WO2017109951A1 - Speed estimation device - Google Patents

Abstract

The present invention is provided with: reception antennas (11a, 11b) that receive, via corresponding satellites (2a, 2b), a signal transmitted from a moving body (3) and a signal transmitted from a reference station (4); frequency measurement units (161a, 161b) that measure the frequency of the signal from the moving body (3) and the frequency of the signal from the reference station (4) received by the corresponding reception antennas (11a, 11b); Doppler frequency calculation units (162a, 162b) that calculate, from the frequencies measured by the corresponding frequency measurement units (161a, 161b), the Doppler frequencies of uplinks from the moving body (3) to the corresponding satellites (2a, 2b); and a speed calculation unit (163) that calculates the speed of the moving body (3) from the Doppler frequencies calculated by the Doppler frequency calculation units (162a, 162b).

Description

Speed estimation device

The present invention relates to a speed estimation device for estimating the speed of a moving object.

Conventionally, the position and speed of a moving body (radio wave source) using a time difference of arrival (TDOA: Time Difference Of Arrival) and a Doppler frequency difference (FDOA: Frequency Difference Of Arrival) between signals obtained via two satellites. Has been proposed (see, for example, Patent Document 1). In this method, TDOA and FDOA are observed a plurality of times, and the position and speed of the moving object on the ground surface are estimated from these values. In this method, it is assumed that the moving body performs a constant velocity linear motion.

JP 2010-60303 A

Here, the conventional configuration requires two or more observations, and in this case, a means for determining whether each observation value is from the same moving body is required. However, there is a problem that the above determination for an unknown moving body is very difficult. If this determination is wrong, observation values from different moving bodies are processed as those of the same moving body, and an incorrect position and speed are estimated.

The present invention has been made to solve the above-described problems, and it is an object of the present invention to provide a speed estimation device capable of accurately estimating the speed of a moving object by one observation.

The speed estimation device according to the present invention is provided for every two geostationary satellites whose positions and velocities are known, and a signal transmitted from a mobile body whose transmission frequency and position are known via the corresponding geostationary satellite, and transmission A receiving antenna that receives a signal transmitted from a stationary reference station having a known frequency and position, and a frequency of a signal from a mobile unit that is provided for each receiving antenna and is received by the corresponding receiving antenna, and from the reference station A frequency measurement unit that measures the frequency of the signal and a Doppler that is provided for each frequency measurement unit and calculates the Doppler frequency in the uplink from the moving object to the corresponding geostationary satellite from the frequency measured by the corresponding frequency measurement unit A frequency calculator and a speed calculator that calculates the speed of the moving object from the Doppler frequencies calculated by the two Doppler frequency calculators A.

According to this invention, since it is configured as described above, it is possible to accurately estimate the speed of the moving object with one observation.

It is a figure which shows the hardware structural example of the speed estimation apparatus which concerns on Embodiment 1 of this invention. It is a figure which shows the function structural example of the speed calculation processor in Embodiment 1 of this invention. It is a flowchart which shows the operation example of the speed estimation apparatus which concerns on Embodiment 1 of this invention. It is a figure which shows the definition of the coordinate system of a satellite and the earth in the speed estimation apparatus which concerns on Embodiment 1 of this invention. It is a figure which shows the signal reception from the mobile body and reference station via two satellites in the speed estimation apparatus which concerns on Embodiment 1 of this invention. It is a figure which shows the definition of the speed plane and direction on the ground surface in the speed estimation apparatus which concerns on Embodiment 1 of this invention. In the velocity estimation apparatus according to the first embodiment of the invention, showing a constant Doppler frequency f _up1 curve and equal Doppler frequency f _up2 curve. It is a figure which shows the function structural example of the speed calculation processor in Embodiment 4 of this invention. It is a figure which shows the ratio curve of _isodoppler frequency _fup1 , _fup2 in the speed estimation apparatus which _concerns on Embodiment 4 of this invention. It is a flowchart which shows the operation example of the moving direction estimation part in Embodiment 4 of this invention. It is a figure which shows the function structural example of the speed calculation processor in Embodiment 5 of this invention. It is a figure which shows the arctangent function of the ratio curve of _isodoppler frequency _fup1 , _fup2 in the speed estimation apparatus which _concerns on Embodiment 5 of this invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
Embodiment 1 FIG.
FIG. 1 is a diagram showing a hardware configuration example of a speed estimation device 1 according to Embodiment 1 of the present invention.
As shown in FIG. 1, the speed estimation apparatus 1 includes receiving antennas 11a and 11b, bandpass filters 12a and 12b, a local oscillator 13, down converters 14a and 14b, A / D converters 15a and 15b, a speed calculation processor 16, and a display. A device 17 and a memory 18 are provided.

The receiving antenna 11a receives a signal transmitted from the moving body 3 and a signal transmitted from the reference station (reference station) 4 via a geostationary satellite (hereinafter referred to as satellite) 2a. The satellite 2a has a known three-dimensional position vector (hereinafter referred to as a position) and a three-dimensional velocity vector (hereinafter referred to as a speed). Moreover, the mobile body 3 has a known transmission frequency and a three-dimensional position vector (hereinafter referred to as a position). The reference station 4 has a known transmission frequency and a three-dimensional position vector (hereinafter referred to as a position), and is stationary. In the first embodiment, it is assumed that the transmission frequency of the moving body 3 and the transmission frequency of the reference station 4 are approximate. The three-dimensional position vector (hereinafter referred to as position) of the receiving antenna 11a is also known. These pieces of information are stored in the memory 18, for example. The signal received by the receiving antenna 11a is sent to the band pass filter 12a.

The receiving antenna 11b receives a signal transmitted from the mobile unit 3 and a signal transmitted from the reference station 4 via a geostationary satellite (hereinafter referred to as satellite) 2b. The satellite 2b has a known three-dimensional position vector (hereinafter referred to as position) and a three-dimensional velocity vector (hereinafter referred to as speed). The three-dimensional position vector (hereinafter referred to as position) of the receiving antenna 11b is also known. These pieces of information are stored in the memory 18, for example. The signal received by the receiving antenna 11b is sent to the band pass filter 12b.

The band-pass filter 12a performs a filtering process on the signal received by the receiving antenna 11a, thereby allowing a signal existing in a desired frequency channel to pass therethrough and removing others. The signal that has passed through the bandpass filter 12a is sent to the down converter 14a.
The band-pass filter 12b performs a filtering process on the signal received by the receiving antenna 11b, thereby allowing a signal existing in a desired frequency channel to pass therethrough and removing others. The signal that has passed through the bandpass filter 12b is sent to the down converter 14b.

The local oscillator 13 generates a frequency signal. The frequency signal generated by the local oscillator 13 is sent to the down converter 14a and the down converter 14b.
The down converter 14a uses the frequency signal generated by the local oscillator 13 to convert the frequency of the signal that has passed through the bandpass filter 12a to a low level. The signal whose frequency is converted by the down converter 14a is sent to the A / D converter 15a.
The down converter 14b converts the frequency of the signal that has passed through the bandpass filter 12b to a low level using the frequency signal generated by the local oscillator 13. The signal whose frequency is converted by the down converter 14b is sent to the A / D converter 15b.

The A / D converter 15a converts a signal (analog signal) whose frequency has been converted by the down converter 14a into a digital signal. The signal converted into a digital signal by the A / D converter 15 a is sent to the speed calculation processor 16.
The A / D converter 15b converts the signal (analog signal) whose frequency has been converted by the down converter 14b into a digital signal. The signal converted into a digital signal by the A / D converter 15b is sent to the speed calculation processor 16.

The band- pass filters 12a and 12b, the local oscillator 13, the down converters 14a and 14b, and the A / D converters 15a and 15b constitute a reception device 19 that performs reception processing on the signals received by the reception antennas 11a and 11b. To do. Note that the internal configuration of the receiving device 19 may be changed as appropriate as long as the subsequent speed calculation processor 16 receives and processes the signal of the moving body 3 into a signal that can be calculated.

The speed calculation processor 16 calculates the speed of the moving body 3 using the signal converted into a digital signal by the A / D converter 15a and the signal converted into a digital signal by the A / D converter 15b. The speed calculation processor 16 implements the above functions by executing a program stored in the memory 18. The speed calculation processor 16 corresponds to, for example, a single circuit, a composite circuit, a programmed processor, a parallel programmed processor, an ASIC, an FPGA, or a combination thereof. Information (speed information) indicating the speed of the moving body 3 calculated by the speed calculation processor 16 is sent to the display unit 17.

The display 17 displays information from the speed calculation processor 16. In the first embodiment, information indicating the speed of the moving object 3 calculated by the speed calculation processor 16 is displayed. The indicator 17 is not an essential component for the speed estimation device 1, and a separate indicator connected to the outside of the speed estimation device 1 may be used.

The memory 18 stores a program for realizing the function of the speed calculation processor 16. Examples of the memory 18 include a nonvolatile or volatile semiconductor memory such as a RAM, a ROM, a flash memory, an EPROM, and an EEPROM, a magnetic disk, a flexible disk, an optical disk, a compact disk, a mini disk, and a DVD.

Next, details of the speed calculation processor 16 will be described with reference to FIG.
As shown in FIG. 2, the speed calculation processor 16 includes frequency measurement units 161 a and 161 b, Doppler frequency calculation units 162 a and 162 b, and a speed calculation unit 163.

The frequency measuring unit 161a measures the frequency of the signal received by the receiving antenna 11a using the signal converted into a digital signal by the A / D converter 15a. At this time, the frequency measurement unit 161a measures the frequency by, for example, Fourier transforming a signal from the A / D converter 15a. Information indicating the frequency measured by the frequency measuring unit 161a is sent to the Doppler frequency calculating unit 162a.

The frequency measuring unit 161b measures the frequency of the signal received by the receiving antenna 11b using the signal converted into a digital signal by the A / D converter 15b. At this time, the frequency measuring unit 161b measures the frequency by, for example, Fourier transforming a signal from the A / D converter 15b. Information indicating the frequency measured by the frequency measuring unit 161b is sent to the Doppler frequency calculating unit 162b.

The Doppler frequency calculation unit 162a calculates the Doppler frequency in the uplink from the moving body 3 to the satellite 2a from the frequency measured by the frequency measurement unit 161a. At this time, in the Doppler frequency calculation unit 162a in the first embodiment, the reference station 4 measured by the frequency measurement unit 161a from the frequency of the signal corresponding to the signal transmitted from the moving body 3 measured by the frequency measurement unit 161a. The Doppler frequency is calculated by subtracting the frequency of the signal corresponding to the signal transmitted from. Information indicating the Doppler frequency calculated by the Doppler frequency calculation unit 162 a is sent to the speed calculation unit 163.

The Doppler frequency calculation unit 162b calculates the Doppler frequency in the uplink from the moving body 3 to the satellite 2b from the frequency measured by the frequency measurement unit 161b. At this time, in the Doppler frequency calculation unit 162b in the first embodiment, the reference station 4 measured by the frequency measurement unit 161b from the frequency of the signal corresponding to the signal transmitted from the moving body 3 measured by the frequency measurement unit 161b. The Doppler frequency is calculated by subtracting the frequency of the signal corresponding to the signal transmitted from. Information indicating the Doppler frequency calculated by the Doppler frequency calculation unit 162 b is sent to the speed calculation unit 163.

The speed calculator 163 calculates the speed of the moving body 3 from the Doppler frequency calculated by the Doppler frequency calculator 162a and the Doppler frequency calculated by the Doppler frequency calculator 162b. Information indicating the speed of the moving object 3 calculated by the speed calculator 163 is sent to the display unit 17.

Next, an operation example of the speed estimation device 1 configured as described above will be described with reference to FIGS.
In the operation example of the speed estimation device 1, as shown in FIG. 3, first, the receiving antenna 11a receives a signal transmitted from the mobile body 3 and a signal transmitted from the reference station 4 via the satellite 2a. Similarly, the receiving antenna 11b receives the signal transmitted from the mobile body 3 and the signal transmitted from the reference station 4 via the satellite 2b (step ST31). Examples of the moving body 3 include a radio wave source that transmits (uplinks) illegal radio waves such as interference waves to the satellites 2a and 2b.

Next, the reception device 19 performs reception processing on the signals received by the reception antennas 11a and 11b (step ST32). That is, the signal received by the receiving antenna 11a is filtered by the band pass filter 12a, converted to a low frequency by the down converter 14a, and converted to a digital signal by the A / D converter 15a. Similarly, the signal received by the receiving antenna 11b is filtered by the band pass filter 12b, converted to a low frequency by the down converter 14b, and converted to a digital signal by the A / D converter 15b.

Here, as shown in FIGS. 4 and 5, the moving body 3 is moving on the ground surface. In the first embodiment, the signals transmitted from the moving body 3 are received by the two satellites 2a and 2b and are downlinked to the two reception antennas 11a and 11b of the speed estimation device 1.
Note that the orbit information indicating the position p ₁ and the velocity v ₁ of the satellite 2a and the orbit information indicating the position p ₂ and the velocity v ₂ of the satellite 2b are known from the operating companies of the satellites 2a and 2b and the like. Furthermore, the transmission frequency _{f t} and the position _{p t} of the movable body 3 is also known. The position p _t of the movable body 3, for example, to acquire the position of the radio source suspected of sending illegal radio wave by monitoring the satellite images from other satellites, surveillance to the periphery of the radio wave source It can be obtained by running a special aircraft or car and acquiring its position. Further, the position p _b1 of the receiving antenna 11a and the position p _{b2 of the} receiving antenna 11b are also known.

Then, the frequency f _t of the signal transmitted from the mobile 3 is subject to various influences before sent to the receiving antenna 11a via the satellite 2a. Specifically, the Doppler frequency _{f up1} in the uplink from a mobile 3 to the satellite 2a, the frequency shift _{f s1} in the transponder of the satellite 2a, Doppler frequency _f of the downlink from the satellite 2a to the receiving antenna 11a _dn1 Etc. Therefore, the frequency f _b1 of the signal received by the receiving antenna 11a is a frequency different from the transmission frequency f _t of the movable body 3.

Similarly, the frequency f _t of the signal transmitted from the mobile 3 is subject to various influences before sent to the receiving antenna 11b via satellite 2b. Specifically, the Doppler frequency f _up2 in the uplink from the mobile unit 3 to the satellite 2b, the frequency shift f _s2 in the transponder of the satellite 2b, and the Doppler frequency f _dn2 in the downlink from the satellite 2b to the receiving antenna 11b. Etc. Therefore, the frequency f _b2 of the signals received by the receiving antenna 11b is a frequency different from the transmission frequency f _t of the movable body 3.

Further, in the first embodiment, as shown in FIG. 5, the signals transmitted from the reference station 4 are also received by the two satellites 2a and 2b and downlinked to the two receiving antennas 11a and 11b of the speed estimation device 1. Yes.
Incidentally, the reference station 4, the transmission frequency f _r and the position p _r are known and stationary. In the first embodiment, it is assumed that the transmission frequency f _r of the reference station 4 approximates the transmission frequency f _t of the mobile unit 3 (f _r ≈f _t ).

Then, the frequency f _r of the signal transmitted from the reference station 4 receives various influences before sent to the receiving antenna 11a via the satellite 2a. Specifically, the Doppler frequency f _rup1 in the uplink from the reference station 4 to the satellite 2a, the frequency shift f _s1 in the transponder of the satellite 2a, and the Doppler frequency f _rdn1 in the downlink from the satellite 2a to the receiving antenna 11a ( _{≈f dn1} ) and the like. Therefore, the frequency f _rb1 of received by the receiving antenna 11a signal is a frequency different from the transmission frequency f _r of the reference station 4.

Similarly, the frequency f _r of the signal transmitted from the reference station 4 receives various influences before sent to the receiving antenna 11b via satellite 2b. Specifically, the Doppler frequency f _rup2 in the uplink from the reference station 4 to the satellite 2b, the frequency shift f _s2 in the transponder of the satellite 2b, and the Doppler frequency f _rdn2 in the downlink from the satellite 2b to the receiving antenna 11b ( _{≈f dn2} ) etc. Therefore, the frequency f _rb2 of received by the receiving antenna 11b signal is a frequency different from the transmission frequency f _r of the reference station 4.

Thus, the signals received by the receiving antennas 11 a and 11 b and subjected to the receiving process by the receiving device 19 are sent to the speed calculation processor 16.

Next, the frequency measurement unit 161a of the speed calculation processor 16 measures the frequencies f _b1 and f _rb1 of the signal received by the reception antenna 11a using the signal converted into the digital signal by the A / D converter 15a. Similarly, the frequency measurement unit 161b of the speed calculation processor 16 measures the frequencies f _b2 and f _rb2 of the signal received by the reception antenna 11b using the signal converted into a digital signal by the A / D converter 15b ( Step ST33). At this time, the frequency measurement unit 161a measures the frequencies f _b1 and f _rb1 by, for example, Fourier transforming the signal from the A / D converter 15a. Similarly, the frequency measurement unit 161b measures the frequencies f _b2 and f _rb2 by, for example, Fourier transforming a signal from the A / D converter 15b.

Next, the Doppler frequency calculation unit 162a calculates the Doppler frequency f _up1 in the uplink from the moving body 3 to the satellite 2a from the frequencies f _b1 and f _rb1 measured by the frequency measurement unit 161a. Similarly, the Doppler frequency calculating unit 162b calculates the frequency _{f b2, f rb2} measured by the frequency measurement unit 161b, the Doppler frequency _{f up2} in the uplink from a mobile 3 to the satellite 2b (step ST34). At this time, in the Doppler frequency calculation unit 162a in the first embodiment, the reference measured by the frequency measurement unit 161a from the frequency f _{b1 of} the signal corresponding to the signal transmitted from the moving body 3 measured by the frequency measurement unit 161a. The Doppler frequency f _up1 is calculated by subtracting the frequency f _rb1 of the signal corresponding to the signal transmitted from the station 4. Similarly, in the Doppler frequency calculation unit 162b in the first embodiment, the reference measured by the frequency measurement unit 161b from the frequency f _{b2 of} the signal corresponding to the signal transmitted from the moving body 3 measured by the frequency measurement unit 161b. The Doppler frequency f _up2 is calculated by subtracting the frequency f _rb2 of the signal corresponding to the signal transmitted from the station 4.

As described above, the receiving antenna 11a, the frequency _f b1 of the signal received by _{11b, f b2,} the frequency shift _{f s1, f s2} and Doppler frequency _{f up1, f up2, f dn1} , various effects such as _{f dn2} Is receiving. Of these, the frequency shifts f _s1 and f _s2 are generally unknown because they are not disclosed to the outside, and are difficult to measure and estimate. Therefore, the frequency shifts f _s1 and f _s2 are canceled using the reference station 4. As a result, the extracted receiving antenna 11a, the frequency _{f b1, f b2, f rb1} , f rb2 of the signals received by 11b, finally, only the frequency _{f up1, f up2} due to Doppler during uplink be able to.

The use of the reference station 4 not only has the above effect but also cancels the influence of the error when the orbit information of the satellites 2a and 2b includes an error.
Hereinafter, details of the processing by the Doppler frequency calculation units 162a and 162b will be described.

First, the frequencies f _b1 and f _rb1 of the signal received by the receiving antenna 11a can be expressed by the following equations (1) and (2).

Similarly, the frequencies f _b2 and f _rb2 of the signal received by the receiving antenna 11b can be expressed by the following equations (3) and (4).

Further, the Doppler frequency f _rup1 in the uplink from the reference station 4 to the satellite 2a can be calculated from the orbit information of the satellite 2a as shown in the following equation (5).

Here, λ _r is the wavelength of the signal from the reference station 4 during uplink.

Similarly, the Doppler frequency f _rup2 in the uplink from the reference station 4 to the satellite 2b can be calculated from the orbit information of the satellite 2b as shown in the following equation (6).

Here, the downlink terms f _s1 and f _dn1 of the equation (1) and the downlink terms f _s1 and f _rdn1 of the equation (2) are substantially the same value. Also in the first embodiment, the transmission frequency f _r of the transmission frequency f _t and the reference station 4 of the movable body 3 is almost the same value. Therefore, when the equation (2) is subtracted from the equation (1), the Doppler frequency f _up1 in the uplink from the mobile unit 3 to the satellite 2a is expressed by the following equation (7).

Therefore, the frequency _{f b1, f rb1} measured by the frequency measurement unit 161a, and a Doppler frequency _{f RUP1} calculated from Equation (5), by substituting the equation (7), a measurement of the Doppler frequency _{f up1} Obtainable.

Similarly, downlink term _{f s2, f rdn2} of formula (3) downlink term _{f s2, f dn2} the formula (4) is substantially the same value. Also in the first embodiment, the transmission frequency f _r of the transmission frequency f _t and the reference station 4 of the movable body 3 is almost the same value. Therefore, when the equation (4) is subtracted from the equation (3), the Doppler frequency f _up2 in the uplink from the mobile unit 3 to the satellite 2b is expressed by the following equation (8).

Therefore, the frequency _{f b2, f rb2} measured by the frequency measurement unit 161a, and a Doppler frequency _{f RUP2} calculated from equation (6), by substituting the equation (8), a measurement of the Doppler frequency _{f up2} Obtainable.

On the other hand, the Doppler frequency f _up1 in the uplink from the mobile unit 3 to the satellite 2a can be calculated from the orbit information of the satellite 2a as shown in the following equation (9).

Here, λ _t is the wavelength of an uplink signal from the mobile unit 3, and v _t is an unknown three-dimensional velocity vector (hereinafter referred to as speed) of the mobile unit 3.

Similarly, the Doppler frequency f _up2 in the uplink from the mobile unit 3 to the satellite 2b can be calculated from the orbit information of the satellite 2b as shown in the following equation (10).

Here, the position p ₁ and velocity v _{1 of} the satellite 2a, the position p ₂ and velocity v _{2 of} the satellite 2b, and the position p _t of the moving body 3 are known. Therefore, a material obtained by subtracting a term of the equation (9) to the speed _{v 1} of the satellite 2a newly defined as the Doppler frequency _{f up1,} similarly, subtracting the term of the velocity _{v 2} of the satellite 2b from equation (10) This is newly defined as the Doppler frequency f _up2 . Thereby, Formula (9) and (10) can be simplified and simultaneous equations like following Formula (11) and (12) can be obtained.

In the equations (11) and (12), the unknown variable is only the speed v _t of the moving body 3. However, since the speed of the moving body 3 is a three-dimensional speed vector, the number of equations is two, while there are three unknown variables, and cannot be solved.

Therefore, the speed v _t of the moving body 3 is reduced to two dimensions so that there are two unknown variables. Specifically, as shown in FIG. 6, it is assumed that the moving body 3 moves on the ground surface at a two-dimensional velocity v _{t, surf} shown in the following equation (13).

At this time, a known position on the ground surface of the moving body 3 is expressed in latitude and longitude as in the following formula (14).

Here, R _E is the earth radius, lonE _t is longitude (east longitude), and latN _t is latitude (north latitude).

In this case, the velocity _{v t} of the moving body 3, two-dimensional velocity _{v t} in the plane coordinate system with the origin position _{p t} of the movable body _3, conversion formula and _surf is represented by the following formula (15).

D is represented by the following formula (16).

Therefore, when Expression (15) is substituted into Expressions (11) and (12), the number of unknown variables becomes two as in Expressions (17) and (18) below.

Note that when the velocity v _t of the moving body 3 is dropped in two dimensions, it is not limited to the ground surface, but may be dropped in an arbitrary two-dimensional plane.
In this manner, information indicating the Doppler frequencies f _up1 and f _up2 calculated by the Doppler frequency calculation units 162a and 162b (information indicating the equations (7), (8), (17), and (18)) is the speed. It is sent to the calculation unit 163.

Next, the speed calculation unit 163 calculates the speed v _t of the moving body 3 from the Doppler frequencies f _up1 and f _up2 calculated by the Doppler frequency calculation units 162a and 162b (step ST35). At this time, the speed calculation unit 163 calculates the speed v _t of the moving body 3 using a general least square method such as the following equation (19).

Note that f _{up1 and obs} are measured values of the Doppler frequency f _up1 obtained by Expression (7), and f _up1 (v _{t, surf} ) corresponds to the Doppler frequency f _up1 shown by Expression (17). . Similarly, f _{up2, obs} is a measured value of the Doppler frequency f _up2 obtained by Expression (8), and f _up2 (v _{t, surf} ) corresponds to the Doppler frequency f _up2 shown by Expression (18). To do. R is a frequency measurement error covariance matrix and is represented by the following equation (20).

Here, σ _FOA ² is a frequency measurement error variance value. The frequency measurement error variance value _σFOA ² represents a measurement error generated when the frequency is measured by the frequency measurement units 161a and 161b as a variance value. The variance is a value indicating how much the distribution of the random variable is scattered from the expected value in the probability theory, that is, an error has occurred. In this case, the expected value is the true value of the frequency.

It should be noted that various methods other than the least square method are known for solving the optimization problem when calculating the velocity v _t of the moving body 3 from the Doppler frequencies f _up1 and f _up2. The detailed explanation is omitted.
In addition, since equations (17) and (18) are linear simultaneous equations, it is possible to explicitly derive a solution. Also for this, detailed description is omitted.

Next, the display unit 17 displays information indicating the speed v _t of the moving body 3 calculated by the speed calculation processor 16 (step ST36).

FIG. 7 is a diagram showing an example of the equal Doppler frequency f _up1 curve and the equal Doppler frequency f _up2 curve, and shows the relationship between the Doppler frequencies f _up1 and f _up2 and the velocity v _t . In FIG. 7, the horizontal axis indicates the east-west direction, and the vertical axis indicates the north-south direction. Further, the equal Doppler frequency f _up1 curve is indicated by a solid line, and the equal Doppler frequency f _up2 curve is indicated by a broken line. In FIG. 7, the intersection point between the equal Doppler frequency f _up1 curve and the equal Doppler frequency f _up2 is the velocity v _t .

As described above, according to the first embodiment, the receiving antennas 11a and 11b that receive the signal transmitted from the moving body 3 and the signal transmitted from the reference station 4 via the corresponding satellites 2a and 2b, , Frequency measurement units 161a and 161b that measure the frequencies f _b1 , f _b2 , f _rb1 , and f _rb2 of the signals received by the corresponding reception antennas 11a and 11b, and frequencies measured by the corresponding frequency measurement units 161a and 161b. from _{f b1, f b2, f rb1} , f rb2, satellite 2a corresponding from the mobile 3, the Doppler frequency calculating unit 162a for calculating the Doppler frequency _{f up1, f up2} in the uplink to 2b, a 162b, Doppler frequency calculation unit 162a, the Doppler frequency _{f up1, f up2} calculated by 162b, mobile Since a speed calculation unit 163 that calculates the speed v _t, in one observation, it is possible to accurately estimate the velocity v _t of the moving body 3. That is, two or more observations as in the conventional configuration are not required, and a difficult determination as to whether each observation value is from the same moving body 3 is not necessary, and an erroneous determination can be avoided. Further, since the observation is performed once, it is not necessary to make assumptions about the movement of the moving body 3 as in the conventional case, and the speed v _t of the moving body 3 can be accurately estimated.

In the conventional configuration, the position of the moving body 3 is unknown and needs to be estimated, whereas in the speed estimation apparatus according to the first embodiment, the position of the moving body 3 is known and the number of variables to be estimated is reduced. . As a result, the speed estimation device according to Embodiment 1 is expected to have higher estimation accuracy than the conventional configuration.

Embodiment 2. FIG.
In the first embodiment, the transmission frequency f _t and the transmission frequency f _r of the reference station 4 of the movable body 3 has been described on the assumption that approximates always be selected such reference station 4 Not necessarily. That is, it may be difficult to restrict the transmission frequency f _r of the reference station 4 to the transmission frequency f _t of the mobile unit 3 so that the difference can be ignored. In this case, the value itself of the transmission frequency f _r of the transmission frequency f _t and the reference station 4 of the movable body 3 is both a GHz order in some cases the difference is order of MHz. Therefore, even if the reference station 4 is used, the downlink term cannot be canceled. In the second embodiment, a method for canceling components that cannot be canceled by the reference station 4 in the above case will be described. In the following description, only the system of the satellite 2a will be described, but the same applies to the system of the satellite 2b.

The basic configuration of speed estimation device 1 according to Embodiment 2 is the same as that of speed estimation device 1 according to Embodiment 1 shown in FIG.
However, in the Doppler frequency calculation unit 162a in the second embodiment, first, the transmission frequency f _t of the mobile unit 3, the transmission frequency f _r of the reference station 4, the position p _b1 of the receiving antenna 11a, and the position p _{1 of the} satellite 2a. And the correction value C ₁ is calculated from the speed v ₁ . The Doppler frequency calculating section 162a, from the frequency f _b1 of the signal corresponding to the signal transmitted from the mobile 3 measured by the frequency measurement unit 161a, which is transmitted from the reference station 4, which is measured by the frequency measurement unit 161a by subtracting the frequency _{f rb1} and the correction value _{C 1} of the signal corresponding to the signal, to calculate the Doppler frequency _{f up1.} The details of the processing by the Doppler frequency calculation unit 162a will be described below.

The frequencies f _b1 and f _rb1 of the signal received by the receiving antenna 11a are expressed by the following equations (21) and (22), as in the first embodiment.

In this case, as in the first embodiment, the following equation (23) is obtained by subtracting equation (22) from equation (21).

When this equation (23) is arranged, the following equation (24) is obtained.

Here, since f _t ≠ f _r and f _dn1 ≠ f _rdn1 , the term of the following expression (25) remains on the right side of the expression (24).

Among these, the term (f _t −f _r ) has a great influence. That is, since each has a value on the order of GHz, even if each value is slightly different, measurement accuracy is greatly affected.
In the second embodiment, in order to cancel the term (f _t −f _r ) + (f _dn1 −f _rdn1 ), the transmission frequency f _t of the mobile 3, the transmission frequency f _r of the reference station 4, the reception position _{p b1} antenna 11a, and, from the position _{p 1} and velocity _{v 1} of the satellite 2a, calculates a correction value _{C 1,} is subtracted from the right side of the equation (24).
Since the transmission frequencies f _t and f _r are known, the correction value C ₁ can be calculated from the equation (25) if the Doppler frequencies f _dn1 and f _rdn1 can be calculated.

Here, the Doppler frequency _f of the downlink from the satellite 2a to the receiving antenna 11a _{dn1, f RDN1} from orbital information of a satellite 2a, the following equation (26), can be calculated as (27).

Here, λ _a1 is the wavelength of the signal corresponding to the signal transmitted from the mobile unit 3 during downlink from the satellite 2a. Further, λ _ra1 is a wavelength of a signal corresponding to a signal transmitted from the reference station 4 at the time of downlink from the satellite 2a.

Therefore, by subtracting the correction value C ₁ obtained by the equation (25) from the right side of the equation (24), (f _t −f _r ) + (f _dn1 −f _rdn1 ) as in the following equation (28): The terms can be canceled, and the remaining terms can be calculated in the same manner as in Embodiment 1 to obtain the Doppler frequency f _up1 .

The Doppler frequency f _up2 can be calculated in the same manner as described above.

Embodiment 3 FIG.
In the third embodiment, the transmission frequency f _t and the transmission frequency f _r of the reference station 4 of the mobile body 3 as what to do if not approximation, the case of using the scaling. In the following description, only the system of the satellite 2a will be described, but the same applies to the system of the satellite 2b.

The basic configuration of speed estimation device 1 according to Embodiment 3 is the same as that of speed estimation device 1 according to Embodiment 1 shown in FIG.
However, in the Doppler frequency calculation unit 162a in the third embodiment, first, the transmission frequency f _t of the mobile 3, the transmission frequency f _r of the reference station 4, the position p _b1 of the receiving antenna 11 a, and the position p _{1 of the} satellite 2 a. and from the speed _{v 1,} to calculate a correction value _{C 2.} In addition, the Doppler frequency calculation unit 162a sets the frequency f _rb1 corresponding to the signal transmitted from the reference station 4 measured by the frequency measurement unit 161a, to the transmission frequency f _t of the mobile unit 3 and the transmission frequency f _{r of the} reference station 4. Scale with. The Doppler frequency calculating section 162a, from the frequency f _b1 of the signal corresponding to the signal transmitted from the mobile 3 measured by the frequency measurement unit 161a, by subtracting the frequency and the correction value C ₂ of the above scaling , Calculate the Doppler frequency f _up1 . The details of the processing by the Doppler frequency calculation unit 162a will be described below.

The frequencies f _b1 and f _rb1 of the signal received by the receiving antenna 11a are expressed by the following equations (29) and (30), as in the first embodiment.

In this case, as in the second embodiment, the effect is large is the transmission frequency f _t, f _r. That is, the value of the transmission frequency f _r of the transmission frequency f _t and the reference station 4 of the mobile body 3 due to its order of GHz, each value affects greatly slightly different alone measurement accuracy. Therefore, a difference is obtained by scaling the frequency f _rb1 of the signal received by the receiving antenna 11a with respect to the equations (29) and (30) as in the following equation (31).

When this equation (31) is arranged, the following equation (32) is obtained.

Here, since f _t ≠ f _r and f _dn1 ≠ f _rdn1 , the term of the following expression (33) remains on the right side of the expression (32).

In the third embodiment, the transmission of the mobile unit 3 is performed in order to cancel the term of f _s1 (1− (f _t / f _r )) + (f _dn1 − (f _t / f _r ) f _rdn1 ). A correction value C ₂ is calculated from the frequency f _t , the transmission frequency f _r of the reference station 4, the position p _b1 of the receiving antenna 11 a, the position p ₁ and the velocity v _{1 of} the satellite 2 a, and from the right side of the equation (32) Subtract.
Since the transmission frequencies f _t and f _r are known, the correction value C ₂ can be calculated from the equation (33) if the Doppler frequencies f _dn1 and f _rdn1 can be calculated.

Here, the Doppler frequency _f of the downlink from the satellite 2a to the receiving antenna 11a _{dn1, f RDN1} from orbital information of a satellite 2a, the following equation (34), can be calculated as (35).

Therefore, by subtracting the correction value C ₂ obtained by the equation (33) from the right side of the equation (32), as shown in the following equation (36), f _s1 (1− (f _t / f _r )) + (f _dn1 - term it is possible to cancel the _{(f t / f r) f} rdn1).

Here, since even if the value of the transmission frequency _{f r} of the transmission frequency _{f t} and the reference station 4 of the movable body 3 is different in MHz of the order, the value itself is the GHz order _both, (f t _{/ f} r) Is close to 1. Therefore, the expression (36) can be approximately expressed as the following expression (37), and the Doppler frequency f _up1 can be obtained by calculating the remaining terms in the same manner as in the first embodiment.

The Doppler frequency f _up2 can be calculated in the same manner as described above.

As described above, even in the order difference of MHz value of the transmission frequency f _r of the transmission frequency f _t and the reference station 4 of the movable body 3, relatively close between values of GHz order both values itself Therefore, (f _t / f _r ) is close to 1. In contrast, the frequency shift _{f s1} is order of MHz, the value of the correction value _{C 2} is very small. Therefore, it is assumed that the range of measurement error, there is the option of not subtracting the correction value C _2.

Embodiment 4 FIG.
FIG. 8 is a diagram showing a functional configuration example of the speed calculation processor 16 according to the fourth embodiment of the present invention. The speed calculation processor 16 in the fourth embodiment shown in FIG. 8 is obtained by adding a moving direction estimation unit 164 to the speed calculation processor 16 in the first embodiment shown in FIG. Other configurations are the same, and only the different parts are described with the same reference numerals.

The moving direction estimation unit 164 estimates the moving direction of the moving body 3 from the Doppler frequency ratio curve calculated by the Doppler frequency calculation units 162a and 162b. At this time, the moving direction estimation unit 164 solves the moving direction ambiguity generated in the ratio curve from the sign of the Doppler frequency. Information (movement direction information) indicating the movement direction of the moving body 3 estimated by the movement direction estimation unit 164 is sent to the display unit 17.
In addition to the function in the first embodiment, the display 17 also displays information indicating the moving direction of the moving body 3 estimated by the moving direction estimating unit 164.

When the ratio of the equal Doppler frequency f _up1 curve and the equal Doppler frequency f _up2 curve shown in FIG. 7 is taken, an equivalent ratio curve (f _up1 / f _up2 ) as shown in FIG. 9 is obtained. From FIG. 9, it can be seen that the iso- _ratio curve (f _up1 / f _up2 ) is obtained radially from the origin. And by calculating the value of this ratio, the moving direction can be estimated, although the magnitude of the velocity v _t of the moving body 3 is not known.

Note that the geometric curve (f _up1 / f _up2 ) has a direction that diverges to ± ∞ due to zero _division , but other moving directions can be estimated. In the vicinity of this speed, the value of the _equiratio curve (f _up1 / f _up2 ) changes abruptly from ± ∞ to 0, so that the isocurve is dense as shown in FIG. Further, in this geometric curve (f _up1 / f _up2 ), an ambiguity in the moving direction occurs. For example, in FIG. 9, 1.05 is seen in the northeast direction and the southwest direction, but there is a situation where it is unknown which is correct. However, it is possible to solve from the signs of the Doppler frequencies f _up1 and f _up2 . For example, in FIG. 9, 1.05 is seen in the northeast and southwest directions. If both signs of the Doppler frequency f _up1 and the Doppler frequency f _up2 are positive, the northeast is correct, and if the signs are negative, the southwest is the correct moving direction.
Note that the movement direction estimation unit 164 holds, as a movement direction database, the value of the ratio curve for each direction based on, for example, the _equiratio curve (f _up1 / f _up2 ) as shown in FIG.

Next, an operation example by the movement direction estimation unit 164 will be described with reference to FIG.
As shown in FIG. 10, the moving direction estimation unit 164 first calculates the ratio curve (f _up1 / f _up2 ) of the Doppler frequencies f _up1 and f _up2 calculated by the Doppler frequency calculation units 162a and 162b (step ST111). ).

Next, the moving direction estimation unit 164 collates the held moving direction database and selects a moving direction candidate of the moving body 3 (step ST112). In other words, a candidate for the moving direction is selected by determining on which line in FIG. 9 the calculated ratio curve (f _up1 / f _up2 ) is closest.

Then, the moving direction estimation unit 164 solves the moving direction of the ambiguity caused by the ratio curve _(f up1 _/ f _up2) from the sign of the Doppler frequency _{f up1, f up2} (step ST113). That is, since there is an ambiguity in the moving direction generated in the ratio curve (f _up1 / f _up2 ), this ambiguity is solved from the signs of the Doppler frequencies f _up1 and f _up2 . Thereby, the moving direction of the mobile body 3 can be estimated.

In the above description, the case where the moving direction estimation unit 164 is added to the speed calculation processor 16 in the first embodiment has been described. However, the present invention is not limited to this, and the moving direction estimation unit 164 may be added to the speed calculation processor 16 in the second and third embodiments.

Embodiment 5 FIG.
FIG. 11 is a diagram showing a functional configuration example of the speed calculation processor 16 according to the fifth embodiment of the present invention. The speed calculation processor 16 in the fifth embodiment shown in FIG. 11 is obtained by adding a moving direction estimation unit 165 to the speed calculation processor 16 in the first embodiment shown in FIG. Other configurations are the same, and only the different parts are described with the same reference numerals.

The moving direction estimation unit 165 estimates the moving direction of the moving body 3 from the arc tangent function of the ratio curve of the Doppler frequencies calculated by the Doppler frequency calculation units 162a and 162b. At this time, the moving direction estimation unit 165 solves the moving direction ambiguity generated by the arctangent function of the ratio curve from the sign of the Doppler frequency. Information indicating the moving direction of the moving body 3 estimated by the moving direction estimating unit 165 (moving direction information) is sent to the display unit 17.
In addition to the function in the first embodiment, the display unit 17 also displays information indicating the moving direction of the moving body 3 estimated by the moving direction estimating unit 165.

In the fifth embodiment, similar to the fourth embodiment, an arctangent function arctan (f _up1 / f _up2 ) of the ratio curve (f _up1 / f _up2 ) is used instead of the ratio curve (f _up1 / f _up2 ). . By taking the arc tangent function in this way, the ratio curve (f _up1 / f _up2 ) becomes ± π / 2 at a speed at which the ratio curve becomes ± ∞, so that reading is easy. However, since the speed at which the ratio curve (f _up1 / f _up2 ) becomes ± ∞ and the speed at which it becomes 0 are close, in this case, the arctangent function arctan (f _up1 / f _up2 ) is changed from ± π / 2 to 0, Switches suddenly. Therefore, also in FIG. 12, the isocurve is dense near the speed.
In addition, since the operation | movement of the movement direction estimation part 165 is the same as that of the movement direction estimation part 164 of Embodiment 4, the description is abbreviate | omitted.

In the above, the case where the moving direction estimation unit 165 is added to the speed calculation processor 16 in the first embodiment has been described. However, the present invention is not limited to this, and a moving direction estimation unit 165 may be added to the speed calculation processor 16 in the second and third embodiments.

Further, within the scope of the present invention, the invention of the present application can be freely combined with each embodiment, modified with any component in each embodiment, or omitted with any component in each embodiment. .

The speed estimation apparatus according to the present invention can correctly estimate the speed of the moving object in one observation, and is suitable for use in a speed estimation apparatus that estimates the speed of the moving object.

1 speed estimation device, 2a, 2b satellite, 3 mobile, 4 reference station, 11a, 11b receiving antenna, 12a, 12b bandpass filter, 13 local oscillator, 14a, 14b down converter, 15a, 15b A / D converter, 16 Speed calculation processor, 17 display, 18 memory, 19 receiving device, 161a, 161b, frequency calculation unit, 162a, 162b, Doppler frequency calculation unit, 163 speed calculation unit, 164, 165 movement direction estimation unit.

Claims (8)

1. Provided for every two geostationary satellites whose positions and velocities are known, via the corresponding geostationary satellites, signals transmitted from mobiles whose transmission frequency and position are known, and stationary that the transmission frequency and position are known A receiving antenna for receiving a signal transmitted from a reference station;
   A frequency measurement unit that is provided for each reception antenna and measures the frequency of the signal from the moving body and the frequency of the signal from the reference station received by the corresponding reception antenna;
   A Doppler frequency calculation unit that is provided for each frequency measurement unit and calculates a Doppler frequency in the uplink from the mobile body to the corresponding geostationary satellite from the frequency measured by the corresponding frequency measurement unit;
   A speed estimation device comprising: a speed calculation unit that calculates the speed of the moving object from the Doppler frequencies calculated by the two Doppler frequency calculation units.
2. The Doppler frequency calculation unit corresponds to the signal transmitted from the reference station measured by the frequency measurement unit, from the frequency of the signal corresponding to the signal transmitted from the moving body measured by the frequency measurement unit. The speed estimation apparatus according to claim 1, wherein the Doppler frequency is calculated by subtracting the frequency of the signal.
3. The Doppler frequency calculation unit calculates a correction value from the transmission frequency of the mobile object, the transmission frequency of the reference station, the position of the corresponding receiving antenna, and the position and velocity of the corresponding geostationary satellite, and the frequency measurement The frequency of the signal corresponding to the signal transmitted from the reference station measured by the frequency measuring unit and the correction value are subtracted from the frequency of the signal corresponding to the signal transmitted from the moving body measured by the unit. The speed estimation device according to claim 1, wherein the Doppler frequency is calculated.
4. The Doppler frequency calculation unit calculates a correction value from the transmission frequency of the mobile object, the transmission frequency of the reference station, the position of the corresponding receiving antenna, and the position and velocity of the corresponding geostationary satellite, and the frequency measurement The mobile unit measured by the frequency measurement unit by scaling the frequency of the signal corresponding to the signal transmitted from the reference station measured by the unit using the transmission frequency of the mobile unit and the transmission frequency of the reference station The velocity estimation apparatus according to claim 1, wherein the Doppler frequency is calculated by subtracting the scaled frequency and the correction value from a frequency of a signal corresponding to a signal transmitted from.
5. The speed estimation device according to claim 1, further comprising a movement direction estimation unit that estimates a movement direction of the moving body from a ratio curve of Doppler frequencies calculated by the two Doppler frequency calculation units.
6. The speed estimation device according to claim 5, wherein the moving direction estimation unit solves the ambiguity of the moving direction generated in the ratio curve from the sign of the Doppler frequency calculated by the two Doppler frequency calculation units. .
7. The speed estimation apparatus according to claim 1, further comprising a movement direction estimation unit that estimates a movement direction from an arctangent function of a ratio curve of Doppler frequencies calculated by the two Doppler frequency calculation units.
8. The said moving direction estimation part solves the ambiguity of the moving direction which arises with the arctangent function of the said ratio curve from the code | symbol of the Doppler frequency calculated by two said Doppler frequency calculation parts. Speed estimation device.

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