AU2021102140A4 - In-orbit Real-time Calibration System and Method of Vector Magnetometer - Google Patents
In-orbit Real-time Calibration System and Method of Vector Magnetometer Download PDFInfo
- Publication number
- AU2021102140A4 AU2021102140A4 AU2021102140A AU2021102140A AU2021102140A4 AU 2021102140 A4 AU2021102140 A4 AU 2021102140A4 AU 2021102140 A AU2021102140 A AU 2021102140A AU 2021102140 A AU2021102140 A AU 2021102140A AU 2021102140 A4 AU2021102140 A4 AU 2021102140A4
- Authority
- AU
- Australia
- Prior art keywords
- calibration
- magnetometer
- resistor
- magnetic field
- vector magnetometer
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Ceased
Links
- 238000000034 method Methods 0.000 title claims abstract description 19
- 238000004364 calculation method Methods 0.000 claims abstract description 31
- 238000012545 processing Methods 0.000 claims abstract description 20
- 230000008569 process Effects 0.000 claims abstract description 7
- 239000003990 capacitor Substances 0.000 claims description 23
- 238000013500 data storage Methods 0.000 claims description 13
- 238000005259 measurement Methods 0.000 claims description 7
- 238000010586 diagram Methods 0.000 abstract description 9
- 238000005070 sampling Methods 0.000 abstract 1
- 238000004891 communication Methods 0.000 description 4
- 230000001419 dependent effect Effects 0.000 description 4
- HHLZCENAOIROSL-UHFFFAOYSA-N 2-[4,7-bis(carboxymethyl)-1,4,7,10-tetrazacyclododec-1-yl]acetic acid Chemical compound OC(=O)CN1CCNCCN(CC(O)=O)CCN(CC(O)=O)CC1 HHLZCENAOIROSL-UHFFFAOYSA-N 0.000 description 3
- 241001061260 Emmelichthys struhsakeri Species 0.000 description 3
- 238000009434 installation Methods 0.000 description 2
- 238000012360 testing method Methods 0.000 description 2
- 230000032683 aging Effects 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000005540 biological transmission Effects 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 238000001514 detection method Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 230000035699 permeability Effects 0.000 description 1
- 238000010998 test method Methods 0.000 description 1
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R33/00—Arrangements or instruments for measuring magnetic variables
- G01R33/0017—Means for compensating offset magnetic fields or the magnetic flux to be measured; Means for generating calibration magnetic fields
Landscapes
- Physics & Mathematics (AREA)
- Condensed Matter Physics & Semiconductors (AREA)
- General Physics & Mathematics (AREA)
- Measuring Magnetic Variables (AREA)
Abstract
An in-orbit real-time calibration system and method of a vector magnetometer is disclosed in
the invention. Wherein the system includes calibration coil, calibration control circuit, scalar
magnetometer and vector magnetometer. The calibration control circuit controls the calibration
coil to generate stable magnetic field and the scalar magnetometer is used to detect the
generated magnetic field. The calibration coil is located on satellite platform. The scalar
magnetometer and the vector magnetometer are located on the satellite boom. In calibration
mode, the calibration control circuit combined with the calibration coil firstly generates the
background magnetic field to cancel the data measured by the scalar magnetometer to zero,
and then calculates the new base value and scale factor of the vector magnetometer. Finally,
the calibration control circuit shuts down and the vector magnetometer switches back to the
normal sampling processing mode. Using the new scale factor and base value to calculate the
magnetic field data, the invention can automatically complete the in-orbit calibration with fast
calibration processing speed and accurate calibration result, and it does not need manual
intervention in the calibration process, which is suitable for the in-orbit real-time calibration of
long-life satellite-bome vector magnetometer.
1/1
FIGURES
100 400
300
200
Figure 1 A schematic diagram of a system composition according to an embodiment of
the present invention.
- 2032021
10D 204 ->205 4
200
Figure 2 A schematic diagram of a system structure according to an embodiment of the
present invention
VbVR-2
R
V-f-V
R. Ry
Figure 3A circuit diagram of acurrent parameter calculation control unit according toan
embodiment of the present invention
Description
1/1 FIGURES
100 400 300
200
Figure 1 A schematic diagram of a system composition according to an embodiment of
the present invention.
- 2032021
10D 204 ->205 4
200
Figure 2 A schematic diagram of a system structure according to an embodiment of the
present invention
VbVR-2 R V-f-V R. Ry
Figure 3A circuit diagram of acurrent parameter calculation control unit according toan
embodiment of the present invention
In-orbit Real-time Calibration System and Method of Vector Magnetometer
The invention relates to the field of vector magnetometer calibration, in particular to an
in-orbit real-time calibration system and method of a vector magnetometer.
Vector magnetometer is the most commonly used magnetic field measurement equipment
in planetary magnetic field detection because it can measure three-component vector of
magnetic field. Fluxgate magnetometer is the most commonly used vector magnetometer,
which has the advantages of small size, high reliability and high measurement accuracy.
However, due to the aging of materials and devices, the scale factor and base value of
fluxgate magnetometer will shift to a certain extent during long-time operation. When the
deviation is large, the measured data will not be corrected and processed correctly.
Generally, in-orbit calibration often needs the rotation of satellite platform, but it is
difficult to calibrate by the rotation of satellite platform for some satellite platforms with
the same direction or rover working on the planet surface. In addition, although the
rotation operation is simple, the calibration accuracy is not high. When the position of the
satellite platform is almost unchanged or the rover is stationary, it can be considered that
the background magnetic field does not change in a short time, so the in-orbit real-time
calibration of the vector magnetometer can be completed by using the scalar
magnetometer mounted on the platform plus a calibration coil and calibration control
circuit.
The technical problem to be solved by the invention is to provide an in-orbit real-time
accurate calibration system for a satellite with almost constant position or a vector
magnetometer working on a rover on the surface of a planet.
The invention provides an in-orbit real-time calibration system of a vector magnetometer,
which comprises a calibration coil, a calibration control circuit, a scalar magnetometer
and a vector magnetometer to be calibrated. The calibration control circuit is used to
generate current, control calibration to generate standard magnetic field, and be
responsible for calculating calibration parameters. Scalar magnetometer is used to
confirm the calibration control circuit parameters when the magnetic field generated by
calibration coil cancels the background magnetic field, so as to eliminate the influence of
the background magnetic field.
The invention provides an in-orbit real-time calibration system of a vector magnetometer,
which comprises the following parts of a calibration coil, a calibration control circuit, a
scalar magnetometer and a vector magnetometer.
The calibration control circuit is respectively connected with the calibration coil, the
scalar magnetometer and the vector magnetometer.
The calibration control circuit comprises a first interface unit, a second interface unit, a
calibration data storage and processing unit, a current parameter calculation control unit
and a current source output unit.
The scalar magnetometer is connected with the current parameter calculation control unit
through the first interface unit.
The current parameter calculation control unit is respectively connected with the
calibration data storage and processing unit and the current source output unit.
The calibration data storage and processing unit is connected with the vector
magnetometer through the second interface unit.
The current source output unit is connected with the calibration coil.
Preferably, the calibration control circuit is arranged inside the satellite and used for
controlling the calibration coil to generate a standard magnetic field and calculating
calibration parameters.
The scalar magnetometer is connected with the satellite boom and used for eliminating
the influence of the background magnetic field by confirming the circuit parameters of
the calibration control circuit when the standard magnetic field cancels the background
magnetic field.
Preferably, the vector magnetometer is a magnetometer to be calibrated and it is
connected with the boom of the satellite. Based on the three directions of the vector
magnetometer, through the angular relationship between the scalar magnetometer and the
vector magnetometer, it breaks up the scalar magnetic field of the scalar magnetometer
into three component magnetic fields consistent with the three directions.
Preferably, the calibration coil comprises a plurality of groups of coils, wherein the
directions of magnetic fields generated by these coils are consistent with the three
directions of the vector magnetometer.
Preferably, the calibration control circuit controls the calibration coil to generate a
magnetic field at the position of the vector magnetometer by adjusting output parameters, and the range of the magnetic field is larger than the measuring range of the vector magnetometer.
Preferably, the current source output unit comprises a DAC output module, an arithmetic
summation module and a voltage-to-current module, wherein the current parameter
calculation control unit is connected with the DAC output module. The DAC output
module is connected with the voltage-to-current module through the arithmetic
summation module.
The current parameter calculation control unit is used for obtaining the output
parameters through calculation, and based on the output parameters, the DAC module
outputs a first voltage, and the arithmetic summation module includes a second voltage,
then the arithmetic summation module obtains an output voltage based on the first
voltage and the second voltage. The voltage-to-current module controls the output current
of the current source output unit according to the output voltage.
Preferably, the DAC output module comprises a DAC module and a first operational
amplifier. And the DAC module is connected with the arithmetic summation module
through the first operational amplifier.
Preferably, the arithmetic summation module comprises a first resistor Ro, a second
resistor Ri, a third resistor R2, a first capacitor C and a second operational amplifier. The
first operational amplifier is respectively connected with the second resistor Ri, the third
resistor R2, the first capacitor Ci and the second operational amplifier through the first
resistor Ro. The second resistor Ri comprises a first end and a second end, wherein the
second voltage is set at the first end of the second resistor, and the second end of the
second resistor is respectively connected with the first resistor Ro, the third resistor R2, the first capacitor Ci and the second operational amplifier. The third resistor R2 is connected in parallel with the first capacitor Ci and the second operational amplifier. A first output end of the second operational amplifier is connected with the voltage-to current module.
Preferably, the voltage-to-current module comprises a fourth resistor R3, a fifth resistor
R4, a sixth resistor R6, a seventh resistor R5, an eighth resistor R7, a second capacitor C2
and a third operational amplifier. The first output end of the second operational amplifier
is respectively connected with the fifth resistor R4, the second capacitor C2 and the third
operational amplifier through the fourth resistor R3. The fifth resistor R4 is connected in
parallel with the second capacitor C2 and the third operational amplifier. The negative
input end of the third operational amplifier is respectively connected with the fourth
resistor R3, the fifth resistor R4 and the second capacitor C2. The positive input end of the
third operational amplifier is connected to the seventh resistor R5 and the eighth resistor
R7 respectively. A second output end of the third operational amplifier is respectively
connected with the fifth resistor R4, the second capacitor C2 and the sixth resistor R6. The
sixth resistor R6 is connected to the eighth resistor R7 through the seventh resistor R5. A
third output end of the voltage-to-current module is respectively connected with the sixth
resistor R6 and the seventh resistor R5.
An in-orbit real-time calibration method of a vector magnetometer comprises the
following steps.
Si. Turn off the vector magnetometer and turn on the calibration control circuit and the
scalar magnetometer. Then the calibration control circuit controls the calibration coil to generate the standard magnetic field and transmit the scalar magnetic field output by the scalar magnetometer to the calibration control circuit.
S2. The calibration control circuit breaks up the scalar magnetic field into component
magnetic fields corresponding to the vector directions, then adjusts the output current
according to the magnitude of the component magnetic field. Further, it controls the
standard magnetic field of the calibration coil to make the magnetic field measured by the
scalar magnetometer zero. Finally, the output parameters of the calibration control circuit
and the first magnetic field of the vector magnetometer corresponding to the calibration
coil are recorded.
S3. The calibration control circuit controls the load control platform of the satellite to
start the vector magnetometer and enter a calibration mode.
S4. The calibration control circuit adjusts the output parameters based on the
measurement range of the vector magnetometer with the output parameters as the base
values, wherein each output parameter has the same duration.
S5. The calibration control circuit receives and processes the second magnetic field
intensity in the output direction of the vector magnetometer corresponding to each output
parameter, averages and subtracts the first magnetic field of the vector magnetometer,
and obtains the first magnetic field data based on the vector magnetometer corresponding
to each output parameter.
S6. Based on each output parameter, the calibration control circuit subtracts the first
magnetic field data from the data actually generated by the vector magnetometer to obtain
the second magnetic field data.
S7. Based on the first magnetic field data and the second magnetic field data, calculating
a scale factor and a base value of the output direction by a least square method.
S8. The calibration control circuit returns the scale factor and the base value to the vector
magnetometer and switches the vector magnetometer. After the vector magnetometer sets
parameters according to the scale factor and the base value, the vector magnetometer
switches back to the normal working mode, and the vector magnetometer works
according to the scale factor and the base value.
The invention discloses the following technical effects.
Compared with the prior art, the technical scheme provided by the invention has the
beneficial effects that the in-orbit real-time calibration system of the vector magnetometer
provided by the invention can automatically complete in-orbit calibration when needed
through the calibration control circuit, and the calibration processing speed is fast, the
calibration result is accurate, the calibration process does not need manual intervention,
and the system is suitable for in-orbit real-time calibration of the vector magnetometer
with long service life.
In order to explain the embodiments of the present invention or the technical scheme in
the prior art more clearly, the figures used in the embodiments will be briefly introduced
below. Obviously, the figures in the following description are only some embodiments of
the present invention. For ordinary technicians in the field, other figures can be obtained
according to these figures without paying creative labour.
Figure 1 is a schematic diagram of a system composition according to an embodiment of
the present invention.
Figure 2 is a schematic diagram of a system structure according to an embodiment of the
present invention.
Figure 3 is a circuit diagram of a current parameter calculation control unit according to
an embodiment of the present invention.
In figures, 100- calibration coil, 200- calibration control circuit, 300- scalar
magnetometer, 400-vector magnetometer, 201- the first interface unit, 205- the second
interface unit, 204- calibration data storage and processing unit, 202- current parameter
calculation control unit, and 203- current source output unit.
The technical scheme in the embodiments of the present invention will be described
clearly and completely with reference to the figures in the embodiments of the present
invention. Obviously, the described embodiments are only part of the embodiments of the
present invention, not all of them. Based on the embodiments of the present invention, all
other embodiments obtained by ordinary technicians in the field without creative labour
belong to the protection scope of the present invention.
As shown in figs. 1-3, the invention discloses an in-orbit real-time calibration system of a
vector magnetometer, which comprises a calibration coil, a calibration control circuit, a
scalar magnetometer and a vector magnetometer to be calibrated. The calibration control
circuit is used to generate current, control calibration to generate standard magnetic field,
and be responsible for calculating calibration parameters. Scalar magnetometer is used to
confirm the calibration control circuit parameters when the magnetic field generated by
calibration coil cancels the background magnetic field, so as to eliminate the influence of
the background magnetic field.
The invention provides an in-orbit real-time calibration system of a vector magnetometer,
which comprises the following parts of an in-orbit real-time calibration system of a vector
magnetometer, characterized by comprising a calibration coil (100), a calibration control
circuit (200), a scalar magnetometer (300) and a vector magnetometer (400). The
calibration control circuit (200) is respectively connected with the calibration coil (100),
the scalar magnetometer (300) and the vector magnetometer (400). The calibration
control circuit (200) comprises a first interface unit (201), a second interface unit (205), a
calibration data storage and processing unit (204), a current parameter calculation control
unit (202) and a current source output unit (203). The scalar magnetometer (300) is
connected with the current parameter calculation control unit (202) through the first
interface unit (201). The current parameter calculation control unit (202) is respectively
connected with the calibration data storage and processing unit (204) and the current
source output unit (203). The calibration data storage and processing unit (204) is
connected with the vector magnetometer (400) through the second interface unit (205).
The current source output unit (203) is connected with the calibration coil (100).
The calibration control circuit (200) is arranged inside the satellite and used for
controlling the calibration coil (100) to generate a standard magnetic field and calculating
calibration parameters.
The scalar magnetometer (300) is connected with the satellite boom and used for
eliminating the influence of the background magnetic field by confirming the circuit
parameters of the calibration control circuit (200) when the standard magnetic field
cancels the background magnetic field.
The vector magnetometer (400) is a magnetometer to be calibrated and it is connected
with the boom of the satellite. Based on the three directions of the vector magnetometer
(400), through the angular relationship between the scalar magnetometer (300) and the
vector magnetometer (400), it breaks up the scalar magnetic field of the scalar
magnetometer (400) into three component magnetic fields consistent with the three
directions.
The calibration coil (100) comprises a plurality of groups of coils, wherein the directions
of magnetic fields generated by these coils are consistent with the three directions of the
vector magnetometer (400).
The calibration control circuit (100) controls the calibration coil (100) to generate a
magnetic field at the position of the vector magnetometer (400) by adjusting output
parameters, and the range of the magnetic field is larger than the measuring range of the
vector magnetometer (400).
The current source output unit (203) comprises a DAC output module, an arithmetic
summation module and a voltage-to-current module, wherein the current parameter
calculation control unit (202) is connected with the DAC output module. The DAC
output module is connected with the voltage-to-current module through the arithmetic
summation module.
The current parameter calculation control unit (202) is used for obtaining the output
parameters through calculation, and based on the output parameters, the DAC module
outputs a first voltage, and the arithmetic summation module includes a second voltage,
then the arithmetic summation module obtains an output voltage based on the first voltage and the second voltage. The voltage-to-current module controls the output current of the current source output unit according to the output voltage.
The DAC output module comprises a DAC module and a first operational amplifier. And
the DAC module is connected with the arithmetic summation module through the first
operational amplifier.
The arithmetic summation module comprises a first resistor Ro, a second resistor Ri, a
third resistor R2, a first capacitor Ci and a second operational amplifier. The first
operational amplifier is respectively connected with the second resistor Ri, the third
resistor R2, the first capacitor Ci and the second operational amplifier through the first
resistor Ro. The second resistor Ri comprises a first end and a second end, wherein the
second voltage is set at the first end of the second resistor, and the second end of the
second resistor is respectively connected with the first resistor Ro, the third resistor R2,
the first capacitor Ci and the second operational amplifier. The third resistor R2 is
connected in parallel with the first capacitor Ci and the second operational amplifier. A
first output end of the second operational amplifier is connected with the voltage-to
current module.
The voltage-to-current module comprises a fourth resistor R3, a fifth resistor R4, a sixth
resistor R6, a seventh resistor R5, an eighth resistor R7, a second capacitor C2 and a third
operational amplifier. The first output end of the second operational amplifier is
respectively connected with the fifth resistor R4, the second capacitor C2 and the third
operational amplifier through the fourth resistor R3. The fifth resistor R4 is connected in
parallel with the second capacitor C2 and the third operational amplifier. The negative
input end of the third operational amplifier is respectively connected with the fourth resistor R3, the fifth resistor R4 and the second capacitor C2. The positive input end of the third operational amplifier is connected to the seventh resistor R5 and the eighth resistor
R7 respectively. A second output end of the third operational amplifier is respectively
connected with the fifth resistor R4, the second capacitor C2 and the sixth resistor R6. The
sixth resistor R6 is connected to the eighth resistor R7 through the seventh resistor R5. A
third output end of the voltage-to-current module is respectively connected with the sixth
resistor R6 and the seventh resistor R5.
An in-orbit real-time calibration method of a vector magnetometer comprises the
following steps.
Si. Turn off the vector magnetometer (400) and turn on the calibration control circuit
(200) and the scalar magnetometer (300). Then the calibration control circuit (200)
controls the calibration coil (100) to generate the standard magnetic field, and transmit
the scalar magnetic field output by the scalar magnetometer (300) to the calibration
control circuit (200).
S2. The calibration control circuit (200) breaks up the scalar magnetic field into
component magnetic fields corresponding to the vector directions, then adjusts the output
current according to the magnitude of the component magnetic field. Further, it controls
the standard magnetic field of the calibration coil (100) to make the magnetic field
measured by the scalar magnetometer (300) zero. Finally, the output parameters of the
calibration control circuit and the first magnetic field of the vector magnetometer (400)
corresponding to the calibration coil (100) are recorded.
S3. The calibration control circuit (200) controls the load control platform of the satellite
to start the vector magnetometer (400) and enter a calibration mode.
S4. The calibration control circuit (200) adjusts the output parameters based on the
measurement range of the vector magnetometer (400) with the output parameters as the
base values, wherein each output parameter has the same duration.
S5. The calibration control circuit (200) receives and processes the second magnetic field
intensity in the output direction of the vector magnetometer (400) corresponding to each
output parameter, averages and subtracts the first magnetic field of the vector
magnetometer (400), and obtains the first magnetic field data based on the vector
magnetometer (400) corresponding to each output parameter.
S6. Based on each output parameter, the calibration control circuit (200) subtracts the
first magnetic field data from the data actually generated by the vector magnetometer
(400) to obtain the second magnetic field data.
S7. Based on the first magnetic field data and the second magnetic field data, calculating
a scale factor and a base value of the output direction by a least square method.
S8. The calibration control circuit (200) returns the scale factor and the base value to the
vector magnetometer (400) and switches the vector magnetometer (400). After the vector
magnetometer (400) sets parameters according to the scale factor and the base value, the
vector magnetometer (400) switches back to the normal working mode, and the vector
magnetometer (400) works according to the scale factor and the base value.
Embodiment 1
The invention discloses an in-orbit real-time calibration system of a vector
magnetometer, as shown in fig. 1, which comprises a calibration coil (100), a calibration
control circuit (200), a scalar magnetometer (300) and a vector magnetometer (400) to be
calibrated. The calibration control circuit (200) is used to generate current, control the calibration coil (100) to generate a standard magnetic field, and be responsible for calculating calibration parameters. Scalar magnetometer (300) is used to confirm the calibration control circuit parameters when the magnetic field generated by calibration coil (100) cancels the background magnetic field, so as to eliminate the influence of the background magnetic field.
The calibration coil (100) is a field-adding coil, which is composed of a plurality of coils
and is installed on a satellite platformoraroverplatform. The installation position
requires that the magnetic field generated by the calibration coil (100) is consistent with
the three measurement directions of a vector magnetometer.
In an embodiment of the present invention, the calibration control circuit (200) and the
calibration coil (100) are connected by cables.
As shown in fig. 2, the calibration control circuit (200) includes a first interface unit
(201), a current source output unit (203), a current parameter calculation control unit
(202), a calibration data storage and processing unit (204), and a second interface unit
(205) connected with the vector magnetometer.
The first interface unit (201) and the second interface unit can be realized by RS422 bus,
and the transmission mode can be simplex communication. The scalar magnetometer
transmits the scalar magnetic field data measured by the calibration control circuit in one
direction.
The current parameter calculation control unit (202) calculates the component magnetic
field magnitude in one direction according to the scalar magnetic field data input by the
scalar magnetometer (300) and the angular relationship with the vector magnetometer in
three directions, and then sets the control output parameters, so that the scalar magnetometer finally measures that the component magnitude of the scalar magnetic field in this direction is zero. The adjustment principle is that the output parameters of the calibration control circuit are proportional to the output current, and thus proportional to the magnetic field generated on the calibration coil, which is determined by the coil parameters and the parameters of the current source output unit. Therefore, according to the current calculated magnetic field magnitude, if the output value is increased or decreased a certain output value linearly every time, when the measured magnetic field is very small, it can be linearly increased by 1 every time until the measured magnetic field is 0. At this time, the current parameter calculation control module records and saves the output parameters as DO.Then, after the vector magnetometer to be calibrated enters the calibration mode, the output parameters are gradually changed by A from DO, that is, the current output parameters are adjusted as DO+A, DO-A, DO+2A, DO+3A, DO-3A,
... DO+NA, DO-NA. In an embodiment of the present invention, the above processing
can be realized by a microprocessor or a DSP.
The current source output unit (203) works with the current parameter calculation control
module to ensure that the current source output unit can output a corresponding
proportional stable magnetic field after the current output parameters are set.
In an embodiment of the present invention, as shown in fig. 3, the current source output
unit (203) includes a DAC output module, an arithmetic summation module and a
voltage-to-current module. Wherein, the output parameter Di calculated by the current
parameter calculation control module will be written into the register of DAC, and the
DAC will be driven to output the corresponding voltage Vi, and there is a linear
V =Vnah (D /) / 2 wNe relationship between Vi and parameter Di, that is i ',with n as the digit of
DAC. Vi and Vb are summed proportionally by an operational amplifier, so as to generate
negative voltage, thus generating positive and negative opposite currents, and the
calibration coil also generates corresponding positive and negative opposite magnetic
R2 R2
fields. The output voltage is calculated by R 0 R
The ratio of RO and Ri can be adjusted by adjusting their values. People can also adjust
Vi and Vb to adjust the output voltage. Voltage-to-current module is also realized by the
operational amplifier. When R3 (R, + R6 )= R4 R R3 / R4 = R, / R? , and the output
current IL is independent of the load size, it can be got that IL = kVout, wherein k is a
constant determined by R3~R6, and the magnetic field generated by the calibration coil
also satisfies the corresponding linear relationship with the output current. B = k2IL, and
k2 is a constant determined by coil turns, coil radius, and permeability of vacuum.
Therefore, the output parameters calculated by the current parameter calculation control
module and the magnetic field generated by the calibration coil satisfy a linear
relationship.
The function of the calibration data storage and processing unit (204) is to store the
calculated and input measured magnetic field data BO, BO', B, B1'... BN, BN',
corresponding to current output parameter D+A,D-A,D+2A,D-2A,D+3A,DO-3
A,......DO+NA,D-NA. These measured data are calculated by the following way.
The calibration control circuit will keep it for a period of time after setting the current
output parameters. In one embodiment of the invention, it will keep it for 1min, during
which time it will continuously receive data from the interface with the vector
magnetometer, but only average the data in the middle 30s, which can be selected by a timer. After setting the current adjustment parameters, the timer will be started. When the timer is timed to 15s, it starts to accumulate and receive vector magnetic field data. When the timer is timed to 45s, it calculates the average value. Finally, Bres is subtracted from the average value, and the result is saved in the storage unit. The storage unit can be implemented with independent SRAM or FIFO in FPGA.
The above Bres is obtained by ground test. The test method is as follows. Adjust the
parameters of the control calibration circuit so that when the magnetic field generated by
the calibration coil is 0 in the direction of the scalar magnetometer, the magnetic field can
be measured at the vector magnetometer (which can be obtained by the calibrated vector
magnetometer at the installation position or directly using the result of the magnetometer
to be calibrated after the magnetometer is calibrated on the ground). The data has nothing
to do with the background magnetic field and it is Bres.
The calibration data storage and processing unit (204) also needs to store the magnetic
fields generated by the corresponding calibration coils under the current output
parameters of DO+A, DO-A, DO+2A, DO-2A, DO+3A, DO-3A, ... , DO+NA, DO-NA
at the position of the vector magnetometer. The corresponding relationship can be
obtained by actual measurement on the ground or by calculating the distance between the
calibration coil and the vector magnetometer. By subtracting Bres from the magnetic field
generated by the calibration coil at the position of the vector magnetometer under
different current output parameters, Ba, Ba', Bal, Bal', ... , BaN, BaN' are obtained
and saved to the storage unit.
After the current parameter calculation control module adjusts the current output
parameters (in this embodiment, after setting DO+NA and DO-NA), the calibration number storage and processing unit (204) starts to calculate the calibration parameters of the vector magnetometer, namely the scale factor and the base value. The least square method can be used for calculation, as follows.
With the data B0, B0', BI, B1', ... , BN, BN' measured and processed by vector
magnetometer as the independent variable X and the standard magnetic fields Ba, Ba',
Bal, Bal' ... BaN, BaN' generated by the calibration coil as the dependent variable Y, the
relationship between the independent variable and the dependent variable should be Y=
i=(X' - x)(y' - Y) a ==
aX+b, and a and b are calculated by the formula ofb =y ax
Wherein,X and Yis the average of the independent variable sequence X and the
dependent variable sequence Y. a and b are the scale factor and base value of vector
magnetometer.
The second interface (205) can also be realized by duplex communication or RS422
interface with two simplex communication. One is used to help vector magnetometer to
transmit measured data to calibration control circuit in real time, and the other is used to
help calibration control circuit to transmit calculated calibration results back to vector
magnetometer.
In addition, the calibration control circuit (200) also has an interface with the load control
unit of the satellite platform, which is connected by an indirect board plug-in, and the
communication between the two can be realized by RS422 or CAN bus. When the
calibration control circuit makes the scalar magnetic field measured by the scalar
magnetometer zero, it will inform the load control unit, and the load control unit will control the vector magnetometer (400) to start up and enter the calibration mode by command.
The scalar magnetometer (300) can be an optically pumped magnetometer, and the vector
magnetometer (400) to be calibrated is a fluxgate magnetometer, which has a calibration
mode and a normal processing mode, and the two modes are switched by sending
commands from the load control unit of the satellite platform. In the calibration mode, the
vector magnetometer will transmit the output vector magnetic field to the calibration
control circuit in real time through the interface connected with the calibration control
circuit.
The workflow of in-orbit real-time calibration of the system is as follows.
1. Turn off the vector magnetometer (400) and turn on the calibration control circuit
(200) and the scalar magnetometer (300). Then the scalar magnetometer transmits the
scalar magnetic field to the calibration control circuit.
2. The calibration control circuit (200) decomposes the component magnetic field Bx
corresponding to the vector direction according to the scalar magnetic field, adjusts the
output parameters according to its magnitude, controls the calibration coil to generate the
corresponding magnetic field, and finally makes the magnetic field measured by the
scalar magnetometer (300) zero. Recording the output parameter as DO of the calibration
control circuit (200) at this time.
3. The calibration control circuit (200) informs the satellite load control platform to turn
on the vector magnetometer (4000 and enter the calibration mode. In the calibration
mode, the vector magnetometer (400) will transmit the vector magnetic field data
measured in real time to the calibration control circuit (200).
4. The calibration control circuit (200) takes DO as the base value and adjusts the output
parameters to be DO+A, DO-A, DO+2A, DO+3A, DO-3A, ... , DO+NA, DO-NA.
Among them, DO+NA and DO-NA can cover the measuring range of vector
magnetometer, and each output parameter is kept for a period of time.
5. The calibration control circuit (200) receives and processes the magnitude of the vector
magnetic field in this direction output by the vector magnetometer (400) under each
output parameter, and averages a piece of data in the holding time and subtracts Bres as
the magnitude of the magnetic field output by the vector magnetometer (400) under this
control output parameter, wherein Bres is the magnetic field generated by the calibration
coil at the position of the vector magnetometer (400) when the magnetic field measured
by the scalar magnetometer (300) is 0, which is independent of the background magnetic
field and can be measured on the ground. Saving the corresponding processed magnetic
field data BO, BO', B1, BI', ... , BN, BN' under the output parameters.
6. The calibration control circuit (200) records and saves the magnetic field data BaO,
ba', Bal, Bal' ... , BaN, BaN' that should actually be generated at the vector
magnetometer (400) under the output parameters. (The magnetic field magnitudes
corresponding to different output parameters have been determined during the ground
test, and here is the value after subtracting the above Bres from the standard magnetic
field generated under the corresponding output parameters).
7. Taking stored data BO, BO', BI, B1' ... BN, BN' as independent variables X and BaO,
Ba', Bal, Bal' ... , BaN, BaN' as dependent variables Y to calculate the scale factor and
base value in this direction according to the least square method: Y=aX+b, wherein a is
scale factor and b is base value.
8. The calibration control circuit (200) transmits the calculated scale factor and base
value back to the vector magnetometer (400) and shuts itself down. After receiving the
new scale factor and base value, the vector magnetometer (400) sets them in the
corresponding parameters and saves them, and then switches back to the normal
operation mode. Subsequent magnetic field calculations use the new scale factor and base
value.
The in-orbit real-time calibration system of the vector magnetometer provided by the
invention can automatically complete in-orbit calibration when needed through the
calibration control circuit, and the calibration processing speed is fast, the calibration
result is accurate, the calibration process does not need manual intervention, and the
system is suitable for in-orbit real-time calibration of the vector magnetometer with long
service life.
The above embodiments only describe the preferred mode of the invention, but do not
limit the scope of the invention. On the premise of not departing from the design spirit of
the invention, various modifications and improvements made by ordinary technicians in
the field to the technical scheme of the invention shall fall within the protection scope
determined by the claims of the invention.
Claims (10)
1. An in-orbit real-time calibration system of a vector magnetometer, characterized by
comprising a calibration coil (100), a calibration control circuit (200), a scalar
magnetometer (300) and a vector magnetometer (400). The calibration control circuit
(200) is respectively connected with the calibration coil (100), the scalar magnetometer
(300) and the vector magnetometer (400). The calibration control circuit (200) comprises
a first interface unit (201), a second interface unit (205), a calibration data storage and
processing unit (204), a current parameter calculation control unit (202) and a current
source output unit (203). The scalar magnetometer (300) is connected with the current
parameter calculation control unit (202) through the first interface unit (201). The current
parameter calculation control unit (202) is respectively connected with the calibration
data storage and processing unit (204) and the current source output unit (203). The
calibration data storage and processing unit (204) is connected with the vector
magnetometer (400) through the second interface unit (205). The current source output
unit (203) is connected with the calibration coil (100).
2. The in-orbit real-time calibration system of a vector magnetometer according to Claim
1, characterized in that the calibration control circuit (200) is arranged inside the satellite
and used for controlling the calibration coil (100) to generate a standard magnetic field
and calculating calibration parameters.
The scalar magnetometer (300) is connected with the satellite boom and used for
eliminating the influence of the background magnetic field by confirming the circuit
parameters of the calibration control circuit (200) when the standard magnetic field
cancels the background magnetic field.
3. The in-orbit real-time calibration system of a vector magnetometer according to Claim
2, characterized in that the vector magnetometer (400) is a magnetometer to be calibrated
and it is connected with the boom of the satellite. Based on the three directions of the
vector magnetometer (400), through the angular relationship between the scalar
magnetometer (300) and the vector magnetometer (400), it breaks up the scalar magnetic
field of the scalar magnetometer (400) into three component magnetic fields consistent
with the three directions.
4. The in-orbit real-time calibration system of a vector magnetometer according to Claim
3, characterized in that the calibration coil (100) comprises a plurality of groups of coils,
wherein the directions of magnetic fields generated by these coils are consistent with the
three directions of the vector magnetometer (400).
5. The in-orbit real-time calibration system of a vector magnetometer according to Claim
3, characterized in that the calibration control circuit (100) controls the calibration coil
(100) to generate a magnetic field at the position of the vector magnetometer (400) by
adjusting output parameters, and the range of the magnetic field is larger than the
measuring range of the vector magnetometer (400).
6. The in-orbit real-time calibration system of a vector magnetometer according to Claim
, characterized in that the current source output unit (203) comprises a DAC output
module, an arithmetic summation module and a voltage-to-current module, wherein the
current parameter calculation control unit (202) is connected with the DAC output
module. The DAC output module is connected with the voltage-to-current module
through the arithmetic summation module.
The current parameter calculation control unit (202) is used for obtaining the output
parameters through calculation, and based on the output parameters, the DAC module
outputs a first voltage, and the arithmetic summation module includes a second voltage,
then the arithmetic summation module obtains an output voltage based on the first
voltage and the second voltage. The voltage-to-current module controls the output current
of the current source output unit according to the output voltage.
7. The in-orbit real-time calibration system of a vector magnetometer according to Claim
6, characterized in that the DAC output module comprises a DAC module and a first
operational amplifier. And the DAC module is connected with the arithmetic summation
module through the first operational amplifier.
8. The in-orbit real-time calibration system of a vector magnetometer according to Claim
7, characterized in that the arithmetic summation module comprises a first resistor Ro, a
second resistor R, a third resistor R2, a first capacitor Ci and a second operational
amplifier. The first operational amplifier is respectively connected with the second
resistor Ri, the third resistor R2, the first capacitor Ci and the second operational
amplifier through the first resistor R. The second resistor Ri comprises a first end and a
second end, wherein the second voltage is set at the first end of the second resistor, and
the second end of the second resistor is respectively connected with the first resistor Ro,
the third resistor R2, the first capacitor Ci and the second operational amplifier. The third
resistor R2 is connected in parallel with the first capacitor Ci and the second operational
amplifier. A first output end of the second operational amplifier is connected with the
voltage-to-current module.
9. The in-orbit real-time calibration system of a vector magnetometer according to Claim
7, characterized in that the voltage-to-current module comprises a fourth resistor R3, a
fifth resistor R4, a sixth resistor R6, a seventh resistor R5, an eighth resistor R7, a second
capacitor C2 and a third operational amplifier. The first output end of the second
operational amplifier is respectively connected with the fifth resistor R4, the second
capacitorC2 and the third operational amplifier through the fourth resistor R3. The fifth
resistor R4 is connected in parallel with the second capacitorC2 and the third operational
amplifier. The negative input end of the third operational amplifier is respectively
connected with the fourth resistor R3, the fifth resistor R4 and the second capacitorC2.
The positive input end of the third operational amplifier is connected to the seventh
resistor R5 and the eighth resistor R7 respectively. A second output end of the third
operational amplifier is respectively connected with the fifth resistor R4, the second
capacitorC2 and the sixth resistor R6. The sixth resistor R6 is connected to the eighth
resistor R7 through the seventh resistor R5. A third output end of the voltage-to-current
module is respectively connected with the sixth resistor R6and the seventh resistor R5.
10. An in-orbit real-time calibration method of a vector magnetometer according to any
one of Claims 1-9, characterized in that it comprises the following steps.
Si. Turn off the vector magnetometer (400) and turn on the calibration control circuit
(200) and the scalar magnetometer (300). Then the calibration control circuit (200)
controls the calibration coil (100) to generate the standard magnetic field and transmit the
scalar magnetic field output by the scalar magnetometer (300) to the calibration control
circuit (200).
S2. The calibration control circuit (200) breaks up the scalar magnetic field into
component magnetic fields corresponding to the vector directions, then adjusts the output
current according to the magnitude of the component magnetic field. Further, it controls
the standard magnetic field of the calibration coil (100) to make the magnetic field
measured by the scalar magnetometer (300) zero. Finally, the output parameters of the
calibration control circuit and the first magnetic field of the vector magnetometer (400)
corresponding to the calibration coil (100) are recorded.
S3. The calibration control circuit (200) controls the load control platform of the satellite
to start the vector magnetometer (400) and enter a calibration mode.
S4. The calibration control circuit (200) adjusts the output parameters based on the
measurement range of the vector magnetometer (400) with the output parameters as the
base values, wherein each output parameter has the same duration.
S5. The calibration control circuit (200) receives and processes the second magnetic field
intensity in the output direction of the vector magnetometer (400) corresponding to each
output parameter, averages and subtracts the first magnetic field of the vector
magnetometer (400), and obtains the first magnetic field data based on the vector
magnetometer (400) corresponding to each output parameter.
S6. Based on each output parameter, the calibration control circuit (200) subtracts the
first magnetic field data from the data actually generated by the vector magnetometer
(400) to obtain the second magnetic field data.
S7. Based on the first magnetic field data and the second magnetic field data, calculating
a scale factor and a base value of the output direction by a least square method.
S8. The calibration control circuit (200) returns the scale factor and the base value to the
vector magnetometer (400) and switches the vector magnetometer (400). After the vector
magnetometer (400) sets parameters according to the scale factor and the base value, the
vector magnetometer (400) switches back to the normal working mode, and the vector
magnetometer (400) works according to the scale factor and the base value.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| AU2021102140A AU2021102140A4 (en) | 2021-04-22 | 2021-04-22 | In-orbit Real-time Calibration System and Method of Vector Magnetometer |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| AU2021102140A AU2021102140A4 (en) | 2021-04-22 | 2021-04-22 | In-orbit Real-time Calibration System and Method of Vector Magnetometer |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| AU2021102140A4 true AU2021102140A4 (en) | 2021-06-17 |
Family
ID=76327721
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| AU2021102140A Ceased AU2021102140A4 (en) | 2021-04-22 | 2021-04-22 | In-orbit Real-time Calibration System and Method of Vector Magnetometer |
Country Status (1)
| Country | Link |
|---|---|
| AU (1) | AU2021102140A4 (en) |
-
2021
- 2021-04-22 AU AU2021102140A patent/AU2021102140A4/en not_active Ceased
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN108267701B (en) | Active environmental magnetic interference compensation system for magnetic field reproduction coil | |
| KR101753459B1 (en) | System for monitoring electrical power usage of a structure and method of same | |
| US4989155A (en) | Intelligent power monitor | |
| CN112362941B (en) | Annular current transformer and current measuring method thereof | |
| US5237277A (en) | Apparatus for indirect measurement and control of a magnetic gradient field in a nuclear magnetic resonance imaging system | |
| AU2021102140A4 (en) | In-orbit Real-time Calibration System and Method of Vector Magnetometer | |
| CN110501570A (en) | Device for measurement of electrical energy and its current measurement mechanism | |
| EP1476762A1 (en) | Signal processing circuit for an optical sensor | |
| GB1563677A (en) | Error correction in electrical meters | |
| JPS57199968A (en) | Method and device for measuring magnetic field | |
| US4999569A (en) | Method to calibrate magneto-optic based metering system | |
| KR101471969B1 (en) | System and method for monitoring power consumption in real time | |
| CN113109751B (en) | System and method for on-orbit real-time calibration of vector magnetometer | |
| US5113140A (en) | Microprocessor-controlled high-voltage capacitance bridge | |
| US5861740A (en) | Load loss standard for calibrating power loss measurement systems | |
| CN112816757A (en) | All-fiber current transformer and half-wave voltage correction method thereof | |
| CA1276234C (en) | Electrical measuring instrument for high voltage power measurements | |
| JP2011141196A (en) | Insulation monitoring device | |
| CN112816758A (en) | All-fiber current transformer and half-wave voltage correction method thereof | |
| RU2224266C1 (en) | Meter of metrological characteristics of current transformer | |
| So et al. | A new current-comparator-based high-voltage low-power-factor wattmeter | |
| CN220795349U (en) | Current detection circuit and current detection device | |
| CN113804962B (en) | Metering chip and measuring system | |
| Xinliang et al. | Fluxgate Current Transducer based on Multi-point Zero Flux Technology | |
| SU918908A1 (en) | Magnetometer |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| FGI | Letters patent sealed or granted (innovation patent) | ||
| MK22 | Patent ceased section 143a(d), or expired - non payment of renewal fee or expiry |