a second Doppler signal from the transmission wave of a second frequency different from the first frequency and the reflection wave thereof;
determining whether the spectrum of the first Doppler signal and the spectrum of the second Doppler signal are analogous to each other or not; and
calculating the distance to a reflection object based on the first and second Doppler signals in the case where the spectra of the first and second Doppler signals are determined as analogous to each other.
-
Specification