JP2019109064A - Signal processing system, signal processing method, and signal processing program of active sensor - Google Patents

Abstract

To enhance, in an active sensor, detection capability of an object, in particular a moving object, having low reflectance to a radiation wave and an object whose Doppler effect by change in relative distance is small while it moves.SOLUTION: In signal processing of an active sensor, the active sensor outputs received signal distribution corresponding to one scan in a relative coordinate system. A set of a plurality of pieces of the received signal distribution with the relative coordinate system being converted into an absolute coordinate system is stored in a storage device. One coordinate extracted from each of the plurality of pieces of received signal distribution in the set is considered to be a trajectory and the received signal of the coordinate composing the trajectory is integrated. Presence or absence of an object which has moved along the trajectory is determined on the basis of an integration result.SELECTED DRAWING: Figure 6

Description

  The present invention relates to an active sensor which is a sensor that transmits a radiation wave and receives its reflected wave to detect the presence of an object, and in particular to signal processing of the active sensor.

  Generally, there are active and passive radars. The active type radar emits radio waves from an antenna and receives radio waves reflected by an object such as the air, the ground, or the water, thereby detecting the direction and distance of the object. The passive type radar detects the direction of an object by receiving radio waves emitted by the object such as the air, the ground, and the water with an antenna.

  In general, sonars have an active system and a passive system. An active sonar emits sound waves from a hydrophone and receives sound waves reflected by an object in water to detect the direction and distance of the object. The passive sonar receives the sound wave emitted by an object in water by a hydrophone to detect the orientation of the object.

  Active radars and sonars emit radar waves and sound waves and detect surrounding objects based on the reflected waves. Hereinafter, such types of sensors that emit waves such as electromagnetic waves and sound waves and detect surrounding objects based on the reflected waves are generically called active sensors. Also, the wave emitted by the active sensor is referred to as a radiation wave, and the wave reflected by the radiation wave from surrounding objects is referred to as a reflected wave. In recent years, stealth technology has been developed to avoid detection by active sensors. Stealth technology is a technology to reduce the reflectance that reflects radio waves and sound waves in the direction of the active sensor.

  Aircraft using stealth technology have small RCS (Radar Cross Section), so it is difficult to detect with radar. In recent years, the spread of small unmanned aerial vehicles and drones has progressed. These small flying objects are also difficult to detect with radar because RCS is small.

  On the other hand, in water, it is difficult to detect an object with a small TS (Target Strength) by active sonar. For example, small underwater vehicles (torpedoes etc.), small underwater dangerous substances (mines etc.), divers (divers etc.) have small TSs, so detection by active sonar is difficult.

  As a method of detecting an object which is difficult to detect with such an active sensor, it is conceivable to increase the output level of the radiation wave. When this method is applied to an active sensor, the current capacity of the electric circuit increases, the power consumption increases, and the heat generation amount increases. Therefore, the active sensor to which this method is applied tends to be large. Such an approach is not particularly suitable for active sensors mounted on ships, aircraft, underwater vehicles, vehicles, etc., which have limited payloads.

  As another method for detecting an object difficult to detect by radar or the like, a method of improving an SN ratio by integrating a received signal generated based on a reflected wave can be considered. However, applying such an approach to an active sensor is difficult for the following reasons.

  When the object to be detected is a moving object, the orientation and the distance of the moving object are not constant but temporally change. Therefore, even if the received signal from the reflected wave is integrated as it is, the SN ratio can not be improved.

  In addition, active sensors are often mounted on moving objects such as ships, aircraft, underwater vehicles, vehicles and the like. When active sensors are mounted on these moving objects, the direction and distance of the received signal change as the moving object moves, even when the detection target is stopped. Therefore, as in the case where the detection target moves, the SN ratio can not be improved even if the received signal from the reflected wave is integrated as it is.

  In relation to the present invention, Patent Document 1 discloses that an SN ratio is improved by integrating a sonar received wave signal for each absolute position coordinate of latitude and longitude, and an underwater vehicle is settled on the seabed. It is described.

JP, 2013-11475, A

  Patent Document 1 is a technology that assumes the detection of an underwater vehicle that is seated on the seabed. Therefore, when the detection target is a moving object, the effect of improving the SN ratio can not be obtained.

  The present invention has been made in view of such a situation, and the problem to be solved by the present invention is to improve the detection capability of an object with low reflectance to radiation waves, particularly a moving object, in an active sensor. It is.

  In order to solve the problems described above, the present invention, as one aspect thereof, emits the radiation wave, receives the radiation wave reflected by the object, and receives the reception signal of the active sensor that detects the object by the reception signal. A signal processing system for processing, wherein the active sensor scans at predetermined time intervals, and the signal processing system detects the received signal obtained by one scan of the active sensor. A distribution of relative received signals, which is a distribution, the distribution of the received signal representing the position in relative coordinates determined with reference to the position of the active sensor, and a distribution of the received signal representing the position in absolute coordinates Absolute position coordinate conversion processing means, which is a means for converting into a certain absolute coordinate reception signal distribution; Absolute coordinate received signal distribution which is the absolute coordinate received signal distribution generated, and the absolute coordinate received signal distribution which is generated by the first scan which is a scan performed immediately before the zeroth scan A first absolute coordinate received signal distribution, and a second absolute coordinate received signal distribution that is the absolute coordinate received signal distribution generated by a second scan that is a scan performed immediately before the first scan ,..., Nth absolute coordinate reception signal distribution (N is 2 or more), which is the absolute coordinate reception signal distribution generated by the Nth scan performed immediately before the N−1th scan Storage means which is a means for storing a natural number), a received signal of starting point coordinates which is one coordinate included in the zeroth absolute coordinate received signal distribution, and the first absolute coordinate received signal distribution The first position, which is one of the included coordinates , The received signal of the second coordinate which is one coordinate included in the second absolute coordinate received signal distribution,..., The one coordinate included in the Nth absolute coordinate received signal distribution Integral processing is performed based on the received signal of the Nth coordinate, and based on the result of the integral processing, the presence or absence of an object moved following a locus consisting of the starting point coordinate and the first to Nth coordinates A signal processing system comprising: estimated trajectory integration processing means, which is means for detecting.

  In another aspect, the present invention is a signal processing method for processing a reception signal of an active sensor that emits a radiation wave, receives the radiation wave reflected by an object, and generates a reception signal. The active sensor scans at predetermined time intervals, and is a distribution of the received signal obtained by one scan of the active sensor, based on the position of the active sensor. Converting the relative coordinate received signal distribution, which is the distribution of the received signal representing the position by relative coordinates defined, to an absolute coordinate received signal distribution, which is the distribution of the received signal representing the position by absolute coordinates, An absolute position coordinate conversion processing step, and a zeroth absolute coordinate reception signal as the absolute coordinate reception signal distribution generated by the zeroth scan which is one of the scans A distribution, a first absolute coordinate reception signal distribution which is the absolute coordinate reception signal distribution generated by the first scan which is a scan performed immediately before the 0th scan, and a position immediately before the first scan A second absolute coordinate received signal distribution which is the absolute coordinate received signal distribution generated by a second scan which is a scan performed in the second scan,..., A scan performed immediately before the (N-1) th scan Storing the Nth absolute coordinate received signal distribution (N is a natural number of 2 or more) which is the absolute coordinate received signal distribution generated by a certain Nth scan; The received signal of the starting point coordinate which is one coordinate included in the coordinate received signal distribution, the received signal of the first coordinate which is one coordinate included in the first absolute coordinate received signal distribution, and the second absolute At one coordinate included in the coordinate reception signal distribution Integration processing is performed on the basis of the reception signal of the second coordinate and the reception signal of the Nth coordinate which is one coordinate included in the Nth reception of the absolute coordinate distribution, and the result of the integration processing A signal processing method including an estimated trajectory integration processing step, which is a step of detecting the presence or absence of an object moved by tracing a locus consisting of the starting point coordinates and the first to Nth coordinates based on provide.

  Further, according to another aspect of the present invention, a signal processing program for processing a reception signal of an active sensor that emits a radiation wave, receives the radiation wave reflected by an object, and generates a reception signal. The active sensor performs a scan at predetermined time intervals, and a computer is a distribution of the received signal obtained by one scan of the active sensor, the position of the active sensor To convert the relative coordinate received signal distribution, which is the distribution of the received signal representing the position in relative coordinates defined with reference to the absolute coordinate, into an absolute coordinate received signal distribution, which is the distribution of the received signal representing the position in absolute coordinates Absolute position coordinate conversion processing means, and the absolute coordinate reception signal generated by the zeroth scan which is one of the scans A first absolute coordinate received signal distribution which is the absolute coordinate received signal distribution generated by a first scan which is a scan performed immediately before the zeroth scan A second absolute coordinate reception signal distribution which is the absolute coordinate reception signal distribution generated by a second scan which is a scan performed immediately before the first scan,. Means for storing the Nth absolute coordinate reception signal distribution (N is a natural number of 2 or more) which is the absolute coordinate reception signal distribution generated by the Nth scan which is a scan performed immediately before the scan A storage means, a received signal of a starting point coordinate which is one coordinate included in the zeroth absolute coordinate received signal distribution, and a first signal which is one coordinate included in the first absolute coordinate received signal distribution A coordinate received signal and the second absolute coordinate receiver Integration based on the received signal of the second coordinate which is one coordinate included in the signal distribution, and the received signal of the Nth coordinate which is one coordinate included in the Nth absolute coordinate received signal distribution Estimated trajectory integration, which is a means for performing processing and detecting the presence or absence of an object moved by tracing a locus consisting of the origin coordinates and the first to Nth coordinates based on the result of the integration processing A signal processing program for functioning as processing means is provided.

  According to the present invention, it is possible to improve the detection capability of an object having a low reflectance to radiation waves of an active sensor.

It is a schematic diagram for demonstrating the detection system by an active sensor. It is a graph for demonstrating the effect of the method of improving the SN ratio of a received signal by integrating a received signal used by the passive sensor. It is a schematic diagram for demonstrating the subject at the time of applying the method of improving the SN ratio of a received signal by integrating a received signal used for a passive sensor to an active sensor. It is a figure for demonstrating the signal processing system of the active sensor which is the 1st Embodiment of this invention, and is a schematic diagram which shows the received signal for every direction and distance obtained by one scanning, its direction and It is a schematic diagram for demonstrating the procedure which converts the received signal for every distance into an absolute coordinate. It is a schematic diagram for demonstrating the data stored in the reception signal level distribution memory 12 for every absolute position coordinate. The absolute position coordinate-based received signal level distribution memory 12 stores the absolute coordinate-based received signal level distribution data 11 obtained by one scan for the most recent N + 1 scans. FIG. 6 is a diagram for explaining an operation of an estimated trajectory integration processing unit 20. The absolute position coordinate data (0) to (2) correspond to the reception signal level distribution data 11 for each absolute position coordinate. It is a block diagram of active sensor system 100 which is one embodiment of the present invention. It is a schematic diagram for demonstrating the update of the absolute position coordinate of the active sensor 2 from the start of 1 time of a scan until it complete | finishes. It is a schematic diagram for demonstrating the conversion from a three-dimensional relative coordinate system to a three-dimensional absolute coordinate system which the absolute position coordinate conversion process part 19 performs in 3rd Embodiment. It is a figure for demonstrating the correction | amendment which considered the roundness of the earth performed in 3rd Embodiment. It is a figure for demonstrating the process which the presumed path integral process part 20 performs in a three-dimensional coordinate system. It is a figure for demonstrating correction | amendment of the reference | standard direction measured by the navigation apparatus 18 in 3rd Embodiment.

  As shown in FIG. 1, an active sensor 2 which is an active type radar or sonar emits a radiation wave 3. When an object 1 is present around the active sensor 2, the radiation wave 3 is reflected by the object 1 and returns to the active sensor 2 as a reflected wave 4. The active sensor 2 receives the reflected wave 4, generates a reception signal, and outputs the reception signal to the signal processing device 101 shown in FIG. Based on the received signal, the signal processing device 101 calculates a detected azimuth 5 which is an azimuth based on a reference azimuth 9 determined in advance for the active sensor 2 and a detected distance 6 which is a distance from the active sensor 2 to the object 1 Do. In recent years, with the development of stealth technology, the reflectance of radio waves and sound waves in ships, aircraft, underwater vehicles and the like to be detected has been reduced. For this reason, it is difficult to detect a ship, an aircraft, an underwater vehicle or the like to which the stealth technology is applied as the object 1.

The passive radar and sonar adopt a method of improving the SN ratio of the received signal by integrating the received signal. In general, when the received signal is integrated N times (N is a natural number), the improvement effect of the SN ratio as shown in the following equation is obtained. This effect is also called addition gain.
SN ratio = √ (N) (Equation 1)

  The improvement effect of SN ratio is shown in FIG. For example, when the received signal is integrated nine times, the SN ratio improves threefold. The SN ratio improves fourfold in 16 integrations. However, it has not been possible to apply the method of integrating the received signal to improve the SN ratio as it is for the active sensor.

  The reason is explained. The active sensor 2 mounted on a moving ship, aircraft, underwater vehicle, vehicle, etc. (A moving object carrying these active sensors will be referred to as a mounting moving object) Orientation and distance change.

  When not only the mounted moving body but also the object 1 to be detected moves, the object 1 moves irregularly as viewed from the mounted moving body. In particular, when the object 1 is a moving object moving at high speed such as a ship, aircraft, underwater vehicle, vehicle, etc., it is difficult to integrate the received signal based on the position of the active sensor 2.

  For example, as shown in FIG. 3, it is assumed that the positional relationship between the object 1 and the active sensor 2 is initially in the arrangement on the left side of FIG. As time passes, the positional relationship between the object 1 and the active sensor 2 changes to the arrangement on the right side of FIG. In this time course, both the object 1 and the active sensor 2 are moving. As can be seen by comparing them, the movements of the object 1 and the active sensor 2 are both simple and small. However, the detected orientation 5 of the object 1 and the detected distance 6 as viewed from the active sensor 2 change significantly with the passage of time. Therefore, the desired effect can not be obtained even if the detected azimuth 5 and the detected distance 6 are integrated as they are.

First Embodiment
An active sensor system according to a first embodiment of the present invention will be described. The active sensor system performs the following signal processing.

  (Step 1) As shown in FIG. 4, a single scan of the active sensor provides a received signal whose position is expressed in a relative coordinate system based on the position of the active sensor. The coordinate system of this received signal is converted into an absolute coordinate system (longitudinal, etc.).

  (Step 2) FIG. 5 shows the received signal (received signal level distribution data 11 for each absolute position coordinate) expressed in the absolute coordinate system obtained by the latest scan and the past N scans as in step 1. As shown, it is stored in advance in a storage unit (absolute position coordinate reception signal level distribution memory 12).

  As shown in FIG. 6, one locus (example 16 of estimated locus) of N + 1 coordinates (start point coordinate 13, absolute position coordinate 14, absolute position coordinate 15) extracted one set at a time from each set of these N + 1 sets It is regarded as Integral processing is performed using the received signal of each coordinate forming one locus. Based on the result of the integration process, the traced object is tentatively detected following the trajectory. The integration process improves the SN ratio of the received signal.

  (Step 3) For an object moved following a certain trajectory provisionally obtained in step 2, the moving direction and moving speed of the object are determined based on the trajectory. At this point, trajectories that do not match the characteristics of the moving speed of the object to be detected are excluded from the detection results. For example, when the object to be detected is a fixed wing aircraft, it is possible to judge that a trajectory of 200 km / h or less is an object other than the detection target such as a bird. Therefore, even if the object is detected in step 2, if the moving speed is 200 km / h or less, it is excluded from the detection result.

  (Step 4) The signal processing in steps 1 to 3 is performed corresponding to one scan. Such signal processing is performed for each of a plurality of scans performed successively. For each of the trajectories included in the plurality of detection results obtained, it is determined whether or not the trajectories are continuous. If there is continuity, the active sensor system finally determines and detects that there is an object moved by following the locus, and for example, the locus obtained in step 2 regarding the object on a display device such as a liquid crystal display, The movement direction, movement speed, etc. obtained in step 3 are output as the image information and the detection result is output. The output form of the detection result is not limited to the image, and may be output as sound or a combination of sound and image.

  According to the signal processing method of the present embodiment, an object that moves at high speed using an active sensor (a radar or a sonar) mounted on a mounted moving body (a moving ship, an aircraft, an underwater vehicle, a vehicle, etc.) Even at the time of detection, effective integration processing can be performed.

  The present signal processing method is particularly effective for an active sensor system mounted on a mounted mobile unit, but is not limited thereto. It is also effective in fixed active sensor systems, such as fixed radars on the ground and fixed sonars in the water.

Second Embodiment
An active sensor system 100 according to a second embodiment of the present invention will be described. The active sensor system 2 is a system mounted on a ship, an aircraft, a underwater vehicle, a vehicle or the like. Hereinafter, the moving body on which the active sensor 2 is mounted is referred to as a mounting moving body. Active sensor 2 transmits radiation 3.

  The active sensor 2 transmits a radiation wave 3 like a radar, a sonar or the like, receives the reflected wave 4 reflected by the radiation wave 3 from the object 1 to be detected, and outputs a reception signal. The radiation wave 3 is a radio wave or a sound wave radiated from the active sensor 2. The reflected wave 4 is a radio wave or a sound wave in which the radiation wave 3 is reflected by the object 1.

  The active sensor 2 is a sensor that measures and outputs a received signal level for each azimuth and for each distance. For example, as shown in FIG. 3, the received signal level for the object 1 is set to the direction of the detection direction 5 which is determined based on a predetermined reference direction 9 (for example, the direction of the front of the mounted moving body) The received signal level from the detection distance 6 is output. That is, the active sensor 2 outputs the received signal level expressed in the relative coordinate system based on the current position of the active sensor 2.

  The active sensor 2 is installed on a moving ship, aircraft, underwater vehicle, vehicle, and the like. Further, it is assumed that the object 1 which is the detection target of the active sensor 2 is also moving. In such a case, as shown in FIG. 3, in addition to the movement of the object 1, the detection azimuth 5 and the detection distance 6 change with time under the influence of the movement of the active sensor 2 itself. As described above, when both the object 1 and the active sensor 2 move, the detection azimuth 5 and the detection distance 6 both change irregularly. For this reason, integration processing can not simply be applied.

  The active sensor 2 measures the reception signal level at each distance for the azimuth of a predetermined angular range determined with reference to the reference azimuth 9. Measuring the received signal level once for each azimuth and for each distance over the entire predetermined angular range is referred to as one scan. The operation of the active sensor 2 such as a radar or a sonar outputting a received signal corresponding to the direction and distance is well known to those skilled in the art, and thus the detailed description is omitted.

  The active sensor system 100 detects the object 1 by performing signal processing on the received signal. Active sensor system 100 includes, in addition to active sensor 2, received signal normalization processing unit 17, absolute position coordinate conversion processing unit 19, received signal level distribution memory 12 for each absolute position coordinate, estimated trajectory integration processing unit 20, course velocity calculation A processing unit 21 and an object detection determination processing unit 22 are provided.

  The received signal normalization processing unit 17 normalizes the received signal based on the reflected wave 4. The reflected wave 4 is attenuated in inverse proportion to the square of the distance between the active sensor 2 and the object 1. The received signal normalization processing unit 17 cancels the attenuation of the received signal caused by such a distance.

  The navigation device 18 is a device for measuring absolute position coordinates (longitude and latitude), course, speed and the like of the active sensor 2. That is, the navigation device 18 is a device for positioning the position of the active sensor 2 in an absolute coordinate system and acquiring the absolute position and the reference azimuth 9 of the active sensor 2 for each elapsed time during one scan.

  The navigation device 18 may use a navigation device of a mounted mobile unit on which the active sensor system 100 is mounted. In general, there are various types of navigation devices, but as long as the required accuracy can be obtained, the navigation device 18 can be used regardless of the measurement principle and method. In the present embodiment, the navigation device 18 is described as including a GPS (Global Positioning System) receiver as a means for positioning the position of the active sensor 2 in an absolute coordinate system. Further, in the present embodiment, the navigation device 18 is described as including a gyroscope as a means for acquiring the reference azimuth 9 for each elapsed time during one scan.

  The absolute position coordinate conversion processing unit 19 converts the coordinate expression of the received signal level value from the relative coordinate system to the absolute coordinate system. The received signal normalization processing unit 17 outputs received signal level values according to the direction from the reference direction 9 viewed from the active sensor 2 and the distance from the active sensor 2 as shown in FIG. 4.

  The coordinates of the received signal level value are expressed in a relative coordinate system based on the current position of the active sensor 2. The absolute position coordinate conversion processing unit 19 converts the coordinates of the received signal level value into an absolute coordinate system based on the position in the absolute coordinate system of the active sensor 2 measured by the navigation device 18.

  In FIG. 4, a reference azimuth 9 is an azimuth serving as a reference of scanning of the active sensor 2. The reference azimuth 9 changes according to the attitude of the mobile unit on which the active sensor 2 is mounted. In general, the reference orientation 9 is a horizontal orientation that represents the front of the torso of a ship, an aircraft, a underwater vehicle, a vehicle or the like. The detected azimuth 5 is a horizontal angle from the reference azimuth 9. The distribution 10 of received signal level values for each azimuth and distance is a received signal represented in a relative coordinate system. That is, the distribution 10 of received signal level values for each azimuth and distance indicates the distribution of received signal level values for each of the detected azimuth 5 and the detected distance 6 obtained by one scan of the active sensor 2. On the other hand, the reception signal level distribution data 11 for each absolute coordinate is a reception signal represented by a relative coordinate system. The reception signal level distribution data 11 for each absolute coordinate is a reception signal level value representing the position by the detected azimuth 5 and the detection distance 6 obtained by one scanning of the active sensor 2 by the absolute position coordinates such as latitude and longitude. Convert to received signal level value representing position.

  The absolute position coordinate reception signal distribution memory 12 is a storage device for storing the reception signal level distribution data 11 for each absolute coordinate, for the amount corresponding to the latest N + 1 times (N is a predetermined natural number) scanning results. That is, the absolute position coordinate received signal distribution memory 12 stores N + 1 sets of received signal level distribution data 11 for each absolute coordinate. When the absolute position coordinate conversion processing unit 19 generates a new reception signal level distribution data 11 for each absolute coordinate along with the scanning of the active sensor 2, the absolute position coordinate reception signal distribution memory 12 stores the absolute coordinate for each absolute coordinate currently stored. The oldest of the received signal level distribution data 11 is erased, and a new one is stored instead. The number of times N + 1 corresponds to the number of integrations per trajectory performed by the estimated trajectory integration processing unit 20 described later.

  The estimated trajectory integration processing unit 20 integrates the received signal level value from the elapsed time and the estimated trajectory based on the N + 1 set of received signal level distribution data for each absolute position coordinate 11 stored in the absolute position coordinate received signal distribution memory 12. Do.

  In the absolute position coordinate reception signal distribution memory 12, the reception signal level distribution data 11 for each absolute position coordinate by the latest scan, the reception signal level distribution data 11 for each absolute position coordinate by the previous scan,. The N + 1 sets of reception signal level distribution data 11 for each absolute position coordinate, which are composed of the reception signal level distribution data 11 for each absolute position coordinate, are stored. The estimated trajectory integration processing unit 20 obtains a trajectory consisting of coordinates selected one by one from each of the N + 1 sets of reception signal level distribution data 11 for each absolute position coordinate.

  First, any coordinate is selected as the start point coordinate 13 from the reception signal level distribution data 11 for each absolute position coordinate by the latest scan.

  Next, X is an arbitrary integer from 1 to N, and one coordinate is selected as follows from the reception signal level distribution data 11 for each absolute position coordinate from the 1 to N previous scans. In the reception signal level distribution data 11 for each absolute position coordinate from the Xth previous scan, coordinates corresponding to the start point coordinate 13 are used as a starting point, and coordinates within a predetermined distance are extracted as a candidate coordinate group. Then, one coordinate is selected from the candidate coordinate group. The predetermined distance mentioned here is determined in relation to the elapsed time from the latest scan to the X-th previous scan and the assumed moving speed of the object 1.

  Thus, when coordinates are selected one by one from each of the N + 1 sets of reception signal level distribution data 11 for each absolute position coordinate, N + 1 coordinates are obtained. Let this be one trajectory.

  The estimated trajectory integration processing unit 20 determines the presence or absence of the moved object by tracing the trajectory between the N-th previous scan and the latest scan. If there is such an object, the estimated trajectory integration processing unit 20 follows the trajectory to detect the moved object.

  The determination of the presence or absence of an object is performed by integrating the received signal level value of each coordinate forming a locus and comparing it with a predetermined threshold. If the integral value is equal to or greater than the threshold value, the estimated trajectory integration processing unit 20 follows the trajectory and detects the moved object. If it is less than the threshold value, the estimated trajectory integration processing unit 20 does not detect an object moved by following the trajectory.

  The course velocity calculation processing unit 21 calculates the starting point and the end point of the object 1 based on the estimated trajectory of the object 1 output by the estimated trajectory integration processing unit 20. Further, the estimated trajectory integration processing unit 20 calculates the course and velocity of the object 1 based on the calculated starting point, end point and elapsed time of the object 1. The course velocity calculation processing unit 21 outputs the estimated trajectory in the absolute coordinate system of the object 1 output by the estimated trajectory integration processing unit 20 and the course and velocity in the absolute coordinate system of the object 1 calculated by itself.

  The object detection determination processing unit 22 compares the velocity output by the passage velocity calculation processing unit 21 with the feature related to the velocity of the object to be detected, and the velocity output by the passage velocity calculation processing unit 21 becomes the detection object. It is determined whether or not the object belongs. Based on the determination result, the object detection determination processing unit 22 outputs only the output from the course velocity calculation processing unit 21 that matches the feature.

  When it conforms to the velocity range of the object to be detected, the object detection determination processing unit 22 outputs the course velocity calculation processing unit 21 for the object as it is. On the other hand, when it does not conform to the velocity range of the object to be detected, the object detection determination processing unit 22 discards the course velocity calculation processing unit 21 for the object without outputting it. Instead of discarding, it may be output together with information indicating that the speed range does not fit.

  The operation of the object detection determination processing unit 22 when the detection target of the active sensor system 100 is a fixed wing aircraft will be described as an example. Here, the active sensor 2 is an active radar. In general, a fixed-wing aircraft has a speed range with, for example, 3675 Km / hr corresponding to Mach 3 as an upper limit and, for example, a stall speed of 250 Km / hr as a lower limit. When the active sensor system 100 assumes a fixed wing aircraft as a detection target, an estimated trajectory corresponding to this speed range is detected as an object. An object is considered not to be a fixed wing aircraft if it is above or below the upper limit. In this case, the object detection determination processing unit 22 discards the output of the course velocity calculation processing unit 21 for the object, or outputs it together with information indicating that the object is other than a fixed wing aircraft.

  As another example, the operation of the object detection determination processing unit 22 when the detection target of the active sensor system 100 is a rotary wing aircraft or a small unmanned aerial vehicle (drone) will be described. Here, the active sensor 2 is an active radar. In general, a rotorcraft or small unmanned aerial vehicle has a speed range in which the lower limit is 0 km / h in the hovering state and the upper limit is 300 km / h, for example. For this reason, the object detection determination processing unit 22 outputs, for example, only the output of the passage speed calculation processing unit 21 for an object that matches the speed range of 0 to 300 km / hr. For an object that does not match, the object detection determination processing unit 22 discards the output of the course speed calculation processing unit 21 or outputs it together with information indicating that it is other than a rotary wing aircraft and a small unmanned aerial vehicle.

  As another example, the operation of the object detection determination processing unit 22 when the detection target of the active sensor system 100 is an underwater vehicle will be described. Here, the active sensor 2 is a sonar. For example, an underwater vehicle is considered to have a velocity range of 30 to 60 knots. Therefore, the object detection determination processing unit 22 outputs the output of the course velocity calculation processing unit 21 as it is for an object that falls within the velocity range of, for example, 30 to 60 knots. On the other hand, for an object which does not fall within the velocity range of, for example, 30 to 60 knots, the object detection determination processing unit 22 discards the output of the course velocity calculation processing unit 21 or an underwater vehicle Output with information indicating that it is something other than.

  As another example, the on-board moving body is a ship, the active sensor 2 is a sonar, and the detection target of the active sensor system 100 is a dangerous drifting object for which the on-board moving body should avoid collision. The operation of the object detection determination processing unit 22 will be described. Dangerous drifting objects include, for example, driftwood and mines. Dangerous drifting objects do not travel by themselves, but travel along tidal currents and ocean currents. For this reason, dangerous drifts have a speed range of, for example, 5 knots or less, which corresponds to tidal currents or currents. At this time, the object detection determination processing unit 22 outputs the output of the course velocity calculation processing unit 21 as it is, for example, for an object of 5 knots or less. On the other hand, for an object exceeding 5 knots, for example, the object detection determination processing unit 22 discards the output of the course velocity calculation processing unit 21 or is something other than a dangerous drifting object (having any navigation means) With information indicating

  Next, the operation of the active sensor system 100 will be described. The active sensor system 100 is mounted on a mobile body, and the active sensor 2 is moving.

  (Step 11) The active sensor 2 emits a radiation wave 3 such as a radio wave or a sound wave in order to detect the object 1. As shown in FIG. 1, the active sensor 2 emits a radiation wave 3.

  (Step 12) When the object 1 is present, the object 1 reflects the radiation wave 3 and emits the reflected wave 4. As shown in FIG. 1, the radiation wave 3 is reflected by the object 1 to be detected to be a reflected wave 4. The active sensor 2 receives the reflected wave 4. A technique for minimizing the reflected wave 4 is called a general stealth technique. Even when the size of the object 1 is originally very small, the reflected wave 4 is small.

  (Step 13) When the active sensor 2 receives the reflected wave 4 from the object 1 within a predetermined scanning range as a reception signal by one scan, the active sensor 2 detects the coordinates of the detection direction 5 and the detection distance 6 shown in FIG. The received signal is output to the received signal normalization processing unit 17.

  (Step 14) The reception signal normalization processing unit 17 performs processing to cancel the effect of the reception signal of the reflected wave 4 being attenuated in proportion to the square of the distance between the object 1 and the active sensor 2. This processing is called normalization processing.

  The normalization processing performed by the received signal normalization processing unit 17 is as follows. First, for the reception signal of the scanning result of one time by the active sensor 2, the average value of the reception signals of all the detected azimuths 5 is calculated for the reception signals of the same detection distance 6. Next, the reception signal for each detected azimuth 5 is divided by the calculated average value. Next, normalization is performed using the average value for each detection distance 6. Finally, the reception signal normalized in this manner is output to the absolute position coordinate conversion processing unit 19.

  For example, it is assumed that the active sensor 2 has an azimuth resolution of 0.1 deg, a distance resolution of 50 m, and a scan azimuth range of ± 45 deg. At this time, 900 received signals with a detection distance 6 of 10,000 m exist in the scan orientation range of -45.0 to +45.0. This means that there is a received signal whose detection distance 6 is 10,000 m for each of the azimuths -45.0, -44.9, -44.8 ... +44.9, +45.0 in steps of 0.1 deg. Because The average value of these 900 received signals is calculated. Then, these 900 received signals are each divided by the calculated average value.

  (Step 15) The absolute position coordinate conversion processing unit 19 converts the coordinate system representing the received signal from the relative coordinate system to the absolute coordinate system. That is, the absolute position coordinate conversion processing unit 19 receives the position (eg, latitude and longitude) of the active sensor 2 in the absolute coordinate system input from the navigation device 18 and the received signal normalization processing unit 17 based on the information of the reference azimuth and the speed. Reception signal distribution data (received signal expressed in relative coordinate system) for each of detection azimuth 5 and detected distance 6 of position reference of active sensor 2 inputted is expressed as received signal distribution data (absolute coordinate system) for each absolute position coordinate Convert to received signal). This process is called coordinate conversion process.

  The coordinate conversion processing performed by the absolute position coordinate conversion processing unit 19 is as follows. As mentioned above, the navigation device 18 comprises a GPS receiver as a means for acquiring the position of the active sensor 2 in the absolute coordinate system (e.g. longitude and latitude). The navigation device 18 also comprises a gyroscope as a means for measuring the absolute position and the reference heading 9 for each time lapse during one scan. The absolute position coordinate conversion processing unit 19 acquires position information in the absolute coordinate system from the GPS receiver. Also, the absolute position and reference azimuth 9 position and reference azimuth 9 for each time lapse during one scan are acquired from the gyroscope, and based on this absolute position and reference azimuth 9, the detected azimuth 5 for each detection distance 6 is decide.

  Here, the update of the absolute position coordinates of the active sensor 2 from the start to the end of one scan will be described with reference to FIG. At the time of starting one scan, the active sensor 2 is at the absolute position 23. At this time, the reference orientation of the active sensor 2 is 24. The navigation device 18 measures the absolute position 23 with a GPS receiver. Also, the navigation device 18 measures the reference azimuth 24 with an inertial navigation device such as a gyroscope. The active sensor 2 (or the mounted mobile equipped with the active sensor 2) moves along the path 25 also during this single scan. At the end of the one scan, the active sensor 2 moves to the absolute position 26. The reference orientation of the active sensor 2 at this time is 27. The navigation device 18 measures the absolute position 26 with a GPS receiver. In addition, the navigation device 18 measures the reference azimuth 27 with an inertial navigation device such as a gyroscope. The navigation device 18 measures changes in absolute position and reference orientation over time of the active sensor 2 on the path 25 by an inertial navigation device such as a gyroscope.

  In a later step, the estimated trajectory integration processing unit 20 performs integration processing in the absolute coordinate system. In order to make this integration process function correctly, it is required to measure the absolute position coordinates of the active sensor 2 and the course (reference direction) with high accuracy every time.

  For example, in the case of sonar, assuming that the sound velocity in water is 1500 m / sec and the detection distance 6 is 3000 m, one scan takes 4 seconds in consideration of the time required for the sound wave to reciprocate. A ship or underwater vehicle equipped with a sonar moves in these 4 seconds, and the position and the reference direction change. For this reason, it is necessary to correct the error accompanying the movement.

  Further, for example, in the case of a radar mounted on an aircraft, the active sensor 2 moves at a speed of 1000 km / hour or more. Assuming that the accuracy of the absolute position coordinate is 50 m in the active sensor 2 moving at 300 m per second, the absolute position coordinate and course (reference orientation) of the active sensor 2 at a rate of 12 times / sec or more to obtain the position accuracy of ± 25 m Have to be updated. In order to effectively realize the integration process according to the present invention, it is desirable to update information on absolute position coordinates such as latitude and longitude, reference azimuth, and speed at an update rate of 20 times or more per second.

  In addition, a slight deviation occurs in the attitude and the movement direction of a moving ship, an aircraft, an underwater vehicle, a vehicle, or the like. For example, in the course of a ship, it is a common phenomenon that the direction of travel and the direction of the bow deviate due to the influence of waves. Therefore, it is necessary to determine the heading (reference orientation) based on posture information from an inertial navigation device such as a gyroscope, without determining the heading (reference orientation) from changes in absolute position coordinates.

  Next, once the absolute position coordinate and heading (reference orientation) of active sensor 2 have been determined for each passage of time during one scan, reception for each of detection azimuths 5 and detection distances 6 for each passage of time as shown in FIG. Signal data is converted into received signal data of absolute position coordinates.

In the distribution 10 of received signal level values for each azimuth and distance, the received signal data also has attributes of a detected azimuth 5 and a detected distance 6. For this reason, the conversion from the distribution 10 of the received signal level value for each azimuth and distance to the latitude and longitude that is absolute position coordinates is expressed by the following formula.
Latitude y1 = y + SIN (A-θ) x L ÷ R (Equation 2)
Longitude x1 = x + COS (A-θ) x L ÷ R x COS (y) (Equation 3)
However, the values for the active sensor 2 are determined as follows. Let y (deg) be the latitude of absolute coordinates. The longitude is x (deg). The detected orientation 5 is A (deg). Let L (m) be the detection distance 6. The reference azimuth is θ. Let the latitude converted to absolute position coordinates be y1 (deg). The longitude converted to absolute position coordinates is x1 (deg). Further, a distance corresponding to latitude 1 (deg) on the surface of the earth is represented by R (m). Since the distance of 1 deg of longitude changes depending on the latitude, in Equation 2, correction with COS (latitude) is performed.

  As described above, the position coordinates of the level distribution 10 of the received signal for each direction and distance are converted into (x1, y1) represented by the latitude and longitude which are absolute position coordinates using Equation 1 and Equation 2. After conversion, it is converted into absolute position coordinates (x2, y2) on the reception signal level distribution data 11 for each absolute position coordinate.

Let the latitude at the absolute position coordinate on the absolute position coordinate per received signal level distribution data 11 be y2 (deg) and the longitude be x2 (deg). Let the distance between latitude y1 (deg) and latitude y2 (deg) be W (deg). W (deg) can be calculated by the following equation.
W (deg) = [[{(x 1-x 2) x COS (y 1)} ^ 2 + (y 1-y 2) ^ 2] (Equation 4)

  The absolute position coordinate conversion processing unit 19 compares the latitude and longitude of the distribution 10 of the received signal level value for each azimuth and distance for each grid latitude and longitude of the reception signal level data 11 for each absolute coordinate shown in FIG. 4. Calculate the distance W. Find the latitude y1 and longitude x1 at which the distance W is shortest, and set the received signal level value of the distribution 10 of the received signal level value for each direction and distance to the received signal level value for each absolute coordinate of latitude y2 and longitude x2. It substitutes and stores it in the received signal level distribution memory 12 for each absolute position coordinate.

  However, if the distance W (deg) is extremely larger than the distance resolution (deg) which is the grid interval of the reception signal level distribution data 11 for each absolute coordinate (for example, W (deg)> 2 times the distance resolution), the latitude The received signal level value for each absolute coordinate of y2 and longitude x2 is set to NULL (invalid value).

  For example, it is assumed that the reception signal level distribution data 11 for each absolute coordinate is 10 deg latitude by latitude and the distance resolution is 0.0005 deg (about 55 m). At this time, the number of received signal level values included in one absolute position coordinate-based received signal level distribution data 11 is (10 ÷ 0.0005) ^ 2 = 400 million. Therefore, the number of absolute position coordinates represented by latitude y2 and longitude x2 is 400 million.

  For example, the detection range of the active sensor 2 is assumed as follows. The azimuth range is ± 45 deg. The azimuth resolution is 0.1 deg. The maximum distance is 10 deg latitude. The distance resolution is set to 0.0005 deg (about 55 m). At this time, the number of reception signal level values of the latitude y1 and the longitude x1 for each direction and distance is (90) 0.1) × (10 ÷ 0.0005) = 18 million. In the above example, the combination for calculating the distance W (deg) is 400 million × 18 million = 7.2 × 10 ^ 15 if the number of calculations is not made efficient. Normally, the distance W (deg) is calculated only for the latitude y1 and the latitude x1 near the longitude x2.

  (Step 16) The estimated trajectory integration processing unit 20 stores the received signal level distribution data 11 for each absolute position coordinate stored in the received signal level distribution memory 12 for each absolute position coordinate shown in FIG. Perform integration processing for each combination.

  As shown in FIG. 5, the absolute position coordinate received signal level distribution memory 12 includes N sets of absolute position coordinate received signal level distribution data 11 obtained by the latest scan and N sets corresponding to the number of integrations N. A total of N + 1 sets of reception signal level distribution data 11 for each position coordinate are stored as reception signal level distribution data 11 for each absolute position coordinate.

  In FIG. 6, reference numeral 13 denotes the origin coordinates (x, y, 0) of the estimated trajectory integration process. The origin coordinates (x, y, 0) are received signal levels at arbitrary absolute position coordinates in the reception signal level distribution data for each absolute position coordinate 11 based on the latest scanning result by the active sensor 2. The absolute position coordinate data (0), (1) and (2) sequentially indicate the reception signal level distribution data 11 for each absolute position coordinate 0 times, 1 time ago and 2 times ago counted from the latest scan. 14 shows absolute position coordinates (x-1, y + 1, 1) according to the result of the previous scan. Reference numeral 15 indicates absolute position coordinates (x-2, y + 2, 2) according to the results of two previous scans. 16 indicates an absolute position coordinate 15 (x-2, x-2, y, 0, 1) from an origin coordinate 13 (x, y, 0) to an absolute position coordinate 14 (x-1, y + 1, 1) for three scanning results. An example of an estimated trajectory leading to y + 2, 2) is shown.

  Now, let the origin coordinate 13 be (x, y, 0). 0 in parenthesis () is the 0th previous scan counting from the latest scan, that is, the coordinates in the absolute position coordinate data (0) of FIG. Indicates that there is. (X, y, 1) are received signal level distribution data 11 for each absolute coordinate based on the previous scan, that is, to the starting point coordinate 13 (x, y, 0) in the absolute position coordinate data (1) of FIG. Indicates the corresponding coordinates. (X, y, 2) are received signal level distribution data 11 for each absolute coordinate based on the second previous scan, that is, to the starting point coordinates 13 (x, y, 0) in the absolute position coordinate data (2) of FIG. Indicates the corresponding coordinates. The same applies to (x, y, 3), (x, y, 4), ... (x, y, N) below. N is an arbitrary natural number.

  Here, the resolution of the grid of the reception signal level distribution 11 for each absolute position coordinate determines the resolution such that the object 1 and the active sensor 2 are larger than the distance traveled during the time required for one scan. At this time, in the reception signal level distribution data 11 for each absolute coordinate generated based on the previous scan by the active sensor 2, the range of the locus to which the object 1 has moved is (x−1, y−1, 1) to It can be estimated as (x + 1, y + 1, 1). In other words, when it is estimated that the object 1 moves from the previous scan to the latest scan and the object 1 exists at the start point coordinate 13 which is the current coordinates, the object 1 is At the time of scanning, it can be estimated that it was within a certain distance centered on the origin coordinates 13. This distance is determined in relation to the latest scan, that is, the elapsed time from the scan in generating the reception signal level distribution data 11 for each absolute coordinate including the start point coordinate 13. That is, it is determined in relation to the time interval in which the active sensor 2 performs a scan.

  For example, it is assumed that the moving speed of the object 1 is 3000 Km at the maximum, the moving speed of the aircraft equipped with the active sensor 2 is 3000 Km at the maximum, and one scanning time is 0.05 seconds. In this case, the relative velocity of the object 1 with respect to the active sensor 2 is a maximum velocity of 6000 km / h (about 1667 m / sec). In addition, the relative movement distance for 0.05 seconds between the active sensor 2 and the object 1 is about 83 m at maximum. The movement of the active sensor 2 can be corrected by the position information from the navigation device 18. Therefore, only the moving distance of the object 1 is a problem. During a single scan time of 0.05 seconds, the distance traveled by the object 1 is up to about 42 m. At this time, assuming that the resolution of the lattice of the reception signal level distribution 11 for each absolute position coordinate is, for example, about 55 m, the movement distance of the object 1 in one scanning time is within one square of the reception signal level distribution 11 for each absolute position coordinate. become.

  That is, when the object 1 is present at (x, y, 0) which is the starting point coordinate 13, if the time required for one scanning is traced back, the object 1 has nine coordinates (x-1, y-1, 1) It can be considered that it existed in any of (x + 1, y + 1, 1). Similarly, when the object 1 is present at (x, y, 0) which is the starting point coordinate 13, if the time required for two scans is traced back, the object 1 has 25 coordinates (x-2, y-2) , 2) to (x + 2, y + 2, 2). Furthermore, in the same manner, the trajectories of movement of the object 1 during the three scans are 9 × 9 = 81. Thus, a combination of trajectories in which the object 1 is moved by N scans is represented by 9 ^ (N-1). For example, the combination of trajectories of movement of one object in 16 scanning results is as follows: 9 ^ 15 = 2.059 x 1014.

  The estimated trajectory integration processing unit 20 integrates the reception signal level distribution data 11 for each absolute coordinate in these combinations, and when it exceeds a preset threshold value, determines that the object 1 is present in the trajectory, and detects it. Do.

  Here, this detection method will be described with N = 2. It is assumed that some mobile object exists at the origin coordinates 13. At this time, as described above, the moving object should have been present in any of 9, 25 coordinate groups centered on the origin coordinate 13 at the time of the previous and second scans, respectively. It is. This coordinate group is called a candidate coordinate group.

  The locus followed by the moving object from the second previous scan to the latest scan consists of a combination of three coordinates. One coordinate (starting point coordinate 13) of the reception signal level distribution data 11 for each absolute coordinate by the latest scan, one coordinate of the reception signal level distribution data 11 for each absolute coordinate by the previous scan, absolute by the second scan The total of three coordinates of one coordinate of the received signal level distribution data 11 for each coordinate.

  As described above, the candidate coordinate groups of the reception signal level distribution data 11 for each absolute coordinate in the two-time and one-time scans are nine and nine, respectively. The origin coordinate 13 is one. Therefore, there are 9 × 9 × 1 = 81 trajectories of combinations of these three coordinates.

  In the example of FIG. 6, these coordinates are, in order, starting point coordinates 13 (x, y, 0), absolute position coordinates 14 (x-1, y + 1, 1), absolute position coordinates 15 (x-2, y + 2, 2) Corresponding to). The estimated trajectory integration processing unit 20 performs integration processing based on the reception signals of N + 1 (three in this case) coordinates forming the same trajectory. In the case of the estimated trajectory example 16 of FIG. 6, the received signal of the starting point coordinate 13 (x, y, 0), the received signal of the absolute position coordinate 14 (x-1, y + 1, 1), the absolute position coordinate 15 ( Integration processing is performed based on three received signals of the (x−2, y + 2, 2) received signal. The estimated trajectory integration processing unit 20 performs such integration processing for all 81 trajectories, and calculates an integral value for each trajectory.

  The estimated trajectory integration processing unit 20 compares the calculated integral value with a predetermined threshold value. If the integral value is greater than or equal to the threshold value, the estimated trajectory integration processing unit 20 determines that there is an object moved by tracing the trajectory, and detects the object. If the integral value is less than the threshold, the estimated trajectory integration processing unit 20 determines that there is no object following the trajectory, and does not detect the object.

  The coordinates selected as those constituting the locus in the reception signal level distribution data 11 for each absolute position coordinate by the N-th previous scan are set as the start point of the locus. The start point coordinate 13 is taken as the end point of the trajectory.

  The estimated trajectory integration processing unit 20 performs the processing as described above for each of the reception signal levels of the reception signal level distribution data 11 for each absolute position coordinate based on the latest scanning result. In the above description, the coordinate (x, y) is selected as the start point coordinate 13 with reference to FIG. 6, and the locus from the second previous scan is detected, but the same operation is updated This is performed for each coordinate of the reception signal level distribution data 11 for each absolute position coordinate based on the scanning result. For example, if the received signal level distribution data 11 for each absolute position coordinate is composed of received signals of lattice points such that x and y are integers and 0 ≦ x ≦ 99 and 0 ≦ y ≦ 99, 100 × 100 = The above processing is performed with 10000 grid points as the start point coordinates 13 respectively.

  In the case of N = 3, 4, 5,..., One coordinate of the candidate coordinate group of the reception signal level distribution data 11 for each absolute coordinate by scanning three times before, four times before, five times before,. Perform the same process in addition to. The number of coordinates that make up the locus is one coordinate extracted from each of the received signal level distribution data 11 for each absolute position coordinate from one scan to N previous scans, a total of N coordinates, and an absolute count from the latest scan The position coordinates of each of the received signal level distribution data 11 are combined with the starting point coordinate 13 to be N + 1.

  The improvement effect of the detectable distance 7 and the SN ratio 8 by the estimated trajectory integration processing unit 20 will be described with reference to FIG.

  The SN ratio 8 represents the SN, which is improved by the integration effect of the received signal, in dB. The integration effect of the received signal improves the SN ratio 8 in proportion to the square root of the number of integrations. As the SN ratio 8 improves, it becomes possible to detect the reflected wave 4 from the same object from a longer distance, and the detectable distance 7 is extended.

  In the example of FIG. 2, it is assumed that the active sensor 2 capable of detecting the object 1 when the SN ratio 8 is 1. When an integration effect is applied to a signal received by such an active sensor 2, both of the detectable distance 7 and the SN ratio 8 can be improved. For example, by integrating 16 scanning results, the detectable distance 7 is doubled, and the SN ratio 8 is improved by 6 dB (4 times).

  If all the received signal levels of the combination of trajectories in which the object 1 has moved in the 16 scan results are calculated, the amount of calculation becomes enormous and it is difficult to realize. For this reason, instead of performing all integrals of estimated trajectory integration processing at once, the whole number of integrations is divided into a plurality of stages, and integration is performed at a certain stage, and only for the coordinates where the received signal level is large. It is also possible to perform integration of stages.

  For example, at the stage of calculating the received signal level of the combination of trajectories along which the object 1 moved in the first four scanning results, first, the presence or absence of the effect that the noise component has become 1/1 / (4) = 1/2 It discriminates by the set threshold. Next, estimated trajectory integration processing in the next four scanning results is performed only on data whose received signal level is large due to signal components after noise reduction. If the estimated trajectory integration process is performed in this manner, unnecessary calculations can be reduced.

  (Step 17) When the estimated trajectory integration processing unit 20 detects an object following a certain trajectory, the heading velocity calculation processing unit 21 determines the direction from the start point to the end point of the trajectory, the linear distance from the start point to the end point, and the start point Calculate the elapsed time to the end point. For example, in the case of the estimated trajectory example 16 of FIG. 6, the start point is the absolute position coordinate 15, that is, (x-2, y + 2). The end point is the origin coordinates 13, ie, (x, y). The azimuth from the start point to the end point is (x, y)-(x-2, y + 2) = (2, 2). The linear distance from the start point to the end point is √ [{x- (x-2)} ^ 2+ {y- (y + 2)} ^ 2] == 8. The elapsed time from the start point to the end point is obtained, for example, by N × T seconds, where T seconds is the cycle in which the active sensor 2 scans.

  Next, the course velocity calculation processing unit 21 obtains the velocity from the start point to the end point of the object based on the linear distance from the start point to the end point and the elapsed time thereof. In the case of the estimated trajectory example 16 of FIG. 6, (√8) / NT seconds. As a result, the course velocity calculation processing unit 21 detects the object detected as an example 16 of the estimated trajectory in FIG. 6 at the velocity (.sqroot.8) / NT seconds toward the direction (2, -2) from the start point to the end point. It determines that it is moving.

  The course velocity calculation processing unit 21 may pass the above result as it is to the object detection information output unit 22 described later, but performs filtering based on the characteristics of the velocity of the object to be detected, and the object to be detected The output of may be extracted. In addition, filtering may be performed based on the characteristics related to the velocity of an object other than the detection target, and the output of an object not the detection target may be excluded. Furthermore, these extraction and exclusion filtering may be used in combination.

  For example, in general, fixed-wing aircraft can not fly by generating lift on their wings unless they move in the air at a certain speed. Also, fixed-wing aircraft move faster than birds and other organisms. Therefore, when the active sensor 2 is an active radar and the active sensor system 100 detects an aircraft of a fixed wing, the output of the estimated trajectory integration processing unit 20 related to an object having a speed lower than a certain degree is the course speed The calculation processing unit 21 may be excluded.

  In addition, in the case of dangerous drifting materials such as mines and driftwood drifting in water or over water, the moving speed is close to zero. For this reason, when the active sensor system 100 is mounted on a ship, underwater vehicle or the like, and the active sensor 2 is a sonar, in particular for detection of dangerous drifting objects, the output of the estimated trajectory integration processing unit 20 Among the above, the course velocity calculation processing unit 21 may extract only the object relating to an object slower than a certain degree.

  Furthermore, filtering based on the duration of the speed may be performed in addition to the filtering based on the level of the speed. For example, with some exceptions, such as migrating birds, most flying creatures have high speed flight limited to sustainable times in a short time. For this reason, for example, in order to detect a drone separately from common flying creatures, filtering based on the speed of the above-described speed may be performed, and a time during which a speed of a certain level or more is sustained may be measured. In this case, the course velocity calculation processing unit 21 compares the duration of the predetermined velocity or more with the threshold of the preset duration. Then, among the outputs of the estimated trajectory integration processing unit 20, only the output exceeding the threshold of the duration is output to the object detection information output processing unit 22.

  When filtering based on the characteristics of the velocity of the object to be detected, setting information (a threshold indicating a range of velocity, a threshold of duration, etc.) regarding the velocity of the object to be detected is, for example, It is stored in advance in the storage device of the information processing apparatus that operates. Based on this setting, the course velocity calculation processing unit 21 performs filtering from the output of the estimated trajectory integration processing unit 20. The course velocity calculation processing unit 21 extracts one that matches the velocity characteristics of the object to be detected, or excludes one that matches the velocity characteristics of the object not to be detected.

  (Step 18) The object detection information output processing unit 22 displays the estimated trajectory (including the latest position) of the object 1 calculated by the passage velocity calculation processing unit 21, the passage and the velocity on a map such as a computer display Do.

  The description of the operation (steps 11 to 18) of the active sensor system 100 is as described above.

  In the above description, the received signal normalization processing unit 17, the navigation device 18, the absolute position coordinate conversion processing unit 19, the received signal level distribution memory 12 for each absolute position coordinate, the estimated trajectory integration processing unit 20, and the course velocity calculation processing unit 21 The above-described operation is performed for each scan of the active sensor 2, and the result is output from the object detection information output processing unit 22. That is, one scan by the active sensor 2 and one output by the object detection information output processing unit 22 correspond to each other.

  Instead of this, a plurality of scans by the active sensor 2 and one output by the object detection information output processing unit 22 may be made to correspond. At this time, the course velocity calculation processing unit 21 performs the above-mentioned signal processing for one scan by the active sensor 2 and detects one or more objects moved by tracing a certain trajectory. It does not output to the detection information output processing unit 22.

  Instead, the course velocity calculation processing unit 21 stores the detection result in the storage device in correspondence with, for example, the time when the latest scan was performed at that time. That is, one set of detection results is stored in the storage device for one scan. After performing this for a plurality of consecutive scans, the course velocity calculation processing unit 21 evaluates whether or not the trajectories included in the detection results of the scans performed continuously are continuous with each other. The evaluation of the presence or absence of continuity may be simply evaluated based on whether or not the course, velocity, and trajectory of each other are similar.

  For example, in the detection results of three consecutive scans, when the trajectories are continuous with each other, the heading speed calculation processing unit 21 outputs the three detection results to the object detection information output processing unit 22. By doing this, the active sensor system 100 can improve the reliability of the detection result.

In order to operate the active sensor system 100 effectively, it is preferable to satisfy the following conditions.
The measurement accuracy of the direction and distance of the received signal by the active sensor 2 is high.
The measurement accuracy of the attitude information and position information input from the navigation device 18 is high.
Having a computing ability to perform huge number of combinations of estimated trajectory integration processing.

  According to this embodiment, the following effects can be obtained.

  As a first effect, in object detection by active sensors such as radar and sonar, it is possible to detect a weak signal which has been difficult to detect so far. In the case of a radar, an object with small stealth with RCS (Radar Cross Section) can be detected from a longer distance than before. In the case of a sonar, a small underwater vehicle or diver with a small TS (Target Strength) can be detected from a longer distance than before.

  As a second effect, in detection of an object by an active sensor such as radar or sonar, an object of an expected speed can be selectively detected by including the path (movement direction) and speed of the object in the detection condition.

  The method of detecting the frequency change of the received signal using the Doppler effect separates the reflected wave from the object and the noise for an object moving at a low speed or an object moving on a heading whose speed is high but the relative distance is hard to change. It is difficult to do. According to the present embodiment, the object detection capability of the active sensor can be improved regardless of the Doppler effect.

Third Embodiment
In the second embodiment, an embodiment has been described in which the present invention is applied to an active sensor such as a radar or a sonar that performs two-dimensional search. In the present embodiment, an embodiment applied to an active sensor that performs three-dimensional search will be described.

  Also in this embodiment, the basic configuration is the same as that of the active sensor system 100 of FIG. However, in the active sensor system 100 according to the present embodiment, the position of the received signal is represented by three-dimensional coordinates. The output of the active sensor 2 has an element of elevation angle in addition to the azimuth and distance. Other blocks of the active sensor system 100 also handle three-dimensional coordinate information.

  In order to process the received signal represented by three-dimensional coordinates, in the present embodiment, as shown in FIG. 10, the following correction calculation is performed in consideration of the roundness of the earth.

  First, each part of FIG. 10 will be described. A indicates the position of the active sensor 2. B shows the position of the object 1. The distance between A and B corresponds to the detection distance 6. The angle θ1 (deg) indicates the elevation angle from the active sensor 2 to the object 1. The distance between AEs indicates the height (the distance from the sea surface) of the active sensor 2. The distance between the ECs corresponds to the horizontal distance from the active sensor 2 to the object 1 when the roundness of the earth is ignored. The distance between B and C corresponds to the height of the object 1 when the earth is ignored. D indicates the position of the object 1 expressed by the latitude and longitude on the earth. E indicates a position represented by latitude and longitude on the earth with respect to the active sensor 2. G shows the center of the earth. The distance between DG and the distance between EG corresponds to the earth's radius of about 6378 Km. The angle θ2 (deg) represents an angle representing the positional relationship between the active sensor 2 and the object 1 in latitude as a coordinate system on the earth. Actually, A and B are expressed by latitude and longitude, but the distance corresponding to longitude on the earth surface changes with latitude, so it is converted to latitude. The distance between BDs indicates the height of the object 1 (the distance from the sea surface) in consideration of the roundness of the earth.

  From the positional relationship in FIG. 10, from the distance (AB) to the object 1 detected by the active sensor 2 and the elevation angle θ 1 and the altitude (AE) of the active sensor 2, the object from the active sensor 2 in the coordinate system represented by latitude and longitude It is necessary to calculate the distance to 1 (θ 2) and the altitude of the object 1 (BD).

In order to explain the above calculation method, assuming that the AG direction is Y axis in FIG. 10 and the direction orthogonal to the Y axis is X axis, each position of A, B, C, D, E, F, G is calculated as follows It can be expressed by an expression.
A = (0, EG + AE) (Equation 5)
B = (cos θ1 × AB, sin θ1 × AB + EG + AE) (6)
C = (cos θ1 × AB, EG + AE) (Equation 7)
D = (sin θ 2 × EG, cos θ 2 × EG) (Equation 8)
θ2 = a tan {(cos θ1 × AB) ÷ (sin θ1 × AB + EG + AE)} (9)
BG = √ {(EG + AE + sin θ1 × AB) ^ 2 + (cos θ1 × AB) ^ 2} (10)
BD = BG-EG (Equation 11)

  According to the above formula, the height (AE) of the active sensor 2, the elevation angle (θ1) of the object 1, the distance to the object (AB), the horizontal distance to the object 1 from the radius of the earth (EG) as known information (Θ2) and altitude (BD) can be calculated.

  Moreover, the process which the presumed locus | trajectory integral process part 20 performs in a three-dimensional coordinate system is demonstrated using FIG.

  Each part of FIG. 11 will be described. The starting point coordinates 28 (x, y, z, 0) indicate the latest absolute coordinate reception signal level distribution data 11 at any position in the absolute position coordinate reception signal distribution memory 12. The absolute position coordinates 29 (x-1, y-1, z + 1, 1) indicate the range of the locus of movement of the object 1 in the received signal level distribution data 11 of the previous absolute coordinate by the active sensor 2 (x- The position corresponding to (x−1, y−1, z + 1, 1) when estimated to be 1, y−1, z−1, 1) to (x + 1, y + 1, z + 1, 1) is shown. The X-axis 30 indicates the X-axis that represents the east-west direction in the absolute position coordinate-based reception signal distribution memory 12. The Y axis 31 indicates the Y axis that represents the north-south direction in the reception signal distribution memory 12 for each absolute position coordinate. The Z-axis 32 represents the Z-axis representing the vertical direction in the reception signal distribution memory 12 for each absolute position coordinate. The absolute position coordinates 33 (x + 1, y + 1, z + 1, 1) indicate the range of the trajectory of the object 1 in the received signal level distribution data 11 of the previous absolute coordinate by the active sensor 2 (x-1, y− The position corresponding to (x + 1, y + 1, z + 1, 1) in the case of being estimated as 1, z−1, 1) to (x + 1, y + 1, z + 1, 1) is shown. The absolute position coordinates 34 (x-1, y-1, z-1, 1) indicate the range of the locus of movement of the object 1 in the reception signal level distribution data 11 of the previous absolute coordinate by the active sensor 2 ( Indicates the position corresponding to (x-1, y-1, z-1, 1) when estimated as x-1, y-1, z-1, 1) to (x + 1, y + 1, z + 1, 1) .

  When the object 1 is present at the starting point coordinates 28 (x, y, z, 0) as the latest scanning result by the active sensor 2, the object 1 is not (x-1,. It can be considered as existing in 27 ranges of y-1, z-1, 1) to (x + 1, y + 1, z + 1, 1).

  For example, focusing on the coordinates (x−1, y−1, z−1, 1) that trace back the time required for one scan, if the time required for two scans is traced back, , Y-2, z-2, 2) to (x, y, z, 2). Therefore, the locus of movement of the object 1 during three scans is 27 × 27 = 729.

  As described above, there are 27 ^ (N-1) combinations of trajectories in which the object 1 moves in a three-dimensional space by N times of scanning. For example, combinations of trajectories of movement of the object 1 in 16 scan results are as follows: 27 ^ 15 = 2.954 × 10 ^ 21.

  In these combinations, the reception signal level distribution data 11 for each absolute coordinate is integrated, and it is determined that the object 1 is present in a locus exceeding a preset threshold value, and detected. For example, by integrating 16 scanning results, the SN ratio is quadrupled and the detectable distance is doubled.

  In the present embodiment, in particular, the accuracy of the reference heading 9 output by the navigation device 18 is important. If the error of the posture information by the gyroscope or the like is large, the accuracy of the conversion processing by the absolute position coordinate conversion processing unit 19 is greatly reduced. Therefore, it may be difficult to obtain the improvement effect of the SN ratio by the estimated trajectory integration processing unit 20.

  Therefore, in the present embodiment, the reference azimuth 9 measured by the navigation device 18 is corrected as follows. This will be described with reference to FIG.

  The reference target 36 is a facility provided with measurement means for measuring its position in the absolute coordinate system. The measuring means is, for example, a GPS receiver. Also, the reference target 36 comprises wireless communication means. The measurement value by the above measurement means is transmitted to the active sensor system 100 by the wireless communication means.

  In order to receive this measurement value, the active sensor system 100 is provided with a wireless communication unit capable of wireless communication with the wireless communication unit of the reference target 36 in addition to the units illustrated in FIG. 7. The reference target 36 and the wireless communication means of the active sensor system 100 may communicate at any frequency or may communicate using any communication method.

  The reference target 36 may transmit the measurement value periodically using wireless communication means, or may transmit the measurement value in response to a request from the active sensor system 100.

  The on-board mobile unit equipped with the active sensor 2 flies or navigates so that the reference target 36 falls within the scanning range of the active sensor 2. The absolute position coordinate conversion processing unit 19 acquires the orientation of the reference target 36 in the relative coordinate system based on the output of the active sensor 2 and the output of the attitude information acquisition device (for example, a gyroscope) of the navigation device 18. This direction is referred to as a reference target detection direction 37.

  On the other hand, when the wireless communication means of the active sensor system 100 receives the measurement value and the measurement time from the reference target 36, the absolute position coordinate conversion processing unit 19 receives the measurement value (reference target absolute position 38) received from the reference target 36; Based on the coordinates of the active sensor 2 in the absolute coordinate system measured by the positioning means (for example, GPS receiver) of the navigation device 18, the azimuth of the reference target absolute position 38 is calculated. The calculated direction is set as a reference target absolute direction 39.

  The absolute position coordinate conversion processing unit 19 obtains the difference between the reference target detection direction 37 and the reference target absolute direction 39, and corrects and corrects the gyro reference direction 35 measured by the gyroscope of the navigation device 18 based on this difference. The reference azimuth 40 is calculated. Thereafter, the absolute position coordinate conversion processing unit 19 performs coordinate conversion from the relative coordinate system to the absolute coordinate system based on the corrected reference orientation 40. As described above, the absolute position coordinate conversion processing unit 19 can perform the coordinate conversion with high accuracy after correcting the error included in the attitude information of the gyroscope of the navigation device 18.

  Specifically, the absolute position coordinate conversion processing unit 19 performs the following correction calculation.

Position coordinates of the active sensor 2 by latitude and longitude are (x0, y0). Let (x1, y1) be position coordinates in which the position of the reference target 36 detected by the active sensor is expressed by latitude and longitude. Assuming that the gyro reference azimuth 35 is θ0 and the reference target detection azimuth 37 is θ3, θ3 can be calculated by the following equation.
θ 3 = a tan [(y 1 −y 0) ÷ {(x 1 −x 0) × cos (y 0)}] − θ 0 (12)

The position coordinates of the reference target absolute position 38 to which the reference target 36 has been contacted are defined by latitude and longitude as (x2, y2). Assuming that the reference target absolute orientation 39 is θ4, θ4 can be calculated by the following equation.
θ4 = a tan [(y2−y0) ÷ {(x2−x0) × cos (y0)}] − θ0 (13)

The difference between θ3 and θ4 is the error of the gyro reference azimuth 35. The corrected reference orientation 40, that is, θ5 can be calculated by the following equation.
θ5 = (θ4−θ3) −θ0 (Equation 14)

  By executing the absolute position coordinate conversion processing unit 19 based on the corrected reference orientation 40, the error of the attitude detection gyro of the navigation device 18 can be corrected. As a result, it is possible to secure the calculation accuracy of the absolute position coordinate conversion processing unit 19. As a result, the effect of integration by the estimated trajectory integration processing unit 20 can be obtained.

  Although the correction method of the gyro reference direction of the horizontal direction has been described with reference to FIG. 12, the correction of the gyro reference direction of the vertical direction can also be performed in the same manner.

  When the active sensor 2 is a radar mounted on an aircraft, the reference target 36 is preferably an aircraft equipped with a GPS receiver and a wireless communication device. This aircraft may be a drone or a manned aircraft.

  The reference target 36 in the case of the radar in which the active sensor 2 is fixed on the ground may be a radar wave reflector installed at the top of a high mountain.

  When the active sensor 2 is a radar mounted on a ship, the reference target 36 is preferably a manned or unmanned ship equipped with a GPS receiver and a wireless communication device.

  When the active sensor 2 is a sonar mounted on a watercraft, the reference target 36 is preferably a manned or unmanned watercraft equipped with a GPS receiver and a wireless communication device.

  Some or all of the above embodiments may be described as in the following appendices, but is not limited thereto.

(Supplementary Note 1)
A signal processing system for processing a reception signal of an active sensor emitting radiation, receiving the radiation reflected from an object, and generating a reception signal,
The active sensor scans at predetermined time intervals,
The signal processing system
A relative coordinate reception signal, which is a distribution of the reception signal obtained by one scanning by the active sensor, wherein the distribution of the reception signal represents a position in relative coordinates determined based on the position of the active sensor An absolute position coordinate conversion processing means, which is a means for converting a distribution into an absolute coordinate reception signal distribution which is a distribution of the reception signal representing a position in absolute coordinates;
A zeroth absolute coordinate received signal distribution which is the absolute coordinate received signal distribution generated by the one zeroth scan which is one of the scans, and a first scan which is a scan performed immediately before the zeroth scan A first absolute coordinate reception signal distribution which is the absolute coordinate reception signal distribution generated by the second embodiment and the absolute coordinate reception signal distribution which is generated by a second scan which is a scan performed immediately before the first scan A second absolute coordinate received signal distribution, and..., An Nth absolute coordinate received signal distribution generated by an Nth scan that is a scan performed immediately before the N-1th scan Storage means which is means for storing coordinate reception signal distribution (N is a natural number of 2 or more);
A received signal at a starting point coordinate which is one coordinate included in the zeroth absolute coordinate received signal distribution, and a received signal at a first coordinate which is one coordinate included in the first absolute coordinate received signal distribution; The received signal of the second coordinate, which is one coordinate included in the second absolute coordinate received signal distribution, and the Nth coordinate, which is one coordinate included in the Nth absolute coordinate received signal distribution Integral processing is performed based on the received signal, and based on the result of the integral processing, detection of the presence or absence of an object moved by tracing a locus consisting of the origin coordinates and the first to Nth coordinates is performed. An estimated trajectory integration processing unit which is a unit;
A signal processing system comprising:

(Supplementary Note 2)
When X is any integer from 1 to N,
The X-th coordinate is a coordinate selected from a candidate coordinate group consisting of coordinates within a predetermined distance from the coordinate corresponding to the origin coordinate in the X-th absolute coordinate reception signal distribution,
The distance is determined in relation to the time from the zeroth scan to the Xth scan.
The signal processing system according to appendix 1.

(Supplementary Note 3)
Means for performing processing for canceling the attenuation on the reception signal received by the active sensor on the premise that the reception signal is attenuated in proportion to the square of the distance between the object and the active sensor The signal processing system according to Appendix 1 or 2, further comprising: received signal normalization processing means.

(Supplementary Note 4)
When an object moved by tracing a certain trajectory by the integration process is detected, the object is determined from the start point to the end point based on the linear distance between the start point and the end point of the trajectory and the required time from the start point to the end point The signal processing system according to any one of appendices 1 to 3, further comprising a course velocity calculation processing means, which is a means for calculating the speed of movement up to.

(Supplementary Note 5)
The speed at which the object moves from the start point to the end point obtained by the calculation is compared with the feature regarding the speed of the object to be detected or the object not to be detected, [Claim 4] The signal processing system according to statement 4, wherein at least one of extraction of an output regarding an object to be performed and exclusion of an output regarding an object not to be detected is performed.

(Supplementary Note 6)
The signal processing system further includes positioning means, which is a means for measuring coordinates in the absolute coordinate system of the active sensor, and attitude information acquisition means, which is a means for acquiring attitude information of the active sensor,
In order to correct the reference orientation of the posture information acquisition means based on a reference target whose coordinates in the absolute coordinate system are known in advance:
Based on the output of the active sensor and the output of the posture information acquisition means, a reference target detection direction which is the direction of the reference target in the relative coordinate system is determined.
Based on the coordinates of the reference target in an absolute coordinate system known in advance and the coordinates of the active sensor in the absolute coordinate system measured using the positioning means, a reference target absolute orientation which is an orientation of the reference target Ask for
Correcting the reference orientation based on a difference between the reference target detection orientation and the reference target absolute orientation;
The signal processing system according to any one of appendices 1 to 5.

(Appendix 7)
A signal processing method for processing a received signal of an active sensor emitting radiation, receiving the radiation reflected from an object, and generating a received signal,
The active sensor scans at predetermined time intervals,
A relative coordinate reception signal, which is a distribution of the reception signal obtained by one scanning by the active sensor, wherein the distribution of the reception signal represents a position in relative coordinates determined based on the position of the active sensor An absolute position coordinate conversion processing step, which is a step of converting a distribution into an absolute coordinate reception signal distribution which is a distribution of the reception signal representing a position in absolute coordinates;
A zeroth absolute coordinate received signal distribution which is the absolute coordinate received signal distribution generated by the one zeroth scan which is one of the scans, and a first scan which is a scan performed immediately before the zeroth scan A first absolute coordinate reception signal distribution which is the absolute coordinate reception signal distribution generated by the second embodiment and the absolute coordinate reception signal distribution which is generated by a second scan which is a scan performed immediately before the first scan A second absolute coordinate received signal distribution, and..., An Nth absolute coordinate received signal distribution generated by an Nth scan that is a scan performed immediately before the N-1th scan Storing the coordinate received signal distribution (N is a natural number of 2 or more);
A received signal at a starting point coordinate which is one coordinate included in the zeroth absolute coordinate received signal distribution, and a received signal at a first coordinate which is one coordinate included in the first absolute coordinate received signal distribution; The received signal of the second coordinate, which is one coordinate included in the second absolute coordinate received signal distribution, and the Nth coordinate, which is one coordinate included in the Nth absolute coordinate received signal distribution Performing integration processing on the basis of the received signal, and detecting the presence or absence of a moved object by following a locus consisting of the origin coordinates and the first to Nth coordinates based on the result of the integration processing There is an estimated trajectory integration process stage,
Signal processing methods, including:

(Supplementary Note 8)
When X is any integer from 1 to N,
The X-th coordinate is a coordinate selected from a candidate coordinate group consisting of coordinates within a predetermined distance from the coordinate corresponding to the origin coordinate in the X-th absolute coordinate reception signal distribution,
The distance is determined in relation to the time from the zeroth scan to the Xth scan.
The signal processing method according to appendix 7.

(Appendix 9)
Performing a process for canceling the attenuation on the reception signal received by the active sensor on the premise that the reception signal is attenuated in proportion to the square of the distance between the object and the active sensor The signal processing method according to any one of Appendix 7 or 8, further comprising a received signal normalization processing step.

(Supplementary Note 10)
When an object moved by tracing a certain trajectory by the integration process is detected, the object is determined from the start point to the end point based on the linear distance between the start point and the end point of the trajectory and the required time from the start point to the end point The signal processing method according to any one of appendices 7 to 9, further comprising a course velocity calculation processing step which is a step of calculating a moving speed to the end.

(Supplementary Note 11)
The speed at which the object moves from the start point to the end point obtained by the calculation is compared with the feature regarding the speed of the object to be detected or the object not to be detected, The signal processing method according to claim 10, further performing at least one of extraction of an output regarding an object to be performed and exclusion of an output regarding an object not to be detected.

(Supplementary Note 12)
In order to correct the reference orientation at the time of acquiring the attitude information of the active sensor based on a reference target whose coordinates in the absolute coordinate system are known in advance,
Based on the output of the active sensor and posture information of the active sensor, a reference target detection direction, which is the direction of the reference target in the relative coordinate system, is determined.
Based on the coordinates of the reference target in an absolute coordinate system known in advance and the known coordinates of the active sensor in the absolute coordinate system, a reference target absolute orientation which is an orientation of the reference target is obtained.
Correcting the reference orientation based on a difference between the reference target detection orientation and the reference target absolute orientation;
The signal processing method according to any one of Appendixes 7 to 11.

(Supplementary Note 13)
A signal processing program for processing a reception signal of an active sensor that emits a radiation wave, receives the radiation wave reflected by an object, and generates a reception signal,
The active sensor scans at predetermined time intervals,
Computer,
A relative coordinate reception signal, which is a distribution of the reception signal obtained by one scanning by the active sensor, wherein the distribution of the reception signal represents a position in relative coordinates determined based on the position of the active sensor An absolute position coordinate conversion processing means, which is a means for converting a distribution into an absolute coordinate reception signal distribution which is a distribution of the reception signal representing a position in absolute coordinates;
A zeroth absolute coordinate received signal distribution which is the absolute coordinate received signal distribution generated by the one zeroth scan which is one of the scans, and a first scan which is a scan performed immediately before the zeroth scan A first absolute coordinate reception signal distribution which is the absolute coordinate reception signal distribution generated by the second embodiment and the absolute coordinate reception signal distribution which is generated by a second scan which is a scan performed immediately before the first scan A second absolute coordinate received signal distribution, and..., An Nth absolute coordinate received signal distribution generated by an Nth scan that is a scan performed immediately before the N-1th scan Storage means which is means for storing coordinate reception signal distribution (N is a natural number of 2 or more);
A received signal at a starting point coordinate which is one coordinate included in the zeroth absolute coordinate received signal distribution, and a received signal at a first coordinate which is one coordinate included in the first absolute coordinate received signal distribution; The received signal of the second coordinate, which is one coordinate included in the second absolute coordinate received signal distribution, and the Nth coordinate, which is one coordinate included in the Nth absolute coordinate received signal distribution Integral processing is performed based on the received signal, and based on the result of the integral processing, detection of the presence or absence of an object moved by tracing a locus consisting of the origin coordinates and the first to Nth coordinates is performed. An estimated trajectory integration processing unit which is a unit;
Signal processing program to function as.

(Supplementary Note 14)
When X is any integer from 1 to N,
The X-th coordinate is a coordinate selected from a candidate coordinate group consisting of coordinates within a predetermined distance from the coordinate corresponding to the origin coordinate in the X-th absolute coordinate reception signal distribution,
The distance is determined in relation to the time from the zeroth scan to the Xth scan.
The signal processing program according to appendix 13.

(Supplementary Note 15)
Means for performing processing for canceling the attenuation on the reception signal received by the active sensor on the premise that the reception signal is attenuated in proportion to the square of the distance between the object and the active sensor 24. The signal processing program according to appendix 13 or 14, further causing the computer to function as a received signal normalization processing means.

(Supplementary Note 16)
When an object moved by tracing a certain trajectory by the integration process is detected, the object is determined from the start point to the end point based on the linear distance between the start point and the end point of the trajectory and the required time from the start point to the end point 15. The signal processing program according to any one of appendices 13 to 15, further causing the computer to function as a course velocity calculation processing means, which is a means for calculating a speed of movement up to the end.

(Supplementary Note 17)
The speed at which the object moves from the start point to the end point obtained by the calculation is compared with the feature regarding the speed of the object to be detected or the object not to be detected, 17. The signal processing program according to paragraph 16, further causing the computer to function as means for performing at least one of extraction of an output related to an object to be output and exclusion of an output related to the object not to be detected.

(Appendix 18)
In order to correct the reference orientation of the posture information acquisition means, which is a means for acquiring posture information of the active sensor, based on a reference target whose coordinates in the absolute coordinate system are known in advance.
A means for determining a reference target detection direction, which is the direction of the reference target in the relative coordinate system, based on the output of the active sensor and the output of the posture information acquisition means;
Based on the coordinates of the reference target in an absolute coordinate system known in advance and the coordinates of the active sensor in the absolute coordinate system measured using the positioning means, a reference target absolute orientation which is an orientation of the reference target The means to seek
The signal processing program according to any one of appendices 13 to 17, further causing a computer to function as means for correcting the reference orientation based on a difference between the reference target detected orientation and the reference target absolute orientation.

1 object 2 active sensor 3 radiation wave 4 reflected wave 5 detection azimuth 6 detection distance 7 detectable distance 8 SN ratio 9 reference azimuth 10 azimuth and distribution of received signal level value for each distance 11 received signal level distribution data for each absolute position coordinate 12 Received signal level distribution memory for each absolute position coordinate 13, 28 Starting point coordinates 14, 15, 29, 33, 34 Absolute position coordinate 16 Example of estimated trajectory 17 Received signal normalization processing unit 18 Navigation device 19 Absolute position coordinate conversion processing unit 20 Estimation Trajectory integration processing unit 21 Pathway velocity calculation processing unit 22 Object detection information output processing unit 23 Scanning start position of active sensor 2 Reference orientation at the start of scanning 25 Position change during scanning 26 Scanning end position of active sensor 2 Scanning end time of scanning 27 Reference azimuth 30 X axis 31 Y axis 32 Z axis 35 Gyro reference azimuth 36 Reference target (detection position)
37 Reference target detection direction 38 Reference target absolute position 39 Reference target absolute direction 40 Corrected reference direction 100 Active sensor system 101 Signal processing system

Claims (10)

A signal processing system for processing a received signal of an active sensor emitting radiation, receiving the radiation reflected from an object, and detecting the object according to the received signal,
The active sensor scans at predetermined time intervals,
The signal processing system
A relative coordinate reception signal, which is a distribution of the reception signal obtained by one scanning by the active sensor, wherein the distribution of the reception signal represents a position in relative coordinates determined based on the position of the active sensor An absolute position coordinate conversion processing means, which is a means for converting a distribution into an absolute coordinate reception signal distribution which is a distribution of the reception signal representing a position in absolute coordinates;
A zeroth absolute coordinate received signal distribution which is the absolute coordinate received signal distribution generated by the one zeroth scan which is one of the scans, and a first scan which is a scan performed immediately before the zeroth scan A first absolute coordinate reception signal distribution which is the absolute coordinate reception signal distribution generated by the second embodiment and the absolute coordinate reception signal distribution which is generated by a second scan which is a scan performed immediately before the first scan A second absolute coordinate received signal distribution, and..., An Nth absolute coordinate received signal distribution generated by an Nth scan that is a scan performed immediately before the N-1th scan Storage means which is means for storing coordinate reception signal distribution (N is a natural number of 2 or more);
A received signal at a starting point coordinate which is one coordinate included in the zeroth absolute coordinate received signal distribution, and a received signal at a first coordinate which is one coordinate included in the first absolute coordinate received signal distribution; The received signal of the second coordinate, which is one coordinate included in the second absolute coordinate received signal distribution, and the Nth coordinate, which is one coordinate included in the Nth absolute coordinate received signal distribution Integral processing is performed based on the received signal, and based on the result of the integral processing, detection of the presence or absence of an object moved by tracing a locus consisting of the origin coordinates and the first to Nth coordinates is performed. An estimated trajectory integration processing unit which is a unit;
A signal processing system comprising: When X is any integer from 1 to N,
The X-th coordinate is a coordinate selected from a candidate coordinate group consisting of coordinates within a predetermined distance from the coordinate corresponding to the origin coordinate in the X-th absolute coordinate reception signal distribution,
The distance is determined in relation to the time from the zeroth scan to the Xth scan.
The signal processing system according to claim 1.   Means for performing processing for canceling the attenuation on the reception signal received by the active sensor on the premise that the reception signal is attenuated in proportion to the square of the distance between the object and the active sensor The signal processing system according to claim 1, further comprising: received signal normalization processing means.   When an object moved by tracing a certain trajectory by the integration process is detected, the object is determined from the start point to the end point based on the linear distance between the start point and the end point of the trajectory and the required time from the start point to the end point The signal processing system according to any one of claims 1 to 3, further comprising a course velocity calculation processing means, which is a means for calculating the speed of movement up to.   The speed at which the object moves from the start point to the end point obtained by the calculation is compared with the feature regarding the speed of the object to be detected or the object not to be detected, 5. The signal processing system according to claim 4, wherein at least one of extraction of an output regarding an object to be detected and exclusion of an output regarding an object not to be detected is performed. The signal processing system further includes positioning means, which is a means for measuring coordinates in the absolute coordinate system of the active sensor, and attitude information acquisition means, which is a means for acquiring attitude information of the active sensor,
In order to correct the reference orientation of the posture information acquisition means based on a reference target whose coordinates in the absolute coordinate system are known in advance:
Based on the output of the active sensor and the output of the posture information acquisition means, a reference target detection direction which is the direction of the reference target in the relative coordinate system is determined.
Based on the coordinates of the reference target in an absolute coordinate system known in advance and the coordinates of the active sensor in the absolute coordinate system measured using the positioning means, a reference target absolute orientation which is an orientation of the reference target Ask for
Correcting the reference orientation based on a difference between the reference target detection orientation and the reference target absolute orientation;
A signal processing system according to any one of claims 1 to 5. A signal processing method for processing a received signal of an active sensor which emits a radiation wave, receives the radiation wave reflected by an object, and detects an object according to a received signal,
The active sensor scans at predetermined time intervals,
A relative coordinate reception signal, which is a distribution of the reception signal obtained by one scanning by the active sensor, wherein the distribution of the reception signal represents a position in relative coordinates determined based on the position of the active sensor An absolute position coordinate conversion processing step, which is a step of converting a distribution into an absolute coordinate reception signal distribution which is a distribution of the reception signal representing a position in absolute coordinates;
A zeroth absolute coordinate received signal distribution which is the absolute coordinate received signal distribution generated by the one zeroth scan which is one of the scans, and a first scan which is a scan performed immediately before the zeroth scan A first absolute coordinate reception signal distribution which is the absolute coordinate reception signal distribution generated by the second embodiment and the absolute coordinate reception signal distribution which is generated by a second scan which is a scan performed immediately before the first scan A second absolute coordinate received signal distribution, and..., An Nth absolute coordinate received signal distribution generated by an Nth scan that is a scan performed immediately before the N-1th scan Storing the coordinate received signal distribution (N is a natural number of 2 or more);
A received signal at a starting point coordinate which is one coordinate included in the zeroth absolute coordinate received signal distribution, and a received signal at a first coordinate which is one coordinate included in the first absolute coordinate received signal distribution; The received signal of the second coordinate, which is one coordinate included in the second absolute coordinate received signal distribution, and the Nth coordinate, which is one coordinate included in the Nth absolute coordinate received signal distribution Performing integration processing on the basis of the received signal, and detecting the presence or absence of a moved object by following a locus consisting of the origin coordinates and the first to Nth coordinates based on the result of the integration processing There is an estimated trajectory integration process stage,
Signal processing methods, including: When X is any integer from 1 to N,
The X-th coordinate is a coordinate selected from a candidate coordinate group consisting of coordinates within a predetermined distance from the coordinate corresponding to the origin coordinate in the X-th absolute coordinate reception signal distribution,
The distance is determined in relation to the time from the zeroth scan to the Xth scan.
The signal processing method according to claim 7. A signal processing program for processing a reception signal of an active sensor that emits a radiation wave, receives the radiation wave reflected by an object, and detects an object according to a reception signal,
The active sensor scans at predetermined time intervals,
Computer,
A relative coordinate reception signal, which is a distribution of the reception signal obtained by one scanning by the active sensor, wherein the distribution of the reception signal represents a position in relative coordinates determined based on the position of the active sensor An absolute position coordinate conversion processing means, which is a means for converting a distribution into an absolute coordinate reception signal distribution which is a distribution of the reception signal representing a position in absolute coordinates;
A zeroth absolute coordinate received signal distribution which is the absolute coordinate received signal distribution generated by the one zeroth scan which is one of the scans, and a first scan which is a scan performed immediately before the zeroth scan A first absolute coordinate reception signal distribution which is the absolute coordinate reception signal distribution generated by the second embodiment and the absolute coordinate reception signal distribution which is generated by a second scan which is a scan performed immediately before the first scan A second absolute coordinate received signal distribution, and..., An Nth absolute coordinate received signal distribution generated by an Nth scan that is a scan performed immediately before the N-1th scan Storage means which is means for storing coordinate reception signal distribution (N is a natural number of 2 or more);
A received signal at a starting point coordinate which is one coordinate included in the zeroth absolute coordinate received signal distribution, and a received signal at a first coordinate which is one coordinate included in the first absolute coordinate received signal distribution; The received signal of the second coordinate, which is one coordinate included in the second absolute coordinate received signal distribution, and the Nth coordinate, which is one coordinate included in the Nth absolute coordinate received signal distribution Integral processing is performed based on the received signal, and based on the result of the integral processing, detection of the presence or absence of an object moved by tracing a locus consisting of the origin coordinates and the first to Nth coordinates is performed. An estimated trajectory integration processing unit which is a unit;
Signal processing program to function as. When X is any integer from 1 to N,
The X-th coordinate is a coordinate selected from a candidate coordinate group consisting of coordinates within a predetermined distance from the coordinate corresponding to the origin coordinate in the X-th absolute coordinate reception signal distribution,
The distance is determined in relation to the time from the zeroth scan to the Xth scan.
The signal processing program according to claim 9.

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