A fire monitoring system and monitoring method based on GNSS-R

Abstract

The present invention provides a fire monitoring system based on GNSS-R, including a GNSS satellite that transmits a direct signal and a temperature sensing device, a GNSS-R receiver, a data storage system, a data discrimination system and an alarm system that are connected in sequence; the temperature sensing device receives a first reflected signal and obtains the peak value and signal-to-noise ratio data of a delayed Doppler waveform; the GNSS-R receiver receives the data, the direct signal and the second reflected signal; the data storage system extracts position information and time information from the direct signal; the data discrimination system receives the above data and information, and makes a judgment based on the peak value and signal-to-noise ratio data of the delayed Doppler waveform; the alarm system sounds an alarm in the area judged to be a fire occurrence area based on the judgment result. The present invention also provides a monitoring method. The present invention utilizes the direct signal and reflected signal of GNSS and adopts a temperature sensing device that is extremely sensitive to forest temperature, so that forest fires can be judged in real time.

Description

Technical Field

[0001] The present invention relates to a fire monitoring system and a monitoring method, in particular to a fire monitoring system based on

[0002] Fire monitoring system and monitoring method based on GNSS-R. Background Art

[0003] Forest, grassland fires and seasonal burning have important impacts on climate and economy, and there is an urgent need for humans to effectively monitor them.

[0004] Fire has a significant impact on the biosphere, and monitoring the location and extent of forest fires is an important part of global change research programs.

[0005] Fires change the physical state of vegetation and release many greenhouse gases into the atmosphere. Chemically reactive gases released during biomass burning have a significant impact on chemical processes in the troposphere. The release of smoke and other particulate matter during fires causes significant physical changes in the troposphere below the fires. Natural fires and other fire-related processes affect the exchange of energy and moisture between the land surface and the atmosphere.

[0006] Traditional forest fire monitoring, firefighting, fire risk prediction and other fire prevention technologies have many shortcomings, such as high power consumption, low temporal and spatial resolution, low coverage, difficulty in real-time monitoring, scattered data, inconvenient communication, slow emergency response, difficulty in archiving statistics, and incomparable evaluation and prediction. Using aviation means requires aircraft to fly specifically for a purpose every time an aircraft flies, so monitoring fires is expensive and difficult to cover all areas.

[0007] The emerging GNSS-R remote sensing technology is a new method of remote sensing of ground object parameters using GNSS reflection signals. This remote sensing method does not require the development of a special transmitter, but directly uses the signal of the GNSS satellite group as the signal source. Therefore, it has many advantages such as low cost, low power consumption, and high temporal and spatial resolution.

[0008] At present, GNSS-R is mainly used in the ocean field to monitor effective wave height, sea wind, sea waves, sea ice and sea surface overflow; its application in land involves monitoring of soil moisture, vegetation, snow accumulation, surface freeze-thaw process, sea level change, etc. No research has yet been carried out on GNSS-R monitoring of forest fires. Summary of the invention

[0009] The present invention aims to provide a fire monitoring system and a monitoring method based on GNSS-R, so as to realize forest fire monitoring with low cost, low power consumption, high spatiotemporal resolution and high coverage.

[0010] In order to achieve the above-mentioned purpose, the present invention provides a fire monitoring system based on GNSS-R, comprising a GNSS satellite and a temperature sensing device, a GNSS-R receiver, a data storage system, a data identification system and an alarm system connected in sequence; the GNSS satellite is configured to transmit a direct signal; the temperature sensing device is configured to receive a first reflection signal of the direct signal passing through each forest area to be tested, and obtain the peak value and signal-to-noise ratio data of the delayed Doppler waveform of each forest area to be tested according to the first reflection signal; the GNSS-R receiver is configured to receive the peak value and signal-to-noise ratio data of the delayed Doppler waveform, and receive the peak value and signal-to-noise ratio data from the direct signal. signal and the second reflected signal of the direct signal through the forest area to be tested; the data storage system is configured to receive and record the peak value, signal-to-noise ratio data, the direct signal and the second reflected signal of the delayed Doppler waveform, and extract the position information and time information of the forest area to be tested from the direct signal; the data discrimination system is configured to receive the peak value, signal-to-noise ratio data, the position information and the time information of the delayed Doppler waveform, and judge whether each forest area to be tested is a fire area according to the peak value and signal-to-noise ratio data of the delayed Doppler waveform; the alarm system is configured to sound the alarm of the forest area to be tested that is judged to be a fire area according to the judgment result of the data discrimination system.

[0011] A denoising system is provided between the GNSS-R receiver and the data storage system, and the denoising system is configured to receive the peak value and signal-to-noise ratio data of the delayed Doppler waveform, the direct signal and the second reflected signal, and perform denoising processing on the direct signal and the second reflected signal.

[0012] The number of the GNSS satellites is plural, and the GNSS satellites are satellites of the GPS, GLONASS, GALileo or Beidou navigation systems.

[0013] The GNSS-R receiver includes a circularly polarized antenna and a linearly polarized antenna. The circularly polarized antenna includes a left-hand circularly polarized antenna and a right-hand circularly polarized antenna. The GNSS-R receiver uses the right-hand circularly polarized antenna to receive the direct signal, and uses the circularly polarized antenna or the linearly polarized antenna to receive the second reflected signal.

[0014] In another aspect, the present invention provides a fire monitoring method based on GNSS-R, comprising:

[0015] S1: Use multiple GNSS satellites to transmit direct signals;

[0016] S2: using a temperature sensing device to receive the first reflected signal of the direct signal passing through each forest area to be tested, and obtaining the peak value and signal-to-noise ratio data of the delayed Doppler waveform of each forest area to be tested according to the first reflected signal;

[0017] S3: using a GNSS-R receiver to receive the peak value and signal-to-noise ratio data of the delayed Doppler waveform, and receiving the direct signal and the second reflected signal of the direct signal passing through the forest area to be measured;

[0018] S4: using a data storage system to receive and record the peak value of the delayed Doppler waveform, the signal-to-noise ratio data, the direct signal and the second reflected signal, and extracting the location information and time information of the forest area to be measured from the direct signal;

[0019] S5: using a data identification system to receive the peak value, signal-to-noise ratio data, location information and time information of the delayed Doppler waveform, and judging whether each forest area to be tested is a fire occurrence area according to the peak value and signal-to-noise ratio data of the delayed Doppler waveform;

[0020] S6: Based on the judgment result of the data discrimination system, an alarm system is used to sound an alarm in the forest area to be tested that is judged to be a fire occurrence area.

[0021] The step S3 also includes: using a denoising system to perform denoising on the direct signal and the second reflected signal.

[0022] In the step S1, the GNSS satellite is a satellite of the GPS, GLONASS, GALileo or Beidou navigation system; and in the step S4, the location information is longitude and latitude information.

[0023] The step S4 also includes: using the data storage system to extract the forest height, forest density, forest dielectric constant, forest biomass, and forest water content of the forest area to be measured from the second reflection signal.

[0024] In step S5, when the peak value of the delayed Doppler waveform is higher than a peak value threshold of the delayed Doppler waveform and the SNR data is higher than an SNR data, the corresponding forest area to be tested is determined to be a fire occurrence area.

[0025] The peak threshold of the delayed Doppler waveform is set between 1-1.5, and the threshold of the SNR data is set between 24-30.

[0026] The fire monitoring system based on GNSS-R of the present invention uses the direct signal and reflected signal of GNSS to monitor forest fires. It does not need to develop a special transmitter, and adopts a temperature sensing device that is extremely sensitive to forest temperature, so that forest fires can be judged in real time. Since it directly uses the direct signal of the existing navigation satellite group (GNSS) as the signal source, the cost is low. Since the signal source of GNSS-R, that is, the GNSS satellite group, continuously transmits signals, a GNSS-R receiver can receive data from multiple navigation satellites within its field of view, so the time resolution of GNSS-R is relatively high. For GPS-R (Global Positioning Satellite) used in geophysics and surveying and mapping, GNSS-R remote sensing has a high spatial resolution, which can greatly improve the level of forest fire monitoring, thus preventing fires before they happen and detecting small fires. In addition, since GNSS-R receivers can use direct signals for positioning and have self-positioning and self-timing capabilities, they are conducive to data processing, positioning, sensor sleep and scheduling, easy to enter geographic information systems, and easy to establish a large-scale soil moisture and vegetation observation network. In addition, since the incident zenith angle of GNSS satellites is between 0 and 90 degrees, and the incident azimuth angle is between 0 and 360 degrees, multi-angle observation of GNSS-R can be achieved. Unlike the linear polarization of radar and microwave radiometers, the direct signals emitted by GNSS satellite constellations are RHCP (Right Hand Polarization). The signal polarity changes after being reflected by the ground, which makes multi-polarization (LR, RR, HR, VR) reception possible and solves the problem that the polarization direction of the linear polarization signal cannot match the linear polarization direction of the signal source at any time due to the movement of the antenna platform, greatly improving the quality of the antenna receiving signal. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 Schematic diagram of the structure of a fire monitoring system based on GNSS-R according to an embodiment of the present invention.

[0028] Reference numerals

[0029] 1. GNSS satellite; 2. Forest monitoring area; 3. Temperature sensing device; 4. GNSS-R receiver; 5. De-noising system; 6. Data storage system; 7. Data identification system; 8. Alarm system. DETAILED DESCRIPTION

[0030] The present invention is further described below in conjunction with specific examples. It should be understood that the following examples are only used to illustrate the present invention and are not used to limit the scope of the present invention.

[0031] like Figure 1 The figure shows a GNSS-R-based fire monitoring system according to an embodiment of the present invention, which is used for forest fire monitoring and includes: a GNSS satellite 1, and a temperature sensing device 3, a GNSS-R receiver 4, a denoising system 5, a data storage system 6, a data identification system 7 and an alarm system 8 connected in sequence.

[0032] GNSS satellite 1 is configured to transmit direct signals. There are multiple GNSS satellites 1, which may be satellites of navigation systems such as GPS, GLONASS, GALileo, Beidou, etc. The incident zenith angle of the GNSS satellite 1 is between 0 and 90°, and the incident azimuth angle is between 0 and 360°, thereby enabling multi-angle observation of GNSS-R. The direct signal of GNSS satellite 1 contains positioning and time information.

[0033] The temperature sensing device 3 mainly includes a thermistor, so it is more sensitive to temperature. It is configured to receive the first reflected signal of the direct signal through each forest area 2 to be tested, and obtain the peak value and signal-to-noise ratio (SNR) data of the delayed Doppler waveform of each forest area 2 to be tested according to the first reflected signal, so as to transmit it to the GNSS-R receiver 4. The peak value and signal-to-noise ratio (SNR) data of the delayed Doppler waveform reflect the surface temperature of the forest canopy of the forest area 2 to be tested. The higher the temperature, the higher the peak value of the delayed Doppler waveform and the higher the SNR data.

[0034] The GNSS-R receiver 4 is installed at the same position as the temperature sensing device 3, and is configured to receive the peak value and SNR data of the delayed Doppler waveform obtained by the temperature sensing device 3, and receive the direct signal from the GNSS satellite 1 and the second reflected signal of the direct signal transmitted by the GNSS satellite 1 through each forest area 2 to be measured. The GNSS-R receiver 4 includes a circularly polarized (LHCP, RHCP) antenna and a linearly polarized (V polarization, H polarization) antenna, and the circularly polarized antenna includes a left-hand circularly polarized (LHCP) antenna and a right-hand circularly polarized (RHCP) antenna, and the GNSS-R receiver 4 uses an RHCP (right-hand circularly polarized) antenna to receive the direct signal from the GNSS satellite 1, and at the same time uses the circularly polarized (LHCP, RHCP) or linearly polarized (V polarization, H polarization) antenna to receive the second reflected signal of the direct signal through the forest area 2 to be measured (i.e., receiving the surface reflected signal from the forest-covered area). Compared with the temperature sensing device 3, the GNSS-R receiver 4 is less sensitive to temperature, but can record information such as the amount, biomass, and density of the forest. The second reflected signal specifically includes the reflected energy of the first Fresnel zone near the mirror point and the diffuse scattered energy of the scintillation zone, and thus includes information such as the forest height, forest density, forest dielectric constant, forest biomass, and forest water content of the forest area 2 to be measured.

[0035] The denoising system 5 receives the peak value and SNR data of the delayed Doppler waveform, the direct signal and the second reflected signal, and performs denoising processing on the direct signal and the second reflected signal.

[0036] The data storage system 6 receives and records the peak value, SNR data, and the denoised direct signal and the second reflected signal of the delayed Doppler waveform, and extracts the location information and time information of the forest area 2 to be measured from the direct signal. In addition, the data storage system 6 can also extract information such as the forest height, forest density, forest dielectric constant, forest biomass, and forest water content of the forest area 2 to be measured from the second reflected signal. The location information is preferably longitude and latitude information.

[0037] The data identification system 7 receives the peak value of the delayed Doppler waveform, the SNR data, and the location information and time information of the forest area 2 to be tested in the data storage system 6, and determines whether each forest area 2 to be tested is a fire occurrence area according to the peak value of the delayed Doppler waveform and the SNR data. When the peak value of the delayed Doppler waveform is higher than a peak value threshold of the delayed Doppler waveform, and the SNR data is higher than a threshold of the SNR data, the corresponding forest area 2 to be tested is determined to be a fire occurrence area. The peak value threshold of the delayed Doppler waveform is set between 1-1.5, and the threshold of the SNR data is set between 24-30.

[0038] The alarm system 8 generates an alarm according to the judgment result of the data discrimination system 7, that is, the alarm of the forest area to be detected 2 determined as the fire occurrence area is sounded. The alarm includes the location information and time information of the forest area to be detected 2 determined as the fire occurrence area.

[0039] Based on the GNSS-R based fire monitoring system described above, the implemented GNSS-R based fire monitoring method specifically includes the following steps:

[0040] Step S1: using multiple GNSS satellites 1 to transmit direct signals;

[0041] Step S2: using a temperature sensing device 3 to receive the first reflected signal of the direct signal passing through each forest area 2 to be tested, and obtaining the peak value and signal-to-noise ratio data of the delayed Doppler waveform of each forest area 2 to be tested according to the first reflected signal;

[0042] Step S3: using a GNSS-R receiver 4 to receive the peak value and signal-to-noise ratio data of the delayed Doppler waveform, and receiving the direct signal and the second reflected signal of the direct signal passing through the forest area 2 to be measured;

[0043] In addition, the step S3 further includes: using a denoising system 5 to perform denoising on the direct signal and the second reflected signal.

[0044] Step S4: using a data storage system 6 to receive and record the peak value of the delayed Doppler waveform, the signal-to-noise ratio data, the direct signal and the second reflected signal, and extracting the position information and time information of the forest area 2 to be measured from the direct signal;

[0045] In addition, the step S4 also includes: using the data storage system 6 to extract information such as forest height, forest density, forest dielectric constant, forest biomass, forest water content, etc. of the forest area 2 to be measured from the second reflection signal.

[0046] In the step S4, the location information is preferably longitude and latitude information.

[0047] Step S5: using a data identification system 7 to receive the peak value, signal-to-noise ratio data, location information and time information of the delayed Doppler waveform, and judging whether each forest area 2 to be tested is a fire occurrence area according to the peak value and signal-to-noise ratio data of the delayed Doppler waveform;

[0048] When the peak value of the delayed Doppler waveform is higher than a peak value threshold of the delayed Doppler waveform, and the SNR data is higher than a threshold of the SNR data, the corresponding forest area 2 to be tested is determined to be a fire occurrence area. The peak value threshold of the delayed Doppler waveform is set between 1-1.5, and the threshold of the SNR data is set between 24-30.

[0049] Step S6: According to the judgment result of the data judgment system 7, an alarm system 8 is used to sound an alarm of the forest area 2 to be detected that is judged as the fire area. The alarm includes the location information and time information of the forest area 2 to be detected that is judged as the fire area.

[0050] The above is only a preferred embodiment of the present invention, and is not intended to limit the scope of the present invention. The above embodiment of the present invention can also be modified in various ways. That is, all simple, equivalent changes and modifications made according to the claims and the description of the present invention fall within the scope of protection of the claims of the present invention. The contents not described in detail in the present invention are all conventional technical contents.

Claims

1. A fire monitoring system based on GNSS-R, characterized in that: It comprises a GNSS satellite (1) and a temperature sensing device (3), a GNSS-R receiver (4), a data storage system (6), a data identification system (7) and an alarm system (8) which are connected in sequence; The GNSS satellite (1) is configured to transmit a direct signal; The temperature sensing device (3) is configured to receive a first reflected signal of the direct signal passing through each forest area (2) to be tested, and to obtain the peak value and signal-to-noise ratio data of the delayed Doppler waveform of each forest area (2) to be tested based on the first reflected signal; The GNSS-R receiver (4) is configured to receive the peak value and signal-to-noise ratio data of the delayed Doppler waveform, and receive the direct signal and the second reflected signal of the direct signal passing through the forest area (2) to be measured; The data storage system (6) is configured to receive and record the peak value of the delayed Doppler waveform, the signal-to-noise ratio data, the direct signal and the second reflected signal, and extract the position information and time information of the forest area (2) to be measured from the direct signal; The data identification system (7) is configured to receive the peak value, signal-to-noise ratio data, location information and time information of the delayed Doppler waveform, and to determine whether each forest area (2) to be tested is a fire occurrence area based on the peak value and signal-to-noise ratio data of the delayed Doppler waveform; The alarm system (8) is configured to sound an alarm in the forest area (2) to be tested that is judged to be a fire occurrence area based on the judgment result of the data judgment system (7).

2. The GNSS-R based fire monitoring system according to claim 1, characterized in that: A denoising system (5) is provided between the GNSS-R receiver (4) and the data storage system (6), and the denoising system (5) is configured to receive the peak value and signal-to-noise ratio data of the delayed Doppler waveform, the direct signal and the second reflected signal, and perform denoising processing on the direct signal and the second reflected signal.

3. The GNSS-R based fire monitoring system according to claim 1, characterized in that: The number of the GNSS satellites (1) is plural, and the GNSS satellites (1) are satellites of the GPS, GLONASS, GALileo or Beidou navigation systems.

4. The GNSS-R based fire monitoring system according to claim 1, characterized in that: The GNSS-R receiver (4) comprises a circularly polarized antenna and a linearly polarized antenna, wherein the circularly polarized antenna comprises a left-hand circularly polarized antenna and a right-hand circularly polarized antenna. The GNSS-R receiver (4) uses the right-hand circularly polarized antenna to receive the direct signal, and simultaneously uses the circularly polarized antenna or the linearly polarized antenna to receive the second reflected signal.

5. A fire monitoring method based on GNSS-R, characterized in that: include: Step S1: using multiple GNSS satellites (1) to transmit direct signals; Step S2: using a temperature sensing device (3) to receive the first reflected signal of the direct signal passing through each forest area (2) to be tested, and obtaining the peak value and signal-to-noise ratio data of the delayed Doppler waveform of each forest area (2) to be tested according to the first reflected signal; Step S3: using a GNSS-R receiver (4) to receive the peak value and signal-to-noise ratio data of the delayed Doppler waveform, and to receive the direct signal and the second reflected signal of the direct signal passing through the forest area to be measured (2); Step S4: using a data storage system (6) to receive and record the peak value of the delayed Doppler waveform, the signal-to-noise ratio data, the direct signal and the second reflected signal, and extracting the position information and time information of the forest area to be measured (2) from the direct signal; Step S5: using a data identification system (7) to receive the peak value, signal-to-noise ratio data, location information and time information of the delayed Doppler waveform, and judging whether each forest area to be tested (2) is a fire occurrence area according to the peak value and signal-to-noise ratio data of the delayed Doppler waveform; Step S6: Based on the judgment result of the data judgment system (7), an alarm system (8) is used to sound an alarm in the forest area to be tested (2) judged as a fire occurrence area.

6. The fire monitoring method based on GNSS-R according to claim 5, characterized in that: The step S3 also includes: using a denoising system (5) to perform denoising processing on the direct signal and the second reflected signal.

7. The fire monitoring method based on GNSS-R according to claim 5, characterized in that: In the step S1, the GNSS satellite (1) is a satellite of the GPS, GLONASS, GALileo or Beidou navigation system; and in the step S4, the position information is longitude and latitude information.

8. The fire monitoring method based on GNSS-R according to claim 5, characterized in that: The step S4 also includes: using the data storage system (6) to extract the forest height, forest density, forest dielectric constant, forest biomass, and forest water content of the forest area (2) to be measured from the second reflection signal.

9. The fire monitoring method based on GNSS-R according to claim 5, characterized in that: In step S5, when the peak value of the delayed Doppler waveform is higher than a peak value threshold of the delayed Doppler waveform and the SNR data is higher than an SNR data, the corresponding forest area (2) to be tested is determined to be a fire occurrence area.

10. The fire monitoring method based on GNSS-R according to claim 9, characterized in that: The peak threshold of the delayed Doppler waveform is set between 1-1.5, and the threshold of the SNR data is set between 24-30.

Images