Detection and ranging apparatus

Patent metadata

Field	Value
Publication number	US-9645230-B2
Application number	US-201414464386-A
Country	US
Kind code	B2
Filing date	Aug 20, 2014
Priority date	Sep 6, 2013
Publication date	May 9, 2017
Grant date	May 9, 2017

Abstract

A detection and ranging apparatus includes a probe signal generating unit that generates a probe signal according to a first modulation method, a transmitting unit that transmits the generated probe signal, a receiving unit that receives a signal including at least one of a reflection signal and an interference signal according to a second modulation method, a demodulating unit that demodulates the reception signal according to a method corresponding to at least one of the first modulation method and the second modulation method, an interference signal detecting unit that detects the interference signal from the demodulated signal, an interference signal identifying unit that identifies specifications and a delay amount of the interference signal from the demodulated signal, and an interference signal removing unit that removes the interference signal within the reception signal by using the identified specifications and the identified delay amount of the interference signal.

First claim

What is claimed is:

1. A detection and ranging apparatus, comprising:
a probe signal generating unit configured to generate a probe signal according to a first modulation method;
a transmitting unit configured to transmit the probe signal generated by the probe signal generating unit;
a receiving unit configured to receive a signal including at least one of a reflection signal generated in such a way that the probe signal transmitted from the transmitting unit is reflected by a target and an interference signal demodulated according to a second modulation method;
a demodulating unit configured to demodulate the reception signal received by the receiving unit;
an interference signal identifying unit configured to identify specifications and a delay amount of the interference signal from the signal demodulated by the demodulating unit; and
an interference signal removing unit configured to remove the interference signal within the reception signal by using the specifications and the delay amount of the interference signal which are identified by the interference signal identifying unit.

2. The detection and ranging apparatus according to claim 1 , further comprising
a controlling unit configured to instruct the transmitting unit to stop and restart a transmission of the probe signal, wherein
the demodulating unit demodulates, according to a demodulation method corresponding to the second modulation method, the reception signal which is received by the receiving unit while the transmitting unit is stopping the transmission of the probe signal according to an instruction of the controlling unit, and
the interference signal identifying unit identifies the specifications of the interference signal from the signal demodulated by the demodulating unit.

3. The detection and ranging apparatus according to claim 2 , wherein
stopping and restarting the transmission of the probe signal by the controlling unit include controlling a decrease and increase in transmission power level of the probe signal transmitted from the transmitting unit by the controlling unit.

4. The detection and ranging apparatus according to claim 2 , wherein
the first modulation method is a frequency modulation continuous wave method, and the second modulation method is a direct spectrum spreading signal method using a pair of complimentary codes as codes for modulation,
the demodulating unit demodulates, according to a demodulation method corresponding to frequency modulation method, a reception signal which is received by the receiving unit while the transmitting unit is stopping the transmission of the probe signal, and
the interference signal identifying unit identifies a carrier frequency and a pulse repetition interval of the interference signal from a signal which is obtained by performing fast Fourier transform of the demodulation signal demodulated according to the demodulation method corresponding to the frequency modulation method.

5. The detection and ranging apparatus according to claim 4 , wherein
the demodulating unit demodulates the reception signal received by the receiving unit while the transmitting unit is stopping the transmission of the probe signal by using the identified carrier frequency, extracts the demodulated signal for each identified pulse repetition interval, and performs complimentary code demodulation for the extracted signal while changing at least one of a pulse time width and the pair of complimentary codes, the pulse time width being a duration of a rectangular pulse on which the complimentary code is superposed, and
the interference signal identifying unit determines whether or not a correlation peak is detected from the signal for which the complimentary code demodulation is performed by the demodulating unit, and identifies at least one of the pulse time width and the pair of complimentary codes, which is used for the complimentary code demodulation for the signal from which the correlation peak is detected.

6. The detection and ranging apparatus according to claim 4 , wherein
the demodulating unit adjusts a passband width of a reception signal based on the pulse repetition interval identified by the interference signal identifying unit, and demodulates only the reflection signal included in the reception signal.

7. The detection and ranging apparatus according to claim 1 , further comprising
a controlling unit configured to instruct the transmitting unit to stop and restart a transmission of the probe signal, wherein
the demodulating unit demodulates the reception signal which is received by the receiving unit after the transmitting unit restarts the transmission of the probe signal according to an instruction of the controlling unit, and
the interference signal identifying unit identifies the delay amount of the interference signal from the signal demodulated by the demodulating unit.

8. The detection and ranging apparatus according to claim 7 , wherein
the interference signal removing unit generates a copy of an interference signal by using the identified specifications and delay amount which are identified by the interference signal identifying unit, and removes the interference signal within the reception signal by subtracting the generated copy of the interference signal from a reception signal which is received by the receiving unit after the transmission of the probe signal is restarted.

9. The detection and ranging apparatus according to claim 1 , wherein
the first modulation method is a direct spectrum spreading signal method that uses a pair of complimentary codes as codes for demodulation, and the second modulation method is a frequency modulation continuous wave method,
the demodulating unit performs complimentary code demodulation for the reception signal received by the receiving unit, and
the interference signal detecting unit identifies the interference signal as a frequency modulation signal from a correlation output pattern of the signal for which the complimentary code demodulation is performed by the demodulating unit.

10. The detection and ranging apparatus according to claim 9 , wherein
the demodulating unit demodulates, according to a demodulation method corresponding to frequency modulation method, a reception signal received by the receiving unit while the transmitting unit is stopping the transmission of the probe signal while changing each value of a single-side maximum frequency shift, a basic cycle, and a phase, and
the interference signal identifying unit determines whether or not the signal demodulated by the demodulating unit exceeds a certain threshold value, and identifies the each value of the single-side maximum frequency shift, the basic cycle, and the phase which are used to demodulate the signal that exceeds the certain threshold value.

11. The detection and ranging apparatus according to claim 10 , further comprising
a controlling unit configured to instruct the transmitting unit to stop and restart a transmission of the probe signal, wherein
the demodulating unit outputs correlation values between a reception signal received by the receiving unit and one of the pair of complimentary codes for each slot occupied by the one of the pair of complimentary codes after the transmitting unit restarts the transmission of the probe signal according to an instruction of the controlling unit, and
the interference identifying unit concatenates the correlation values output from the demodulating unit along a time axis, demodulates the concatenated signal with a demodulation method corresponding to frequency modulation method by using the each value of the single-side maximum frequency shift, the basic cycle, and the phase which are ident

Assignees

• Fujitsu Ltd

Inventors

• Shirakawa Kazuo

Classifications

• G01S13/584

  adapted for simultaneous range and velocity measurements · CPC title

• G01S13/325

  using transmission of coded signals, e.g. P.S.K. signals · CPC title

• G01S13/34

  using transmission of continuous, frequency-modulated waves while heterodyning the received signal, or a signal derived therefrom, with a locally-generated signal related to the contemporaneously transmitted signal · CPC title

• G01S7/354 Primary

  Extracting wanted echo-signals (Doppler systems G01S13/50) · CPC title

• G01S7/023

  Interference mitigation, e.g. reducing or avoiding non-intentional interference with other HF-transmitters, base station transmitters for mobile communication or other radar systems, e.g. using electro-magnetic interference [EMI] reduction techniques (auxiliary means for detecting or identifying radar signals or the like G01S7/021; means for anti-jamming G01S7/36) · CPC title