• 专利附录
  • 专利说明
  • 权利要求
  • 类似技术
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    • 专利摘要:
    The invention comprises an airborne radiometer-receptor installed in a remote control aeroplane or an unmanned aerial vehicle (UAV), with an autonomy of between 100 and 1000m, said microwave radiometer comprising an aerodynamic low-loss antenna with at least two sub-arrays of elemental adjacent overlapping antennae, with two beams in two directions and with different polarisations, at least one microwave-receiving unit connected to said antenna, and a device for measuring the humidity of the ground and water content of the vegetation on the basis of the brightness temperature, with two angles of incidence, and different polarisations. The invention also relates to a method wherein a table of emissivities for each one of the sub-arrays of antennae of the radiometer-receptor set is used, and measurements are taken by said antenna in the flyover zone.
    公开号:ES2547585A1
    申请号:ES201390102
    申请日:2012-06-28
    公开日:2015-10-07
    发明作者:Adriano Camps Carmona；Rene ACEVO HERRERA；Albert AGUASCAS SOLÉ；Xavier Bosch Lluis；Isaac Ramos Perez；Nereida RODRÍGUEZ ÁLVAREZ；Enric VALENCIA DOMÈNECH；Juan Francisco MARCHÁN HERNÁNDEZ
    申请人:Universitat Politecnica de Catalunya UPC；
    IPC主号:
    专利说明:

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    P201390102
    06-26-2015
    - a measuring device capable of recovering the soil moisture map (units [m3 / m3]), the water content of the vegetation (units [kg / m2]) from the brightness temperature, or measurement of the spontaneous radioelectric emission of the surface under observation at at least two angles of incidence, and different polarizations.
    5 In Fig. 2 one of the EREs is shown, which in turn is part of a group of EREs that are explained below), where the patch on a dielectric substrate can be observed, in order to reduce the dimensions of the patches ( at least 30%) compared to airborne patch type EREs.
    In an exemplary embodiment, the antenna used, as can be seen in Fig. 3
    10 comprises a grouping of six EREs arranged in hexagonal formation plus a central ERE creating a beam at half power (at -3 dB) less than 25 °. As indicated, it is proposed to use two (or more) groups of EREs as explained, partially intertwined, which affects the central ERE of the first group and three of the EREs located at the consecutive vertices of the first hexagon of the first group.
    15 Each of the EREs is a patch type (microstrip patch) manufactured and printed on a dielectric whose dielectric constant is greater than 1, the same substrate having been used preferentially (for example a “Rogers” type substrate). To reduce the dimensions of the ERE it is necessary to increase the thickness D of the substrate where the patch is manufactured. If a substrate with the required thickness is not available, the plate can be joined
    20 with the ERE mass plane, and another plate with the ERE patch. The joining of both plates is done with an adhesive material that does not affect the total dielectric constant. Fig. 4 shows the block diagram of one of the two receivers used, one for each grouping of EREs as indicated in Fig. 5. Alternatively, the two receivers can be replaced by a switch and a single receiver, as indicated in the
    25 Fig. 6. In Fig. 4, 1 is one of the antennas, 2 is the reference load, 3 is the Active Cold Load, 4 is a Dicke and calibration switch, 5 is an insulator , 6 represents a stage of high gain and low noise, 7 represents a pass-band filter centered on the band of interest, 8 represents a power detection stage, 9 represents a switch to select the detected signal depending on the input,
    30 10 represents a synchronous demodulator, 11 represents a clock signal to perform the
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    06-26-2015
    Switching and 12 represents the integration (averaging) and signal conditioning block to obtain the analog output signal.
    Additionally, for calibration purposes, two calibration signals are provided in the receiving unit: a signal from an adapted load (2), fulfilling the function of hot load, and another signal from the door of a transistor, fulfilling the function of cold load (3) what is known in the literature as "Active Cold Load" as explained in the article "An active cold noise source," by RH Frater and DR Williams, published in IEEE Trans. Microw. Theory Tech., Vol. 29 (4), 344-347, 1981.
    The radiometer measurements are stored periodically, with a period to be determined and dependent on the specific application, and can preferably be stored digitally on a physical support, on the airborne platform or sent in real time, by means of a radio link to a central station where they are stored All measures are accompanied by the relevant attitude information, position of the mobile platform, as well as stored together with its temporary identifier. The internal, external calibration periods and integration times are variable and are adjusted for each specific application or activity.
    In Fig. 5, a block diagram of the microwave radiometer is shown, where 1 represents the antenna at 0 ° of pointing, 1a represents the antenna at 25 ° of pointing, 13 and 14 are the receivers associated with each grouping of EREs (as explained above in relation to Fig. 4), and 15 is a unit that performs the process of analog to digital conversion (ADC) and passes the data in digital format, and stores it, for example, by using of a microcontroller programmed to perform the operations on demand of the user. As part of the invention, a protocol for data transmission has been developed, with a set of codes to identify the frames of data sent. This digital data can be stored in a physical support storage unit (U.A.), preferably a solid state hard disk or transmitted in real time via a communications radio link.
    In Fig. 6, an alternative block diagram of the microwave radiometer is shown, where 1 and 1a represent the groupings of EREs. In this figure, 17 represents a switch to select the signal from one of the groupings of EREs, 18 represents a receiver, 19 represents a microcontroller device which executes a
    P201390102
    06-26-2015
    program to interrogate the sensor, through the protocol chosen by the user and save the data in a storage unit (U.A.) for the subsequent processing of the data. Block 20 indicates an optional radio frequency link for the transmission of sensor data.
    5 The results stored as indicated are preferably processed once the platform has finished flying over an area, although it can be done in real time, to project on the ground the shape of the antenna diagram, where the power measured by the radiometer comes from of microwave. The results in the adjoining areas where there has been no coverage during the measurement phase are interpolated to create
    10 TB maps projected on the ground and, finally, least squares algorithms are applied to recover the parameters of soil moisture and vegetation water content.
    Interpolation is performed using the position information of each measurement and the antenna diagram. The recovery of the geophysical parameters is carried out through a process of minimization of the error, comparing the measured results with models
    theoretical, without preference for any one in particular.
    The information is duly geo-referenced to generate maps, preferably in KML format, of the aforementioned parameters, and these maps can be linked directly to a map viewer program such as for example
    20 Google Earth. The flow chart of the data processing is shown in Fig. 7, where 21 represents the measurements made by the sensor, which are calibrated at point 22, to transform this information into antenna temperature, point 23. Subsequently in 24 performs the interpolation of the measurements, taking into account the position of the antenna. This
    25 information is provided by a positioning sensor represented by 25 (eg GPS). With this data the TB is obtained, point 26 with which the maps of TB can be generated, point 27. Starting from point 26, algorithms are applied for the recovery of soil moisture, point 28, and the humidity maps are generated of ground, point 29. The same procedure is performed for the measurements of both antennas (1 and 1a), and finally,
    30 using an algorithm to combine multiangular and double polarization information
    P201390102
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    From both groups of EREs, information on the water content of the vegetation is obtained, point 30, and maps of water content of the vegetation are generated, point 31.
    The immediate procedure to determine the soil moisture and water content of the vegetation from radiometric measurements is to minimize a cost function with iterative methods. However, this approach imposes very high computational costs and presents convergence problems, proving to be impractical.
    Therefore, the invention proposes a method for the determination of soil moisture and vegetation water content from the radiometric measurements obtained using the airborne system explained, which comprises creating a table of emissivities for each of the groupings , and in an exhaustive manner for each of the possible values of soil moisture and water content of the vegetation using semi-empirical models widely known and disclosed in the literature. These pre-calculated tables depend on the radiation pattern of each of the clusters and therefore must be calculated for each one in particular. The resolution (increase or step in the input variables of the table) in the dimensions of soil moisture and water content of the vegetation depend on the radiometric resolution of the system. The higher, the lower changes in TB can be detected, and the smaller the step in the tables should be.
    With each measured emissivity a subtraction is made for all the values in the table, and the absolute value of this subtraction is saved. This is the case for each emissivity measured in each of the groupings, subtracting the corresponding pre-calculated table and obtaining the absolute value. Finally, the subtractions made (one for each grouping) are added and the minimum value is sought. The coordinates of this minimum value provide the soil moisture value and vegetation water content estimated uniquely.
    The implementation of the invention also contemplates a protocol for data transmission, which includes a set of codes to identify the frames of data sent. This digital data can be stored in a physical support unit, preferably a solid state hard disk, or it can be transmitted in real time via a communications radio link.
    P201390102
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    The aforementioned protocol proposes to initiate communication externally with the transmission of one byte (8 bits), which is internally encoded in a system processor to perform an action accordingly. The response of the microcontroller is systematically the following plot:
    • frame identification byte, consisting of increasing a unit the same byte received; Y
    • 2 bytes for each grouping of the existing antenna in the system, these 2 bytes encode the measurement made in an int16 format, which has been sorted externally with the byte in transmission.
    To save transmission time and simplify the protocol to the maximum, there is no frame termination byte, since all frames have the same length, nor is there a control or error detection byte, for this purpose the byte is used frame identification If this is not exactly the transmitted byte incremented by one unit, the entire frame is discarded.
    Among the different measurement possibilities offered by the protocol can be found for example:
    - Antenna temperature measurement in “total power radiometer” or TPR (byte TPR) mode,
    - Measurement of noise temperature of the hot reference (byte CAL),
    - Noise temperature measurement of the cold reference (FRI byte),
    - Physical temperature measurement of the hot reference,
    - Measurement of physical temperature of the cold reference,
    - Measurement of physical temperature of the receiver, and
    - Measurement of physical temperature of the antenna, among others
     By alternating the different types of measurement, different types of radiometers can be achieved, as defined in the article "Microwave Radiometer Resolution Optimization Using Variable Observation Times," by A. Camps and J.M. Tarongí published in the magazine Sensors volume 2, number 7 from page 1826 to 1843. As it is well developed in the article, each type of radiometer has its advantages and disadvantages,
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    权利要求:
    Claims (1)
    [1]
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    同族专利:
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    ES2547585B1|2016-07-14|
    WO2013001129A1|2013-01-03|
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    优先权:
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    ES201131085|2011-06-28|
    ES201131085|2011-06-28|
    PCT/ES2012/070477|WO2013001129A1|2011-06-28|2012-06-28|Airborne system for measuring the humidity of the terrain and the water content of the vegetation, and implementation method|
    ES201390102A|ES2547585B1|2011-06-28|2012-06-28|AIR TRANSPORT SYSTEM FOR THE MEASUREMENT OF THE HUMIDITY OF THE LAND AND THE WATER CONTENT OF THE VEGETATION AND IMPLEMENTATION METHOD|ES201390102A| ES2547585B1|2011-06-28|2012-06-28|AIR TRANSPORT SYSTEM FOR THE MEASUREMENT OF THE HUMIDITY OF THE LAND AND THE WATER CONTENT OF THE VEGETATION AND IMPLEMENTATION METHOD|
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