CN102975662A - Ultrasonic wave reversing radar system based on time difference of arrival (TDOA) - Google Patents

Abstract

A TDOA-based ultrasonic reversing radar system, including: a car and several distance measuring modules installed on the car, a receiving module, a display module and an alarm output module, the distance measuring module includes an ultrasonic sensor, a radio frequency sensor, and a first transmitting module and the second transmitting module, the ultrasonic sensor is connected with the first transmitting module, the radio frequency sensor is connected with the second transmitting module, the receiving module is respectively connected with the first transmitting module and the second transmitting module, and the display module and the alarm output module are respectively connected with the receiving module . The invention has the advantages of strong anti-interference ability, no measurement blind area, high measurement precision and high safety performance.

Description

Ultrasonic parking radar system based on TDOA

technical field

The invention relates to a reversing radar, in particular to an ultrasonic reversing radar system based on TDOA.

Background technique

Ultrasonic ranging is a non-contact detection technology, which is not affected by light, the color of the measured object, etc., and has certain adaptability in harsh environments (such as dust-containing), so it is extremely versatile and widely used For reversing reminder. At present, the ultrasonic ranging scheme adopted by the ultrasonic reversing radar widely used in the market is as follows: the transmitted power is known, the received power is measured at the receiving node, and the propagation loss is calculated to obtain the measured distance. However, the anti-interference ability of this ultrasonic reversing radar is poor. Although the characteristics are good in the experimental environment, in the real environment, conditions such as temperature obstacles and propagation modes are often changed, so that the ultrasonic signal is less affected by interference. large, affecting the measurement accuracy.

Contents of the invention

The purpose of the present invention is to provide a TDOA-based ultrasonic reversing radar system to solve the technical problems of poor anti-interference ability and low measurement accuracy of existing ultrasonic reversing radars.

In order to achieve the above object, the present invention provides a TDOA-based ultrasonic reversing radar system, including: automobiles and several distance measuring modules, receiving modules, display modules and alarm output modules installed on automobiles, and the distance measuring modules include ultrasonic sensors , a radio frequency sensor, a first transmitting module and a second transmitting module, wherein,

The ultrasonic sensor is used to detect obstacle information, and sends the detected information to the first transmitting module;

The radio frequency sensor is used to detect obstacle information, and sends the detected information to the second transmitting module;

The first transmitting module is respectively connected with the ultrasonic sensor and the receiving module to convert the received information into a digital signal and send it to the receiving module;

The second transmitting module is respectively connected with the radio frequency sensor and the receiving module to convert the received information into a digital signal and send it to the receiving module;

The receiving module is respectively connected with the first transmitting module and the second transmitting module to compare the received digital signals, obtain the arrival time difference of the signals transmitted by the first transmitting module and the second transmitting module, and calculate the obstacle distance ; It further includes: a receiving unit, a processing unit and an output unit, wherein:

The receiving unit is respectively connected to the first transmitting module and the second transmitting module, to receive the digital signals sent by the first transmitting module and the second transmitting module and send them to the processing unit;

The processing unit is connected with the receiving unit to process the received digital signal, calculate the arrival time difference between the ultrasonic signal and the radio frequency signal, obtain the obstacle distance, and send a prompt message to the output unit according to the calculation result;

The output unit is used to receive prompt information, and send the prompt information to the display module and the alarm output module;

The display module is connected with the output unit to receive the prompt information, give a visual reminder and display the obstacle distance according to the prompt information;

The alarm output module is connected with the output unit to receive prompt information and output alarm information according to the prompt information.

According to the TDOA-based ultrasonic reversing radar system described in the preferred embodiment of the present invention, the first transmitting module includes a Kalman filter for removing random noise in the ultrasonic signal to obtain a better estimated value.

According to the TDOA-based ultrasonic reversing radar system described in the preferred embodiment of the present invention, the display module and the alarm output module are integrated in the receiving module.

According to the ultrasonic reversing radar system based on TDOA described in the preferred embodiment of the present invention, the receiving module adopts AT89S52 single-chip microcomputer.

According to the TDOA-based ultrasonic reversing radar system described in a preferred embodiment of the present invention, the display module includes an LED light-emitting diode to display whether there is an obstacle in the detection range, if there is an obstacle in the detection range, the LED light-emitting diode Flashes at a certain frequency, and the flashing frequency is determined by the distance, the closer the distance, the higher the frequency.

According to the TDOA-based ultrasonic reversing radar system described in the preferred embodiment of the present invention, the display module includes an 8-bit digital tube for displaying the distance of obstacles.

According to the TDOA-based ultrasonic reversing radar system described in the preferred embodiment of the present invention, the 8 is the second digit in the nixie tube is the decimal point.

According to the TDOA-based ultrasonic reversing radar system described in a preferred embodiment of the present invention, the alarm output module includes a voice output unit for outputting voice prompts for obstacle distances, and the detection range of the voice prompts is 0-1.5m. If the detection range is indicated, the distance is too large.

According to the TDOA-based ultrasonic reversing radar system described in the preferred embodiment of the present invention, the alarm output module includes a buzzer alarm for outputting alarm information.

According to the TDOA-based ultrasonic reversing radar system described in the preferred embodiment of the present invention, the ultrasonic sensor adopts the SRF08 ultrasonic ranging chip.

TDOA (time difference ofarrival) ranging is to calculate the time difference between two different wireless signals arriving at the unknown receiving terminal, and then calculate the distance between the unknown receiving terminal and the transmitting terminal according to the propagation speed of the two signals. It is one of the wireless sensor network node ranging methods, because of its high ranging accuracy, it has been widely used in wireless sensor network positioning schemes. The invention uses an ultrasonic sensor and a radio frequency sensor in combination with the TDOA ranging principle to detect the distance of obstacles, has strong anti-interference ability, accurate measurement, the precision reaches 1cm, and can perform voice broadcast and digital tube display. At the same time, the present invention adopts a plurality of ranging modules, which are arranged at intervals behind the car, and can detect whether there are obstacles within 1.5m behind the car, the left rear, and the right rear, and the measurement accuracy is high, which can be widely used in automatic parking The car's perception of the parking environment in the car system enhances the sensitivity of the ultrasonic sensor to detect environmental information and the stability of the data. , Accurately measure the distance between the obstacle and the car. In addition, the present invention adopts the kalman filtering method to remove the random noise in the ultrasonic signal, so as to obtain a better estimated value and reduce the occurrence of blind spots. Compared with the prior art, the invention has the advantages of strong anti-interference ability, no measurement blind area, high measurement precision and high safety performance.

Description of drawings

Fig. 1 is a structural principle diagram of the generating wave ranging system of the present invention.

Detailed ways

The present invention will be described in detail below in conjunction with the accompanying drawings.

Please refer to Fig. 1, a kind of ultrasonic reversing radar system based on TDOA, including: car 1 and three ranging modules 2 installed on the car 1, receiving module 3, display module 4 and alarm output module 5, ranging module Group 2 includes an ultrasonic sensor 21 , a radio frequency sensor 22 , a first transmitting module 23 and a second transmitting module 24 .

The ultrasonic sensor 21 is used to detect obstacle information, and send the detected information to the first transmitting module 23 . The radio frequency sensor 22 is used to detect obstacle information, and send the detected information to the second transmitting module 24 . The first transmitting module 23 and the second transmitting module 24 are used to convert the received information into a digital signal and send it to the receiving module 3, and the first transmitting module 23 also includes a Kalman filter to remove the randomness in the ultrasonic signal noise to get a better estimate. The receiving module 3 is respectively connected with the first transmitting module 23 and the second transmitting module 24, in order to compare the received digital signals to obtain the time difference of arrival of the signals emitted by the first transmitting module 23 and the second transmitting module 24, And calculate the obstacle distance, which further includes:

Receiving unit 31 : connected to the first transmitting module 23 and the second transmitting module 24 respectively, for receiving the digital signals sent by the first transmitting module 23 and the second transmitting module 24 and sending them to the processing unit 32 .

Processing unit 32: connected to the receiving unit 31, used to process the received digital signal, calculate the arrival time difference between the ultrasonic signal and the radio frequency signal, obtain the obstacle distance, and send prompt information to the output unit 33 according to the calculation result.

Output unit 33 : used to receive prompt information and send the prompt information to the display module 4 and the alarm output module 5 .

The display module 4 is connected with the output unit 33 to receive prompt information, give visual reminder and display obstacle distance according to the prompt information. The alarm output module 5 is connected to the output unit 33 for receiving prompt information and outputting alarm information according to the prompt information.

Further, the display module 4 includes an LED light-emitting diode and an 8-digit digital tube, and the LED light-emitting diode is used to display whether there is an obstacle within the detection range. If there is an obstacle within the detection range, the LED light-emitting diode blinks at a certain frequency, and the blinking Frequency is determined by distance, the closer the distance, the higher the frequency. The 8-digit digital tube is used to display the obstacle distance, and the second digit in the digital tube is the decimal point, one digit before the decimal point, and 6 digits after the decimal point. The alarm output module 5 includes a voice output unit and a buzzer alarm. The voice output unit is used to output a voice prompt for obstacle distance, and the detection range of the voice prompt is 0-1.5m. If the detection range exceeds the prompt, the prompt distance is too large. The buzzer is used to output alarm information after detecting an obstacle.

Furthermore, the display module 4 and the alarm output module 5 are integrated in the receiving module 3, and the receiving module 3 adopts an AT89S52 single-chip microcomputer. The ultrasonic sensor 21 adopts the SRF08 ultrasonic ranging chip.

The above adopts three distance measuring modules 2 to be installed behind the car 1, but it should be noted that the present invention does not limit the specific number of distance measuring modules 2, and the number of distance measuring modules 2 is specifically selected according to needs in practical applications. , can be more than three or less than three. The use of three ranging modules 2 above is just an example, and is not intended to limit the present invention.

The TDOA-based ultrasonic reversing radar system of the present invention runs automatically after being turned on and powered on. It can also be set to switch the distance measurement key. After pressing the distance measurement key, it will automatically run and start distance measurement. When there is an obstacle within the range of 0~1.6m in front , can broadcast the distance of the obstacle, and the LED light-emitting diode flashes, the higher the flashing frequency, the closer the distance, and the distance is displayed on the 8-digit digital tube. When a measurement timeout or external interruption occurs, the system will automatically handle the interruption and restart the measurement.

The invention uses an ultrasonic sensor and a radio frequency sensor in combination with the TDOA ranging principle to detect the distance of obstacles, has strong anti-interference ability, accurate measurement, the precision reaches 1cm, and can perform voice broadcast and digital tube display. At the same time, the present invention adopts three ranging modules, which are arranged at intervals behind the car, and can detect whether there are obstacles within 1.5m behind the car, the left rear, and the right rear, and the measurement accuracy is high, which can be widely used in automatic parking The car's perception of the parking environment in the car system enhances the sensitivity of the ultrasonic sensor to detect environmental information and the stability of the data. , Accurately measure the distance between the obstacle and the car. In addition, the present invention adopts the kalman filtering method to remove the random noise in the ultrasonic signal, so as to obtain a better estimated value and reduce the occurrence of blind spots. Compared with the prior art, the invention has the advantages of strong anti-interference ability, no measurement blind area, high measurement precision and high safety performance.

The above is only a preferred implementation example of the present invention, and is not intended to limit the present invention in any form, any content that does not deviate from the technical solution of the present invention, any simple modification made to the above implementation examples according to the technical essence of the present invention , equivalent changes and modifications all belong to the scope of the technical solution of the present invention.

Claims (10)

1. an ultrasonic reversing radar system based on TDOA, it is characterized in that, comprising: automobile and some range-finding modules, receiving module, display module and alarm output module installed on the car, the range-finding module includes Ultrasonic sensor, radio frequency sensor, first transmitting module and second transmitting module, wherein, The ultrasonic sensor is used to detect obstacle information, and send the detected information to the first transmitting module; The radio frequency sensor is used to detect obstacle information, and send the detected information to the second transmitting module; The first transmitting module is respectively connected with the ultrasonic sensor and the receiving module, so as to convert the received information into a digital signal and send it to the receiving module; The second transmitting module is respectively connected with the radio frequency sensor and the receiving module, to convert the received information into a digital signal and send it to the receiving module; The receiving module is respectively connected to the first transmitting module and the second transmitting module to compare the received digital signals to obtain the time difference of arrival of the signals transmitted by the first transmitting module and the second transmitting module, And calculate the obstacle distance; It further includes: receiving unit, processing unit and output unit, wherein: The receiving unit is respectively connected to the first transmitting module and the second transmitting module, to receive the digital signals sent by the first transmitting module and the second transmitting module and send them to the processing unit; The processing unit is connected to the receiving unit to process the received digital signal, calculate the arrival time difference between the ultrasonic signal and the radio frequency signal, obtain the obstacle distance, and send a prompt message to the output unit according to the calculation result; The output unit is used to receive prompt information, and send the prompt information to the display module and the alarm output module; The display module is connected to the output unit to receive prompt information, give visual reminder and display obstacle distance according to the prompt information; The alarm output module is connected with the output unit to receive prompt information and output alarm information according to the prompt information. 2. the ultrasonic reversing radar system based on TDOA as claimed in claim 1, is characterized in that, described first transmission module comprises a Kalman filter, in order to remove the random noise in the ultrasonic signal, obtains better estimated value. 3. The ultrasonic reversing radar system based on TDOA as claimed in claim 1, wherein the display module and the alarm output module are integrated in the receiving module. 4. The ultrasonic reversing radar system based on TDOA as claimed in claim 3, wherein said receiving module adopts AT89S52 single-chip microcomputer. 5. the ultrasonic reversing radar system based on TDOA as claimed in claim 1, is characterized in that, described display module comprises an LED light-emitting diode, in order to display whether there is obstacle in detection range, if there is obstacle in detection range , the LED light-emitting diodes flicker at a certain frequency, and the flickering frequency is determined by the distance, and the closer the distance, the higher the frequency. 6. The ultrasonic reversing radar system based on TDOA as claimed in claim 1, wherein the display module comprises an 8-bit digital tube for displaying the obstacle distance. 7. The ultrasonic reversing radar system based on TDOA as claimed in claim 6, characterized in that, said 8 means that the second digit in the digital tube is a decimal point. 8. The ultrasonic reversing radar system based on TDOA as claimed in claim 1, wherein the alarm output module includes a voice output unit for outputting a voice prompt obstacle distance, and the detection range of the voice prompt is 0 ~ 1.5 m, if it exceeds the prompt detection range, the prompt distance is too large. 9. The ultrasonic reversing radar system based on TDOA as claimed in claim 1, wherein the alarm output module comprises a buzzer for outputting alarm information. 10. The ultrasonic reversing radar system based on TDOA as claimed in claim 1, wherein the ultrasonic sensor adopts the SRF08 ultrasonic ranging chip.

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