JPH07170241A - Telemetry transmitting system - Google Patents

Abstract

PURPOSE:To provide a telemetry transmitting system for improving the efficiency of a telemetry line by selecting the state data of an equipment with a state change and transmitting them to a ground station. CONSTITUTION:This system is provided with detecting means 2-1 to 2-n for detecting whether digital state data D1 transmitted from respective equipments 1-1 to 1-n are changed or not and for transmitting the changed state data D1, selective transmitting/ID applying means 3 for selecting only the state data D1 transmitted from the detecting means 2-1 to 2-n and for transmitting those state data D3 while applying an ID to identify which equipment of 1-1 to 1-n transmits those selected state data D1, and multiplexing means 4 for multiplexing and transmitting the plural state data D3 from the selective transmitting/ID applying means 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a telemetry transmission system for transmitting status data of equipment mounted on an artificial satellite to a ground station.

[0002]

2. Description of the Related Art In order to inform the ground of the status of the equipment mounted on it, an artificial satellite processes the status data of these equipment as telemetry data to be transmitted to a ground station. Conventionally, in this type of telemetry transmission system, telemetry data is transmitted from an artificial satellite to a ground station at a fixed cycle in a predetermined frame / word / bit format. That is, as shown in FIG. 3, regardless of the state change of each device, the state data of each device is multiplexed and incorporated in each frame, and these frames 0, ..., N are repeatedly transmitted at a constant cycle T. It was

[0003]

However, the above-mentioned conventional telemetry transmission system is a system in which frames 0, ..., n are repeatedly transmitted at a constant cycle T regardless of the state change of each device. Even if there is no change in the state of the device, the unchanged state data is transmitted. That is, since the state data having a small temporal change rate is transmitted at an unnecessarily fast sampling rate, the line efficiency of the telemetry line is very poor. In particular, a large artificial satellite equipped with a large number of devices requires a large number of telemetry items, resulting in an increase in data line capacity and an increase in operating costs.

The present invention has been made in view of the above problems, and a telemetry transmission system for improving the efficiency of a telemetry line by selecting the state data of a device whose state has changed and transmitting it to a ground station. For the purpose of providing.

[0005]

In order to achieve the above object, the present invention is a telemetry transmission system for transmitting status data of a plurality of devices mounted on an artificial satellite. Detecting means for detecting whether or not there is a change in the state data, and only the changed state data detected by the detecting means are selected, and an ID for identifying from which device the selected state data comes Select and send the status data
The ID providing means and the multiplexing means for multiplexing and transmitting the plurality of status data from the selective sending / ID assigning means are provided.

In the telemetry transmission system according to the second aspect of the invention, the detecting means delays the digital state data from the respective devices by a predetermined time and outputs the delayed circuit, and the digital state data from the respective devices. An exclusive OR circuit that inputs the digital state data output from the delay circuit and performs an exclusive logical operation is provided.

[0007]

According to the above-mentioned telemetry transmission system, the detecting means detects whether or not the digital state data sent from each device of the artificial satellite has changed. Then, in the selective transmission / ID assigning means, only the state data detected as having been changed by the detecting means is selected,
ID that identifies which device this status data is from
Is sent to the multiplexing means.
These state data are multiplexed by the multiplexing means and transmitted.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing a telemetry transmission method according to an embodiment of the present invention. The telemetry transmission method of the present embodiment uses a plurality of devices 1-onboard an artificial satellite.
A plurality of detection circuits 2-1, ..., 2-n as detection means connected to the output sides of 1, ..., 1-n, and the output side of these plurality of detection circuits 2-1, ..., 2-n Selective transmission / ID provision circuit 3 as selective transmission / ID provision means connected to
And a multiplexer 4 as a multiplexing means connected to the output side of the selective transmission / ID assigning circuit 3.

The detection circuit 2-1 is a circuit for detecting whether or not there is a temporal change in the digital state data D1 sent from the device 1-1, and the delay circuit 21 and the exclusive OR circuit. 22 and 22. Delay circuit 21
Is to input the state data D1 from the device 1-1 and output the delayed state data D2 obtained by delaying the state data D1 by the input time thereof to the exclusive OR circuit 22.
The exclusive OR circuit 22 uses the status data D from the device 1-1.
1 and the delay state data D2 from the delay circuit 21 are subjected to an exclusive logical operation, and a detection signal S indicating the result is output to the selective transmission / ID assigning circuit 3. Therefore, the detection circuit 2-1 outputs a set of state data D1.
And the detection signal S are output to the selective sending / ID assigning circuit 3. Other detection circuits 2-2, ..., 2-n
Also has the same function.

In this way, each of the detection circuits 2-1 to 2-n
The selective sending / ID assigning circuit 3 to which the status data D1 and the detection signal S are input from has a selective sending circuit 31 and an ID assigning circuit 32. When the input detection signal S has an H level bit, the selective transmission circuit 31 has a function of selecting the state data D1 input together with the detection signal S and outputting it to the ID assigning circuit 32. . When the input detection signal S has only L level bits,
The state data D1 input together with the detection signal S is not selected. The ID assigning circuit 32 assigns the state data D1 an ID for identifying which device the state data D1 from the selective sending circuit 31 belongs to and outputs the selected state data D3 to the multiplexing device 4. Have

The multiplexing device 4 multiplexes a plurality of selection state data D3 from the selective transmission / ID assigning circuit 3 and transmits the frame as telemetry data F to a ground station (not shown) via a telemetry line. is there.

Next, the operation of this embodiment will be described.
FIG. 2 is a time chart of data. 1 and 2
As shown in (a) of item 1, from device 1-1 first (at T0)
When the state data D1 of 1 is output to the detection circuit 2-1, the state data D1 is input to the delay circuit 21 and the exclusive OR circuit 22.

The first state data D1 is the exclusive OR circuit 2
The delay state data D2 from the delay circuit 21 is zero at the time of being input to 2, and is composed of all bits at the L level. Therefore, the state data D1 and the delay state data input to the exclusive OR circuit 22 are Different from D2. For this reason,
The detection signal S including the H level bit is selectively transmitted / ID
It is output to the selection transmission circuit 31 of the application circuit 3.

At the same time, the first state data D
1 is output to the selective transmission circuit 31. As a result, the first state data D1 from the selective sending circuit 31 is the ID assigning circuit 3
2 and the selected state data D3 in which the ID of the device 1-1 is added to the state data D1 is output to the multiplexing device 4.

The state data D1 from the other detection circuits 2-2, ..., 2-n are similarly selected, and the selected state data D3 is output from the selective transmission / ID assignment circuit 3 to the multiplexer 4. The plurality of selection state data D3 are transmitted to the multiplexer 4
Are multiplexed and transmitted as the first telemetry data F.

Then, as shown in FIG. 2C, T1
At this time, when the next state data D1 different from the first state data D1 is output from the device 1-1 to the detection circuit 2-1, this state data D1 is input to the exclusive OR circuit 22. As shown in FIG. 2B, delay state data D2 obtained by delaying the first state data D1 by T1-T0 time is input from the delay circuit 21.

These state data D1 and delay state data D2 are subjected to exclusive logical operation processing in the exclusive OR circuit 22. As a result, as shown in (d) of FIG. 2, the exclusive OR circuit 22 outputs the detection signal S including the H-level bit to the selective transmission / ID assignment circuit 3, and at the same time, the detection circuit 2-. The next status data D1 from 1 is output to the selective transmission / ID assignment circuit 3.

As a result, the state data D1 is selected by the selective transmission circuit 31 and output to the ID assigning circuit 32, which then outputs the selected state data D3 to the multiplexer 4.

As shown in (e) of FIG. 2, when the next state data D1 input to the detection circuit 2-1 is the same as the first state data D1, the exclusive OR circuit 22 inputs it. Since the state data D1 and the delayed state data D2 to be processed have the same waveform, the exclusive OR circuit 22 outputs the L-level detection signal S as shown in (f) of FIG. Therefore, since the L level detection signal S is input to the selective transmission circuit 31 of the selective transmission / ID assignment circuit 3, the state data D1 is not selected. The same operation is performed in the processing after T2.

As described above, according to the telemetry transmission method of this embodiment, the state data D1 from the devices 1-1, 1-, and 1-n are changed from the previous state by the detection circuits 2-1 to 2-n. And sends out the detection signal S by detecting whether or not
The status data D1 output to the ID assigning circuit 3 is selectively specified by the selective sending / ID assigning circuit 3, and the status data D1 selected by the multiplexer 4 is specified.
Does not occur and the state data D1 having no state change is not continuously transmitted, and the line efficiency of the telemetry line can be improved.

[0021]

As described above, according to the telemetry transmission system of the present invention, it is possible to select and transmit only the changed status data, so that it is possible to improve the line efficiency of the telemetry line. In a large artificial satellite equipped with a large number of devices, a large number of telemetry items can be transmitted without increasing the data line capacity, and the operating cost can be reduced.

[Brief description of drawings]

FIG. 1 is a block diagram showing a telemetry transmission method according to an embodiment of the present invention.

2A and 2B are time charts of data, where FIG. 2A shows state data, FIG. 2B shows delayed state data, and FIG. 2C shows changed state data. 2, (d) shows the detection signal at that time, (e) of FIG. 2 shows the unchanged Shirota data, and (f) of FIG. 2 shows the detection signal at that time.

FIG. 3 is a frame diagram of a telemetry format used in a telemetry transmission system according to a conventional example.

[Explanation of symbols]

 1-1, ~, 1-n Device D, D31 State data 2-1, ~, 2-n Detection circuit 3 Selective sending / ID assigning circuit 4 Multiplexing device 21 Delay circuit 22 Exclusive OR circuit 31 Selective sending circuit 32 ID assignment circuit

Claims (2)

[Claims] 1. In a telemetry transmission system for transmitting status data of a plurality of devices mounted on an artificial satellite, a detection means for detecting whether or not there is a change in digital status data sent from each device, Selective sending / ID assigning means for selecting only the change state data detected by the detecting means and for assigning an ID identifying from which device the selected state data is sent, and sending the state data. A telemetry transmission system, comprising: a multiplexing means for multiplexing and transmitting a plurality of status data from the selective sending / ID assigning means. 2. The delay circuit for delaying the digital state data from each device by a predetermined time and outputting the digital state data from each device and the digital state data output from the delay circuit. The telemetry transmission system according to claim 1, further comprising an exclusive OR circuit which receives and performs an exclusive logical operation.