CN109375240B - Low-altitude target detection system and method based on GNSS forward scattering characteristics - Google Patents
Low-altitude target detection system and method based on GNSS forward scattering characteristics Download PDFInfo
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- CN109375240B CN109375240B CN201811305964.1A CN201811305964A CN109375240B CN 109375240 B CN109375240 B CN 109375240B CN 201811305964 A CN201811305964 A CN 201811305964A CN 109375240 B CN109375240 B CN 109375240B
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S19/00—Satellite radio beacon positioning systems; Determining position, velocity or attitude using signals transmitted by such systems
- G01S19/01—Satellite radio beacon positioning systems transmitting time-stamped messages, e.g. GPS [Global Positioning System], GLONASS [Global Orbiting Navigation Satellite System] or GALILEO
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- G01S19/14—Receivers specially adapted for specific applications
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S19/00—Satellite radio beacon positioning systems; Determining position, velocity or attitude using signals transmitted by such systems
- G01S19/01—Satellite radio beacon positioning systems transmitting time-stamped messages, e.g. GPS [Global Positioning System], GLONASS [Global Orbiting Navigation Satellite System] or GALILEO
- G01S19/13—Receivers
- G01S19/35—Constructional details or hardware or software details of the signal processing chain
- G01S19/37—Hardware or software details of the signal processing chain
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Abstract
The invention discloses a low-altitude target detection system and method based on GNSS forward scattering characteristics, and the system comprises a GNSS omnidirectional antenna, a digital intermediate frequency processing module, a data quantization module, a time base module and an ARM module, wherein the ARM module consists of a GNSS satellite signal capturing processing module, a GNSS satellite signal tracking processing module, an average filter module, a target peak value detection module and a target early warning module. When the target passes through the effective detection area, the device detects the change trend of the signal amplitude of the GNSS satellite signals by receiving and processing the GNSS satellite signals in real time, and judges whether the target appears in real time according to a set detection threshold. Because the GNSS has the advantages of real-time performance, all-weather performance and the like, the target in the effective area can be detected in real time, continuously, intelligently and fully automatically.
Description
Technical Field
The invention relates to the technical field of low-altitude target detection, in particular to a low-altitude target detection system and method based on GNSS forward scattering characteristics.
Background
The target detection technology based on the forward scattering property of the GNSS (Global Navigation Satellite System) has the following advantages: 1. the system does not emit electromagnetic wave signals, but utilizes a non-cooperative GNSS satellite as a radiation source, so that the system is not easy to be perceived by an enemy and has strong survivability and concealment; 2. the working performance is excellent, and the device can work continuously around the clock. 3. When a target passes through the vicinity of a connecting line between a GNSS satellite and a base station, the RCS of the target is rapidly increased, a GNSS signal received by the base station also has obvious change, and the radar has better anti-stealth capability compared with the traditional radar; 4. because the technology uses GNSS signals, the ground base station can directly use a mature GNSS receiver or a data collector, and the overall deployment difficulty and cost of the system are reduced.
At present, the research mode in the field is limited to the acquisition of data by utilizing a GNSS receiver or an intermediate frequency collector, and the secondary development of the acquired data is carried out on a computer terminal, so that the real-time detection capability of a target is not provided, and the practical application of the radar in the field of radars is influenced.
Disclosure of Invention
The invention aims to provide a low-altitude target detection system and method based on GNSS forward scattering characteristics.
In order to achieve the purpose, the invention is implemented according to the following technical scheme:
the utility model provides a low latitude target detection system based on GNSS forward scattering characteristic, includes GNSS omnidirectional antenna, digital intermediate frequency processing module, data quantization module, time base module, ARM module, the ARM module comprises GNSS satellite signal acquisition processing module, GNSS satellite signal tracking processing module, mean value filter module, target peak detection module and target early warning module, wherein:
the GNSS omnidirectional antenna is connected with the signal input end of the digital intermediate frequency processing module, is a GNSS multimode, omnidirectional and high-gain antenna and is used for receiving GNSS satellite signals in a detection area in real time;
the signal output end of the digital intermediate frequency processing module is connected with the signal input end of the data quantization module and is used for acquiring GNSS satellite signals received by the GNSS omnidirectional antenna in real time and converting the GNSS satellite signals into intermediate frequency signals;
the signal output end of the data quantization module is connected with the signal input end of the GNSS satellite signal capturing and processing module, and the data quantization module is used for converting the intermediate frequency signal converted by the digital intermediate frequency processing module into a 2-bit digital intermediate frequency signal and transmitting the 2-bit digital intermediate frequency signal to the GNSS satellite signal capturing and processing module;
the signal output end of the time base module is connected with the signal input end of the data quantization module and the signal input end of the GNSS satellite signal capturing and processing module, and is used for transmitting clock synchronization signals to the data quantization module and the GNSS satellite signal capturing and processing module;
the signal output end of the GNSS satellite signal capturing and processing module is connected with the signal input end of the GNSS satellite signal tracking and processing module and is used for synchronously receiving the 2-bit digital intermediate frequency signal transmitted by the data quantization module;
the GNSS satellite signal tracking processing module is characterized in that a signal output end of the GNSS satellite signal tracking processing module is connected with a signal input end of the mean filter module and is used for receiving the 2-bit digital intermediate frequency signal received by the GNSS satellite signal capturing processing module, extracting in-phase and quadrature signals of a tracking loop of the 2-bit digital intermediate frequency signal and calculating a satellite signal amplitude;
the signal output end of the mean filter module is connected with the signal input end of the target peak value detection module and is used for carrying out mean filtering processing on the satellite signal amplitude calculated by the GNSS satellite signal tracking processing module;
the signal output end of the target peak detection module is connected with the signal input end of the target early warning module, and the target peak detection module is used for detecting the target amplitude and judging whether a target appears according to a set target detection threshold;
and the target early warning module is used for carrying out early warning prompt when a target appears.
A low-altitude target detection method based on a GNSS forward scattering characteristic uses the low-altitude target detection system based on the GNSS forward scattering characteristic to detect a target, and comprises the following specific steps:
1) According to fig. 1-2, when a target passes through a detection area, a GNSS omnidirectional antenna receives satellite signals in real time, converts the satellite signals into intermediate frequency signals through a digital intermediate frequency processing module, converts the intermediate frequency signals into 2-bit digital intermediate frequency signals through a data quantization module, and transmits the quantized 2-bit digital intermediate frequency signals to a GNSS satellite signal capturing processing module and a GNSS satellite signal tracking processing module in an ARM module in real time, wherein the GNSS satellite signal tracking processing module extracts in-phase and quadrature signals, namely time channels, in a tracking loop to calculate satellite signal amplitude:
wherein Mag is satellite signal amplitude, I P Being in phase with the tracking loopSignal, Q P For tracking quadrature signals of the loop, I P And Q P All are obtained from a tracking loop in real time; the satellite signal amplitude variation when the target is present is illustrated in FIG. 3;
2) Determining a mean value Mag in a mean filter module avr : as shown in fig. 3, when the target does not appear, the satellite signal amplitude is relatively stable, and assuming that there are N sampling points in the period of time, the satellite signal amplitude of the ith sampling point is recorded as Mag i Mean value Mag avr Expressed as:
3) According to FIG. 2, the mean value Mag is determined avr Then, using an average filter module to perform average filtering processing on the satellite signal amplitude Mag in the step 1), wherein the satellite signal amplitude Mag after the average filtering processing proc Expressed as:
Mag proc ＝Mag avr -Mag；
4) As shown in fig. 2, after step 3) is completed, the target peak detection module selects satellite signal amplitudes adjacent to 5 sampling points for processing, and assuming that M sampling points are total when the target passes through the detection region, the target signal amplitude Mag processed by the target peak detection module is represented as:
the number of target signal amplitudes processed by the target peak detection module is M-5;
5) Determining a target detection threshold value recorded as D according to the processing result of the step 4) Tres Then, the judgment criteria when the target appears are:
the judgment criteria when the target does not appear are as follows:
6) According to the judgment standard of the step 5), setting a target detection threshold value D Tres And 20, comparing the target signal amplitude processed by the target peak detection module with a target detection threshold, and when a target is judged to appear, sending a control instruction to the target early warning module by the target peak detection module, and carrying out early warning prompt by the target early warning module.
Compared with the prior art, the invention has the following beneficial effects:
1. by adopting the high-performance ARM processing framework, when the target appears in the detection area, the GNSS satellite signal can be rapidly captured and tracked, the amplitude of the GNSS signal is calculated, the low-altitude target is monitored in real time, and the high-performance ARM processing framework has good practicability;
2. when the target appears in the detection area, the GNSS satellite data acquired by the method is processed in real time without storing the acquired data, so that the problem that a large amount of data is generated in the long-term use process of the method is avoided, and the method has better practical value;
3. because the instrument only receives GNSS satellite signals, the system does not need a high-power transmitter, has the characteristics of simple structure, small size and the like, and can work all day and night, all weather and full-automatically.
Drawings
Fig. 1 is a schematic diagram of the hardware configuration of the present invention.
FIG. 2 is a flow chart of data processing according to the present invention.
FIG. 3 is a diagram illustrating a change in GNSS satellite signals when a target is present.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention will be described in further detail with reference to the accompanying drawings and examples. The specific embodiments described herein are merely illustrative of the invention and do not delimit the invention.
The method comprises hardware system design and low-altitude target detection algorithm processing flow, mainly uses GNSS satellite signals, collects the satellite signals in real time through the method, completes low-altitude target detection in a detection area, and carries out real-time early warning when the target appears. The design of the invention is to use the forward scattering characteristic of GNSS, and utilize the principle that the radar scattering sectional area of the target is rapidly increased when the target passes through the vicinity of the connecting line of the GNSS satellite and the ground-based receiver to detect the low-altitude target in real time, thereby making up the defect of the traditional radar in the detection capability of the low-altitude target. The GNSS forward scattering characteristic-based low-altitude target detection system and method of the present invention are described in detail in the following embodiments.
As shown in fig. 1, the present embodiment provides a low-altitude target detection system based on GNSS forward scattering characteristics, including a GNSS omnidirectional antenna, a digital intermediate frequency processing module, a data quantization module, a time base module, and an ARM module, where the ARM module is composed of a GNSS satellite signal capturing processing module, a GNSS satellite signal tracking processing module, an average filter module, a target peak detection module, and a target early warning module, and the ARM module further includes a power supply for supplying power thereto, where:
the GNSS omnidirectional antenna is connected with the signal input end of the digital intermediate frequency processing module and is used for receiving GNSS satellite signals in a detection area in real time; because the GNSS has the advantages of real-time performance, all weather performance and the like, the target in the effective area can be detected in real time, continuously, intelligently and automatically;
the signal output end of the digital intermediate frequency processing module is connected with the signal input end of the data quantization module and is used for acquiring GNSS satellite signals received by the GNSS omnidirectional antenna in real time and converting the GNSS satellite signals into intermediate frequency signals;
the signal output end of the data quantization module is connected with the signal input end of the GNSS satellite signal capturing and processing module, and the data quantization module is used for converting the intermediate frequency signal converted by the digital intermediate frequency processing module into a 2-bit digital intermediate frequency signal and transmitting the 2-bit digital intermediate frequency signal to the GNSS satellite signal capturing and processing module;
the signal output end of the time base module is connected with the signal input end of the data quantization module and the signal input end of the GNSS satellite signal capturing and processing module, and is used for transmitting clock synchronization signals to the data quantization module and the GNSS satellite signal capturing and processing module;
the signal output end of the GNSS satellite signal capturing and processing module is connected with the signal input end of the GNSS satellite signal tracking and processing module and is used for synchronously receiving the 2-bit digital intermediate frequency signal transmitted by the data quantization module;
the GNSS satellite signal tracking processing module is characterized in that a signal output end of the GNSS satellite signal tracking processing module is connected with a signal input end of the mean filter module and is used for receiving the 2-bit digital intermediate frequency signal received by the GNSS satellite signal capturing processing module, extracting in-phase and quadrature signals of a tracking loop of the 2-bit digital intermediate frequency signal and calculating a satellite signal amplitude;
the signal output end of the mean filter module is connected with the signal input end of the target peak detection module and is used for performing mean filtering processing on the satellite signal amplitude calculated by the GNSS satellite signal tracking processing module;
the signal output end of the target peak detection module is connected with the signal input end of the target early warning module, and the target peak detection module is used for detecting the target amplitude and judging whether a target appears according to a set target detection threshold;
and the target early warning module is used for carrying out early warning prompt when a target appears.
In addition, the embodiment also provides a low-altitude target detection method based on the GNSS forward scattering characteristic, which uses the low-altitude target detection system based on the GNSS forward scattering characteristic to detect a target, and includes the following specific steps:
1) When the target is through surveying when regional, GNSS omnidirectional antenna receives the satellite signal in real time, convert the satellite signal to the intermediate frequency signal through digital intermediate frequency processing module, convert the intermediate frequency signal to 2bit digital intermediate frequency signal through data quantization module, and send the 2bit digital intermediate frequency signal after the quantization in real time to GNSS satellite signal capture processing module and the GNSS satellite signal tracking processing module in the ARM module, GNSS satellite signal tracking processing module is in the tracking loop, draw in-phase and quadrature signal that is the way of time, carry out satellite signal amplitude and calculate:
wherein Mag is satellite signal amplitude, I P For in-phase signals of tracking loops, Q P For tracking quadrature signals of the loop, I P And Q P All are obtained from a tracking loop in real time;
2) Determining a mean value Mag in a mean filter module avr : when the target does not appear, the satellite signal amplitude is stable, if the period of time has N sampling points, the satellite signal amplitude of the ith sampling point is recorded as Mag i Mean value Mag avr Expressed as:
3) Determining a mean value Mag avr Then, using an average filter module to perform average filtering processing on the satellite signal amplitude Mag in the step 1), wherein the satellite signal amplitude Mag after the average filtering processing proc Expressed as:
Mag proc ＝Mag avr -Mag；
4) After the step 3) is completed, the target peak detection module selects satellite signal amplitudes adjacent to 5 sampling points for processing, and assuming that when the target passes through the detection region, there are M sampling points in total, the target signal amplitude Mag processed by the target peak detection module is represented as:
the number of target signal amplitudes processed by the target peak detection module is M-5;
5) Determining a target detection threshold value recorded as D according to the processing result of the step 4) Tres Then the judgment criteria when the target appears are:
the judgment criteria when the target does not appear are as follows:
6) According to the judgment standard of the step 5), setting a target detection threshold value D Tres At 20, the amplitude of the target signal processed by the target peak detection module is compared with a target detection threshold, and when it is determined that a target is present, that is, when the target is present
And the target peak value detection module sends a control instruction to the target early warning module, and the target early warning module carries out early warning prompt.
From the perspective of technical advantages, the system does not emit electromagnetic wave signals, but utilizes non-cooperative GNSS satellites as radiation sources, so that the system is not easy to be perceived by enemies and has strong viability and concealment; the working performance is excellent, and the device can work continuously around the clock; when the target passes through the vicinity of the connection between the GNSS satellite and the base station, the RCS of the target is rapidly increased, the GNSS signal received by the base station is obviously changed, and the radar has better anti-stealth capability compared with the traditional radar.
The technical solution of the present invention is not limited to the limitations of the above specific embodiments, and all technical modifications made according to the technical solution of the present invention fall within the protection scope of the present invention.
Claims (2)
1. The low-altitude target detection system based on the GNSS forward scattering characteristic is characterized by comprising a GNSS omnidirectional antenna, a digital intermediate frequency processing module, a data quantization module, a time base module and an ARM module, wherein the ARM module consists of a GNSS satellite signal capturing and processing module, a GNSS satellite signal tracking and processing module, an average filter module, a target peak value detection module and a target early warning module, and the GNSS forward scattering characteristic is as follows:
the GNSS omnidirectional antenna is connected with the signal input end of the digital intermediate frequency processing module and is used for receiving GNSS satellite signals in a detection area in real time;
the signal output end of the digital intermediate frequency processing module is connected with the signal input end of the data quantization module and is used for acquiring GNSS satellite signals received by the GNSS omnidirectional antenna in real time and converting the GNSS satellite signals into intermediate frequency signals;
the signal output end of the data quantization module is connected with the signal input end of the GNSS satellite signal capturing and processing module, and the data quantization module is used for converting the intermediate frequency signal converted by the digital intermediate frequency processing module into a 2-bit digital intermediate frequency signal and transmitting the 2-bit digital intermediate frequency signal to the GNSS satellite signal capturing and processing module;
the signal output end of the time base module is connected with the signal input end of the data quantization module and the signal input end of the GNSS satellite signal capturing and processing module, and is used for transmitting clock synchronization signals to the data quantization module and the GNSS satellite signal capturing and processing module;
the signal output end of the GNSS satellite signal capturing and processing module is connected with the signal input end of the GNSS satellite signal tracking and processing module and is used for synchronously receiving the 2-bit digital intermediate frequency signal transmitted by the data quantization module;
the GNSS satellite signal tracking processing module is connected with the signal input end of the mean filter module at the signal output end thereof and is used for receiving the 2-bit digital intermediate frequency signal received by the GNSS satellite signal capturing processing module, extracting in-phase and orthogonal signals of a tracking loop of the 2-bit digital intermediate frequency signal and calculating the amplitude of the satellite signal;
the signal output end of the mean filter module is connected with the signal input end of the target peak value detection module and is used for carrying out mean filtering processing on the satellite signal amplitude calculated by the GNSS satellite signal tracking processing module;
the signal output end of the target peak detection module is connected with the signal input end of the target early warning module, and the target peak detection module is used for detecting the target amplitude and judging whether a target appears according to a set target detection threshold;
and the target early warning module is used for carrying out early warning prompt when a target appears.
2. A method for detecting a low-altitude target based on a GNSS forward scattering characteristic, wherein the method for detecting a target using the low-altitude target detection system based on a GNSS forward scattering characteristic as claimed in claim 1 comprises the following steps:
1) When the target is through surveying when regional, GNSS omnidirectional antenna receives the satellite signal in real time, convert the satellite signal to the intermediate frequency signal through digital intermediate frequency processing module, convert the intermediate frequency signal into 2bit digital intermediate frequency signal through data quantization module, and send the 2bit digital intermediate frequency signal after the quantization in real time to GNSS satellite signal capture processing module and the GNSS satellite signal tracking processing module in the ARM module, GNSS satellite signal tracking processing module is in the tracking loop, the inphase and the quadrature signal of way promptly are drawed, carry out satellite signal amplitude and calculate:
wherein Mag is satellite signal amplitude, I P For in-phase signals of tracking loops, Q P For tracking quadrature signals of the loop, I P And Q P All are obtained from a tracking loop in real time;
2) Determining a mean value Mag in a mean filter module avr : when the target does not appear, the satellite signal amplitude is stable, if the period of time has N sampling points, the satellite signal amplitude of the ith sampling point is recorded as Mag i Mean value Mag avr Expressed as:
3) Determination of the mean value Mag avr Then, using an average filter module to perform average filtering processing on the satellite signal amplitude Mag in the step 1), wherein the satellite signal amplitude Mag after the average filtering processing is performed proc Expressed as:
Mag proc ＝Mag avr -Mag；
4) After the step 3) is completed, the target peak detection module selects satellite signal amplitudes adjacent to the 5 sampling points for processing, and assuming that when the target passes through the detection region, there are M sampling points in total, the target signal amplitude Mag processed by the target peak detection module is represented as:
the number of target signal amplitudes processed by the target peak detection module is M-5;
5) Determining a target detection threshold value recorded as D according to the processing result of the step 4) Tres Then, the judgment criteria when the target appears are:
the judgment criteria when the target does not appear are as follows:
6) According to the judgment standard of the step 5), setting a target detection threshold value D Tres Comparing the amplitude of the target signal processed by the target peak detection module with a target detection threshold value, and when the target is judged to appear, sending a control instruction to the target early warning module by the target peak detection module, and pre-warning by the target early warning moduleAnd (5) warning.
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| US8370064B1 (en) * | 2010-04-14 | 2013-02-05 | The Boeing Company | Integrated global navigation satellite system and inertial navigation system for navigation and tracking |
| CN104765043A (en) * | 2015-03-17 | 2015-07-08 | 广东工业大学 | High-integration satellite navigation continuously-operating reference station |
| CN107121685A (en) * | 2017-06-08 | 2017-09-01 | 南京理工大学 | A kind of miniature spaceborne high-dynamic GNSS receiver and its air navigation aid |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| US8370064B1 (en) * | 2010-04-14 | 2013-02-05 | The Boeing Company | Integrated global navigation satellite system and inertial navigation system for navigation and tracking |
| CN104765043A (en) * | 2015-03-17 | 2015-07-08 | 广东工业大学 | High-integration satellite navigation continuously-operating reference station |
| CN107121685A (en) * | 2017-06-08 | 2017-09-01 | 南京理工大学 | A kind of miniature spaceborne high-dynamic GNSS receiver and its air navigation aid |
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