SIGNALS, APPARATUS AND METHOD FOR LANE IDENTIFICATION

BACKGROUND OF THE INVENTION

(a) Field of the Invention

The present invention relates to an apparatus and method for generating

lane identification signals, and an apparatus and method for lane identification.

More particularly, the present invention relates to an apparatus and

method for generating lane identification signals for identifying received signals having been reflected by a road for respective lanes, and an apparatus and

method for lane identification for identifying received signals having been

reflected by a road for respective lanes.

(b) Description of the Related Art

Generally, a traffic information system is a system that collects

information data for various roads, such as a crossroad and a highway, and

concentrates the collected information data to a traffic control center, so as to

perform real time traffic management, and the information is then used for

removing a traffic jam by controlling traffic lights or for providing traffic

information. At this time, the traffic information system utilizes various sensors for

detecting vehicles on the road, e.g., an inductive loop detector for detecting a speed of a vehicle driving on the road, a video sensor, an acoustic sensor, and a radar sensor, or the like.

The inductive loop type includes one or more wire loops that is hidden

inside the road or crosses the road, and an end thereof is connected to a detector, e.g., an oscillator. In such an inductive loop type, a vehicle is detected by a change of inductance of the detector when the vehicle moves over the wire loop. However, the inductive loop type has a problem in that the loop coil may be damaged by deformation or destruction of the road while a vehicle drives over the road in which the loop coil is installed and the loop coil may be deformed or cut off by a vehicle. Furthermore, when the inductive loop type is adopted to measure a line of stopped vehicles at a crossroad or the like, there is a problem in that a plurality of loop coils must be installed because of the wide detection area, so that installation and maintenance thereof are difficult.

In addition, because a method using a video sensor recognizes vehicles using a video camera, this method has a drawback in that the vehicle cannot be precisely recognized when it rains, snows, or is dark, and a problem in that lanes of both directions cannot be detected by only one video camera.

In addition, in the case of a method using an acoustic sensor, since a vehicle is detected using an acoustic wave generated by the vehicle, it has poor accurateness, and so it is rarely used.

In addition, a technology using a radar sensor detects a vehicle by generating a radar signal and using a Doppler frequency signal received from a road. Here, in the conventional art, each lane of the road is identified using a probability density function (PDF). That is, when a vehicle passes a radar detection area on each lane, distribution of strength (amplitude) of the received signal is analyzed in a probability method, and a position where a maximum

signal is concentrated is determined as a center of each lane.

However, in such method, since the strength of the received signal is severely affected by a type of a vehicle, a speed, and a size of the vehicle, as well as surrounding clutter, there is a possibility that identification of lanes may be inaccurate.

The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art. SUMMARY OF THE INVENTION

The present invention has been made in an effort to provide an apparatus and a method for generating lane identification signals, and an apparatus and a method for lane identification having advantages of precisely adjusting lane identification signals of a radar detection system to respective lanes.

In addition, the present invention has also been made in an effort to provide an apparatus and a method for generating lane identification signals, and an apparatus and a method for lane identification having advantages of precisely identifying signals received from a road for respective lanes, thereby extracting accurate traffic information of a multi-lane road.

An exemplary apparatus for generating lane identification signals according to an embodiment of the present invention includes: a signal processor calculating a resolution coefficient corresponding to a lane width of a road, based on a predetermined parameter for road circumstances; a radar

clock generator generating an M-SEQ synchronization frequency for generation of an M-SEQ signal of a lane identification signal, based on a predetermined frequency signal and the resolution coefficient provided by the signal processor; and an M-SEQ generating portion generating the M-SEQ signal based on the M-SEQ synchronization frequency.

An exemplary apparatus for generating lane identification signals according to an embodiment of the present invention includes a) calculating a resolution coefficient corresponding to a lane width of a road, based on a predetermined parameter for road circumstances, b) generating an M-SEQ synchronization frequency for generation of an M-SEQ signal of a lane identification signal, based on a predetermined frequency signal and the resolution coefficient provided by the signal processor; and c) generating the M-SEQ signal based on the M-SEQ synchronization frequency.

Further, an exemplary apparatus for lane identification for identifying received signals having been reflected by a road for respective lanes according to an embodiment of the present invention includes: an M-SEQ generating portion generating an M-REF signal of a reference signal of an M-SEQ signal having the same code as the M-SEQ signal generated based on a resolution coefficient corresponding to a road lane width calculated based on a predetermined parameter for road circumstances and having a time delay for respective lanes, so as to identify the received signals for respective lanes; and a plurality of correlators identifying the received signals for respective lanes based on a comparison of a code of the received signal and a code of the M-REF signal.

An exemplary method for lane identification for identifying received

signals having been reflected by a road for respective lanes according to an embodiment of the present invention includes a) generating an M-REF signal of

a reference signal of an M-SEQ signal generated based on a resolution

coefficient corresponding to a road lane width calculated based on a

predetermined parameter for road circumstances, and b) identifying the received

signals for respective lanes based on a comparison of a code of the received

signal and a code of the M-REF signal.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic view of vehicle detection by a multi-lane road radar

detection system.

FIG. 2 is a schematic diagram of a multi-lane road radar detection

system.

FIG. 3 is a schematic diagram of an apparatus for generating lane

identification signals according to an exemplary embodiment of the present

invention.

FIG. 4 is a schematic view for explaining a method of identifying a lane identification signal and a lane of a road in the case of a 4-lane road in both

directions, according to an exemplary embodiment of the present invention.

FIG. 5 is a flowchart of a method of identifying a lane identification signal and a lane of a road according to an exemplary embodiment of the present

invention.

FIG. 6 is a schematic diagram of an apparatus for lane identification according to an exemplary embodiment of the present invention.

FIG. 7 is a drawing for showing each lane and a correlator for identifying received signals for respective lanes according to an exemplary embodiment of the present invention.

FIG. 8 is a flowchart of a method for identifying a lane according to an exemplary embodiment of the present invention.

DETAILED DESCRIPTION OF THE EMBODIMENT An exemplary embodiment of the present invention will hereinafter be described in detail with reference to the accompanying drawings.

As shown in FIG. 1 , in a multi-lane road radar detection system, a continuous wave radar, which is typically called a Doppler radar, is used so as to detect a moving speed of a vehicle using a Doppler effect of an electromagnetic wave depending on a movement of a vehicle, and more particularly, a binary phase shift keying (hereinafter, referred to as BPSK) continuous wave radar is used so as to increase an amount of information of a signal and be able to measure a distance by repeatedly performing a phase shift keying considering a point that a distance cannot be measured only by a genuine sine wave.

At this time, the multi-lane road radar detection system is configured to obtain traffic information by detecting a vehicle 100 driving on each lane of the multi-lane road 120, or stopped thereon, using a radar detector 20 installed to a supporting member 10 on a side of a road or to any conventional structure.

In more detail, the radar detector 20 is installed to an arm of the supporting member 10 such that the radar detector 20 looks at a detection area, and extracts traffic information such as a length of a line of vehicles on the multi-lane road 120, a speed of a vehicle on the multi-lane road 120, an amount

of traffic on the lane, an occupation rate of the lane, or the like.

The radar detector 20 performs a BPSK for a wireless signal of a microwave with an M-SEQ consisting of a binary code and outputs the resultant signal, measures a speed of a vehicle and a length of a line of vehicles by receiving signals reflected by the vehicles 100, and provides information for controlling traffic flow by measuring a traffic amount of the road, an occupation rate, and the like.

As shown in FIG. 2, the multi-lane road radar detection system may include a local oscillator 310, a transmitter 320, a receiver 330, and a signal processor 224. The local oscillator 310 generates a local oscillator signal in a microwave. The transmitter 320 modulates a transmitting signal input from the signal processor using the local oscillator signal generated by the local oscillator 310 and outputs the modulated signal to a detection area via a transmitting antenna. The receiver 330 demodulates the received signal from a received microwave signal through a receiving antenna. The signal processor 224 may include an M-SEQ generator 404 generating an M-SEQ signal formed by a binary code and functioning as a lane identification signal and a unit of data acquisition, a correlator 412 identifying the received signals for respective lanes by comparing codes of the received signals, a traffic information extractor 416 extracting traffic information using the signals identified for respective lanes by the correlator 412, and a microprocessor 402 controlling a system.

The local oscillator 310 may include an oscillator 311 outputting a microwave of a specific frequency (for example, 9.64 GHz), a distributor 312 distributing the output signal of the oscillator 311 , a divider 313 dividing one of

the distributed oscillator signals, an amplifier 314 amplifying the divided signal, an amplifier 315 amplifying the other distributed oscillator signal, a multiplier 316 multiplying the amplified oscillator signal, and a band pass filter 317 filtering the output of the multiplier 316. The signal processor 224 may include a microprocessor 402 for controlling overall operations, an M-SEQ generator 404, first and second analogue digital converters 410-1 and 410-2, a correlator 412 comparing a code of digital data received from the analogue digital converters 410-1 and 410-2 to a code of an M-REF signal of a reference signal of the M-SEQ generator 404 having time delay for respective lanes, a filter 414 filtering the output of the correlator, and a traffic information extractor 416 extracting traffic information from the filtered received signal.

The transmitter 320 may include an amplifier 321 amplifying a transmitting signal input from the signal processor 224, a modulator 322 modulating the amplified transmitting signal with a first local oscillator signal, an amplifier 323 amplifying the modulated signal lower than a certain level, a mixer 324 mixing the amplified modulated signal with a second local oscillator signal, and high power amplifiers 325 and 326 amplifying the output of the mixer 324 and outputting the same via an antenna Tx ANT. The receiver 330 may include low noise amplifiers 331 and 332 amplifying the microwave signal received from an antenna Rx ANT, a mixer 333 mixing the amplified received microwave signal with the second local oscillator signal and outputting a received medium frequency signal, a synchronization phase detector 334 detecting the received medium frequency signal through a

synchronization phase detection and demodulating the same as a received base band signal, and an amplifier 335 amplifying the output of the synchronization phase detector 334.

As shown in FIG. 3, an apparatus for generating lane identification signals according to an exemplary embodiment of the present invention may include an oscillator 406, a signal processor 405, a radar clock generator 408, and an M-SEQ generating portion 504. The oscillator 406 generates a predetermined frequency signal for a digital signal process, as an example, a frequency signal of 40MHz. The signal processor 405 calculates a resolution coefficient corresponding to a lane width using various parameters set by an adaptation process of the multi-lane road. The radar clock generator 408 may include a PLL multiplier 408a multiplying the frequency signal output from the oscillator 406 to a signal having a higher frequency, as an example, a signal of 100MHz or 300MHz, a calculator 408b generating an M-SEQ synchronization frequency by a calculation using the signal multiplied by the PLL multiplier 408a and the resolution coefficient provided by the signal processor 405, a synchronization frequency generator 408c generating clock frequency, or the like, necessary for an internal digital circuit, etc., and a fractional delay (hereinafter, referred to as F/delay) determining portion 408d. The M-SEQ generating portion 504 may include an M-SEQ generator 504a generating an M-SEQ signal using the M-SEQ synchronization frequency provided by the radar clock generator 408, and an integer delay (hereinafter, referred to as I/delay) determining portion 504b.

At this time, the M-SEQ generator 504a generates a signal having a

resolution corresponding to a lane width, using the M-Sequence so as to collect road information for respective lanes. In addition, the M-SEQ generator 504a may be realized as the M-SEQ generator 404 shown in FIG. 2.

The M-SEQ (M-Sequence) signal, which is a lane identification signal, is a signal developed by Huffman among binary code random signals, and is a kind of a pseudo random signal. Accordingly, since the M-SEQ signal satisfies random characteristics and a self-correlation function thereof is close to a white noise, it has an advantage in that a correlation calculation between the input signal and the received signal is simple. In more detail, the M-SEQ signal is a random binary signal having a specific number of codes (elements), and one element has a resolution corresponding to a width of one lane and can be changed depending on a lane width. At this time, the resolution means a unit in which the multi-lane road radar detector acquires information. Meanwhile, a road may have a median strip and a different width depending on its circumstances, and a distance from a multi-lane road radar detection system to a first lane may also be different. Therefore, a process for the multi-lane road radar detection system to precisely recognize circumstances of the road by setting parameters corresponding to an installation angle and an installation height of the multi-lane road radar detection system, a distance to a first lane, a road width, a number of lanes, a width of a median strip, and the like, is required, and this process may be called an adaptation process.

As a part of the adaptation process, an M-SEQ signal in a specific frequency is generated, based on a resolution coefficient calculated by

parameters corresponding to road circumstances, so as to identify precisely the received radar signals for respective lanes.

That is, the signal processor 405 receives a value for a road width, a value for a distance from a radar detector to a first lane before a median strip, and a value for a distance to a first lane beyond the median strip, among parameters obtained by the adaptation process, and calculates the resolution coefficient by the following Equation 1. (Equation 1) K=2*F*L/C In the equation 1 , K is the resolution coefficient, C is the speed of light, F is a radar clock synchronization frequency, and L is a width of a lane obtained by the adaptation process.

The calculator 408b of the radar clock generator 408 generates the M-SEQ synchronization frequency by a calculation using the resolution coefficient calculated by the signal processor 405 and the frequency signal multiplied by the PLL multiplier 408a, and then transmits the M-SEQ synchronization frequency to the M-SEQ generator 504a of the M-SEQ generating portion 504. Then, the M-SEQ generator 504a generates the M-SEQ signal formed with a binary code based on the M-SEQ synchronization frequency. Inside the M-SEQ generator 504a are a specific number, e.g., 12, of shift registers and XOR circuits performing XOR calculation for the output of the shift registers, and so the M-SEQ signal, i.e., the lane identification signal having radar resolution corresponding to various numbers of codes and various lane widths by the M-SEQ synchronization frequency, is generated.

For example, if a width of one lane is 3m, this is changed to a frequency of 50MHz using the K value obtained by Equation 1 , and the frequency of

50MHz corresponds to a time of 20ns. That is, a time delay between lanes is

20ns, and this corresponds to one element (pulse) of the M-SEQ signal. Therefore, the element of the M-Sequence also has a time width of 20ns.

At this time, as shown in FIG. 4, in the case that the road has a total of four lanes in both directions, a width of each respective lane is 3m, there is a road shoulder of a width of 5m between an installation position of the radar detector 20 and a first lane, and a median strip of a width of 1m exists in the middle of the road, there is a distance of the width of the road shoulder between the radar detector 20 and the first lane.

Therefore, the I/delay determining portion 504b of the M-SEQ generating portion 504 has delay information in a unit of a width of a lane, and the F/delay determining portion 408d of the radar clock generator 408 has delay information in a unit of a lesser width, e.g., in a unit of 0.25m. Accordingly, the M-SEQ signal can be precisely adjusted to a starting point of the first lane.

In more detail, the I/delay is a delay corresponding to a road width measured while setting parameters for the road, and it is equal to a width (pulse width) of one element of the M-SEQ signal (in the above example, 20ns : 3m). Since it is difficult to accord precisely a lane of the road with a radar detector signal only with the I/delay, the F/delay, corresponding to a delay obtained by dividing the I/delay, (in the above example, 1.7ns : 0.25m) is used.

Therefore, a first starting point of an M-SEQ signal clock is roughly adjusted to a first lane by applying the I/delay signal by the I/delay determining

portion 504b, and the M-SEQ signal is then precisely adjusted to the starting point of the first lane by regulating the F/delay in a unit of 0.25m by the F/delay determining portion 408d. In a similar way, the M-SEQ signal is precisely adjusted to a starting point of a first lane beyond a median strip by regulating the F/delay in a unit of 0.25m by the F/delay determining portion 408d, for the lanes beyond the median strip.

That is, the I/delay and the F/delay are respectively calculated by measuring a distance from the detector to a first lane before the median strip and a distance from the detector to a first lane beyond the median strip, and they are respectively applied to portions before and beyond the median strip.

Hereinafter, referring to FIG. 5, a method for generating lane identification signals according to an exemplary embodiment of the present invention will be explained.

At step S10, parameters for a width of a lane, a distance from an installation position of the multi-lane road radar detector to a first lane, and a width of a median strip are set, using data obtained by the road adaptation process.

Subsequently, at step S12, a resolution coefficient K for a lane width, and coefficients for a distance from the multi-lane road radar detector to the first lane and for a width of the median strip are calculated, and at step S14, the M-SEQ synchronization frequency is generated by a calculation using the frequency signal of the PLL multiplier 408a and the resolution coefficient.

The I/delay is determined, at step S16, by coefficients for the distance to the first lane and the width of the median strip calculated at step S 12, and the

F/delay is determined, at step S18, again by coefficients for the distance to the first lane and the width of the median strip.

Subsequently, at step S20, the M-SEQ signal of the lane identification signal having a binary code is generated by the M-SEQ synchronization frequency signal generated at step S14. Then, at step S22, the M-SEQ signal is roughly adjusted to the first lane by applying the I/delay determined at step S16, and the M-SEQ signal is then precisely adjusted to the first lane by applying the F/delay determined at step S18. In addition, the first lane beyond the median strip and the M-SEQ signal are also precisely accorded to each other in a similar way.

Hereinafter, referring to FIG. 6, an apparatus for lane identification for identifying received signals for respective lanes according to an exemplary embodiment of the present invention will be explained.

An apparatus for lane identification may include an oscillator 606, a signal processor 605, a radar clock generator 608, an M-SEQ generating portion 604, two ADCs 610-1 and 610-2, and a correlator 612. The oscillator 606 generates a predetermined frequency signal for a digital signal process, as an example, a frequency signal of 40MHz. The signal processor 605 calculates a resolution coefficient corresponding to a lane width using various parameters set by an adaptation process of the multi-lane road. The radar clock generator 608 may include a PLL multiplier 608a multiplying the frequency signal output from the oscillator 606 to a signal having a higher frequency, as an example, a signal of 100MHz or 300MHz, a calculator 608b generating an M-SEQ synchronization frequency by a calculation using the signal multiplied by the PLL multiplier 608a

and the resolution coefficient provided by the signal processor 605, a synchronization frequency generator 608c generating a clock frequency, or the like, necessary for an internal digital circuit, etc., and a fractional delay (hereinafter, referred to as F/delay) determining portion 608d. The M-SEQ generating portion 604 may include an M-SEQ generator

604a generating an M-SEQ signal formed by a binary code using the M-SEQ synchronization frequency provided by the radar clock generator 608 and generating an M-REF, which is a reference signal of the M-SEQ, formed by the same binary code with the M-SEQ signal so as to identified signals for respective lanes, and an integer delay (hereinafter, referred to as I/delay) determining portion 604b. Two ADCs 610-1 and 610-2 convert the received analogue signal to a digital signal. A correlator 612 compares the M-SEQ code of the received signals converted by the ADCs 610-1 and 610-2 with a code of the M-REF that is a reference signal of the M-SEQ and thereby identifies the received signals for respective lanes.

At this time, the M-REF signal is a signal having the same code as the M-Sequence, and is a reference signal for identifying the received signals for respective lanes by comparing a code and a time delay of the received signals with those of the M-REF signal, since it has a delay period corresponding to a width of one lane (in the above example, 20ns) and accordingly a time delay corresponding to each lane can be calculated.

In addition, the ADCs 610-1 and 610-2, the M-SEQ generator 604a, and the correlator 612 may respectively be equal to the ADCs 410-1 and 410-2, the M-SEQ generator 404, and the correlator 412 of FIG. 2.

In addition, the apparatus for lane identification for received signals may be realized by combining the ADCs 610-1 and 610-2 and the correlator 612 to the apparatus for generating lane identification signals of FIG. 3.

As shown in FIG. 7, the correlator 612 may be provided with the same number of correlators as the number of lanes of the multi-lane road, and in the present exemplary embodiment, the correlator 612 is comprised of eight filter banks 612-1 , 612-2, 612-3, 612-4, 612-6, 612-7, 612-7, and 612-8, so that one correlator processes one signal. Each of the correlators 612-1 , 612-2, 612-3,

612-4, 612-6, 612-7, 612-7, and 612-8 stores a reference signal (M-REF signal) having the same code as the M-SEQ signal generated for the respective lanes and a predetermined time delay.

Since each element of the M-SEQ signal has a resolution corresponding to a width of a lane, the signals received from the respective lanes have a time delay corresponding to each lane. Therefore, each of the correlators 612-1 , 612-2, 612-3, 612-4, 612-6,

612-7, 612-7, and 612-8 compares the reference signal (M-REF) stored by itself and a time delay of the received signal, and recognizes the signal as a signal received from a lane corresponding to itself in the case that the codes are equal. At this time, each of the correlators 612-1 , 612-2, 612-3, 612-4, 612-6, 612-7, 612-7, and 612-8 compares the received signal with a time delay of the reference signal stored by itself, and in the case that the codes are not equal, it considers the signal as a signal received from another lane and does not process the signal.

Hereinafter, referring to FIG. 8, a method for lane identification for

identifying received signals for respective lanes according to an exemplary embodiment of the present invention will be explained.

At first, the M-SEQ generating portion 604 generates M-SEQ signals and

M-REF signals corresponding to the M-SEQ signal for respective lanes, at step S100, and the M-REF signal is stored in respective correlators 612-1 , 612-2,

612-3, 612-4, 612-6, 612-7, 612-7, and 612-8.

Subsequently, the M-SEQ signal generated at step S100 is transmitted toward a road, at step S102, and for example, after the M-SEQ signal is provided to the transmitter 320 of the above-mentioned multi-lane road radar detection system and is modulated by a microwave generated by the local oscillator 310, the signal can be transmitted toward the road via the transmitting antenna Tx

ANT.

In addition, at step S104, the reflected signals with respect to the M-SEQ signal are received from a road. At step S106, the received signals may be input to the respective correlators 612-1 , 612-2, 612-3, 612-4, 612-6, 612-7,

612-7, and 612-8, after the received signals are demodulated by the receiver

330 or the like and are converted to digital signals by the ADCs 610-1 and 610-2.

At this time, the ADC 610 may not send the digital-converted signal to a specific correlator, but may send the signal to all the correlators 612-1 , 612-2, 612-3, 612-4, 612-6, 612-7, 612-7, and 612-8.

At step S108, each of the correlators 612-1 , 612-2, 612-3, 612-4, 612-6,

612-7, 612-7, and 612-8 respectively determines whether codes of the received signal and the M-REF signal coincide with each other by using the time delay of the received signal corresponding to respective lanes and the M-REF signal

having a delay corresponding to respective lanes stored at step S100.

If the codes of the received signal and the M-REF signal coincide with each other, the received signal is considered as a signal received from a corresponding lane, at step S110. On the other hand, if the codes of the received signal and the M-REF signal do not coincide with each other, the received signal is considered as a signal received from another lane, at step S112, and the process ends.

While this invention has been described in connection with what is presently considered to be practical exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.

As mentioned above, an apparatus for generating lane identification signals and a method for generating lane identification signals according to an embodiment of the present invention can precisely generate lane identification signals having radar resolutions corresponding to various lane widths of roads, such that a width of a lane of a road can be precisely detected.

In particular, according to an embodiment of the present invention, lane identification signals can be accorded with a road such that lanes can be precisely identified regardless of whether a road shoulder or a median strip exists or not, the widths of the road shoulder or the median strip, or the various widths of the lanes.

Furthermore, in an apparatus and a method for lane identification for received signals according to an embodiment of the present invention, since the

received signals can be precisely identified for respective lanes, a traffic control of a multi-lane road can be effectively performed.

Throughout this specification and the claims which follow, unless explicitly described to the contrary, the word "comprise" or variations such as "comprises" or "comprising" will be understood to imply the inclusion of stated elements but not the exclusion of any other elements.