Rader system

• US 20090278727A1
• Filed: 08/02/2004
• Published: 11/12/2009
• Est. Priority Date: 08/02/2004
• Status: Active Grant

• Current Assignee: Mitsubishi Electric Corporation
• Original Assignee: Mitsubishi Electric Corporation
• Inventors: Inaba, Takayuki
• Granted Patent: US 7,768,445 B2
• Time in Patent Office: Days
• US Class Current: 342/112
• CPC Class Codes: G01S 13/222 using random or pseudorandom pulse repetition frequency
• CPC Class Codes: G01S 13/345 using triangular modulation
• CPC Class Codes: G01S 13/347 using more than one modulation frequency
• CPC Class Codes: G01S 13/931 of land vehicles
• CPC Class Codes: G01S 7/003 Transmission of data between radar, sonar or lidar systems and remote stations
• CPC Class Codes: G01S 7/021 Auxiliary means for detecting or identifying radar signals or the like, e.g. radar jamming signals
• CPC Class Codes: G01S 7/023 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 Class Codes: G01S 7/0232 Avoidance by frequency multiplex
• CPC Class Codes: G01S 7/0235 Avoidance by time multiplex
• CPC Class Codes: G01S 7/0236 Avoidance by space multiplex
• CPC Class Codes: G01S 7/36 Means for anti-jamming , e.g. ECCM, i.e. electronic counter-counter measures
• CPC Class Codes: H01Q 3/26 varying the relative phase or relative amplitude of energisation between two or more active radiating elements; varying the distribution of energy across a radiating aperture H01Q3/12, H01Q3/22, H01Q3/24 take precedence

Abstract

A radar system utilizing a CW radar system, including an FMCW radar, is capable of avoiding interference wave generation and of simultaneously covering a number of radar systems within limited frequency modulation bands. The radar system 1 for emitting into space transmission radio waves based on a frequency-modulated continuous wave reference, and receiving transmission radio waves reflected from an external object, as well as for obtaining beat signals, from the received signals and the continuous wave reference, and computing from the beat signals obtained, a distance to and a velocity of the external object, comprises a pulse generation means 13 for pulsing the continuous-wave reference at an interval unique to the radar system, and an antenna 16 for emitting into space, the pulse transmit signals as the transmission radio waves.

Claims

1. A radar system for emitting into space transmission radio waves based on frequency modulated continuous wave reference, acquiring received signals by receiving the transmitted radio waves reflected from an external object, and by obtaining a beat signal from the received signals and the continuous wave reference, computing from the obtained beat signal distance from and velocity of the external object, the radar system characterized in comprising:

a pulse generating means for generating pulsed transmit signals by pulsing the continuous wave reference at an interval unique to the radar system; and

an antenna for emitting into space the pulsed transmit signals as said transmission radio waves.

2. A radar system as recited in claim 1, characterized in that the pulse generating means changes the unique interval into intervals that differ on a per-predetermined-period basis.

3. A radar system as recited in claim 1, characterized in that the pulse generating means determines the unique interval based on a random number.

4. A radar system as recited in claim 1, the radar system characterized in further comprising a reference signal generating means for generating frequency modulated continuous waves.

5. A radar system as recited in claim 1, the radar system characterized in further comprising a reference signal generating means for generating stepped-frequency continuous waves.

6. A radar system as recited in claim 1, the radar system characterized in further comprising a multibeam-forming means for forming, based on the continuous wave reference, multibeams that are emits in a plurality of directions, wherein:

the pulse generating means selects a transmission pulse repetition, interval so that the combination of the multibeam direction and the transmission pulse repetition interval is unique to the radar system, and by pulsing on a per-pulse repetition interval basis the multibeam'"'"'s continuous transmission radio waves, generates the pulsed transmit signals on a per-multibeam basis, and

the antenna emits in each beam direction the pulsed transmit signals on a per-multibeam basis.

7. A radar system as recited in claim 1, further comprising an interference wave monitor for detecting occurrence of interference waves, characterized in that the pulse generating means selects, as the unique interval, an interval differing from pulse repetition intervals of interference-wave-monitor-detected interference waves.

8. A radar system as recited in claim 7, characterized in that the p ulse generating means determines the unique interval based on a rand om number.

9. A radar system as recited in claim 1, further comprising:

a code transmit means for encoding, and thereby generating codes from, transmission pulse repetition intervals that the radar system uses, and transmitting the generated codes to other radar systems; and

a code monitor for receiving codes corresponding to transmission pulse repetition intervals that other radar systems use;

characterized in that,

based on other code transmit means-transmitted codes and code monitor-received results, the pulse generating means selects a transmission pulse repetition interval for the radar system to use.

10. A radar system as recited in claim 9, characterized in that:

the code transmit means obtains pulse-generation-means-generated pulse transmit signals, and designates them as first pulse transmit signals, and designates as second pulse transmit signals pulse transmit signal obtained by pulsing the codes, and outputs the first and second pulse transmit signals on a time-division basis;

the antenna emits into space, as the transmission radio waves, the code-transmit-means-outputted first and second pulse transmit signals, and receives transmission radio waves reflected from external objects, and outputs the received signals; and

the code monitor extracts codes from the antenna-output received signals, to obtain codes corresponding to transmission pulse-repetition intervals that the other radar systems use.

11. A radar system as recited in claim 1, the radar system characterized in comprising:

a frequency modulation means for modulating the frequency of the continuous wave reference; and

a control means for rendering unique to the radar system a combination of the pulse repetition interval at which the pulse-generation-means pulses and the spectrum of frequencies in which the frequency-modulation-means modulates.