JP2601163B2 - Earth sensor signal processing system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an earth sensor signal processing system, and more particularly to an earth sensor signal processing system for a spin stable satellite.

[0002]

2. Description of the Related Art As shown in FIG. 3, a conventional earth sensor signal processing system of a spin-stable satellite has a north earth sensor 1 and a south earth sensor 2, and an earth sensor from these earth sensors 1 and 2. A switch circuit 8 for switching signals, a sensor signal processing unit 4 for receiving and processing an output signal from the switch circuit 8, and switching between an earth sensor signal from the sensor signal processing unit 4 and a sun sensor signal from the sun sensor 3. The switch circuit 9 and the switch circuit 9
And a PLL circuit 10 for receiving an output signal from the controller.

The switch circuit 9 selects whether to use a sun sensor signal or an earth sensor signal. The sensor signal processing unit 4 which receives the earth sensor signal from the earth sensor 1 or 2 selected by the switch circuit 8 detects the threshold of the earth sensor signal and converts it into a pulse waveform. Thereafter, the earth sensor signal converted into the pulse waveform passes through the switch circuit 9 and proceeds to the PLL circuit 10, and is used for control as a satellite reference signal.
When the switch circuit 9 is selecting the sun sensor signal from the sun sensor 3, the switch circuit 8 is selecting the earth sensor signal from either the earth sensor 1 or 2.

[0004]

In this conventional earth sensor signal processing system, when the switch circuit 9 selects the sun sensor signal from the sun sensor 3, the switch circuit 8 sends the signal from either the earth sensor 1 or 2. When the reference signal is switched from the sun sensor signal to the earth sensor signal from the earth sensor 1 or 2, which is not normally selected, the earth sensor signal is not processed. It takes time to generate a signal, and a phase shift occurs in the reference signal, causing a shift in antenna pointing.

[0005] In the conventional earth sensor signal processing system, there is height difference of the earth sensor 1 and 2, and, because <br/> height difference this varies depending on the season, the earth sensor 1 from the solar sensor 3 Since the amount of deviation is different between when switching to the earth sensor 2 and when switching from the sun sensor 3 to the earth sensor 2, a stable reference signal cannot be obtained.

A first object of the present invention is to provide a two-
An object of the present invention is to provide an earth sensor signal processing system in which the shift of the reference signal is small even when switching to any one of the earth sensors.

It is a second object of the present invention to provide an earth sensor signal processing system which is hardly affected by a wave height difference between two earth sensors.

[0008]

According to the present invention , the spin
Two sensor signal processing units that convert the earth sensor signals from the two north and south earth sensors of the stable satellite into pulse signals, respectively, and compare the phases of the earth sensor signals from these sensor signal processing units. An earth sensor signal processing system is provided , comprising: two comparison circuits that output pulse signals; and a first switch circuit that selects and outputs one of the output signals of these comparison circuits.
You .

[0009]

Next, an embodiment of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a block diagram showing one embodiment of the present invention. In the embodiment shown in FIG. 1, the same components as those shown in FIG. 3 are denoted by the same reference numerals. As shown in FIG. 1, an output signal T ₁ of the earth sensor ₁ is provided to a sensor signal processing unit 4.
The output signal T ₂ of the is given to the comparing circuit 6. The output signal of the comparison circuit 6 is provided to the switch circuit 8, and the output signal of the switch circuit 8 is provided to the switch circuit 9.

The output signal of the earth sensor 2 is supplied to a sensor signal processing unit 5, and the output signal of the sensor signal processing unit 5 is supplied to a comparison circuit 7. The output signal of the comparison circuit 7 is provided to the switch circuit 8. Further, the output signal of the sensor signal processing unit 4 is supplied to the comparison circuit 7, and,
The output signal of the sensor signal processing unit 5 is provided to a comparison circuit 6. The output signal T ₃ of the solar sensor 3 is supplied to the switch circuit 9.

The switch circuit 9 is connected to the sun sensor 3 or the ground.
Select which of the ball sensors to use for the reference signal. The switch circuit 8 selects which of the earth sensors 1 or 2 to use the earth sensor signal. Earth sensor signals from earth sensors 1 and 2 are sent to sensor signal processing unit 4
At 5 the signal is converted to a pulse signal. The comparison circuit 6,
7 compares the phases of the pulse signals of the earth sensor signals from the earth sensors 1 and 2.

When the sun sensor signal from the sun sensor 3 is used, the earth sensor signals from the earth sensors 1 and 2 are processed in the signal processing units 4 and 5 irrespective of the operation of the switch circuit 8 and compared. Circuits 6 and 7 have been compared. When the switch circuit 9 selects the earth sensor instead of the sun sensor 3, the earth sensor signal on the side selected by the switch circuit 8 is used as a reference signal. To select Earth sensor 1 or 2
The switch circuit 8 is a conventional earth sensor signal processing system shown in FIG.
Like the system, the earth sensor signal processing system
Is also an essential component, and two comparison circuits 6 and 7 are provided.
The two inputs of this switch circuit 8 are
Earth sensor signals from satellites 1 and 2 are sent to signal processors 4 and 5
And the comparison circuits 6 and 7 complete the comparison.
It is to be guided in a state.

Here, assuming that the switch circuit 8 has selected the earth sensor 1, the threshold value of the signal obtained by the earth sensor 1 is detected by the sensor signal processing unit 4 and converted into a pulse signal. The phase of the pulse signal is compared with the pulse signal of the earth sensor 2 processed in the same manner in the comparison circuit 6, and the pulse signal is output at the center of both as shown in FIG. The pulse signal is used as a reference signal as P
Used after the LL circuit 10.

On the other hand, when the switch circuit 8 selects the earth sensor 2, the signal obtained by the earth sensor 2 has its threshold detected by the sensor signal processing unit 5 and is converted into a pulse signal. The phase of the pulse signal is compared with the pulse signal of the earth sensor 1 similarly processed in the comparison circuit 7, and the pulse signal is output at the center of both as shown in FIG. Then, the pulse signal is used as a reference signal by a PLL.
Used for circuit 10 and later.

[0016]

According to the present invention, since wearing a respective sensor signal processing unit into two earth sensor, when switching from the sun sensor to the earth sensor, less deviation of even a reference signal by switching to the earth sensor of Dochi et al Become.

Further, the present invention, since outputs a pulse signal by comparing the phase difference between the pulse <br/> scan wave two earth sensor at the center of both less susceptible to wave height difference of the earth sensor.

[Brief description of the drawings]

FIG. 1 is a block diagram showing one embodiment of the present invention.

FIG. 2 is a waveform chart for explaining the operation of the embodiment of FIG.

FIG. 3 is a block diagram showing a conventional earth sensor signal processing system.

[Explanation of symbols]

 1, 2 Earth sensor 3 Sun sensor 4, 5 Sensor signal processing unit 6, 7 Comparison circuit 8, 9 Switch circuit 10 PLL circuit

Claims (2)

(57) [Claims] 1. Two sensor signal processing units for converting earth sensor signals from two north and south earth sensors of a spin-stable satellite into pulse signals, respectively, and the phases of the earth sensor signals from these sensor signal processing units are compared. Earth sensor signal processing comprising: two comparison circuits for outputting a pulse signal at the center of the two; and a first switch circuit for selecting and outputting one of the output signals of these comparison circuits. system. 2. A second switch circuit for selecting and outputting one of an output signal from the first switch circuit and a sun sensor signal from a sun sensor, and receiving an output signal of the second switch circuit. And a PLL circuit.
3. An earth sensor signal processing system according to claim 1.