JPH03201112A - Attitude estimating device for space navigating vehicle - Google Patents

Abstract

PURPOSE:To suppress the error of an attitude estimating value due to the error of an inertia sensor and to reduce an attitude estimating error due to an optical sensor by automatically changing parameters to be used for the arithmetic processing of an inertia sensor error estimating part. CONSTITUTION:A timer 9 measures time required from the operation start of an attitude estimating device, compares the measured value with a previously set time, generates and supplies a trigger signal Q to a parameter changing part 8. The changing part 8 changes the parameters K1, K2 to be used by an inertia sensor error estimating part 7 by the signal Q. The estimating part 7 executes arithmetic processing by using the attitude estimating error detected by an attitude estimating error detecting part 4 and the applied parameters K1, K2 and outputs an inertia sensor error correction value. On the outer hand, inertia sensor data correction using the correction value and the angular speed detecting value of the inertia sensor 1 and the output of the attitude estimating value are executed by an inertia sensor data correcting part 6 and an integration calculating part 3. Thus, the attitude estimating error can be reduced.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an attitude estimation device for an artificial satellite.

[Prior Art] Fig. 8 is a functional block diagram of a conventionally used attitude estimation device. In Fig. 9, (1) is an inertial sensor that detects the angular velocity ω of the satellite, and (2) is an inertial sensor that detects the attitude angle θ of the satellite. An optical sensor for detection, (3> is an integral calculation section, (4> is a posture estimation error detection section, and (5> is an inertial sensor error estimation section).

(6) is an inertial sensor data correction section.

Next, the operation will be explained. When the angular velocity value ω6 detected by the inertial sensor (1) has no error, the integral calculation unit (3) integrates ω6 and outputs it as the estimated attitude angle δ, then the estimated attitude value δ becomes the attitude angle θ. It matches and there is no problem. However, as a practical matter, ω6 contains an error and ω
Considering 6 as the estimated attitude angle change rate δ and integrating it is ω
The error included in 6 is integrated, and the obtained δ is the true θ and 74 null. Therefore, the attitude angle is directly detected using a sun sensor, earth sensor, star sensor, etc. as the optical sensor (2), and this attitude angle detection value θ is obtained.

is regarded as the true attitude angle, and the attitude estimation error detection unit (4>,
ω using the inertial sensor error estimation unit (5) and the inertial sensor data correction unit (6). Corrections will be made. That is, the attitude estimation error detection unit (4) detects the difference between θ1 and δ, and generates a difference signal θ. -δ is sent to the inertial sensor error estimator (5), where integral calculation using an integral constant and proportional calculation using a proportional constant are performed, and their sum (I[l/S+Kl)
(a, -e) is the inertial sensor error correction value M.

Bind and output. The inertial sensor data correction section (6) corrects ω6 by adding the above a'6 to the detected value ω6 of the inertial sensor (1). Here, and K.

is fixed. FIG. 9 shows the attitude estimation simulation results when the attitude angle is zero and the inertial sensor has a bias error of 0.57 hr. In this figure, in case l, -5
'is. Case! In Case 2, the attitude angle estimate δ does not deviate significantly from zero because the inertial sensor error estimate 1G converges quickly, whereas in case 2, δ deviates significantly from zero because the convergence of . is slow. Therefore, the inertial sensor error In terms of propagation to the attitude angle estimation, Case 1, which has less error, is preferable to Case 2. On the other hand, the optical sensor also has an error in attitude angle detection, and this propagates to the attitude angle estimation value. Figure 11 shows the attitude estimation simulation results when there is an attitude angle detection error of the optical sensor as shown in Fig. 11. In this simulation, the error of the inertial sensor is zero, and Case 1 and Case 2 are the case of J2. As can be seen from Fig. 11, case l is unfavorable because the propagation of the attitude angle detection error is larger than in case 2. In other words, the inertial sensor error and the attitude angle detection error are The form of propagation to the estimated angle value is different.Therefore, in the past, the constant Kt was set to * in consideration of both characteristics.

[Problems to be Solved by the Invention] Since the conventional posture estimation device is configured as described above, the propagation characteristics of the inertial sensor error and the posture angle detection error by the optical sensor to the posture estimated value are fixed. There is a problem in that when the magnitude of the error and the time protomile differ from those predicted in advance on the orbit, the expected attitude estimation accuracy cannot be obtained.

The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to obtain a posture estimation device that can reduce the propagation of various sensor errors to the posture angle estimated value.

[Means for Solving the Problems] A posture estimating device according to the present invention is capable of automatically changing parameters used in arithmetic processing of an inertial sensor error estimating section, which was conventionally fixed.

[Operation] The posture estimation device according to the present invention reduces the posture estimation error by changing the propagation amount of the inertial sensor error and the optical sensor error by automatically changing the parameters used in the calculation process of the inertial sensor error estimating section.

[Embodiment 1] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. 1st
In the figure, (1) is an inertial sensor, (2) is an optical sensor, (3) is an integral calculation unit, (4> is an attitude estimation error detection unit,
(6) is an inertial sensor data correction section, (7) is an inertial sensor error estimation section that uses externally given parameters, (
8) is a parameter change unit, and (9) is a timer.
Inertial sensor (1), optical sensor (2), integral calculation section (3
), the attitude estimation error detection section (4), and the inertial sensor data correction section (6>) are the same as those of the conventional one.

- In the embodiment described in (9), the timer (9) measures the time t after the posture estimation device according to the present invention starts operating, and compares t with a preset time T.

A parameter changing unit (8) generates a flag signal according to the flowchart shown in FIG. 2 and uses this as a trigger signal Q.
pass it on to The parameter changing section (8) changes the parameters 1 and 1 used by the inertial sensor error estimating section (7) using the trigger signal Q according to the flow shown in FIG. That is, if th<T, then K l+ K
, give □ to , , , which are set in advance, respectively, and if t is greater than or equal to T, then K.

The inertial sensor error estimator (7) gives □ to 1□ which is set in advance as K, and the inertial sensor error estimator (7) calculates the parameters K given as θ, -δ detected by the attitude estimation error detector (4).
The inertial sensor error correction value d is obtained by performing arithmetic processing similar to the conventional method using K. Output. In addition, the inertial sensor data correction using this d'6 and the detected angular velocity value ω6 of the inertial sensor and the output of the estimated attitude value are performed using the inertial sensor data correction section (6) and the integral calculation section (3) as in the conventional case. Ru.

Please give a simulation example.

In Figure 3, T=3000sec, K++=5XIO-”
, to, ,=3X10-", K +t-2X 10-'
, K□=6X10-', and the attitude estimation value is shown when the attitude angle is zero and the inertial sensor bias error of 0.5°/hr and the optical sensor error shown in Fig. to act simultaneously.

Here, since the attitude angle is zero, this attitude estimation value is equivalent to the attitude estimation error. Also, for comparison, when using only ni, ni, ni, ni, ni, ni, ni□, ni□
FIG. 4 also shows the simulation results when using a conventional posture estimation device without parameter changes using only . As can be seen from this figure, the embodiment according to the present invention has a smaller attitude estimation error than the conventional one in which K , , K , are not changed.

In the above embodiment, the parameter changing section <8) uses the trigger signal Q output from the timer (9) to change the parameters to:
As shown in Fig. 4, the posture estimation errors θ and -δ are monitored, the convergence status is determined by the convergence determination unit (10), and the result and the timer (9) are output. Parameter K is set as the logical sum of the trigger signals as a new trigger signal.
,,K, may be changed. That is, as shown in the flowchart shown in Figure 5, the magnitude of the absolute value of θ, -8k is compared with a preset threshold value A, and if it is smaller than 8 and this condition is satisfied for time T, convergence is achieved. It is assumed that the flag P is set to 1. This flag is set to zero by default. and a timer (
9) The logical sum of the trigger signals Q and P is created as a new trigger signal Q.
'. In the parameter changing section (8), the trigger signal Q'
is taken as Q and the parameters are changed in the same way as in the previous embodiment. A=0.005deg, K+
+=5X 10-", K t+=3X 10-3.
K 112X 10-'K tt-2X 10-',
T −500sec, T = 2000sec,
A simulation was carried out with an inertial sensor error of 0.5 deg/hr and an optical sensor error of 0.2 times that of Fig. 1O, and the results are shown in Fig. 6. As can be seen from this figure, the attitude estimation error in this embodiment of the present invention is also smaller than that in the case where the parameters are not changed.Here, for convenience of explanation, attitude estimation around two axes is taken as an example. It goes without saying that this device can be applied to the three axes of a spacecraft.

[Effect of the invention 1 As described above, according to the present invention, since the parameters of the inertial sensor error estimation section are changed, it is possible to suppress the error in the attitude estimation value due to the error of the inertial sensor, and also reduce the attitude estimation error due to the optical sensor. effective.

[Brief explanation of drawings]

FIG. 1 is a functional block diagram showing a posture estimation device according to an embodiment of the present invention, FIG. 2 is a flowchart of the operation of the timer in this embodiment, FIG. 3 is a flowchart of the operation of the parameter changing section, and FIG. An example of posture estimation simulation in this embodiment, FIG. 5 is a functional block diagram showing another embodiment of the present invention, FIG. 6 is a processing flowchart of the convergence determination section in the embodiment, and FIG. 7 is a posture estimation simulation example in the embodiment. FIG. 8, which shows estimation simulation results, is a functional block diagram of a conventional posture estimation device. Figure 9 is a diagram showing the attitude estimation simulation results when an inertial sensor error exists as a bias error in a conventional orientation estimation device, Figure 10 is a diagram showing an example of an optical sensor error, and Figure 0 is similar to Figure 1O. FIG. 3 is a diagram showing a simulation result of posture estimation by a conventional posture estimation device when there is an optical sensor error shown in FIG. In the figure, (1) is an inertial sensor, (2) is an optical sensor, (3) is an integral calculation section, (4) is an attitude estimation error detection section, (
6) is an inertial sensor data correction section, (7> is an inertial sensor error estimation section, (8) is a parameter change section, (9) is a timer, and (10) is a convergence judgment section. Note that the same symbols in Figure 1 are the same. , or a significant portion.

Claims (2)

[Claims] (1) An inertial sensor that detects the angular velocity of the spacecraft, an optical sensor that detects the attitude angle based on the angle between the light incident on the spacecraft and the spacecraft, and the attitude angle detection value detected by the optical sensor. and a posture estimation error detection unit that detects a posture estimation error by comparing the posture estimation value output from this estimation device, and an inertial sensor that performs calculation processing using the detected posture estimation error and externally given parameters. an inertial sensor data correction section that performs arithmetic processing using the calculation results of the inertial sensor error estimation section and the value of the angular velocity detected by the inertial sensor; an integral calculation section that obtains an estimated attitude value by performing calculations including It consists of a parameter changing unit that switches the parameters used in the error estimating unit, and by changing the parameters of the inertial sensor error estimating unit, it automatically changes the propagation characteristics of the error of the inertial sensor and the optical sensor to the attitude estimated value. A spacecraft attitude estimation device characterized by: (2) Use the posture estimation error detected by the posture estimation error detection section to judge the convergence status of the calculation of the inertial sensor error estimation section, and set the logical sum of this judgment result and the input trigger signal output of the timer as a parameter. By adding a convergence determination unit that outputs as a trigger signal for switching, and changing the parameters of the inertial sensor error estimation unit using the trigger signal output by this unit, the propagation characteristics of the error of the inertial sensor and optical sensor to the attitude estimation value can be automatically determined. The apparatus for estimating the attitude of a spacecraft according to claim 1, characterized in that: