JPH03180736A - Optical observation calibrating device - Google Patents

Abstract

PURPOSE:To enable highly accurate calibration by providing a D/A converter for a calibration signal from a monitoring station, a power source for a light source which outputs a constant current corresponding to its signal value, and a light source for calibration which emits light with the constant current, and obtaining measurement data corresponding to its variation. CONSTITUTION:The calibration device is operated remotely from the monitoring station and when an observation is made, light 9 from an object passes through a lens 1 and an optical detector 2 to become an electric signal, which is converted by an A/D converter 3 into a digital signal 1 and sent out to the monitoring station. When the calibration is performed, the calibration signal 12 from the monitor station is converted by a D/A converter 4 into an analog signal in the absence of the incident light 9 and sent to the power source 5 for the light source and when the constant current corresponding to the signal level is sent to the power source 6 for the calibration, corresponding calibration light 10 is emitted and sent to the monitoring station as a signal 11 through the lens 1, detector 2, and converter 3. The monitoring station varies the signal of the signal 12 in specific steps within the maximum and minimum range of observation data and receives the signal 11 to obtain detailed measurement data in a similar range. Consequently, the observation data value can be calibrated with high accuracy.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an optical observation calibration device, and more particularly to a calibration device for optical observation equipment that is remotely controlled by signals transmitted from a monitoring station.

[Conventional technology]

Conventionally, in a calibration device for optical observation equipment that is mounted on an earth observation satellite and remotely operated to observe the amount of light from the earth's surface, etc., when in the observation state, the light from the object to be observed is focused on a single point using a lens. A detector converts it into an electrical signal, and then A
- After being converted into a digital signal by a D converter, it is transmitted to a monitoring station, and the monitoring station receives this signal to obtain observation data.

However, due to changes in environmental conditions, aging, etc., the lens may become dirty or the characteristics of the photodetector may change, causing a change in the relationship between the photodetector output and the amount of light incident on the lens. An error occurs in the data value. In order to calibrate this error, a calibration light source and a light source power source are provided to perform calibration. Calibration is performed in response to signals from the monitoring station, but in this case, at night, etc., the light from the object to be observed does not enter the lens, and the light source is connected to the calibration light source from the light source power source. A current is applied to cause the calibration light source to emit light, and the observed data values are calibrated using the measured data values of this light.

[Problem to be solved by the invention]

Lenses may deteriorate due to changes in environmental conditions, aging, etc.

The characteristics of the photodetector may change and the characteristic curve of the photodetector output relative to the amount of light incident on the lens may deviate from the original characteristic curve and move in parallel, or the slope of each point on the characteristic curve may change. It changes. In the conventional optical observation calibration device mentioned above,
A preset current is applied to the calibration light source to cause it to emit light, and one preset amount of light from the calibration light source is measured, so the measurement data value is only at one point, so the characteristic curve will deviate uniformly. However, it is not possible to calibrate changes in the slope of each point on the characteristic curve, and the observed data cannot be corrected with high precision.

The purpose of the present invention is to change the current applied to the calibration light source and obtain measurement data according to changes in the amount of light.
An object of the present invention is to provide an optical observation calibration device that eliminates the drawbacks of the conventional ones.

[Means to solve the problem]

The optical observation calibration device of the present invention is remotely operated by a signal transmitted from a monitoring station, and when in an observation state, the light 9 from an observation target is focused by a lens and converted into an electrical signal by a photodetector. The A-D converter converts it into a digital signal and sends it to the monitoring station. When in the calibration state, a preset current is applied to the calibration light source to emit light, which is focused by a lens and converted into light. The detector converts it into an electrical signal and further A
- an optical observation calibration device for optical observation equipment that converts the digital signal into an analog signal using a digital converter and transmits the digital signal to a monitoring station; It has a light source power source that outputs a constant current according to the signal value of the analog signal from the DA converter, and a calibration light source that emits light by the constant current from the light source power source. Further, according to a signal transmitted from the monitoring station, the output of the D-A converter is switched and connected to the input of the power source for the light source, and the output of the photodetector is switched to the input of the A-D converter. connection,
Alternatively, it has a switching means for switching and connecting the output of the DA converter to the input of the A-D converter.

〔Example〕

Next, the present invention will be explained with reference to the drawings.

FIG. 1 is a block diagram showing a first embodiment of the optical observation and calibration apparatus of the present invention. This device is remotely controlled by a signal from a monitoring station, and under normal observation conditions, light 9 from an object to be observed is focused by a lens 1 onto a photodetector 2 and converted into an electrical signal. The data is converted into a digital signal 11 by the converter 3, and the observation data is transmitted to a monitoring station.

Calibration is performed in response to signals from a monitoring station, but in this case, it is performed in a state where light 9 from the observation object does not enter the lens 1. For example, in the case of an earth observation satellite, observation is performed at night, etc. This is performed in a state where no light 9 from the object is incident.

A DA converter 4 receives a calibration digital signal 12 transmitted from a monitoring station, converts it into an analog signal, and outputs it to a light source power source 5. The light source power supply 5 supplies a constant current according to the analog signal level from the DA converter 84 to the calibration light source 6.

The calibration light source 6 emits calibration light 10 by emitting light in response to a constant current supplied from the light source power source 5, and makes the calibration light 10 enter the photodetector 2 via the lens 1. The calibration light 10 incident on the photodetector 2 is converted into an electrical signal, and further converted into a digital signal 11 by the AD converter 3 and transmitted to a monitoring station.

In the monitoring station, the value of the digital signal 12 for calibration is changed in a predetermined step in the range from the minimum value to the maximum value of the observation data, and is transmitted, and the digital signal 11 corresponding to the output level of the photodetector 2 is received. By doing this, detailed measurement data in the range from the minimum value to the maximum value of observation data can be obtained.

FIG. 2 is a block diagram showing a second embodiment of the optical observation and calibration apparatus of the present invention. The difference from the first embodiment shown in FIG. 1 is that a signal selection switch 7 and a calibration mode switch 8 are added.

In normal observation conditions, the switch contact of the signal selection switch 7 is switched to the A side, and the switch contact of the calibration mode switch 8 is switched to the C side, according to instructions from the monitoring station.
Light 9 from an object to be observed is focused on a photodetector 2 via a lens 1 and converted into an electrical signal, and then converted into a digital signal 11 by an A-D converter 3 and transmitted to a monitoring station.

When performing calibration, it is executed by operating the switches of the signal selection switch 7 and the calibration mode switch 8 in accordance with instructions from the monitoring station. In this case, the light 9 from the object to be observed does not enter the lens l; for example, in the case of an earth observation satellite, the light 9 from the object to be observed does not enter at night.

First, the optical system calibration mode will be explained. This is a mode for calibrating the optical system consisting of the lens and the photodetector 2. In this case, the switch contact of the calibration mode switch 8 is set to the d side, and the switch contact of the signal selection switch 7 is set to the a side. The connection state is the same as in the block diagram of the first embodiment shown in FIG. 1, and the optical system consisting of the lens 1 and the photodetector 2 is calibrated by the same operation.

Next, the electrical system calibration mode will be explained. In this case, the mode is for calibrating the electrical system consisting of the D-A converter 4 and the A-D converter 3, and the switch contact of the calibration mode switch 8 is set to the C side, and the switch contact of the signal selection switch 7 is set to the C side. are respectively switched to the b side. The DA converter 4 receives the calibration digital signal 12 transmitted from the monitoring station, converts it into an analog signal, and outputs the analog signal. The analog signal of the D-A converter 4 is input to the A-D converter 3 via the switch contact C side of the calibration mode switch 8 and further via the switch contact C side of the signal selection switch 7. The signal is then converted into a digital signal 11 and transmitted to a monitoring station. At the monitoring station, the value of the calibration digital signal is changed in a predetermined step in the range from the minimum value to the maximum value of the observation data, and the value is changed in a predetermined step, and the digital signal 11 is received, so that the DA converter 4 and the A - The electrical system consisting of the D converter 3 can be calibrated.

Note that the signal selection switch 7 and the calibration mode switch 8 are
In the block diagram shown in the figure, a switch contact is shown to simplify the explanation, but it is a switch circuit that operates in response to a signal from a monitoring station. Furthermore, an amplifier may be connected to the output side of the photodetector 2, if necessary.

〔Effect of the invention〕

As explained above, according to the optical observation calibration device of the present invention, the value of the calibration digital signal transmitted from the monitoring station is changed in predetermined steps in the range from the minimum value to the maximum value of observation data, By controlling the constant current value applied to the calibration light source and changing the light intensity of the calibration light source, multiple continuous measurement data can be obtained. , a characteristic change occurs in the optical system consisting of a photodetector, etc., and the characteristic curve of the photodetector output with respect to the amount of light incident on the lens deviates from the original characteristic curve and moves in parallel, or the characteristic curve This has the effect that it is possible to calibrate observed data values with high precision even if the slope of each point changes. Furthermore, by providing a changeover switch, it is possible to calibrate not only the optical system but also the electrical system, which consists of DA converters, AD converters, etc., so observation data can be corrected in detail based on the calibration results. This has the effect of further improving observation accuracy.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing a first embodiment of the optical observation calibration device of the present invention, and FIG. 2 is a block diagram showing a second embodiment of the optical observation calibration device of the present invention. DESCRIPTION OF SYMBOLS 1... Lens, 2... Photodetector, 3... A-D converter, 4... D-A converter, 5... Power source for light source, 6
...Calibration light source, 7...Signal selection switch, 8...
Calibration mode switch, 9... Light from observation object, 1
0...Calibration light, 11...Digital signal, ■2...
・Digital signal for calibration.

Claims (2)

[Claims] (1) It is remotely controlled by signals sent from the monitoring station, and when in observation mode, the light from the object to be observed is focused with a lens, converted to an electrical signal by a photodetector, and then converted to an A-D converter. When in the calibration state, a preset current is applied to the calibration light source to emit light, which is focused by a lens and converted into an electrical signal by a photodetector. In an optical observation calibration device for an optical observation instrument, the calibration digital signal transmitted from the monitoring station is converted into an analog signal by an A-D converter, and further converted into a digital signal by an A-D converter and transmitted to a monitoring station. A converter, a light source power source that outputs a constant current according to the signal value of the analog signal from the D-A converter, and a calibration light source that emits light by the constant current from the light source power source. Features optical observation calibration equipment. (2) The D
- Switching and connecting the output of the A converter to the input of the power source for the light source, and switching and connecting the output of the photodetector to the input of the A-D converter, or connecting the output of the D-A converter. The optical observation calibration device according to claim 1, further comprising a switching means for switching and connecting to the input of the A-D converter.