CN106628258A - Satellite spin attitude determination method based on sun vector information - Google Patents

Abstract

The invention provides a satellite spin attitude determination method based on sun vector information. Firstly, the sun is measured through a sun sensor on one time sequence, and a sun vector sequence under a star coordinate system is obtained; then, sun vectors participating in calculation are selected according to the accuracy of the sun sensor; and finally, the spin axis and the spin angular speed of a satellite are calculated according to the changes of the sun vectors. By the adoption of the method, input information can be provided for despinning and precessional motion control adopted for guaranteeing energy safety, bases can be provided for measure evaluation, and the method has quite high engineering operability and realizability.

Description

A kind of satellite spin attitude determination method based on solar vector information

Technical field

The invention belongs to satellite gravity anomaly field, is related to a kind of determination method of satellite spin attitude.

Background technology

When satellite in-orbit period, when causing celestial body angular speed excessive due to exception, in order to ensure the security of satellite system, Need to understand satellite energy state in time；Meanwhile, adopt an effective measure in time for safeguards system energy security, it is required to Obtain the azimuth information of satellite spin axle and solar vector.

Existing method relies primarily on gyro and the angular speed of satellite is measured, and then takes the measures such as jet to satellite Racemization is carried out, but the range of gyro is limited, and under the speed conditions of satellite big angle, gyro can occur saturation, so as to lead to not obtain Take the angular speed of satellite.

The content of the invention

Present invention solves the technical problem that being：Overcome the deficiencies in the prior art, there is provided one kind is based on solar vector information Satellite spin attitude determination method, using change in location of the solar vector under celestial body system, solve celestial body spin axis and Angular speed size, solves in prior art when the in-orbit exception of satellite causes that angular speed is excessive to be caused gyro saturation to obtain to defend The problem of star spin information.

The present invention technical solution be：A kind of satellite spin attitude determination method based on solar vector information, bag Include：

(1) the solar vector S described under celestial body coordinate system is obtained using sun sensor measurement_b, and remember at one Between the solar vector sequence for obtaining is measured in sequence is S_bk, k=1,2,3 ..., N, N is positive integer；

(2) in S_bkIn, take for K and meet n>m、p>1 positive integer m, n, p, and accordingly extract sun vector measurement value sequence Four values S in row_bm、S_bm+p、S_bn、S_bn+p, it is calculated celestial body spin axisAnd spin angle velocity size | ω |：

ΔS_bmp=S_bm+p-S_bm、ΔS_bnp=S_bn+p-S_bn

Wherein Δ t is the time interval in solar vector sequence first between latter two measured value.

Present invention advantage compared with prior art is：

(1) the inventive method is based entirely on solar vector information and proposes, it is to avoid due to big angular speed in prior art Gyro saturation and the problem of satellite angular velocity information cannot be known, and can be generalized in the case of gyro free to determine Satellite Angle Speed；

(2) the inventive method gives the certainty of measurement according to sun sensor to choose measured value calculating satellite angular speed Strategy, can during satellite despun control, particularly in the case of satellite angular speed is less still can keep meter Calculate precision.

Description of the drawings

Fig. 1 is the FB(flow block) of the inventive method；

Fig. 2 is position view of the spin axis under celestial body system in the embodiment of the present invention；

Fig. 3 is the big logotype of the spin angle velocity in the embodiment of the present invention.

Specific embodiment

As shown in figure 1, a kind of satellite spin attitude determination method based on solar vector information, comprises the steps：

S1, obtains in celestial body coordinate system that (usual celestial body coordinate system is defined as using sun sensor measurement：Origin is in satellite Barycenter, butt joint ring direction is -X direction, and windsurfing direction is Y-direction, and Z-direction meets the right-hand rule) under the solar vector S that describes_b, The measurement in a time series obtains solar vector sequence S_bk, k=1,2,3 ..., N, N is positive integer.Without loss of generality, Assume that the time interval of measurement sequence is isometric, be Δ t；

S2, in S_bkIn, appoint and take continuous three sun vector measurement values, you can calculate celestial body spin direction of principal axis and sit in celestial body Unit direction vector under mark systemAnd spin angle velocity size | ω |, computational methods are as follows：

Assume that the corresponding three sun vector measurement values of Continuous Observation moment T1, T1+ Δ t, T1+2* Δ t are S_bT1、S_bT2、 S_bT3, then：

ΔS_b21=S_bT2-S_bT1、ΔS_b32=S_bT3-S_bT2 (1)

The principle of above three formula comes from：Around the unit direction vector of the one fixing axle rotation in space, its rotary shaft Direction and angular velocity of rotation, can be calculated by the unit direction vector variable quantity and rate of change.In the present invention, sun arrow It is fixed in inertial space in the amount short time, the variable quantity of solar vector is, therefore can lead to caused by the rotation by satellite The variable quantity for crossing calculating solar vector obtains the rotary shaft and angular velocity of rotation of satellite.Wherein formula (1) is calculated sun arrow The variable quantity of amount, formula (2) calculates the spin axis of satellite according to the variable quantity of solar vector, and formula (3) is according to solar vector Rate of change calculates the spin angle velocity size of satellite.

S3, when celestial body spin angle velocity can be gradually lowered during racemization, causes the solar vector between double sampling to exist Change under celestial body coordinate system is also less and less, due to being affected by sun sensor certainty of measurement, by double interval Data carry out spin axis determination will be so that determine that error becomes increasing.

In order to overcome sun sensor pair to determine the impact of precision, precision is determined according to sun sensor measure error pair Impact analysis and the accuracy requirement of measurement, need to adjust data break according to spin angle velocity size, and strategy is as follows：

Positive integer m, n, p are taken, n is met>m、p>1, then take four values S in sun vector measurement value sequence_bm、S_bm+p、S_bn、 S_bn+p, computing formula is as follows：

ΔS_bmp=S_bm+p-S_bm、ΔS_bnp=S_bn+p-S_bn (4)

The principle of above three formula is identical with formula (1)～(3), and difference is the change gauge to solar vector Count in.When satellite spin angular speed is larger, solar vector variable quantity is big in the unit interval, can be calculated with formula (1), when defending When star spin angle velocity is less, solar vector variable quantity is less in the unit interval, then the measurement noise of sun sensor is for knot The impact of fruit is larger, in order to obtain larger solar vector variable quantity, needs to elongate the time interval for measuring twice, and this is namely The difference of formula (4) and formula (1).

Embodiment

By taking certain satellite in orbit as an example, celestial body angular speed is excessive to cause all of gyro whole saturation, it is impossible to for judging to defend Star spin states.The satellite configures two sun sensors, there is effective measured value, such as following table in the case：

Calculated using the inventive method according to upper table.

First, solar vector can be obtained in each sampling instant, such as in star 100483763,100483765, 100483767, solar vector can be calculated respectively is：

Secondly, using formula (1)～(3), satellite spin axle unit direction vector can be obtained and spin angle velocity is：

| ω |=384.8315 °/s

Finally, above-mentioned calculating is done to the data in form, you can obtain the calculating knot of satellite spin axle and spin angle velocity Fruit ordered series of numbers, the celestial body spin attitude information for finally obtaining is as shown in Figures 2 and 3.

The content not being described in detail in description of the invention belongs to the known technology of those skilled in the art.

Claims (1)

1. a kind of satellite spin attitude determination method based on solar vector information, it is characterised in that include：

(1) the solar vector S described under celestial body coordinate system is obtained using sun sensor measurement_b, and remember in a time series The upper solar vector sequence for obtaining that measures is S_bk, k=1,2,3 ..., N, N is positive integer；

(2) in S_bkIn, take for K and meet n>m、p>1 positive integer m, n, p, and accordingly extract in sun vector measurement value sequence Four values S_bm、S_bm+p、S_bn、S_bn+p, it is calculated celestial body spin axisAnd spin angle velocity size | ω |：

${\stackrel{\→}{\mathrm{\ω}}}^0=-\frac{{\mathrm{\ΔS}}_{bmp}\×{\mathrm{\ΔS}}_{bnp}}{\left|{\mathrm{\ΔS}}_{bmp}\×{\mathrm{\ΔS}}_{bnp}\right|}$

$\left|\mathrm{\ω}\right|=\frac{arccos\left(\frac{{\mathrm{\ΔS}}_{bmpbmp}^T{\mathrm{\ΔS}}_{bnp}}{\left|{\mathrm{\ΔS}}_{bmp}\right|\·\left|{\mathrm{\ΔS}}_{bnp}\right|}\right)}{(n-m)\·\mathrm{\Δ}t}$

ΔS_bmp=S_bm+p-S_bm、ΔS_bnp=S_bn+p-S_bn

Wherein Δ t is the time interval in solar vector sequence first between latter two measured value.