JP7288632B2 - Growth value calculation method and growth value calculation system - Google Patents

Description

The present invention relates to a growth value calculation method and a growth value calculation system.

In Patent Document 1 below, using sensor devices provided on both left and right sides with respect to the traveling direction of the tractor, normalized difference vegetation index (NDVI), which is information on the growth state of crops, and plant height values is disclosed. However, although the technology disclosed in Patent Document 1 can be used to detect the normalized differential vegetation index and plant height value around the tractor, crops grow in places in the field where the tractor cannot enter. cannot be used if

Therefore, a technique has been proposed for observing the degree of growth of crops in a field by calculating the NDVI value or the like based on image data captured by a camera provided on a drone (see Patent Document 2 below).

JP 2016-208859 A JP 2018-46787 A

The technology disclosed in Patent Document 2 uses a drone to take an aerial image of crops in a field, so image data can be obtained even in a narrow place where a tractor cannot enter.
Here, as a method of observing the degree of growth of crops using a drone, unlike the technology disclosed in Patent Document 2, a method using a distance sensor provided in the drone can be considered. The distance from the drone to the crops is affected by the slope and unevenness of the field. That is, even if the plant height of the crops is the same, the distance from the crops growing on the high ground to the drone is shorter than the distance from the crops growing on the low ground to the drone.

The technology disclosed in Patent Literature 2 does not take into consideration the slopes and unevenness of the field. Therefore, when observing the degree of growth of crops based on the height of the crops measured by the distance sensor, the technique disclosed in Patent Document 2 cannot be applied.
SUMMARY OF THE INVENTION Accordingly, one object of the present invention is to provide a growth value calculation method and a growth value calculation system capable of improving the accuracy of calculation of a growth value in a configuration in which the growth value of a crop is calculated based on the distance from the flight device to the crop. to provide.

According to one embodiment of the present invention, a flight device is horizontally flown at a constant altitude at a first timing before crops start growing in a field, and a distance measuring unit provided in the flight device is used to measure the distance in the field. a first distance measuring step of measuring a first distance between the flying device and the ground below the flying device at each position of , and the first distance measuring step from the altitude of the flying device at the first timing a field undulation information calculation step of calculating field undulation information at each position in the field by subtracting the first distance measured in the above; a second distance measuring step of horizontally flying at a constant altitude and measuring a second distance between the crop below the flying device and the flying device using the distance measuring unit; The crop altitude at each position in the field is calculated by subtracting the second distance measured in the second distance measuring step from the altitude of the flying device, and the value obtained by correcting the crop altitude with the field undulation information is the growth value. and a growth value calculation step of calculating as a growth value calculation method.

According to this method, the crop height calculated by subtracting the second distance between the flying device and the crop measured by the distance measuring unit from the altitude of the flying device is used as the growth value of the crop. A value obtained by correcting the crop height based on the field undulation information is used as the growth value. Specifically, the value obtained by subtracting the field undulation information from the value obtained by subtracting the second distance from the altitude of the flying device is taken as the growth value. Therefore, it is possible to reduce the influence of the slope and irregularities of the field on the growth value. As a result, it is possible to improve the calculation accuracy of the growth value.

In one embodiment of the present invention, the growth value calculation method includes: a position information obtaining step of obtaining position information of the flying device when the flying device is caused to horizontally fly at a constant altitude at the first timing; The method further includes a field undulation map generating step for generating a field undulation map by associating the field undulation information calculated in the undulation information calculating step with the position information obtained in the position information obtaining step.

Therefore, even if the measurement of the second distance in the second distance measurement step is performed at any timing during the growth of the crop, as long as the altitude of the flying device at the second timing is constant, the field undulation map can be grown. It can be used for value calculation.
According to another embodiment of the present invention, a flying device is horizontally flown at a constant altitude at a first timing before the start of growing crops in a field, and at each position in the field, the ground below the flying device and the a first distance measuring unit that measures a first distance to the flying device; and subtracting the first distance measured by the first distance measuring unit from the altitude of the flying device at the first timing, a field undulation information calculation unit for calculating field undulation information at each position in the field; and the second distance measured by the second distance measuring unit from the altitude of the flying device at the second timing. and a growth value calculation unit that calculates the crop height at each position in the field by subtracting , and calculates the value obtained by correcting the crop height with the field undulation information as the growth value.

According to this configuration, the crop height calculated by subtracting the second distance between the flight device and the crop measured by the second distance measuring unit from the altitude of the flight device is used as the growth value of the crop. , the value obtained by correcting the crop height based on the field undulation information is set as the growth value. Specifically, the value obtained by subtracting the field undulation information from the value obtained by subtracting the second distance from the altitude of the flying device is taken as the growth value. Therefore, it is possible to reduce the influence of the slope and irregularities of the field on the growth value. As a result, it is possible to improve the calculation accuracy of the growth value.

In another embodiment of the present invention, the growth value calculation system includes a position information acquiring unit that acquires position information of the flying device when causing the flying device to fly horizontally at a constant altitude at the first timing; It further includes a field undulation map generation section that generates a field undulation map by associating the field undulation information calculated by the field undulation information calculation section and the position information acquired by the position information acquisition section.

Therefore, even if the measurement of the second distance by the second distance measuring unit is performed at any timing during the growth of the crop, as long as the altitude of the flying device at the second timing is constant, the field undulation map can be grown. It can be used for value calculation.

FIG. 1 is a schematic diagram showing the configuration of a growth value calculation system according to one embodiment of the present invention. FIG. 2 is a block diagram showing an electrical configuration of a flight device provided in the growth value calculation system. FIG. 3 is a schematic diagram showing an example of a flight path when the flight device flies. FIG. 4A is a schematic diagram for explaining how a distance measuring sensor provided in the flying device measures a distance between the distance measuring sensor and the ground of an agricultural field. FIG. 4B is a schematic diagram for explaining how the distance measuring sensor measures the distance between the distance measuring sensor and the ground of the field. FIG. 5 is a block diagram showing an electrical configuration of a growth value calculation server provided in the growth value calculation system. FIG. 6 is a schematic diagram showing an example of a field undulation map generated by the growth value calculation server. FIG. 7 is a schematic diagram showing an example of a growth value map generated by the growth value calculation server. FIG. 8 is a schematic diagram for explaining a method of measuring the distance between the distance measuring sensor and the crop at a plurality of timings to calculate the growth value.

Embodiments of the present invention will be described in detail below with reference to the accompanying drawings.
FIG. 1 is a schematic diagram showing the configuration of a growth value calculation system 1 according to one embodiment of the present invention. With reference to FIG. 1, a growth value calculation system 1 calculates the spine of a crop C, which serves as an indicator of the degree of growth of the crop C at each position in the field F, in order to grasp the growth status of the crop C in the field F. This is a system that calculates the height (plant height value) as a growth value.

The growth value calculation system 1 includes a flying device 3 that acquires information necessary for calculating the growth value while flying horizontally over the field F at a constant altitude, and calculates the growth value based on the information acquired by the flight device 3. and a growth value calculation server 4 that
The flying device 3 can wirelessly communicate with the growth value calculation server 4 via the communication network 6 . The growth value calculation server 4 is arranged in the center 5 of the operator who operates the growth value calculation server 4 . The growth value calculation server 4 is operated by an operator in the center 5 .

The flight device 3 is a remotely controllable unmanned aerial vehicle such as a drone. The flight device 3 includes an aircraft body 20, a plurality of propellers 21 attached to the aircraft body 20, a drive unit 22 such as an electric motor for driving the plurality of propellers 21, and an object ( a distance measuring sensor 23 as a distance measuring unit for measuring the distance between the crops C and the ground) and the flight device 3 .
FIG. 2 is a block diagram showing the electrical configuration of the growth value calculation system 1. As shown in FIG.

Referring to FIG. 2 , flight device 3 includes a flight device control section 40 that controls each part of flight device 3 . The flight device control unit 40 includes a microcomputer having a CPU and memory (ROM, RAM, etc.) 41 . Driving unit 22 , positioning data calculating unit 24 , atmospheric pressure sensor 25 , ranging sensor 23 , and communication unit 26 are connected to flight device control unit 40 .
The positioning data calculator 24 is electrically connected to a satellite signal reception antenna 27 attached to the aircraft body 20 . The satellite signal receiving antenna 27 receives signals from positioning satellites that constitute the satellite positioning system. The satellite positioning system is, for example, GNSS (Global Navigation Satellite System).

A positioning signal received by the satellite signal receiving antenna 27 is input to the positioning data calculator 24 . The positioning data calculator 24 calculates positioning data of the flying device 3 at predetermined time intervals (for example, 1-second intervals) based on the positioning signal. The positioning data includes positional information (for example, latitude/longitude information) of the flight device 3 (strictly speaking, the satellite signal receiving antenna 27) and time information corresponding to the positional information. The flight device control section 40 acquires the positioning data calculated by the positioning data calculation section 24 .

The atmospheric pressure sensor 25 is built in the aircraft body 20 . The atmospheric pressure sensor 25 detects the atmospheric pressure around the aircraft body 20 and calculates the altitude H (see FIG. 1) of the flight device 3 based on the detected atmospheric pressure. The altitude H calculated by the atmospheric pressure sensor 25 is, for example, the distance from a predetermined reference position S (see FIG. 1) such as sea level to the atmospheric pressure sensor 25 . Although details will be described later, the atmospheric pressure sensor 25 may use the altitude H as a distance obtained by correcting the distance from the reference position S to the atmospheric pressure sensor 25 to the distance from the reference position S to a reference portion provided in the flight device 3 . The flight device control unit 40 acquires the altitude H calculated by the air pressure sensor 25 and the internal time of the air pressure sensor 25 (air pressure sensor time).

The ranging sensor 23 is attached to the outer surface of the aircraft body 20 (see also FIG. 1). The ranging sensor 23 is, for example, an ultrasonic ranging sensor or a laser ranging sensor. The distance measuring sensor 23 measures, for example, the time it takes for a transmitted wave transmitted toward an object to return after being reflected by the object, and calculates the distance from the distance measuring sensor 23 to the object based on the measured time. is calculated by the TOF method (Time of Flight method).

Although details will be described later, the distance measuring sensor 23 may calculate a distance obtained by correcting the distance from the distance measuring sensor 23 to the object to the distance from the object to a reference part provided in the flight device 3 . The flight device control unit 40 acquires the measured distance calculated by the ranging sensor 23 and the internal time of the ranging sensor 23 (ranging sensor time).
The communication unit 26 is a communication interface for the flight device control unit 40 to communicate with the growth value calculation server 4 .

3 to 4B, how the flight device 3 acquires the information necessary for calculating the growth value will be described.
The flying device 3 flies over the field F at a predetermined first timing before planting crops in the field F. FIG. 3 is a schematic diagram showing an example of a flight path R when the flight device 3 flies. The flight path R extends, for example, meandering from one end to the other end of the field F in a predetermined direction so that the flying device 3 can fly over the entire field F evenly. The flight device 3 flies horizontally along a preset flight path R while maintaining the aircraft body 20 at a constant altitude.

FIG. 4A is a schematic diagram for explaining how the ranging sensor 23 measures the distance (first distance L1) between the flying device 3 and the ground of the field F. FIG. While the flight device 3 flies along the flight route R at the first timing, as shown in FIG. 1 distance measurement step). The ranging sensor 23 is an example of a first distance measuring section.

The flight device control unit 40 acquires positioning data (position information and time information) at predetermined time intervals (for example, 1-second intervals) while the flight device 3 flies along the flight route R at the first timing ( first location information acquisition step). The flight device control unit 40 is an example of a position information acquisition unit. A location in the field F where the distance measurement sensor 23 measures is called a measurement point P. As shown in FIG. The measurement points P are set at equal intervals in the field F in plan view (see also FIG. 3).

While flying along the flight route R, the flight device 3 controls the drive unit 22 so that the altitude H1 acquired by the atmospheric pressure sensor 25 is constant. The height H1 is constant regardless of the height of the ground of the field F. Therefore, the first distance L1 becomes smaller as the ground level is higher in the field F, and becomes larger as the ground level is lower in the field F (see the flying device 3 indicated by the two-dot chain line in FIG. 4A). The flight device 3 indicated by the chain double-dashed line on the left side of FIG. 4A shows an example in which the measured first distance L1 is equal to the altitude H1.

After the flight at the first timing, the flight device control unit 40 receives the positioning data obtained from the positioning data calculation unit 24 via the communication unit 26 and The acquired altitude H1 and barometric pressure sensor time, and the first distance L1 and range sensor time acquired from the ranging sensor 23 are transmitted to the growth value calculation server 4 .

After that, the flying device 3 flies over the farm field F at a second timing after crops start growing in the farm field F. The flight device 3 flies horizontally along a preset flight route R while maintaining the aircraft body 20 at a constant altitude H.
FIG. 4B is a schematic diagram for explaining how the ranging sensor 23 measures the distance (second distance L2) between the flying device 3 and the crop C. As shown in FIG. Referring to FIG. 4B, while flight device 3 flies along flight route R at the second timing, ranging sensor 23 is at the same position (measurement point) as when ranging sensor 23 measured first distance L1. In order to measure the second distance L2 in P), the second distance L2 is measured at predetermined intervals (for example, 10 cm) (second distance measuring step). The ranging sensor 23 is an example of a second distance measuring section.

The flight device control unit 40 acquires positioning data at predetermined time intervals (for example, 1-second intervals) while the flight device 3 flies along the flight route R (second position information acquisition step).
The flight device 3 controls the drive unit 22 so that the altitude H2 acquired by the atmospheric pressure sensor 25 is constant during flight at the second timing. The altitude H2 is constant regardless of the height of the ground of the field F. Therefore, assuming that the growth rate of the crop C is constant, the second distance L2 becomes smaller as the ground level is higher in the field F, and becomes larger as the ground level is lower in the field F (see FIG. 4B See the flight device 3 indicated by a two-dot chain line). The altitude H2 does not need to be the same altitude as the altitude H1 of the flight device 3 at the first timing.

After the flight at the second timing, at the timing when the power of the flight device 3 is turned off, the flight device control unit 40 receives the positioning data obtained from the positioning data calculation unit 24 via the communication unit 26, The acquired altitude H2 and barometric pressure sensor time, and the second distance L2 and range sensor time acquired from the ranging sensor 23 are transmitted to the growth value calculation server 4 .

FIG. 5 is a block diagram showing the electrical configuration of the growth value calculation server 4. As shown in FIG.
The growth value calculation server 4 includes a server control unit 50 that controls the growth value calculation server 4 . The server control unit 50 includes a microcomputer having a CPU and memory (ROM, RAM, etc.) 51 . A communication unit 52 , an operation display unit 53 , an operation unit 54 and a storage unit 55 are electrically connected to the server control unit 50 .

The communication unit 52 is a communication interface for the server control unit 50 to wirelessly communicate with the flight device 3 . Operation display unit 53 is, for example, a touch panel display. Operation unit 54 includes, for example, a keyboard, a mouse, and the like. The storage unit 55 is composed of a storage device such as a hard disk or nonvolatile memory.
The server control unit 50 creates a field undulation map by associating the calculated field undulation information Ae with the position information included in the positioning data and the field undulation information calculation part 60 that calculates the field undulation information Ae at each position in the field F. A field undulation map generator 61 that generates M1, a growth value calculator 62 that calculates the growth value Ce at each position in the field F, and a growth value map based on the calculated growth value Ce and the field undulation map M1. and a growth value map generator 63 that generates M2.

The field undulation information Ae at each position is obtained from the altitude H1 of the flying device 3 when the flying device 3 flies horizontally at the first timing, and the distance measured at each measurement point P when the flying device 3 flies horizontally at the first timing. It is calculated by subtracting the first distance L1 obtained by the sensor 23 (Ae=H1-L1). Thus, the field undulation information calculation process is executed by the field undulation information calculation unit 60 .

In addition, as described above, in the flying device 3 indicated by the two-dot chain line shown on the left side of the paper surface of FIG. 4A, the measured first distance L1 is equal to the altitude H1. In this case, the field undulation information Ae is "0" (Ae=0).
Here, the altitude H1 is the altitude calculated by the atmospheric pressure sensor 25, and the first distance L1 is the distance calculated by the ranging sensor . That is, when the values calculated by the respective sensors 23 and 25 are used as the altitude H1 and the first distance L1, the relative heights of the ranging sensor 23 and the atmospheric pressure sensor 25 affect the altitude. Specifically, the relative heights of the distance measurement sensor 23 and the atmospheric pressure sensor 25 are added to the calculated field undulation information Ae. Therefore, it is necessary to correct at least one of the altitude H1 and the first distance L1.

For example, the distance measurement sensor 23 sets the value obtained by adding the distance between the distance measurement sensor 23 and the atmospheric pressure sensor 25 to the distance between the distance measurement sensor 23 and the ground of the field F as the first distance L1. , the first distance L1 may be corrected. In this case, the first distance L1 is the distance between the atmospheric pressure sensor 25 and the ground of the field F.
Conversely, although not shown, the atmospheric pressure sensor 25 uses the value obtained by subtracting the distance between the ranging sensor 23 and the atmospheric pressure sensor 25 from the distance between the atmospheric pressure sensor 25 and the reference position S as the altitude H1. , altitude H1 may be corrected. In this case, the altitude H1 is the distance between the ranging sensor 23 and the reference position S.

Further, the distance measuring sensor 23 calculates the distance between a predetermined reference portion provided on the flight device 3 and the object, and the atmospheric pressure sensor 25 calculates the distance between the predetermined reference portion provided on the flight device 3 and the reference position S. may be calculated.
FIG. 6 is an example of a field undulation map M1 generated by the field undulation map generator 61. As shown in FIG. In the field undulation map M1, the field F is divided into a plurality of meshes m each containing a plurality of measurement points P, and each mesh m is provided with field undulation information Ae. In other words, the same number of meshes m as the number of measurement points P is assigned to the field F. FIG.

Each mesh m is assigned a number in descending order of the time indicated by the time information included in the positioning data acquired at the measurement point P. FIG. A code "Aei" is attached to the field undulation information in the i-th mesh m. When N meshes m are assigned to the field F, i is a natural number equal to or less than N (1≤i≤N). In this manner, the field undulation map generation process is executed by the field undulation map generation unit 61 .

The growth value calculation unit 62 calculates the height H2 of the flight device 3 when the flight device 3 flies horizontally at the second timing, and calculates the height H2 of the flight device 3 at each measurement point P when the flight device 3 flies horizontally at the second timing. The height of the crop C (crop height Be) at each location in the field F is calculated by subtracting the second distance L2 measured by (Be=H2-L2). A symbol "Bei" is attached to the crop height in the i-th mesh m.

When calculating the crop altitude, at least one of the altitude H2 and the second distance L2 is calculated in the same way as the altitude H1 and the first distance L1 in order to eliminate the influence of the relative heights of the range sensor 23 and the atmospheric pressure sensor 25. need to be corrected.
The growth value calculator 62 calculates a value obtained by correcting the crop height Be with the field undulation information Ae as the growth value Ce. Specifically, the growth value calculation unit 62 sets the value obtained by subtracting the field undulation information Ae from the crop height Be to be the growth value Ce (Ce=Be−Ae). It is an example of a value map M2. In this manner, the growth value calculation step is executed by the growth value calculation unit 62 . A symbol "Cei" is attached to the crop height in the i-th mesh m.

The storage unit 55 includes a flight information storage unit 56 that stores information (positioning data, altitude, first distance, second distance, etc.) transmitted from the flying device 3, and an undulation map that stores the generated field undulation map M1. It includes a storage unit 57 and a growth value map storage unit 58 that stores the generated growth value map M2.
According to this embodiment, the crop height Be calculated by subtracting the second distance L2 from the altitude H2 of the flight device 3 is not used as the crop growth value, but the crop height Be is based on the field undulation information Ae. The value corrected by the above method is taken as the growth value Ce. Specifically, the growth value Ce is obtained by subtracting the field undulation information Ae from the value obtained by subtracting the second distance L2 from the altitude H2 of the flying device 3 . Therefore, it is possible to reduce the influence of the slope and unevenness of the field F on the growth value Ce. As a result, it is possible to improve the calculation accuracy of the growth value Ce.

Further, according to this embodiment, the field undulation map generation unit 61 generates the field undulation map M1 by associating the field undulation information Ae with the positioning data (position information acquired by the flight device control unit 40). Therefore, even if the measurement of the second distance L2 is performed at any timing during the growth of the crop C, as long as the altitude H2 of the flying device 3 when flying at the second timing is constant, the field undulation map M1 can be used to calculate the growth value Ce.

The present invention is not limited to the embodiments described above, but can be embodied in other forms.
For example, the growth value Ce may be calculated multiple times by measuring the distance between the flying device 3 and the crop at a plurality of timings after the crop starts growing in the field F. It is also possible to calculate the growth amount De for a predetermined period by measuring the growth value Ce a plurality of times.

Specifically, referring to FIG. 8, at a third timing after the second timing, the flying device 3 is horizontally flown at a predetermined altitude H3, and the distance measuring sensor 23 at the measuring point P and the crop C (third distance L3). Then, the growth value calculator 62 subtracts the third distance L3 from the altitude H3 of the flying device 3 when the flying device 3 flies horizontally at the third timing, thereby calculating the height of the crop C at each position in the field F. Calculate the altitude Be. Then, the growth value calculator 62 corrects the calculated crop height Be with the field undulation information Ae to calculate the growth value Ce at the third timing.

By subtracting the growth value Ce at the second timing from the growth value Ce at the third timing, the growth amount De of the crop C between the second timing and the third timing can be calculated.
Further, when the altitude H2 of the flying device 3 at the second timing is equal to the altitude H3 of the flying device 3 at the third timing, the third distance L3 is subtracted from the second distance L2 without calculating the growth value Ce. can also calculate the amount of growth De.

In the above-described embodiment, the field undulation information Ae and the growth value Ce are numerically displayed on each mesh m in the field undulation map M1 and the growth value map M2, respectively. However, in the field undulation map M1, for example, the higher the ground altitude, the darker the color of the mesh m may be, or the mesh m may be color-coded according to the ground altitude. Similarly, in the growth value map M2, the larger the growth value Ce, the darker the color of the mesh m may be, or the meshes m may be color-coded according to the growth value Ce.

In addition, various modifications can be made within the scope of the claims.

1: Growth value calculation system 3: Flying device 60: Field undulation information calculation unit 61: Field undulation map generation unit 62: Growth value calculation unit Ae: Field undulation information Aei: Field undulation information Be: Crop height Bei: Crop height C: Crop Ce: Growth value Cei: Growth value F: Field H: Altitude H1: Altitude H2: Altitude H3: Altitude L1: First distance L2: Second distance M1: Field undulation map P: Measurement point

Claims (6)

At a first timing before crops start growing in a field, the flying device is horizontally flown at a constant altitude, and at each measurement position in the field specified by a measurement unit provided in the flying device, the above a first distance measuring step of measuring a first distance between the flight device and the ground below the flight device using a distance measurement unit provided in the flight device ;
a field undulation information calculation step of calculating field undulation information at each of the measurement positions in the field by subtracting the first distance measured in the first distance measurement step from the altitude of the flying device at the first timing; ,
At a second timing after crops have started growing in the field, the flying device is caused to fly horizontally at a constant altitude, and the distance measuring unit is used to measure the distance at each of the measurement positions specified by the measuring unit. a second distance measuring step of measuring a second distance between the plant under the flight device and the flight device;
subtracting the second distance measured in the second distance measuring step from the altitude of the flying device at the second timing to calculate the crop altitude at each of the measurement positions in the field; corrected by the field undulation information as the growth value at the measurement position . In the growth value calculation step, a value obtained by subtracting the field undulation information from a value obtained by subtracting the second distance measured in the second distance measurement step from the altitude of the flying device flying at the second timing is the growth value. The growth value calculation method according to claim 1, comprising the step of calculating as a position information acquiring step of acquiring position information of the flying device when the flying device is caused to horizontally fly at a constant altitude at the first timing;
A field undulation map generation step of generating a field undulation map by associating the field undulation information calculated in the field undulation information calculation step with the position information acquired in the position information acquisition step. 3. The growth value calculation method according to 1 or 2. At a first timing before crops start growing in a field, the flying device is horizontally flown at a constant altitude, and at each measurement position in the field specified by a measurement unit provided in the flying device, the flight is performed. a first distance measurement unit that measures a first distance between the ground below the flight device and the flight device using a distance measurement unit provided in the device ;
A field undulation information calculation unit for calculating field undulation information at each measurement position in the field by subtracting the first distance measured by the first distance measurement part from the altitude of the flying device at the first timing. and,
At a second timing after crops have started growing in the field, the flying device is caused to fly horizontally at a constant altitude , and the distance measuring unit is used to measure the distance at each of the measurement positions specified by the measuring unit. a second distance measurement unit that measures a second distance between crops under the flight device and the flight device;
subtracting the second distance measured by the second distance measuring unit from the altitude of the flying device at the second timing to calculate the crop altitude at each of the measurement positions in the field; a growth value calculation unit that calculates a value obtained by correcting the altitude with the field undulation information as the growth value at the measurement position . The growth value calculation unit calculates a value obtained by subtracting the field undulation information from a value obtained by subtracting the second distance measured by the second distance measurement unit from the altitude of the flying device flying at the second timing as the growth value. The growth value calculation system according to claim 4, wherein the growth value calculation system calculates as a position information acquiring unit that acquires position information of the flying device when the flying device is caused to horizontally fly at a constant altitude at the first timing;
The farm field undulation map generation unit for generating a field undulation map by associating the farmland undulation information calculated by the farmland undulation information calculation unit and the position information acquired by the position information acquisition unit. 6. The growth value calculation system according to 4 or 5.

Images