JPH02213785A - 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 three artificial satellites are observed from the observer who has a signal receiver, a simple watch and a calculation processing argorithm. CONSTITUTION:An X-axis 3 is the axis penetrating the artificial satellites 1, 2 and a Y-axis 4 has the origin at the mid-point of the X-axes of the artificial satellites 1, 2. Another artificial satellite 20 is assumed to exist on another X'Y' coordinates on this X-Y plane. The angle formed by the X-axis and the X'-axis is designated as 23, the hyperbola of the specified difference in the distance between AP and CP inclusive of an observation point P as 24, one of the intersected points of the hyperbola 6 and the hyperbola 24 as 25, and the straight line inclusive of the two points where the hyperbola 6 and the hyperbola 24 intersect as 26. The observation point P exists at the point of the condition under which the differences in the distances between AP and BP and AP and CP are constant between the artificial satellites 1, 2 and 20. The phenomena of these X-Y and X'Y' plane can be developed to the three- dimensional phenomena of the XYZ coordinates and X'Y'Z' coordinates 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.

[Conventional technology]

Conventional radio navigation uses artificial satellites such as Detsuka, Omega, Loran-C, etc., which have oscillation sources on the earth.
S (Navy Navigation 5atell
iteSystem) and GPS (Global Po
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. can be expected to improve. Among these, NN8S is a method that uses Dotsupura, while GPS is based on distance measurement based on time measurement, and compared to the former, the latter has many superior performances. Therefore, it is expected to become the mainstream of navigation satellites in the future. In order to compare with this invention,
The conventional technology will be explained using this GPSi as an object.

Figure 20 shows the configuration of a GPS satellite. (500)
.

(5at), (5oz), (3o3) are NA for GPS
VSTAR (NAVigation system W
ith Timing and Rang-ing)
The positions are indicated by ftA', B', C', and D'.

NAVSTAR has its own precise atomic clock and maintains the accuracy of the clock signal it generates to a high degree of accuracy. At the same time, NAVSTAR is busy calibrating the time information from the control station, so NAVSTAR accurately calculates the current time on SLC based on the beginning of the week. It is expressed in

The location of NAVSTAR is located at the control station.
The orbit is determined based on STAR tracking data.

Once you know the time, you can determine your location.

Therefore, if the observer is at NAVSTAR.

The current time of NAVSTAR, its time, orbital elements, and υ position are known, but the 9th time this observer
What will happen if we leave the AR position and observe NAVSTAR? (504) is now represented by P e as the observation point. Now, suppose that the observer has a time device, but it is not a comparatively calibrated and highly accurate clock, but a clock that has a certain error from the standard time. The time when the observer performed the observation is assumed to be 7nO+Δt.

Tno is an inherent error observed by the observer at the correct time. At this time, NAVSTAR (500), (501), (502
), (305) (D time FiTn 1.Ti2.
'rns, Ti4 is a value delayed by the propagation time between the two parties. *The following equation is established from the measured time and the positional relationship of NAVSTAR.

However, C indicates the speed of light.

Equation (1)' has as unknowns the three-dimensional three-dimensional value of the position of P' and four equations for Δt, so this equation has a solution, and the observer's position and You can calibrate the time.

NAVSTAR's orbit is a circular orbit with an altitude of 20.183 km.

The period is 12 hours, and the orbital inclination angle is 55 degrees. Three satellites are placed at equal intervals on this orbit, and this orbit is 6
A total of 18 satellites of two types fly in orbit. NAVSTAR will always be placed so that #c4 points are visible from any point on the earth.

There are one NAVSTAR control station and four monitor stations, respectively, and when NAVSTAR is within the visible range of nine stations, they acquire data and send necessary commands.

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

[Problem S that the invention attempts to solve]

To spread the reach of the 111th place in GPSJdi to the entire earth.

Requires at least 18 NAVSTARs, and N
When AVSTAR uses source data for ranging, it requires highly accurate time and frequency, and the frequency at which the control station can calibrate the time and frequency is once a week, so 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 all problems]

In this invention, eight artificial satellites are placed in geostationary orbit with an orbital inclination of about 6 degrees to enable distance measurement within 65 degrees of latitude, where most of the world's population lives.
The satellites are arranged so that their periapsis and elongation are appropriately evenly spaced at the moment of formation, and a control station in the visible range constantly monitors the time and frequency generated by each satellite. By comparing the precision time standard and frequency and issuing commands for correction at high frequency, the signal for highly accurate distance measurement by the 9 artificial satellites is generated.

[For production]

This invention consists of a set of three artificial satellites in geostationary orbit, of which the base 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 satellite receives this signal and sends this signal and its own time and distance measurement signals to the observer, and at the same time transmits it again to the next neighboring satellite. This was done for three artificial satellites, and this observation cycle was repeated at least twice, so that observers could 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 a case in which two satellites are used and nine are deployed in two dimensions. (1) and 12) are the artificial satellite Ae in orbit.
B, +3) is the artificial satellite A, B(1), +2
1 is the X axis, (41 is the y axis with the origin at the midpoint between the satellite and the BOX axis, (5+ is the point P where the distance difference from satellites A and B is constant, (6I is the point The trajectory of P on the xy plane,
(7) is a hyperbola that is symmetrical to hyperbola (6) with respect to the y-axis.

A hyperbola on the xy plane can be expressed by the following formula.

Here, the focal point and eccentricity are f=±a1e, and the distance difference from the focal point is d=2a1.

If point P (51) is taken as an observation point, in this invention the difference in distance between two artificial satellites A, B (1+, 12+) and the observation point is measured.In the configuration shown in Figure 1, information on this distance difference is measured. From this, hyperbolas (6) and (71 can be drawn, and the observation point is hyperbola (6).
) and (71), but the distance 1
! If you obtain information on the size of MAP and BP, you can determine which hyperbola the observation point is on. Here, the hyperbola (
Suppose there is a view III A on 61.

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

Since the actual phenomenon exists in three dimensions, 9, the hyperbola on the xy plane is rotated around the +611-x axis to obtain a three-dimensional hyperboloid.

Figure 2 shows a hyperboloid of xyz coordinates, (8) is the biaxial axis, (9) is the hyperboloid, and α and Qll are the circles when the hyperboloid is cut by a plane parallel to the yz plane.

The position on the xyz coordinates where the distance difference AP and BP shown in Fig. 1 satisfy the constant east condition is a hyperboloid (91).

Hyperboloid (9) can be expressed by the following equation on the xyz coordinates.

When the observation point is on the X-axis in the configuration shown in Figure 1 or Figure 2, the hyperbola or biplane may become a straight line. This type of composition does not exist because it consists of observation points near the ground.

Next, a case where three artificial satellites are used will be explained using FIG. 3. The two parts have the configuration already shown in Figure 1, and have the same xy
Assume that another artificial satellite exists on another x T y # coordinate on the plane. ■ is the artificial satellite C9 (2) 1 is X°
axis, ■ is the y′ axis, ■ is the angle θ formed by the X axis and the X° axis, @ is a hyperbola with a constant distance difference between AP and CP including observation point P′jk, c
! i is one of the intersections of the hyperbola (6) and the example, ■ is the intersection of the hyperbola (6)
) and @.

Observation point P (5) is satellite A, B (11, (21,
AP and BP between and satellites A and C (11, ■)
It exists under the condition that the distance difference of AP7cp is constant. Figure 1 shows the former combination of artificial satellites. Assuming that the latter condition is satisfied, a hyperbola @ can be drawn. The same distance difference can be measured between the two hyperbolas (61 and @) at the intersection (5) and ■.

Next, the phenomenon in the XY + x'Y' plane considered in Figure 3 is developed into the three-dimensional phenomenon of the xyzWAme x"y'z' coordinates in Figure 4. ■ is rotated around the hyperbolic aa 1kx' axis. The hyperboloid surface obtained by be.

The hyperboloid (9) on the x'y'z coordinates is expressed by the following formula: *The planes are set to be the same.

z=z' ・・・・・・・・・
・・・・・・・・・・・・(6) According to the condition of equation (6), the formula (
2) and equation (4), zf: When eliminated, the length between a point on the hyperboloid and the focal point is the same. From the hyperbolic formula, the ratio of the length between a point on the hyperboloid and a single line is equal to the eccentricity. I can say it. On the xy, xy° plane in Figure 3, the X and
Regarding ', (61 hyperbolas are in the 1st and 4th quadrants. 9 hyperbolas are in the 2nd and 3rd quadrants, so the following equation stands 512 times.

AP=: 1etx-aI I =l 62X+
82 1 =”=” 18+If we consider the case of Fig. 3 down to the sign, the formula 0 (81 becomes as follows.

elx −al = −(e2x + a2)
”--・between... (9) The relationship in equation (9) is “Y*”Y
The relationship holds true not only for planes, but also for hyperboloids rotated around the X and X'' axes in Figure 4, Ifl,
This is a formula that stands at 6. Therefore, substituting equation (9) into ()1,
Expanding the formula to find the conditions for hyperboloids, we get the final k KIX + K2Y + KA: 0,
, , , , , , , , , , , , , here 1:
-2a2 (e1+e2cosθ)K2 = -26
2a2Slnθ to 3=e123) 2+2e1e2ala2COsθ+e
The equation of the straight line 22a22-(al-a2)2-(b12-b22) is found.

Since the formula αυ does not depend on 2 and 2°, *xY”
Coordinates, z, z' including formula 01 for x'y'z' coordinates
Indicates a plane parallel to the axis.

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

In the configuration shown in Figure 4 using the artificial satellite @SS, view 1113
, a P 151 is found to exist on a circle or an ellipse which is a quadratic curve existing on the plane of ■. If the altitude of the observation point is known as a known number from another system, observation point P(5) can be determined as a point.

It is not possible to detect the warm measurement point P 151 f only from the information on the distance difference obtained from the three artificial satellites.

Therefore, in this invention, the position of the artificial satellite uses an orbit that moves with time when viewed from the earth. Details of the orbit conditions will be described later.

FIG. 5 shows the positional relationship of the artificial satellites used for measurement at two times. XY* at a certain time
Y' coordinates and satellites A, B, C (11°+1,
The position of the satellite after 120 hours is shown in the same drawing. S, number, ω is artificial technique JI
The positions of A', B', and C', 140 is the x" axis,
141 is the y” axis, the bet is the hyperbola calculated from the distance difference, U
is the X” axis, #Ag is the y°°° axis, (52) is a hyperbola found from the distance difference, and (55) Fi is a straight line connecting the intersections of the two hyperbolas.

Satellites A, B, ell), +21.3) will reach A in one second.

B', C' 143.1ffl, move to position υ. for example.

If the ground speed of the satellite is I Km/sec, it will be 30 + 0 in 30 seconds. I Krn/ 3) cm apart at 8eC.

Artificial! ! For A', B', C'G43.14n, #, draw new coordinates x''y''x °I y'''°, and draw a constant distance difference including observation point P(5) on the coordinates. Hyperbola 143. (52)' can be drawn. A straight line (53) connecting the intersection points of the hyperbola can be drawn.

The xy coordinates and the x l y l coordinates could be placed on the same plane consisting of the X and X' axes. However, since the motion of the 9 artificial satellites is three-dimensional, the 9 artificial satellites A', B', C'
(company).

The position of (4n, &I is not on the x)'+''*Y' coordinate plane. In Figure 5, to simplify the explanation, we ignored this relationship and considered the phenomenon to be two-dimensional.2 When expanding from one dimension to three dimensions, the relationship is shown in Figures 3 and 4. The same relationship holds true for the artificial technique INK after movement. and X”
, y'', X''II There is a condition where two planes intersect according to the movement of the satellite between the planes containing the X''II and yIII coordinates.

If we simply consider the surface containing the XYIX'Y' coordinates, then we can draw a surface containing the fix"y" xl II y III coordinates with the condition that a certain line segment intersects at a certain angle, and X″y″xl l l y″°
゛On coordinates, a two-dimensional phenomenon can be expanded into three dimensions as shown in the relationship shown in Figures 3 and 4.

In Figure 6, satellites A, B, and C (11, (2)
, ■ and satellites A', B', C'lO,147
The relationship between 1 and @ is shown in three dimensions. Throat is zll axis, U is X'
′′ axis, 14q is y°°′ axis, (sl) is 2′°
The intersection of the hyperbolas il+ and @ that can be drawn on the ° axis e xyzWAm and x ′y I z # coordinates is indicated by ■, and can be drawn on the Hyperbola +43. Intersecting surface u (55) of (52)
It is indicated by. A quadratic curve (circle or ellipse) that is the intersection of the hyperbolas can be drawn on the two surfaces ■ and (55). Observation point P(5) exists at the point where these quadratic curves intersect.

Up to the surface where observation point P (51 exists) can be found using an algebraic formula like the formula αG, but since it is difficult to solve observation point P (5) using an algebraic formula, the unique solution will be found by numerical analysis. .

Artificial surgery JIA, B, C, A', B', C'+1
1. +21. ■、Wri.

Figure 7 shows the arrangement of the mallet and observation point P (51). (54) is between AP, (55) is between BP, (56) is between cp, and (57) is between A'P.

(58) is between B'P, (s9) u c'P r&
Show #lt.

Observation point P (51 is * (xl)'+”)...
The coordinates of point P are the unknown quantities to be determined.

The observed value is.

04 S values. To find the algebraic solution, K is S
Three is sufficient, and if there are more S, there may be cases where there is no solution, but since the S treated here are observed values obtained from the same phenomenon, 9 is equivalently the same as three values. It is. Therefore, here we use four 81jts to solve the problem.

The difference between the distance between the micro-measurement point P (5+) to be determined and the artificial satellite and the value determined as the observed value is determined using the formula.

f(x, Lz) = ((X-Xmu)2+(y-y
m)2+(z-Z*)2-(x-xc)2+(y-y
c) 2+(z-zc)2-82)2+((x-xmu°)
2+(y-ymu-)2+(zz-zmu-)2...-...
・・Fist・a- The function f(x, y, z) shows the only minimum value at the observation point P (51) near the observation point of the point to be found.

In order to find this point, a repeating operation is performed using the position of the observation point predicted first using the steepest slope method as an initial value, and the observation point P 151 i, which is the minimum value, can be numerically calculated.

The numerical calculation algorithm is shown in FIG. (60) is the initial value setting, which is a value that is not too far from the observation point (xO+
YO*! O). In addition, when the difference between the calculated value and the value obtained by substituting the observed value becomes a small value, the function of Equation 1 a-
Set a value in advance to stop repeated calculations. (61) starts with =O at the first value of the return. (62) calculates the formula aa@ when (xk e yk + Zk ). In (65), the value calculated in (62) is compared with 1'@:, and if f(XklYkl!k) becomes smaller than e, the repeated calculation is stopped and (xk, yk, z
k). In (64), x*y*zrJM of formula 0
Perform partial differentiation of the minutes and 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 ak, which indicates the rate of change in the amount of movement.
While '(xk e Yk * ``k)'' shows a large value, it moves in a large width, and when it approaches the extreme value, it moves in a small width while setting it so that it can capture the extreme value. ( It is an effective means to calculate the equation a4 before and after the points (xk, yk, zk) and search for the extreme values.In (67), a
Multiply k by the differential coefficient calculated in (64) to obtain the amount of movement for each section. Since the differential value in the direction where the extreme value exists shows a larger value, when the vector value consisting of 3Fli becomes +1 step from k, it can approach the extreme value via the shortest route. The new value obtained by subtracting the th movement amount from (xk+ykszk) is (xk+1, yk+1,
Zk+1). In (68), k is advanced by step t-1, and in (65), the operation is repeated until the judgment condition of (65) is reached, and when the judgment value exceeds 1 (xk,)
'l(e ``k) is obtained and output.

Next, I will explain the orbital position of the artificial satellite, which uses a geostationary orbit. However, while the orbital inclination angle of the orbit of a normal geostationary satellite is small, such as 0.05 degrees, this invention uses a large inclination angle. This method prevents lines connecting multiple satellites from becoming straight lines at the same time.

In this invention, three artificial satellites must 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. Now, assuming that there is a satellite on the equatorial plane, the relationship between the elevation angle and the number of satellites that can orbit the entire earth is shown in Table 1.If the elevation angle is set to about 5 degrees as a reasonable value, the number of satellites required is There will be 7 items. Figure 9 shows the appearance of an artificial satellite placed on the earth.m (70) is a view of the earth from above the North Pole. (71) is observation point P.

Table 1 (72) is the horizontal line at observation point (71), (75
) is the line connecting the other center and the geostationary orbit and is indicated by R. (74) is the elevation angle shown as 02 @ (75) is the angle θ1. (76) Angle θ3e (77) is the leg of the perpendicular line descending from Q and is denoted by H. (7B) is the radius of the earth, denoted by r. (7ri is geosynchronous orbit (80), (81).

(82) and (85) are artificial satellites in geostationary orbit according to the present invention. Let Q be the point where the other center 'io, R and the geostationary orbit intersect.

The following equation holds for ΔOQH.

Make sure that QH and the horizontal line (72) are parallel.

θ2:03 You can find the angle of elevation.

Artificial guard Jl in orbit (ao), (at), (82
), (85) etc. are OQ'(
The relationship between the angle of elevation and the number of angles is shown in Table 1, using the angle of elevation as a parameter when there are always three points between the points of symmetry of Q (denoted as Q゛).

Next, the KM oblique angle will be explained. The inclination angle must be selected so that the distance from the equatorial plane to the north and south of the satellite is significant for measurement, relative to the distance between the satellites. 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. FIG. 10 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, (95) is a line on the equatorial plane that is directly connected to the geostationary orbit, and the intersection of the horizontal line (72) and the equatorial plane is T,
The intersection point with the line segment that takes the angle of elevation (91) from P and looks towards the equatorial plane is U, the intersection point of the equatorial plane and the geostationary orbit is V, and the line segment PU
Let W be the intersection of the extension line and the geostationary orbit (95).

Table 2 The latitude (90) indicated by θ4 is fixed, and the elevation angle (91) indicated by 05 is fixed.

? PTO=90°-04=06 ZPUT=180°-〇5-(1ao°-1/6)=0
Applying the law of sine to 6-”5=θ7ΔPUT.

next.

From ZPUT = tVUW = Q7, vw = uvtanθ7...
・・・・・・・・・・・・ In aa table-2, the latitude and the satellite on the equatorial plane when viewed from the point of latitude 1 south or 1 north, which is the direction away from the satellite. The county motion from the equatorial plane is shown.

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

(too) is a circle to indicate the phase, (tal),
(to2).

(105) is the position of the satellite at the same time, (
104).

(1os), (to6) are the positions of the satellites at the same time after the elapse of time, (1oo), (111)
, (112), and (115) are straight lines that show the range of movement when a satellite has a large inclination angle in a geostationary orbit above the equatorial plane. Show characteristics. (+14), (115), (
1t6), (117), (11B), (119)
.

(120) and ((2)) are the positions of the artificial satellites.

In this invention, the distribution of three artificial satellites from the observer's perspective is 1
It is desirable that it be distributed in a planar manner.

It is necessary to avoid connecting three satellites in a straight line.

If the inclination angle is increased in geostationary orbit, where should the satellite in orbit be located on the figure 8 characteristic?

The satellites on the geostationary satellite roof are located at the same time of periapsis at intervals of 120 degrees Kfil<, and the phase relationship is as follows: (101), (10)
2) It is indicated by 1 (tOS), and the actual position on the geostationary orbit is indicated by (114), (115), (120),
Straight lines between the satellites necessary for distance measurement are connected with chain lines.

This chain line is bent as appropriate, and the three satellites are distributed over a wide area. After a while (10
1) is (104), (102) is (tos), (t
os) moves to (106), and similarly (11B), (
119) and (120).

Next, the distance measuring method will be explained. In this invention.

The basic idea is to measure the distance difference between two artificial satellites.

Taking the example of satellite man (1) and satellite B+21i in FIG. 7, the distance difference between AP and BP is measured. If signals are generated from satellite A [11 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, the distance difference is It can be measured.

Artificial technique! K so that A (1) and B (2) have the same time
Then, this method is possible, but in this invention, we consider the case where different artificial satellites do not have clocks that indicate the same time.

Therefore, the signal generated by 1 artificial technique JIA +11 is also used for the measurement of artificial technique JIB (2). AP and AB+BP signals are measured. However, the signal between AB is transmitted using satellite communication, and the distance between them is measured, or the distance AB can be calculated by υ since the positions of the two artificial satellites are known. , It is possible to equivalently measure the distance difference between AP and BP by subtracting the distance between A1 from AB+BPO distance measurement.

Extend the same idea to satellites A, B, and CK.

That is, the artificial technique JiA +11 is sourced from KL, AP, ARP,
Transmit signals to ABCP and observation points. Therefore, estimate the time required for measurement.

When signals are transmitted using ABCP.

The distance between the satellites is set at 3t, 500km, and the conditions are as follows.

','' 3).500 out of 26.4002+(8,60
0X2 )2 That is, there are three artificial satellites in geostationary orbit,
8.600km north and south from the equatorial plane due to the large angle of inclination
We decided to leave and let each other get away from each other as much as possible.

However, in reality, not all the distances between satellites are this far apart, but here we have considered the maximum value for all.

(ABC)max=3). 500X2+36.000=
99.0GO・・・・・・・・・・・・・・・119If the speed of light is 3X108m/sec* (ABC)m
How long does it take for a signal to be transmitted between ax and ax?

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

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

(151) is the reference pulse generated by satellite A(1),
(132) is the reference pulse directly received at observation point P,
(155) is the reference pulse received via satellite B'i, similarly (154) is satellite B, C+2
1 (120).

The distance difference required to calculate the hyperboloid for platform detection can be found as follows.

Here, IAP-ABPI=(T2-T1.)/C
IABP-ABCP+=(T3-T2)/C However, C is the speed of light, and AB and 'BC are determined from the orbital position of the artificial satellite.

At observation point P, measurements can be made simply by equipping a receiver. In the measurement according to this invention, the orbit of the artificial satellite explained on the condition that the orbital position of the artificial satellite is accurately known is determined by measuring the distance and distance change that it owns at the control station, and based on the acquired data. Calculations are performed to determine the trajectory and future values are calculated by trajectory prediction. The predicted orbit value is a function of time and is of the order fi1′f! :Can be known.

Since this invention uses 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 1 artificial satellite. 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 on satellite A (1), (141) is the timing when the second time is received by the control station, (142) is the reference second time of the control station's calibration source, (145) is Orbit determination [Artificial satellite A to be received at the control station based on I (seconds,
(144) is the propagation time in seconds obtained from the orbit determination value,
(+45) is the time difference between time (141) and time (145).

When the control station detects a time difference (145), it sends a command to send this difference to A (11).9 By correcting the time, the satellite can maintain accurate time.

The method of time difference detection is not to compare the seconds and hours once, but for a long time! From K: Continuing measurement. Even if there is a slight error, it becomes easy to detect due to the accumulation of errors 81, so such a detection method is excellent.

In this invention, it is necessary to measure the distance difference. That is, it is necessary to measure the time difference between timing TI (1, 52) and timing T2 (155) in FIG. 12, but the generation time timing of the original signal TO (ts+) is unnecessary information for this measurement. . However, the basis for detecting the position of observation point P(5) is that the position of the artificial satellite at the time of signal generation is determined. The position of an artificial satellite can be expressed as a function of time.

If the timing of the original signal T0 (151) in Fig. 12 is changed to a signal with time information and the observation point P(5)K is notified, the observation point P(5) obtains the distance difference measurement information t- at the same time. By knowing the time when this original signal was generated, it is also possible to accurately obtain the satellite's position 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.

(150) and (151) are PRN codes for distance measurement +11.
+21 shift register, (152) is the time encoder, (155) is the time device, (154) is the carrier wave generation source, (156) is the clock that generates the PRN code and time code, (157) is each code A gate signal that resets the contents of each register at the hour of the second,
1sa) is a MOo 2 combiner of two codes, (15
9), (160) is a modulator, (161) is a 90 degree phase shifter for the carrier wave, and (162) is a QPSK synthesis circuit.

In this invention, the PRN code clock? In the case of IMH2, the reason why a distance measurement signal obtained by combining two codes is required will be described later. PRN code (1) and PRN code (
2) was added by MOD2 to create a new PRN code.

The shift registers (150) and (151) of the PRN code (1) and PRN code (21) are signal generators for this purpose.

After the two codes are added in a MOD 2 adder (15B).

B is modulated by a modulator (159) onto the carrier wave;
PSK (81-phase 5hift keying
) Modulating signal 1.

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

The content of the code changes from that point on, and the timing is determined by the gate signal (
157), the time encoder (152) simultaneously records Km
The current time read from the clock device (153') is driven by a clock (156) and transmitted as a code.

The time code is modulated by a modulator (160) using a carrier wave whose phase is 90 degrees different from that of the ranging signal.Since the ranging signal and the time code are modulated orthogonally, they are combined by one combiner (162), and one into two QPSK signals.

Observation point P(5) can receive the ranging signal and simultaneously know the time of primary 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 AP (132) sent directly from the artificial satellite A (1) and the ARP (155) sent via other artificial satellites, for example, the artificial satellite B (21'i).
Since the principle of position detection is to measure the time difference when the same signal arrives between the two, in order to detect the distance difference, it is sufficient that the frequency of the ranging signal is accurate. However, in order to detect one position, if the geometrical position of the signal source is not accurate, there will be a large error in the detected position. In the previous explanation, 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 must also be accurately known.

In Fig. 12, it is assumed that the original signal for distance measurement is always generated from the artificial satellite A +11, but at the same time, the time and distance signals obtained from the artificial satellite B (2) using the track structure shown in Fig. 14 are also generated. Just send it to observation point P (51).

Figure 15 shows the timing diagram of two satellites, (
170) indicates the time when it occurred at the artificial satellite B(2) at timing T7, and (171) indicates the time when timing T7 (170) was received at the observation point P (51) at timing T8.

At observation point P (5), satellite A is seen from satellite B (2).
It will receive the signal sent from (1) and the 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(2). Also, at observation point P(5), 1
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 signals to two observation points simultaneously from one artificial satellite, it is recommended to use two frequencies, or to use pre-given different subcarriers for each Kueya, different spreading codes for Inabata, etc. Appropriate.

Next, we will explain how an observer can actually take measurements one by one using an artificial satellite placed in orbit. In Figure 16, three artificial guards M are grouped together.

Transmits signals for measurement. Assuming that satellite A (1) is the source of the signal, 1 satellite A, B, C (11, +
21.12+) as one group, and another group of satellites that operate in the same way (c, D, E(2))
, +421. (190) Create another group.

The signal flow of one group will be explained.

From satellite A (1), the source signal (211) is sent to observation point p (5) and satellites B, C (2), and CD via routes (1eo), (tsl), and (182). A signal is sent.

Figure 17 shows nine chronological tables.

At observation point P(5), signal (212) 'I! i - Receive first.

Satellite B +21? : The signal on route (181) is transmitted to Kanoki 1 point P (5) via route (185) and is received at timing (215).

By measuring the time difference between timings (212) and (215), the distance difference between AP and BP can be measured. Expressing this as a formula, it becomes K as follows.

ARP-AP=C(T11-TI2)...
・・・・・・・・・・・・In ABP, the distance between AB can be found by the predicted position of the artificial satellite or by actual measurement, so by subtracting this from the formula @, fiAP and HP
The distance difference can be found.

BP-AP=C(T,,-T12)-AB・
・・・・・・・・・・・・・・・■Similar! ′ is transmitted between satellites B, C (21, and ■) and observation point P (5) via routes (185), (184), and (187), and the timing (215) and ( A signal is received at 214), which can be expressed as:

BP CP=C (T13 T, 2) BC...
・・・・・・・・・・・・■.

Next, the measurement of the distance between the artificial guards JiA, B, and C will be explained. The distance during this time can be calculated by knowing the position of the artificial satellite, but it is also possible to measure it using only the data relay function.

A signal directed from satellite A Tl+ to satellite B (2) and satellite C■ is transmitted through paths (181) and (182), and from satellite B (2) to satellite C (2).
) IK direction is transmitted on path (184). Artificial satellite C■
Now, measure the distance difference between the two signals. This can be expressed as an equation as follows.

ABC-AC=C(T15-T14)...
・・・・・・・・・・・・・・・ ■a-! −c−b=
d1 ・・・・・・・・・・・・・・・
...■Here * d1=c(T, 5 T14
) The following equation holds true for meridians (182) and (185) and route (181).

ACB-AC=C(T17-T16)...
・・・・・・・・・・・・■a+b-(=d2
・・・・・・・・・・・・・・・・・・・・・
...ωHere, *d2=c(Tly Ti6) The following equation holds true based on the path (+136), (18B), and the path (184).

BAC-BC:C (TI?-T18)...
・・・・・・・・・・・・r3υb+c-a=C(T
lg-Tta) ・・・・・・・・・・・・・・・
...■Here # d3=C (T19 T18)
The equation (■) is obtained using the equations ω, ■, and ■, and the distances a, b, and c of the nine artificial satellites are determined. However, in this case, each artificial satellite needs to be equipped with a device for measuring the distance between the satellites.

Satellite, E, F (42), (190)
, Regarding (191).

The same measurement method used for satellites A, B, and C (11, (2), ■) will be used.

The source should match the reference time.

If there are 8 satellites in orbit, A, B, C,
D.

If you add the signs E, F, G, H, (ABC
), (DEF).

(Combine into three groups like Gl() and perform measurements as described in Fig. 18. Next, (BCD).

Observer P (51) performs measurements such as (EFG) and (HA).The observer P (51) moves the three groups one after another and performs measurements. By repeating this multiple times, you can obtain all the information necessary to detect the observer's position.Figure 17 shows how 8 satellites are divided into 3 groups and measurements are taken repeatedly. An example of the time order is shown below. One group of measurements is performed at i second time (25G), and the measurement is completed in about 0.5 seconds. Therefore, the 9th order (i-N) (ZSt) In seconds, the second group (256) measures i + 2 seconds (252), the third group (25
7) is performed, and returns to the original state again at s -1-3 seconds (239), and measurement is performed from the first group.

Next, distance measurement will be explained. In the explanation so far, the first
The signal used for measurement in FIGS. 2 and 11 was a pulse indicating 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
However, when used in space, the reach distance is very long, and the method of concentrating the signal energy for distance measurement in a pulsed manner requires increasing the size of the necessary equipment. , it's not a good idea. Therefore, if we adopt a device that can transmit the 9-time timing signal over a long period of time and detect it on the receiving side for a long period of time,
Easily configure equipment in space.

The maximum propagation distance required for measurement is approximately 99.9 mm, as assumed in Equation 9 (■). It is sufficient if it is about OOOKm. It is only necessary to be able to encode this distance using an unambiguous code.If the basic clock is set to IMHz, approximately 0.
There are 33×10” repeating waveforms.

Therefore, a 20-bit shift register is used.

Pseudo Random Co
de, @l.

220 1UlX1G
' can generate unique patterns. Other K.

PRN generated from two 10-bit shift registers
We uniquely trap the phase of the code and use the Gold code obtained by the logical sum of Modulo 2, 1023
It is also possible to generate a unique pattern between X1023'::lX10'.

On the receiving side, by performing two correlation calculations with a zero 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 and satellites. However, in the case of zero artificial satellites, for example, if laser communication is developed, the 12th
Methods such as those shown in FIG. 1 and FIG. 16 are also possible. When using PRN code.

By using different PRN code types despite the same frequency, there are advantages such as being able to use multiple codes at the same time and making it easier to meet the power flux density assumptions required from the perspective of radio wave interference. are doing.

Next, I will explain the configuration diagram of the artificial satellite used in this invention.
This will be explained using FIG. The crystal oscillator (240) operates the time device (242) and its output.

Telemetry device (245), transmitter (246),
It is sent to the control station via the diplexer (247) and antenna (248). The control station compares this signal with the national primary standard level signal and sends fine adjustment of the zero launch frequency and time calibration to the satellite. This signal is sent to the antenna (
248), diplexer (247), receiver (249)
), command receiver (250) receives via i,
Command CMi crystal launcher (240) for correction
and the time device (242). Telemetry equipment (
245) and the command receiver (250) are also used for general satellite bus equipment other than zero hour calibration. The distance and distance change rate signals from the control station are sent to the receiver (249)
and the transmitter (246) via a return route (261), and is used to determine the orbit of this artificial satellite. Clock (214) 'fr receives PRN code generator (2
52) generates a - series of PRN codes, and receives the reference time signal (24!5) 'i. Kind of faith-ji! are input to a modulator (255) to convert them into the same signal 9, for example, a four-phase phase modulation signal, and its output is .

Via the transmitter (254) and the inter-user antenna (255).

Sent to user. At the same time, the modulation signal (226).

Signals are also sent to other satellites via an amplifier (257), diplexer (25B), 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). Receive and diplexer (25B)
, the signal via the receiver (280) is transmitted to the observation point P via the transmitter (254) and the antenna (255), and at the same time is transmitted to the other artificial satellite by the transmitter (280).
62), via antenna (264), signal C265
[Effect of the invention] In this invention, a satellite with a large inclination angle is placed in a geostationary orbit, and KL, l! is transmitted so that four satellites can be observed by an observer. By having an observer receiver, a simple clock, and a calculation processing algorithm, one can calculate one's own position fltk. 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 this invention. Figure 1 is a diagram showing the case where two artificial satellites are used and deployed in two dimensions, and Figure 2 is a diagram showing the case where two artificial satellites are used and deployed in two dimensions. A diagram showing a curved surface,
Figure 3 is a diagram showing the case where three artificial satellites are used, Figure 4 is a diagram showing the arrangement of Figure 3 in three-dimensional coordinates, and Figure 5 is an xy diagram when three artificial satellites are used. A diagram showing the appearance on the surface,
Figure 6 shows the case where three satellites are used for two observations.
Figure 7 is a diagram showing the arrangement of three artificial satellites and observation points, Figure 8 is a diagram showing the algorithm for position detection, and Figure 9 is a diagram showing the location of artificial satellites placed on the earth. Figure 10 is a diagram showing the satellite's movement relationship 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 geostationary 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 satellites. Figure 16 is a diagram showing a measurement method in which three satellites are grouped together. Figure 17 is a measurement diagram. Diagram showing timing. Figure 18 is a diagram showing the order in which repeated measurements are taken on the 10 satellites 't-3 group, and Figure 19 is a diagram showing the order in which measurements are taken repeatedly on the 10 satellites't-3 group.
FIG. 20 is a diagram showing the configuration of an artificial satellite when position detection is performed. FIG. 20 is a diagram showing the configuration of a GPS satellite. In the figure, (11i21■(80)(81)(82
)(85) is an artificial satellite. +611711241 is a hyperbola, i9B! 71Fi hyperboloid, +51 (71) is observation point PI (101) (1
02) (105) (104) (105) (106) (1
14) (115) (116) (tt7) (its) (t
i9Xt2oX1z1) is the position of the satellite, (+5
1) (152) (153) are the reference pulses, (+34
)(iss) is the received pulse, (1508151) is the shift register, (152) is the time encoder, (
155) is a time device, and (154) is a carrier wave generation source. (156) is the clock, (157) is the gate signal,
(tSa) is a synthesizer, (159) (160) is a modulator, (161) li110&'' phaser, (
162) is a synthesizer, (240) is a crystal booster. ' (241) is the crystal oscillator output, (242
) is the time device, (243) is the reference time output, (
214) is a clock. (246) (262) is a transmitter, (247) is a diplexer. (24B) is the antenna for telemetry command, (
249) is a receiver, (250) is a command receiver,
(261) is the return route for distance measurement, (252)
is the PRN code generator, (253) is the modulator, (
254) is the transmitter, (255) is the observer antenna, (257) is the amplifier, and (25B) is the guiplexer. (259X21S4) is an antenna for intersatellite communication, (
260) (265) (270) are communication signals between Eiho,
(280) is a receiver. In Figure 1, the same or corresponding parts are designated by the same reference numerals. Figure 1

Claims (3)

[Claims] (1) In a geosynchronous orbit with an orbital inclination close to 6 degrees and the periapsis elongation of adjacent satellites at the same time being close to 120 degrees apart from each other, in the visible range when viewed from near the Earth's surface. Three artificial satellites are introduced at the same time, and based on the time signal calibrated by the control station and the time signal,
One of the three satellites transmits a ranging signal created in synchronization with a time signal directly to the earth's surface, and at the same time transmits the time and ranging signal to the other satellites. The adjacent artificial satellite transmits the time and ranging signals to the adjacent artificial satellite by the inter-satellite data relay means, and at the same time sends these signals to the earth's surface, it transmits them to the next adjacent artificial satellite. The three satellites transmit the above-mentioned time and ranging signals and the time and ranging signals based on their own time to the earth's surface. Near the earth, the position of the three satellites is determined based on the orbit prediction obtained from the control station based on the reception time of this ranging signal, and two adjacent combinations of the three satellites are used as the base point. However, by calculating two types of distance differences between the satellite and the observer using ranging signals, it is possible to draw a hyperboloid with the two satellites as focal points, and furthermore, the position After a significant period of time for detection has elapsed, the same signals mentioned above are obtained from the three artificial satellites mentioned above, and the hyperboloid mentioned above is obtained based on the signals, and such measurements are repeated two or more times. An artificial satellite characterized in that the observation point is determined as the intersection of the hyperboloids by performing the same calculation process as described above using three artificial satellites in order to determine the position of the observation point as the intersection of the obtained hyperboloids. Positioning method used. (2) Four 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 seven 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) Positioning method using the described artificial satellite.