JPH0364360B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention relates to an earth sensor mounted on an artificial satellite,
This invention relates to an earth scan period detection device, particularly to a transient prevention function when interference from celestial bodies such as the moon or the sun occurs in the earth sensor output signal.

[Conventional technology]

FIG. 3 shows the configuration of a conventional earth sensor earth scan period detection device. In FIG. 3, 1 is a signal converter that converts the earth's infrared radiant energy into an electrical signal, and 2 is a waveform processing electronic circuit that generates leading edge signals and trailing edge signals corresponding to the electrical signals generated by the signal converter 1. , 3 inputs the leading edge signal generated by the waveform processing electronic circuit section 2 and generates a leading edge pulse. 4 inputs the trailing edge signal generated by the waveform processing electronic circuit section 2. and a voltage comparator for detecting a trailing edge pulse that generates a trailing edge pulse; 5 is a two-pulse counter circuit that inputs the leading edge pulse as data, inputs the trailing edge pulse as a reset signal, and generates a gate circuit control signal; 6 is a gate circuit; 7 is an earth scan period signal generation circuit that generates an earth scan period signal using the output pulse of the gate circuit 6 as a trigger; 8 is an output signal line of the signal converter 1; and 9 is an output of the waveform processing electronic circuit 2. Signal lines, 10 is the output signal line of the voltage comparator 3 for detecting leading edge pulses, 11 is the output line of the voltage comparator 4 for detecting trailing edge pulses, 12 is the output signal line of the 2-pulse counter circuit 5, 13 is the gate circuit 6 is an output signal line, and 14 is an output signal line of the earth scan periodic signal generating circuit 7.

The conventional earth scan period detection device is constructed as described above, and the waveforms generated on each signal line 9, 10, 11, 12, 13, and 14 are shown in FIG.

In FIG. 4, reference numeral 21 indicates a waveform generated on the output signal line 9 of the waveform processing electronic circuit section 2, which includes, in addition to the earth scan, a celestial interference waveform due to the sun or the moon. In FIG. 4, 22 is a leading edge pulse waveform generated on the output signal line 10 of the leading edge pulse detection voltage comparator 3, and a pulse corresponding to the reference voltage A (V) set in the voltage comparator appears. . In FIG. 4, 23 is a trailing edge pulse waveform generated on the output signal line 11 of the trailing edge pulse detection voltage comparator 4, and the pulse corresponding to the reference voltage -B (V) set in the voltage comparator is appear.
In FIG. 4, reference numeral 24 indicates a gate control signal waveform generated on the output signal line 12 of the two-pulse counter circuit 5, 25 indicates a trigger signal waveform for generating an earth scan periodic signal, which is generated on the output signal line 13 of the gate circuit 6, and 26 is an earth scan periodic signal generated on the output signal line 14 of the earth scan periodic signal generation circuit 7.

As shown in FIG. 4, when the input voltage of the trailing edge pulse detection voltage comparator 4 exceeds -B (V) when the earth sensor scans the moon or the sun, as shown in waveform 23, the input voltage is due to the moon or the sun. The trailing edge signal irregularly triggers the earth scan period signal generation circuit 7, and as shown on waveform 26, an irregular earth scan period signal is generated on the signal line 14 as if the earth scan period had changed. As shown in FIG. 4, when the earth sensor scans the moon or the sun, when the input voltage of the trailing edge pulse detection voltage comparator 4 does not exceed -B (V), as shown in waveform 23, it is due to the moon or the sun. No trailing edge signal is generated on the signal line 11, no irregular trailing edge pulses are generated due to celestial interference, the earth scan period signal generation circuit 7 is not triggered, and the earth scan period is changed due to celestial interference. Such irregular earth scan periodic signals are not generated on signal line 14, as shown on waveform 26. Further, the 2-pulse counter 5 inputs the leading edge pulse outputted to the signal line 10 when the input voltage of the leading edge pulse detection voltage comparator 3 exceeds A (V) as data, and counts the input data. exceeds 2, the output signal line 1 of the 2-pulse counter
2 indicates a high level as shown in waveform 24. Normally, the two-pulse counter 5 is always reset by the trailing edge signal, and the count is "1" during the time period between the leading edge pulse and the trailing edge pulse, and the count is "0" from the trailing edge pulse to the next leading edge pulse. , the output signal line is at a low level as shown in the waveform 24, that is, the gate circuit 6 is in an open state. However, as in the above case, when a leading edge pulse is generated when the earth sensor scans the sun or moon, but a trailing edge pulse is not generated, the 2-pulse counter will count "1" with the leading edge signal of the sun or moon. It counts "2" with the Earth's leading edge signal without being reset, and this state is maintained until it is reset with the Earth's trailing edge signal, and the waveform 24
As shown in the figure, the signal line 12 shows a high level,
The gate circuit 6 is in a closed state, and no trigger signal for triggering the earth scan period generating circuit 7 is generated on the signal line 13 as shown in waveform 25, and the earth scan period as shown in waveform 26 is not generated on the signal line 14. The earth scan periodic signal is lost as if the period had changed.

[Problem that the invention seeks to solve]

With the conventional earth scan period detection device as described above, it is possible to accurately detect the earth scan period when the earth sensor is normally scanning only the earth, but it is possible to accurately detect the earth scan period when the earth sensor is scanning only the earth. When the Earth scans, as shown in Figure 4, the trailing edge pulse generated when the Earth sensor scans the interfering object becomes a trigger, and an erroneous Earth scan period signal is generated, which appears to indicate that the Earth scan period has changed. There was a problem. Furthermore, the output signal of the two-pulse counter provided for detecting celestial interference inhibits the trailing edge pulse from being output to the earth scan periodic signal generation circuit, causing the generation of the earth scan periodic signal to be omitted, and There was a problem in which the earth scan period signal was lost, as if the scan period had changed.

This invention was made to solve this problem, and even when the earth sensor scans an interfering celestial object such as the moon or the sun, the trailing edge pulse generated during the earth scan can be used without being affected by celestial interference. The purpose is to accurately generate earth scan periodic signals.

[Means for solving problems]

The earth scan period detection device according to this invention includes:
When generating the trigger signal input to the earth scan periodic signal generation circuit using the trailing edge pulse,
A timer circuit and a gate circuit are provided to inhibit the generation of a trigger signal according to the time width of the leading edge pulse and the trailing edge pulse, and when the count number of the 2-pulse counter circuit is "2", all trailing edge signals are To accurately generate an earth scan period signal by inputting it as a trigger signal to a scan period signal generation circuit using a trailing edge pulse generated during earth scan even when an earth sensor is affected by interference from the moon or the sun.

[Effect]

In this invention, when outputting the trailing edge signal to the earth scan periodic signal generation circuit as a trigger for generating the earth scan periodic signal, the trailing edge signal is passed through a gate circuit controlled by a timer circuit, and the sun or moon is detected by the earth sensor. The trailing edge signal generated when scanning is inhibited from being output as a trigger signal to the earth scan periodic signal generation circuit, and a gate circuit controlled by the output signal of the two-pulse counter circuit is also passed through, so that the sun or moon is not connected to the earth. When the sensor scans the earth, it outputs the trailing edge signal generated during the earth scan to the earth scan periodic signal generation circuit.

〔Example〕

FIG. 1 is a block diagram showing an embodiment of the present invention, and numerals 1 to 14 are completely the same as the conventional device described above.

15 is a timer circuit, 16 is a gate circuit, 17 is
OR circuit, 18 is the output signal line of the timer circuit 5, 19 is the output signal line of the gate circuit 16, 2
0 is a gate circuit, and 29 is an output signal line of the gate circuit 20.

9, 10, 11, 18, 19, 12 in Figure 1,
The waveforms generated at 13, 29, and 14 are shown in FIG. In FIG. 2, the signal names and output waveforms of each signal line 20 to 26 are exactly the same as in the conventional device. In FIG. 2, 27 is a gate control signal output to the output signal line 18 of the timer circuit 15, and its output time width is set larger than the pulse width generated when the earth sensor scans the moon or the sun. By setting it slightly smaller than the time width, the trailing edge pulse caused by interference from the sun or the moon passes through the gate circuit 16 and is output as a trigger signal to the earth scan period signal generation circuit 7 to generate an earth scan period signal. prevent this from happening. Furthermore, when the earth sensor scans an object such as the moon or the sun whose leading edge pulse and trailing edge pulse have a short time width that cannot pass through the gate circuit 16, and then scans the earth, the two-pulse counter circuit 5 First, the count becomes "1" with the leading edge pulse of the interfering celestial object, and since the trailing edge pulse does not pass through the gate circuit 16 at the time of celestial object interference, the trailing edge pulse of the celestial object is not input as a reset signal to the 2-pulse counter circuit 5, and the count is stopped. "1" is held until the next leading edge signal of the earth is input, and when the leading edge signal of the earth is input, the 2-pulse counter circuit 5 counts up.
Maintains count ``2'' until reset by Earth's trailing edge pulse. The output signal line 12 of the two-pulse counter circuit 5 outputs a low level when the count number is "0" or "1", but outputs a high level when the count number is "2". Therefore, when detecting celestial interference, the trailing edge pulse generated by the earth on the signal line 11 passes through the gate circuit 6, is output to the earth scan period signal generation circuit 7, becomes a trigger signal for generating the earth scan period signal, and is used as a trigger signal for generating the earth scan period signal.・Prevent the Earth scan periodic signal from being lost during solar interference.

〔Effect of the invention〕

As explained above, this invention detects the trailing edge pulse generated when the earth sensor scans the earth.
When used as an earth scan period detection signal for an earth sensor mounted on an artificial satellite, a pulse whose time width between the leading edge pulse generation time and the trailing edge pulse generation time is narrower than the specified value will not be used as a trigger signal for trailing edge pulse generation. By redirecting, it is possible to prevent irregular earth scan period signal generation due to the trailing edge pulse of the moon or the sun, prevent erroneous data detection of the earth scan period, and prevent the earth sensor from scanning the earth when detecting a state of celestial interference. The trailing edge signal generated at the time becomes a trigger signal for generating the earth scan period signal, and this has the effect of preventing the earth scan period signal from being lost in a state of celestial interference and erroneous data detection of the earth scan period.

[Brief explanation of drawings]

FIG. 1 is a configuration diagram showing an embodiment of the present invention, FIG. 2 is a voltage waveform diagram of each signal line in the configuration diagram shown in FIG. 1, and FIG. 3 is a configuration diagram showing a conventional earth sensor signal processing device. 4 are voltage waveform diagrams of each signal line in the configuration diagram shown in FIG. 3. In the figure, 1 is a signal conversion section, 2 is a waveform processing electronic circuit section, 3 is a voltage comparator for leading edge pulse detection, 4 is a voltage comparator for trailing edge pulse detection, 5 is a 2-pulse counter circuit, 6 is a gate circuit, 7 is an earth scan periodic signal generation circuit, 8 is an output signal line of the signal conversion section 1, 9 is an output signal line of the waveform processing electronic circuit section 2, and 10 is an output signal line 611 of the leading edge pulse detection voltage comparator 3. An output signal line of the trailing edge pulse detection voltage comparator 4, 12 an output signal line of the two-pulse counter circuit 5, 13 an output signal line of the gate circuit 6, 14 an output signal line of the earth scan periodic signal generation circuit 7, 15 is a timer circuit, 1
6 is the gate circuit, 17 is the OR circuit, 18 is the output signal line of the timer circuit 15, and 19 is the gate circuit 1.
6 an output signal line, 20 a gate circuit, 21 a voltage waveform generated on the output signal line of the waveform processing electronic circuit section 2, and 22 a leading edge generated on the output signal line 10 of the leading edge pulse detection voltage comparator 3. Pulse waveform 23 is a trailing edge pulse waveform generated on the output signal line 11 of the trailing edge pulse detection voltage comparator 4, 24
is the output signal line 12 of the 2-pulse counter circuit 5
25 is a trigger signal waveform for generating an earth scan periodic signal generated on the output signal line 13 of the gate circuit 6; 26 is a trigger signal waveform for generating an earth scan periodic signal;
27 is the earth scan periodic signal generated on the output signal line 14 of the earth scan periodic signal generation circuit 7.
is a gate control signal output to the output signal line 18 of the timer circuit 15, 28 is a waveform generated on the output signal line 19 of the gate circuit 16, 29 is an output signal line of the gate circuit 20, and 30 is a waveform generated on the output signal line 29. This is the waveform. Note that the same reference numerals in each figure indicate the same or corresponding parts.

Claims (1)

[Claims] 1. An earth sensor is mounted on an artificial satellite, a signal conversion unit that causes the earth sensor to scan the earth and converts the earth's infrared radiation into an electrical signal, a waveform processing electronic circuit unit for the electrical signal, and a waveform processing electronic circuit unit. A leading edge pulse or trailing edge pulse detection voltage comparator inputs the processed signal, and a leading edge pulse detected by the leading edge pulse detection voltage comparator inputs the leading edge pulse detected by the leading edge pulse detecting voltage comparator, and inputs the leading edge pulse detected by the leading edge pulse detecting voltage comparator. a timer circuit that outputs a continuous gate control signal for a predetermined time period from time; a first gate circuit that inputs the gate control signal and the trailing edge pulse detected by the trailing edge pulse detection voltage comparator; a 2-pulse counter circuit that inputs the leading edge pulse and uses the output of the gate circuit 1 as a reset signal; a second gate circuit that inputs the output signal of the 2-pulse counter circuit and the trailing edge signal; a third gate circuit receiving the output signal of the counter circuit and the output signal of the first gate circuit; and an OR circuit receiving the output signal of the second gate circuit and the third gate circuit. , and an earth scan period signal generator inputting the output of the above-mentioned OR circuit, and detects the earth scan period by a trailing edge pulse generated by the earth sensor.