JPH02213786A - Position measuring method using artificial satellite - Google Patents

Abstract

PURPOSE:To calculate an observer's own position by putting artificial satellites having large angles of inclination into the static orbit in such a manner that the four artificial satellites are observed from the observer who has a signal receiver, a simple watch and a calculation processing argorithm. CONSTITUTION:An observation point P cannot be detected with the constitution using the three artificial satellites and, therefore, the four artificial satellites are used. An X''-axis is designated as 40, a Y''-axis as 41, the 4th artificial satellite as 42, the hyperbola obtd. by the observation of the artificial satellites 20 and 42 as 43, the hyperbola obtd. by the observation of the artificial satellite 42 as 43, an angle formed by the X'-axis and X'' as 44, and the straight line running the intersected point of the hyperbolas 6 and 43 as 45. X''Y'' coordinates are newly added and the fresh artificial satellite 42 is added. As a result, the difference in the distance form the artificial satellite 20 is observed and the hyperbola 43 is drawn and the straight line 45 connecting the two intersected points of the hyperbolas 6 and 43 is obtd. The existence of the observation point P at the intersected point of the straight lines 45, 46 is thus confirmed. The phenomena of X'Y' and X''Y'' can be developed to the three-dimensional phenomena of the XYZ coordinates, X'Y'Z' and X''Y''Z'' axes as well.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to detecting the position of a receiving point by receiving radio waves transmitted from an artificial satellite in a geosynchronous orbit and processing the data.

[Prior art] Conventional radio navigation uses artificial satellites such as Detsuka, Omega, and Loran-0, which have oscillation sources on the earth.
8 S (Navy Navigation 5ate
llite By-stem) and GP 8 (Glo
vaI Positioning System). Systems that use artificial satellites can be deployed in outer space, where the range of positioning that serves as the reference point for position detection is large, so accuracy can be expected to improve by expanding the range of two-position detection and by installing advanced equipment. Among these, NN5B is a method that uses Dotsupura, and GP8 is a method that is based on distance measurement by time measurement, and compared to the former, the latter has many superior performances. This is expected to become the mainstream of navigation satellites in the future. In order to compare with this invention, the prior art will be explained using this GPS'i as a target.

Figure 20 shows the configuration of the GP8 satellite.

(500), (301), (302), (303) are G
ONAVSTAR for PS (NAVigatlon sy
stem With Timing and Rang
lng) at its positions 'iiA', B', C',
Indicated by D'. WAVEITAR has its own precise atomic clock and maintains the accuracy of the clock signal it generates with high accuracy. At the same time, by calibrating the time information from the control station, N
AVSTAB accurately represents the current time based on the beginning of the week.

In addition, the location of NAVSTAB is determined by the NAVS from the air traffic control station.
The trajectory is determined from the TAR tracking data, and once the time is known, the vehicle's position will be determined. Therefore, if the observer is at NAVSTARO, NAVS'r''
The position is known from the current time of 'ha, that time, and the orbital elements.Secondly, what will happen if this observer leaves the NAVSTAB position and observes NAVSTAR? as the observation point.

It is represented by P'. Now the observer has a time device.

Assume that the clock is not a highly accurate one that has been comparatively calibrated, but has a certain error from the reference time. Let Tno+Δt be the time when the observer performs the observation. Tno is the inherent error that the Δtij observer has at the correct time. At this time, NAVSTAR (300) measured by the observer
, (301), (302), and (503) are Tnl
, Tn2, Tn3, and Tn4, these times are values delayed by the propagation time between the observer and the satellite. The following equation is established from the observed time and the positional relationship of NAVSTAH.

A'I' = O (Tno + Δt - Tnl) (1 (The equation has three types of three-dimensional values for the position of y as unknowns and four types of equations for Δt, so this equation is It has a solution and can calibrate the observer's position and time.

NAVSTAB's orbit is a circular one with an altitude of 20,183 km.

The period is 12 hours, and the orbital inclination angle is 55 degrees. Three satellites are placed on this orbit at equal intervals, and there are six types of orbits, making a total of 18 satellites flying on this orbit. Four NAVSTARs are always visible from any point on Earth.

NAVSTAB has one control station and one monitor station,
When NAVSTAB is within the visible range of 9 stations placed in groups of 4 stations, it acquires data and sends necessary commands.

The trajectory data is processed using data processing equipment based on the acquired data, and time management is calibrated with the primary standard.

[Problem to be solved by the invention]

GPI3 requires at least 18 0NAV8'l'ARs in order to cover the entire globe in which positioning is possible.

In addition, when NAv8TAR generates the source data for ranging, highly accurate time and frequency are required, and the frequency at which the control station can calibrate the time and frequency is once a week, so there are fluctuations during that time. It is expensive because it is equipped with an atomic clock to keep it within acceptable limits. In contrast, the present invention aims to obtain the same effect as GP8 using a simpler method.

[Means to solve the problem]

In this invention, 10 artificial satellites are placed in geostationary orbit with an orbital inclination of approximately 6 degrees, and each The satellites are placed so that their periapsis and elongation are appropriately evenly spaced apart from each other at the moment of formation, and the time and frequency generated from each satellite are monitored at a control station that is always in the visible range.The high precision obtained at the earth station is By comparing the frequency with the time reference of the satellite and issuing commands for correction at high frequency, one artificial satellite generates a signal for highly accurate distance measurement.

[Effect]

This invention consists of a set of four artificial satellites in geostationary orbit. Among them, the reference satellite synchronizes with time and generates a distance measurement signal, and simultaneously sends this signal directly to the observer. This distance measurement signal is sent to the satellite by inter-satellite data relay, and the neighboring artificial satellite that receives this signal sends this signal and its own time and distance measurement signal to the observer, and at the same time transmits it again to the next neighboring artificial satellite. This was done for four artificial satellites, and observers were able to perform their own position detection processing based on this data.

〔Example〕

First, the measurement principle for positioning using an artificial satellite will be explained.

Figure 1 shows the case where two artificial satellites are used and deployed in two dimensions. (1) and (2) are satellite A in orbit,
B, (31 is the satellite A, B (11, (21t) is the axis that penetrates the At a point P whose distance difference from B is constant, (6) is the locus of point P on the X7 plane, ())
is a hyperbola symmetrical to hyperbola (6) with respect to the y-axis.

! The hyperbola on the 7-plane can be expressed by the following formula.

12b12 Here, the focal point and eccentricity are: f=distance difference from the focal point d:2a1.

If point P (5) is taken as an observation point, in this invention, the difference in distance between two artificial satellites A, B (11, (21) and the observation point is measured. In the configuration shown in Fig. 1, this distance difference From the information, hyperbolas (6) and (7) can be drawn, and the observation point is hyperbola (6).
This means that solutions can exist for both (7) and (7), but the distance A
If we obtain information on the magnitudes of P and BP, we can determine which hyperbola the observation point is located on. Here, it is assumed that there is an observation point on the hyperboloid a1Bi.

In FIG. 1, a two-dimensional case was explained.

Since the actual phenomenon exists in three dimensions, a hyperbola on the

Figure 2 shows the hyperboloid of the ryz coordinates. (8) is the z-axis.

(9) is a hyperboloid, Q(I and αυ are the circles when the hyperboloid is cut by a plane parallel to the 7Z plane.

The distance differences AP and BP shown in Figure 1 satisfy the constant condition! 71! The position on the + coordinate is a hyperboloid (91).

Hyperboloid (9) can be expressed by the following formula on the X7Z coordinates.

a, 2b12 When the observation point is on the X-axis in the first fixed configuration or in the configuration shown in Figure 2, a hyperbola or hyperboloid may become a straight line, but in this invention, the artificial Because it consists of satellites and observation points near the ground, such a composition does not exist.

Next, a case where three artificial satellites are used will be explained using FIG. 3. The two parts have the same structure as shown in the first prisoner! 7
Suppose that another artificial satellite exists on another X'7'm* on the plane. A is the X' axis for the artificial satellite C2, @ is the y' axis, and @ is the angle θ between the X and X' axes.

The gradient is a hyperbola with a constant distance difference between AP and CP including observation point P,
Kyo is one of the intersections of hyperbola (6) and Nazu, kan is hyperbola (6)
This is a straight line that includes two points where and aa intersect.

Observation point P (5) is artificial satellite A, B mouth 1.121.
and the satellite A, 0(11,@), AP and BP, A
It exists under the condition that the distance difference between P and cp is constant. Figure 1 shows the former combination of artificial satellites. Assuming that the latter condition is satisfied, the hyperbolic ll1ic! I can draw 41.

The two points at which the same distance difference can be measured between the two hyperbolas (6) and @ are the intersection points (5) and 6.

Next, consider FIG. 3 and expand the phenomenon in the ftxy, x'y' plane to the three-dimensional phenomenon of the xyz and X'7'Z' coordinates in FIG. @ is a hyperboloid obtained by rotating the hyperbola @ around the It is a quadratic curve formed by the intersection of two hyperboloids (91 and @).

A hyperboloid on the X7g coordinate and the x'fzl coordinate (91 and @ are expressed by the following formula n.

al2 b12 a 22 b 22 17The relationship between the M coordinate and the X/y'z/ coordinate is as follows! Since the 7 plane and the x/f plane are set to be the same.

Z: Z' −−−・−・−, −(Formula 61 (
According to the condition of 6), pz't-eliminates the equation (2) and equation (4).

From the hyperbola formula, it can be said that the ratio of the length between a point on a hyperboloid and the focal length and a point on the same hyperboloid and the directrix is equal to the eccentricity. On the x y, x/f plane in Figure 3, (5
), the hyperbola in (6) is the first
．． In the fourth quadrant, the @ hyperbola is the second. It's in the third quadrant9
The following formula holds.

Ap=Ie1z-ail=le2x+a21 (
81 If we consider the case of Fig. 3 down to the sign, Equation 2 (8) becomes as follows.

elx −al = −(e2x + a2)
to+Equation (91) is a formula that holds true not only for xy, x/y/planes, but also for hyperboloids rotated around the X and Ga axes in Figure 4.

Therefore, by substituting equation (9) into equation (7) and expanding the equation to find the conditions for the crossing of the hyperboloid, we finally get KIX 10 to 27 10 to 3 = 0 Q(1 where Kj = -2a2(8j + e2cO6θ)
K2 = -282a2Iiaθ Kg = 012a12-1-28182a1a2Q)
6θ+622 a22-(al-a2)2-(b12-
The equation of the straight line b22) is found.

Since the formula QO does not depend on 2 and 2', X7Z
Coordinates, X'fZ' coordinate formula (Z including IG indicates a plane m parallel to the Z' axis.

The intersection of equations (2) and (4) is included in the (to) plane.

In the configuration shown in Figure 4, which uses three artificial satellites, observation point P
(It can be seen that 51 exists on a circle or ellipse that is a quadratic curve existing on the plane of (to).If it can be known as a known number from the system on the altitude gold side of the observation point, then (5
) can be defined as a point.

However, based on information only about distance differences between satellites, the observation point can be set to point P (
5) is insufficient to detect with three satellites. Therefore, the following case will be explained using four artificial satellites.

Figure 5 shows the situation on the X1 plane when four artificial satellites are used. No is the X” axis, U is the y” axis.

(Company) is the fourth artificial satellite, and D is the prisoner artificial satellite C.■
The next station curve obtained by observation of satellites.

- is the angle formed by the X' axis of the gradient and the X'' axis of the throat, and the lie is the straight line passing through the intersection of the hyperbola of (6) and the hyperbola of 0.

As a result of adding the new X"y# coordinates and the addition of the company's new satellite, a hyperbola of 0 was drawn by observing the distance difference with the 12G satellite C. (6) A straight line is obtained that connects the intersection of the two hyperbolas and IO.

It can be determined that the observation point is located at the intersection (5) of the two straight lines. ! On the seven planes, an observation point can be determined as the intersection of two straight lines using four artificial satellites.

Next, using FIG. 6, it will be explained that the same idea can be applied to three dimensions. ■ is the X”y”2121 coordinate axis, (45
indicates the intersection of two hyperboloids in three dimensions.

As explained in Figure 3, X7Z coordinates and z/M/ coordinates of artificial satellites A, B, (!+11. +21.Draw the plane of y″2#2# coordinate satellite A, O, D (11,
Ci! Q. You can draw the plane of (sha) using pus. It is required that an observation point exists on a quadratic curve that exists within these two planes, and that the observation point be located at the father point of these two planes.

The surface where observation point P(5) exists can be found using an algebraic formula like equation (1), but it is difficult to scale observation point P15 using an algebraic formula, so the unique solution can be found by numerical analysis. I'll decide.

Satellites A, B, C! , D(IT, (2)
, [stock], a and the arrangement of observation point P(5) are shown in FIG.

(50) is between APs.

(51) is between BP, (52) is between CP, (53)
Each distance between FiD P, (54) #:t
Between A and B, (55) is between BO.

(56) indicates the distance between CDs.

[611 points P(5) is (X, 7.Z) -----
---112, and the coordinates of point P are the unknowns to be determined.

The observed value is.

These are the three 8 values.

The distance difference between the observation point P(5) to be determined and the artificial satellite and the difference between the value determined as the observation value are determined using a formula.

f(x, y, z) = (J55A)2+(y-7A)
2+(z-ZA)2------------+141 The function f(x, y, z) is the only one at observation point P(5) near the observation point of the point to be found. Since this indicates the minimum value, in order to find this point, use the steepest slope method to perform repeated calculations using the initially predicted position of the observation point as the initial value, and then numerically calculate the minimum value, observation point P (5). I can do it.

The numerical calculation algorithm is shown in Figure 8. e (60) is the initial value setting, which is not far from the observation point* (x
o, yo, zo) 'r: Set. Also 1 set ttio
The function presets a value to stop the repeated calculations when the difference between the calculated value and the value obtained by substituting the observed value becomes a minute value. (61) is the first value of the repetition = o
At step (62), calculate the second value (14) when (Xk 7, when 2k) becomes smaller than ε, stop the repeated operation +(”k*7
Output +zlO to '. In (64), X in equation 44,
Partially differentiate the y and z components to obtain the differential coefficient. In (66), calculate the numerical value that determines the magnitude of movement when moving from the -th point to the +1th point. This value is used as f(Xk, yk, zk)d, which indicates the rate of change in the amount of movement; while it shows a large value, it moves in a large width, and when it approaches the extreme value, it moves in a small width while moving to the extreme. We will set it up so that we can capture the value. Calculate equation a4 before and after the (xk, yk, zk) point.

Searching for extreme values is an effective method. , in (67), α
Multiply k by the differential coefficient calculated in (64) to obtain the amount of movement on each component side. Since the differential value of the diagram in which the extreme value exists shows a larger value, the vector value consisting of three components is +1 from k.
At 9 o'clock when you reach the step, you can approach the extreme value in the shortest way. The value obtained by subtracting the th movement amount from (Xk, 7, Zk) is now set as (zk+1.yk+1°sk+t). In (68), advance k by one step 'It.

In addition, in (65), the calculation is repeated until the judgment condition of (63) is reached, and when the judgment value exceeds 2 ("k, yk - Jc
) and output it.

Next, the orbital position of the artificial satellite will be explained. Satellites use geostationary orbits. However, 2. Whereas the orbital inclination angle of the orbit of a normal geostationary satellite is small, such as 105 degrees, this invention uses a large inclination angle. This method prevents lines connecting multiple satellites from becoming straight lines at the same time.

This invention requires four artificial satellites to be visible from the observation point at all times. It is better to locate the satellite in a place with as high an angle of elevation as possible from the ground surface so that the view is not obstructed by buildings, but in that case the number of artificial satellites will increase. Assuming that there are satellites on the equatorial plane, Table 1 shows the relationship between the elevation angle and the number of satellites covering the entire earth. If the elevation angle is set to about 8 degrees as a reasonable value, the number of satellites required will be 10. Figure 9 shows an artificial satellite placed on the earth. (70) is the Earth, and this figure is viewed from above the North Pole. (71) is the observation point.

Table 1 (72) is the horizontal line at the observation point (70), (73) is the line R connecting the male center and the geostationary orbit, (74) is the elevation angle of 0
Shown as 2. (75) is the angle θ1. (75) is the angle θ3.
(77) is indicated as H by the foot of the perpendicular line descending from Q. (78
) is the radius of the earth, denoted by r. (79) is a geostationary orbit (80
), (81).

(82), (83), (84), and (85) are artificial satellites in geostationary orbit according to the present invention. Other heroic hearts O
, R is the point where the geostationary orbit intersects with Q.

The following equation holds for ΔOQH.

RCO&θ-0F Since QH is parallel to the horizontal line (72) fl.

θ2=03 You can find the angle of elevation.

Satellites in orbit (80), (81), (82), (8
3), (8ri etc. made OQ and OH symmetrical.Q'(c
Table 1 shows the relationship between the angle of elevation and the number of satellite cylinders, using the angle of elevation as a parameter, assuming that there are always four points between the points of symmetry of z (denoted as Q').

Next, the inclination angle will be explained. The angle of inclination must be selected so that the distance from the equatorial plane to the north and south of the satellite relative to the distance between the satellites is significant for measurement. however,
If the inclination angle is too large, it will not be possible to obtain a large elevation angle in high latitude regions. Latitude 65 degrees, which includes most of the areas where humans live on Earth, and latitude 7 degrees, which is a little higher
Table 2 shows the relationship between the elevation angle and the inclination angle at 0 degrees. The 10th example shows the relationship between satellite movement depending on latitude and inclination angle.

(90) is the latitude # (91) is the elevation angle seen from point P,
(92) is the equatorial plane, and (93) is the line perpendicular to the geostationary orbit on the equatorial plane.

Take the intersection of the horizontal line (72) and the equatorial plane, P to Table-2 Take the angle of elevation (91) to the equatorial plane t - the intersection with the desired line segment to U, the intersection of the equatorial plane and the geostationary orbit to V, * Let W be the intersection of the line on the extension of minute PU and the geostationary orbit (93).

The next latitude (90), indicated by θ4, is determined, and the elevation angle (91), indicated by θ5, is determined.

, MPTO=@O'-04; θ6 jPtl? =180''-05-(110'-46)-0
Applying the law of sine to 6-05=θ7ΔPUT.

T.P. SiIlθ7 next.

From ZPUT=ZVUW=Q7, VW=TJVtanθ7 −−−−−−−−−−
118 Table-2 shows the latitude and the direction from which an artificial satellite on the equatorial plane moves away from the satellite.
It shows the amount of movement of the satellite from the equatorial plane when viewed north.

Next, the position of the artificial satellite on the geostationary orbit will be explained. FIG. 11 shows a circle for explaining the phase and the position tt of an artificial satellite on a geostationary orbit.

(100) is a circle to indicate the phase, (101),
(102).

(1o3) is the position of the satellite at the same time, (10
4).

(105), (104) are the positions of the satellites at the same time after the elapse of time, (110), (11j), (
112) and (115) are line segments that show the range in which the satellite moves at 9 o'clock with a large inclination angle in a geostationary orbit on the equatorial plane. show. (114), (115), (11t5),
(117), (118), (1f9).

(120) and (121) are the positions of the artificial satellites.

In this invention, the distribution of four artificial satellites from the observer's perspective is 1
It is desirable that the satellites be distributed in a planar manner, and it is necessary to avoid connecting four satellites in a straight line.

At what point on the figure 8 characteristic should an artificial satellite in a simulated orbit with a large inclination angle be in a geostationary orbit?

It is indicated by the position on the circumference of a circle (100). The two-phase relationship in which satellites on a geostationary satellite have their periapsis elongation at the same time 120 degrees apart is (101), (102)
.

(io3), and the actual position on the geostationary orbit is (
114), (115), (120), and (121), and are connected with mFi chain lines between the satellites necessary for ranging.

This dotted line is appropriately bent, and the 9 and 4 artificial satellites are distributed over a wide area. If a little more time passes than this (10
1) is (104), (102) is (105), (105
) moves to (106), and similarly (118 le (t19)
, (t2o), and (121).

Next, the distance measuring method will be explained. This invention is based on measuring the distance difference between two artificial satellites. Taking satellite A (11) and satellite B (2) in Figure 7 as an example,
Measure the distance difference between AP and BP.

If a signal is generated from satellite A (1) and satellite B (2) at the same time, and it is received at observation point P and the difference in arrival time of the two signals is measured, then the distance difference is can be measured. Is this method possible so that satellites A (11 and B (2) have the same time? In this invention, we consider the case where different satellites do not have clocks that indicate the same time. 1 The signal generated by artificial satellite A (1) is also used for measurement of artificial satellite B (2).

AP and AB+BP signals are measured. However, the signal between A3 and A3 is transmitted using satellite communication, and the distance between them is measured.The distance A B (54) can be calculated from the known positions of the two artificial satellites. The distance difference between AP and BP can be measured equivalently by subtracting the distance between AB from the distance measurement of AB+BP.

A similar idea is extended to artificial satellites A, B, O, and D. That is, with artificial satellite A(1) as the source, AP, ABP, ABO
P, ABODP and transmit the signal to the observation point. Therefore, estimate the time required for measurement.

When signals are transmitted using ABODP.

The distance between the satellites is set at 31,500 km, and the conditions are as follows.

,',31,500=26.4002+(8,60
0
We decided to leave each other by the maximum distance.

However, although not all satellites are actually far apart like this, the maximum *i- is considered for all of them here.

(ABOP) Ina! =31.500X3+38,0
Mouth 0==130.500-------- a9 Speed of light f 3
If X 1 as @/sea, (An
cP) The time required for a signal to be transmitted between max.

A measurement method based on the above conditions is shown in FIG.

(130) indicates time on the horizontal axis and route on the vertical axis.

(131) is the artificial satellite A (the basis from which 11 occurred) Kurus.

(132) is the reference pulse directly received at observation point P.

(133) is received via satellite B and is a 9-standard noculus;
20) Received pulse via, (135) is satellite B
, O, D (2).

@, This is the received pulse via (company).

The distance difference required to calculate the hyperboloid for position detection is obtained as follows.

Here, IAP-ABPI=(T2-T1)/cl
ABP-ABOP 1=(T3-T2)10IABc
! P-ABPI: (T4 T5) 10 However, C is the speed of light,
AB, BO, and CD are determined from the orbital position of the artificial satellite.

At observation point P, measurements can be made simply by equipping a receiver. The measurement according to the present invention has been explained on the condition that the orbital position of the artificial satellite is accurately known. The satellite's orbit is determined by measuring its own distance and distance change rate at the control station, calculating the orbit based on the acquired data, and determining the orbit and calculating future values by orbit prediction. The predicted trajectory value allows you to know the position as a function of time.

Since this invention uses a geostationary orbit, the control station can constantly observe these satellites, so the control station can observe the time from the satellites.

It is possible to calibrate satellite clocks with high precision.

Artificial satellites can easily keep highly accurate time. Since the control station can obtain highly accurate time from the national primary standard, it can manage the 2nd time while constantly coordinating with the secondary standard and control station 2 artificial guard. In other words, the control station corrects the time delay required for signal propagation based on the orbit information about the satellite that the control station has for the time signal received from the satellite, and then compares it with the reference time of the ground system. There will be time.

This relationship will be explained with reference to FIG. (140) is the second time at artificial satellite A (11), (141) is the timing when the second time is received at the control station, (142) is the calibrated standard second time at the control station, (143) is the orbit determination Satellite A to be received at the control station based on the value (11 seconds,
(144) is the propagation time in seconds obtained from the orbit determination value,
(145) is the time difference between time (141) and time (143).

The control station detects the time difference (145) and sends this difference by command to satellite A (11) to correct the time by 1, allowing the satellite to maintain highly accurate time.

The method of time difference detection is not to compare seconds and hours once, but by continuing observation over a long period of time, even if there is a slight error, it becomes easier to detect as the error accumulates. Such a detection method is superior.

In this invention, it is necessary to measure the distance difference. That is, it is necessary to measure the time difference between timing TI (132) and timing T2 (j!ri) in FIG. However, the basis for being able to detect the position of observation point P(5) is that the position of the satellite at the time of the signal generation is determined.Since the position of the satellite can be expressed as a function of time, .

Turn the timing of the original signal TQ (13) in Figure 12 into a time information signal and notify it to observation point P (5).
Observation point P(5) obtains information on the distance difference measurement, and at the same time knows the time when this original signal was generated, and can also accurately obtain the position of the artificial satellite in space at that time.

FIG. 14 shows an example of a signal format for simultaneously transmitting a ranging signal and a time signal for measuring distance differences.

(15 ri and (15 ri is PRN code for distance measurement + 11. (2
1 shift register, (152) is a time encoder,
(153) is a time device, (15 is a carrier wave generation source,
('156) is the clock that generates the PRN code and time code, (157) is the gate signal that resets the contents of each register at the minute of each code, (158) is the MOD2 synthesizer of the two codes, ( 159), (160)
is the modulator, (161) is the 110 degree phase shifter of the carrier wave,
(162) #: Synthesis circuit for tQP8.

In the present invention, when the clock of the PRN code is set to I MHz, a distance measurement signal obtained by combining two codes is required. The reason why this is necessary will be explained later. A new RPN code was created by adding MOD2 to PRN code (1) and PRN code (2). The shift registers (150) and (151) of PRN code (1) and PRN code (2) are the ninth signal generators. The two codes are added by a MOD 2 adder (158) and then modulated by a modulator (159) onto a carrier wave, resulting in BPSK (B1-phase 5hift k8
71ng) Obtain a modulation/tuning signal.

This code is set to zero at the hour of the second.

From that point on, the contents of the code change.The timing is determined by the gate signal (157) obtained from the time device (ISS), which causes the time encoder (152) to simultaneously read the current time from the time device (153). The 9 time code, which is driven by a clock (156) and transmitted as a code, is modulated by a modulator (160) with a carrier wave whose phase is 90 degrees different from that of the ranging signal. Since the distance measurement signal and the time code are orthogonally modulated, they are combined by nine combiners (162) and converted into one QP8 signal.

Observation point P(5) can receive the ranging signal and simultaneously know the time of original occurrence.

It is also necessary to accurately know the time at which this signal passes.

In this invention, at the observation point P (5), the satellite A (1) directly sends A P (132) and another artificial satellite 2.
For example, the principle of position detection is to measure the time difference when the same signal arrives between 72ABP (13) via artificial satellite B (2), so in order to detect the distance difference, the frequency of the ranging signal is It is good as long as it is accurate.However.

For position detection, if the geometric position of the signal oscillation source is not accurate, there will be a large error in the detected position. In the previous explanation, we explained that the position where the 2nd artificial satellite A (1) generates the original signal can be known from time information and orbit information based on orbit observation, but at the same time, the position of the artificial satellite involved in this observation can also be known. must be determined accurately.

In Fig. 12, it is assumed that the original signal for ranging is always generated from artificial satellite A (1), but at the same time, the time and distance signals obtained from artificial satellite B (2) using the circuit configuration shown in Fig. 14 are also transmitted from the observation point. Just send it to P(5).

FIG. 15 shows a timing diagram for two satellites. (
170) occurs on artificial satellite B(2) at timing T7 and indicates 9 o'clock. (171) is observation point P at timing T8.
(5) indicates when timing T7 (170) is received.

At observation point P (5), satellite B (2) receives a signal sent from satellite 11 and a signal generated by itself. The former is used as a ranging signal.

The latter can be used as a time signal for calculating the position of artificial satellite B (21).
By comparing the time information of both signals, it is also possible to calculate the distance between two artificial satellites.

In this invention, when transmitting two signals from one artificial satellite to an observation point at the same time, it is appropriate to use two frequencies, or to use different subcarriers or different types of spreading codes for each satellite given in advance. It is.

Next, we will explain how an observer can actually take measurements one by one using an artificial satellite placed in orbit. In FIG. 16, three artificial satellites are grouped into one group and transmit signals for measurement. Assuming that satellite A (1) is the source of the signal, 1 satellite A, B, 0fll.

(21, ■ is one group, and another group of satellites that operate in the same way is satellite 0.D, ■, ■.

(t90) Create another group. The signal flow of one group will be explained.

From satellite person (1), source signal (211) is sent to observation point P (5) and satellite B, 0 (21, W) at the same time.
A signal is transmitted via paths (180), (181), (182) t-.

Figure 11 is a table showing the time series at that time.

At observation point P(5), signal (212) i-is first received.

via the artificial satellite B 121, the route (18 signals is
It is transmitted to observation point P (5) via route (185) and received at timing (213). Timing (212
) and (215), the distance difference between AP and BP can be measured. This can be expressed as an equation as follows.

ABP-AP=(!(T11-T12) ------
--(To) In ARP, the distance between AB can be found by the predicted position of the artificial satellite or by actual measurement, so by subtracting this part from the formula @, the distance difference between AP and BP can be found.

BP-AP=O(T11-'r12)-AB ---
-1.(2) Similar measurements were made between satellites B, 0(2) and observation point P(51), along routes (183), (184),
(187), the signal is transmitted, and the timing (2'1
5) and (214) the signal is received. This can be expressed as a formula.

BP-CP=O(T13-T12)-Be -----
− becomes @.

Next, measurement of the distance between the artificial satellites A, B, and O will be explained.

Satellites A (1) to 9 Satellites B (2) and Satellites C
The signal is transmitted through paths (181) and (182) to the satellite 9B (2) and the satellite 0C2G.
The direction is transmitted by the route (18).The artificial satellite Cc!1 measures the distance difference between the two signals.This is expressed as follows.

ABC-AC! =O (TI pi 14) --------
■a+ Cb=a1 ----- C13
Here, d1=o('r1s-T14) where a d
2=o(T17-'r16) -=---09 route (
182) and (183) and the path (181) give the following formula %
Formula % The following formula holds true from routes (186), (18B), and route (184).

BAO-BO=0 (T19-TIB) ------1・(to) b + O-a = O(T19-T18)
@Here, d5=o('r19-T1
s) Equation (2) is obtained using the formula ■, '@, clll, (to), and the distances a+'b, a between the nine artificial satellites are obtained. however.

In this case, each satellite would need to be equipped with a device to measure the distance between the satellites.

Satellite, K, Fi43. (190) Be1
Regarding satellites A, B, 0fll,
+21.121) using the same measurement method.

If there are 10 satellites in orbit I Al BI
CtD, JP, G, H, I, , r.

They are combined into three groups such as (ABC), (DKF), (G)I), and (,7), and measurements are performed as explained in FIG. 16. Next, (B(!D), (EF'G), (
Measurements such as H Engineering J) and (Al are carried out. In this way, the three groups are moved one after another and measurements are carried out. Observer P (5) takes two measurements such as (ABe) and (BaD). By performing two combinations of measurements, it is possible to obtain all the information necessary to detect the observer's position.Figure 17 shows how to repeat measurements divided into 10 artificial satellite JLT-3 groups. Shows the order of time. One group of measurements is taken at 1 second (230), and the measurement is completed in about a5 seconds. Therefore, the 9th order (1+1) (at 230 seconds, the second group (230)
At 1+2 seconds (232) of the measurement in 6), the third group (237) is performed, and at 1+3 seconds (259), the process returns to the original state and measurement is performed from the first group.

Next, distance measurement will be explained. In the explanation so far, the first
Please note that the signals used for measurements in Figures 2 and 17 are pulses that indicate instantaneous time. Distance measurement by pulse injection is a method used in radar, but in the case of ground equipment,
Easily generates high-amplitude pulses and has a reachable distance of 1
．． In many cases, it is around 000 km. However, when used in space, the reach distance is very long, and the method of instantaneously consolidating the signal energy for distance measurement in the form of a pulse increases the size of the necessary equipment, which is not a good idea. Therefore, a timing signal of one time is transmitted over a long period of time.

If a device that can perform detection for a long time on the receiving side is adopted, it will be easier to configure equipment in space.

The maximum propagation distance required for measurement is assumed to be based on equation 1, and should be approximately 50 degrees. It is sufficient if the distance between these distances can be encoded with an unambiguous code. If the basic clock f I MHz is used, there will be approximately a43×10 6 repetitive waveforms during this period.

Therefore, a 20-bit shift register is used.

Pseudo-random code (Pauedo RandOm Co
de (PRN code for short) is generated, 220
A unique pattern of -1=txl 06 can be generated. In addition, the phase of the PRN code generated from two 10-bit shift registers is made unique, and Modulo
Using the gold code obtained by the logical sum of 2.

1023X1023=1x106 between O
-7f can also occur.

On the receiving side, by performing two correlation calculations with a one-time difference, it is possible to measure the phase difference, that is, the distance difference, between the two codes. This measurement principle can be applied to both measurements between satellites. However, in the case of one artificial satellite, for example, if laser communication is developed.

As soon as pulses are used, methods such as those shown in FIGS. 12 and 16 become possible. When using PRN codes, by using different PRN code types even though the frequency is the same,
It has advantages such as being able to use multiple codes at the same time and making it easier to meet assumptions regarding power flux and density required from the viewpoint of radio wave interference.

Next, I will explain the configuration diagram of the artificial satellite used in this invention.
Explain using 9 factors. The crystal oscillator (240) operates a two-time device (242), and sends its output to the control station via a telemetry device (245), a transmitter (246), a diplexer (247), and an antenna (248). The control station compares this signal with the national primary standard level signal and transmits fine tuning of the single oscillation frequency and time calibration to the satellite. This signal is sent to an antenna (248), a diplexer (247), and a receiver (249).

A command receiver (250) receives it via i and sends a correction command OMt to the crystal oscillator (240) and time device (242). Telemetry device (245
) and command receiver (250) are also used for general satellite bus equipment other than two-hour calibration. The distance and distance change rate signals from the control station are returned via a return route (261)'lk between the receiver (249) and the transmitter (246), and are used to determine the orbit of this artificial satellite.

In response to the clock (21), the PRN code generator (252)
generates a series of PRN codes and generates a reference time signal (245
) The received time information is sent to a modulator in order to make these two types of signals into the same signal 2, for example, a 4-phase phase modulation signal, so that the specific time and the specific phase of the above-mentioned PRN code are synchronized. (253), and its output is sent to the transmitter (
254) and the inter-user antenna (255)' (z, and is transmitted to the user. At the same time, the modulated signal (226) is
Signals are also sent to other satellites via the amplifier (257), diplexer (258), and antenna (259).

In a type of satellite that receives signals from other satellites and transmits the signals to the user and at the same time transmits them to the next satellite, the signals (270) received from other satellites are sent to the antenna (259). received by the diplexer (258)
, the ratio signal is passed through the receiver (280).

There is a transmitter (25 antenna (255)) at observation point P.
At the same time, it is transmitted to the other artificial satellite via a transmitter (262) and an antenna (260) as a signal (265).

〔Effect of the invention〕

In this invention, an artificial satellite with a large inclination angle is placed in a geostationary orbit, so that an observer can observe four artificial satellites, and the theatergoer has a receiver, a simple clock, and a calculation processing algorithm. , can calculate its own position. Observers can perform this measurement except in high latitude regions such as polar regions.

[Brief explanation of the drawing]

Figures 1 to 19 are diagrams for explaining the present invention, and Figure 1 is a diagram showing the case where two artificial satellites are used and expanded in two dimensions. Figure 3 shows the curved surface, Figure 3 shows the case where three artificial satellites are used, Figure 4 shows the case where three artificial satellites are used.
The figure shows the arrangement of Figure 3 in three-dimensional coordinates, Figure 5 shows the appearance on the xy plane when four artificial satellites are used, and Figure 6 shows 41! Et-3 using ll artificial satellites
Fig. 7 shows the arrangement of four artificial satellites and observation points, Fig. 8 shows the algorithm for position detection, and Fig. 9 shows the nine artificial satellites arranged on the earth. Figure 10 is a diagram showing the satellite's movement according to latitude and inclination angle. Figure 11 is a diagram showing circles to explain the phase and the position of the satellite on the geosynchronous orbit. The figure is a timing diagram to explain the method for measuring the distance difference between satellites, Figure 13 is a diagram showing the time calibration method, and Figure 14 is a diagram showing the distance measurement signal and time signal for measuring the distance difference at the same time. Figure 15 shows an example of the signal format to be transmitted. Figure 15 is a timing diagram of two artificial satellites. Figure 16 is F! Figure 17 is a diagram showing a good measurement method for grouping three satellites into one group, Figure 17 is a diagram showing the timing of the measurement, and Figure 18 is a diagram showing a method for measuring 3 groups of 10 satellites repeatedly. Figure 1S is a diagram showing the configuration of the artificial satellite when performing position detection as shown in Figure 13. FIG. 20 is a diagram showing the configuration of a GP8 artificial satellite. In the figure, (11, 121, to, (80),
(81), (82). (85), (84), (85) are artificial satellites, +61.
(7), ea is a hyperbola. +91. @ is a hyperboloid, (51, (71) is observation point P,
(101). (102), (103), (104), (105), (
106), (114), (115). (11t5), (H7), (118n, (119), (
'120), (121) are the positions of the satellites, (13
1), (132), and (133) are reference pulses. (134), (135) are received pulses, (15[1
), (15 shift register, (152) time encoder, (153) #2 time unit, (15 is carrier wave generation source, (156) is clock. (157) i-! gate signal, (158) ) is a synthesizer, (159n. (160) is a modulator, (+61) is a 90 degree phase shifter,
(162) is a synthesizer, (240) is a crystal oscillator, (24 is a crystal oscillator output, (24)
2) is the time device, (245) is the reference time output, (
244) is a clock, (246), (262) are transmitters, (247) is a diplexer, (248)
is the telemetry command antenna, and (249) is the receiver. (250) is a command receiver, (261) is a return route for distance measurement, (252) is a PRN code generator,
(253) is a modulator, (25 is a transmitter, (25
5) is the same antenna as the observer, (257) is the amplifier,
(258) is a diplexer. (259), (26ri is an antenna for intersatellite communication, (
260). (265) and (270) are intersatellite communication signals, (2
80) is a receiver. Note that the middle or corresponding portions of Figure 9 are indicated by the same reference numerals.

Claims (3)

[Claims] (1) Visible range seen from near the Earth's surface on a geostationary orbit where the orbital inclination is close to 6 degrees and the perigee elongation between adjacent satellites at the same time is close to 120 degrees apart. Four artificial satellites are placed at the same time, and based on the time signal calibrated by the control station and the time signal, a ranging signal created while maintaining a synchronized relationship with the time signal is sent to one of the four locations. One artificial satellite transmits the above-mentioned time and ranging signals directly to the earth's surface, and at the same time transmits the above-mentioned time and ranging signals to other artificial satellites by means of inter-satellite data relay means, The adjacent artificial satellites that received the ranging signal send this signal to the earth's surface, and at the same time,
Furthermore, it is sent to the next adjacent artificial satellite, and this is applied to the four artificial satellites in sequence, and from the four artificial satellites, the time and ranging signals based on each of the above-mentioned time and ranging signals and their own time are transmitted. is transmitted to the earth's surface, and near the earth, the positions of the four artificial satellites determined based on the orbit prediction obtained from the control station based on the reception time of this ranging signal are used as base points.
By calculating two types of distance differences between the satellite and the observer using the ranging signal for two adjacent combinations of artificial satellites, the two satellites can be set as a focal point. By performing the same calculation process as described above for the three sets of two pairs of satellites obtained by combining four satellites, the observation point can be found as the intersection of the hyperboloids. A positioning method using artificial satellites characterized by: (2) It is characterized in that five or more of the artificial satellite configurations according to claim (1) are arranged on a geosynchronous orbit to expand the area on the earth's surface, and nine or more are arranged almost equally on the geosynchronous orbit. A positioning method using artificial satellites. (3) Equipped with a clock device that can correct the time and finely adjust the frequency based on command signals from the outside, and a device that generates a signal for measuring distance differences, and uses the signals generated by the two devices mentioned above. A device that can simultaneously modulate and transmit signals to observers near the Earth's surface, and an intersatellite data relay device that can transmit the same time and distance measurement signals to other satellites and receive them from other satellites. In addition to the device that can transmit signals for measuring time and distance differences to observers near the Earth's surface, we also provide an inter-satellite data relay device that can transmit these signals to other artificial satellites. Claim (1) or claim (2) characterized in that
) Positioning method using artificial satellites as described.