US-12618705-B2 - Method and apparatus for measuring level for calculating flow of propellant tank

US12618705B2US 12618705 B2US12618705 B2US 12618705B2US-12618705-B2

Abstract

A method and apparatus for measuring a level for calculating a flow of a propellant tank are provided. The method of measuring a level for calculating a flow of a propellant tank includes, in response to an instruction to measure a level in a propellant tank storing a liquid fuel, generating propagated power for level measurement at a specified generation intensity inside the propellant tank through a transmission antenna, receiving the propagated power for level measurement passing through the liquid fuel through a reception antenna, calculating a degree of attenuation between the generation intensity and a reception intensity of the propagated power for level measurement, and measuring a height level of the liquid fuel by considering the degree of attenuation.

Inventors

Sung Hyuck IM
Kee Joo LEE
Jae Sung Park

Assignees

KOREA AEROSPACE RESEARCH INSTITUTE

Dates

Publication Date: 20260505
Application Date: 20231019

Claims (15)

1 . A method of measuring a level for calculating a flow of a propellant tank, the method comprising: in response to an instruction to measure a level in a propellant tank storing a liquid fuel, generating propagated power for level measurement at a specified generation intensity inside the propellant tank through a transmission antenna; receiving the propagated power for level measurement passing through the liquid fuel through a reception antenna; calculating a degree of attenuation between the generation intensity and a reception intensity of the propagated power for level measurement; measuring a height level of the liquid fuel by considering the degree of attenuation; when reception antennas are distributed and attached to multiple points of the propellant tank, measuring height levels of the multiple points using reception intensities respectively received through the reception antennas at the multiple points; when a difference among measured heights of the multiple points is within a reference value, determining that a movement state of the liquid fuel in the propellant tank is in a balanced state; when the movement state is determined to be the balanced state, calculating a flow of the liquid fuel in the propellant tank based on an average value of the measured height levels of the multiple points; and estimating fuel consumption of a launch vehicle comprising the propellant tank based on the calculated flow.
2 . The method of claim 1 , further comprising: calculating a transfer time from a generation timepoint to a reception timepoint of the propagated power for level measurement; loading a previous height level and a previous transfer time from a memory unit; and measuring the height level by further considering the previous height level and a degree of transfer latency based on a difference between the previous transfer time and the transfer time.
3 . The method of claim 2 , further comprising: generating a first height level prediction model for the propellant tank through learning a first data set including an attenuation amount of the propagated power for level measurement and a measured height of the attenuation amount, wherein the measuring of the height level comprises: predicting and measuring a height level of the liquid fuel in the propellant tank based on an output value obtained by inputting the degree of attenuation into the first height level prediction model.
4 . The method of claim 3 , further comprising: generating a second height prediction model for the propellant tank through learning a second data set including transfer latency of the propagated power for level measurement, a measured height of the transfer latency, and a previously measured height, wherein the measuring of the height level further comprises: predicting and measuring the height level of the liquid fuel in the propellant tank based on a combined value of an output value when the degree of attenuation is input to the first height prediction model and an output value when the degree of the transfer latency is input to the second height prediction model.
5 . The method of claim 4 , wherein the first data set or the second data set is collected when at least one of level measurement conditions is determined, wherein the level measurement conditions comprise a type of the liquid fuel, a metallic material forming the propellant tank, a size of the propellant tank, and a distance between attached points of the transmission antenna and the reception antenna in the propellant tank.
6 . The method of claim 1 , further comprising: when a difference among measured heights of the multiple points exceeds the reference value, determining that a movement state of the liquid fuel in the propellant tank is in an unbalanced state in response to movement of the launch vehicle; and when the movement state is determined to be the unbalanced state, predicting and calculating a flow of the liquid fuel in the propellant tank using a flow prediction model.
7 . The method of claim 6 , further comprising: generating the flow prediction model through learning a third data set comprising acceleration of the launch vehicle, the height levels of the multiple points in the propellant tank, and the flow of the liquid fuel.
8 . A non-transitory computer-readable storage medium storing instructions that, when executed by a processor, cause the processor to perform a method comprising: in response to an instruction to measure a level in a propellant tank storing a liquid fuel, generating propagated power for level measurement at a specified generation intensity inside the propellant tank through a transmission antenna; receiving the propagated power for level measurement passing through the liquid fuel through a reception antenna; calculating a degree of attenuation between the generation intensity and a reception intensity of the propagated power for level measurement; measuring a height level of the liquid fuel by considering the degree of attenuation; when reception antennas are distributed and attached to multiple points of the propellant tank, measuring height levels of the multiple points using reception intensities respectively received through the reception antennas at the multiple points; when a difference among measured heights of the multiple points is within a reference value, determining that a movement state of the liquid fuel in the propellant tank is in a balanced state; when the movement state is determined to be the balanced state, calculating a flow of the liquid fuel in the propellant tank based on an average value of the measured height levels of the multiple points; and estimating fuel consumption of a launch vehicle comprising the propellant tank based on the calculated flow.
9 . An apparatus for measuring a level for calculating a flow of a propellant tank, the apparatus comprising: a transmitter configured to generate, in response to an instruction to measure a level in a propellant tank storing a liquid fuel, propagated power for level measurement at a specified generation intensity inside the propellant tank through a transmission antenna; a receiver configured to receive the propagated power for level measurement passing through the liquid fuel through a reception antenna; a calculator configured to calculate a degree of attenuation between the generation intensity and a reception intensity of the propagated power for level measurement; a measurement unit configured to measure a height level of the liquid fuel by considering the degree of attenuation; and a processor configured to: when height levels are measured, by the measurement unit, for multiple points using reception intensities respectively received through reception antennas distributed and attached to the multiple points in the propellant tank, when a difference among measured heights of the multiple points is within a reference value, determine that a movement state of the liquid fuel in the propellant tank is in a balanced state, when the movement state is determined to be the balanced state, calculate a flow of the liquid fuel in the propellant tank based on an average value of the measured height levels of the multiple points, and estimate fuel consumption of a launch vehicle comprising the propellant tank based on the calculated flow.
10 . The apparatus of claim 9 , wherein the calculator is further configured to calculate a transfer time from a generation timepoint to a reception timepoint of the propagated power for level measurement, the measurement unit is further configured to: load, from a memory unit, a previous height level and a previous transfer time recorded in the memory unit, and measure the height level by further considering the previous height level and a degree of transfer latency based on a difference between the previous transfer time and the transfer time.
11 . The apparatus of claim 10 , further comprising: a model generator configured to generate a first height level prediction model for the propellant tank through learning a first data set including an attenuation amount of the propagated power for level measurement and a measured height of the attenuation amount, wherein the measurement unit is further configured to: predict and measure a height level of the liquid fuel in the propellant tank based on an output value obtained by inputting the degree of attenuation into the first height level prediction model.
12 . The apparatus of claim 11 , wherein the model generator is further configured to: generate a second height prediction model for the propellant tank through learning a second data set including transfer latency of the propagated power for level measurement, a measured height of the transfer latency, and a previously measured height, and the measurement unit is further configured to: predict and measure the height level of the liquid fuel in the propellant tank based on a combined value of an output value when the degree of attenuation is input to the first height prediction model and an output value when the degree of the transfer latency is input to the second height prediction model.
13 . The apparatus of claim 12 , wherein the first data set or the second data set is collected when at least one of level measurement conditions is determined, wherein the level measurement conditions comprise a type of the liquid fuel, a metallic material forming the propellant tank, a size of the propellant tank, and a distance between attached points of the transmission antenna and the reception antenna in the propellant tank.
14 . The apparatus of claim 9 , wherein, when a difference among measured heights of the multiple points exceeds the reference value, the processor is further configured to: determine that a movement state of the liquid fuel in the propellant tank is in an unbalanced state in response to movement of the launch vehicle, and when the movement state is determined to be the unbalanced state, predict and calculate a flow of the liquid fuel in the propellant tank using a flow prediction model.
15 . The apparatus of claim 14 , further comprising: a model generator configured to generate the flow prediction model through learning a third data set comprising acceleration of the launch vehicle, the height levels of the multiple points in the propellant tank, and the flow of the liquid fuel.

Description

CROSS-REFERENCE TO RELATED APPLICATION This application claims the benefit of Korean Patent Application No. 10-2022-0089528 filed on Jul. 20, 2022, in the Korean Intellectual Property Office, the entire disclosure of which is incorporated herein by reference for all purposes. BACKGROUND 1. Field of the Invention The present disclosure relates to a method of measuring a level of a liquid propellant in a propellant tank using a degree of attenuation of propagated power that is attenuated more when passing through a liquid than passing through gas. 2. Description of the Related Art In general, a launch vehicle, such as a rocket or a satellite, may operate using a cryogenic medium as a propellant (a fuel), such as liquid oxygen, and may include a propellant tank formed of an aluminum material for storing the propellant. For the launch vehicle, measuring a level of a propellant tank may be important to identify consumption and movement of the propellant. Conventionally, a method of measuring a level of a propellant tank through a temperature change using multiple thermometers or a method of measuring a level of a propellant tank through latency of a reflected ultrasonic wave or radio wave using an ultrasonic or radar level measurement instrument attached to an upper end of a tank may be used. However, the methods may impose high costs and may have limitations in durability and measurement accuracy. Particularly, the level measurement method using an ultrasonic wave or radio wave may cause an error depending on movement of a liquid propellant and a level measurement instrument that is available for a cryogenic medium, such as liquid oxygen, may be restricted. Accordingly, there is a demand for a height level measurement instrument that is available for a sensitive cryogenic medium with low cost by considering movement of a liquid propellant in response to movement of a launch vehicle. SUMMARY An embodiment of the present disclosure aims to accurately measure a height level of a liquid propellant in a simple method based on a degree of attenuation of propagated power passing through the liquid propellant in a tank, wherein the propagated power is generated inside a propellant tank. An embodiment of the present disclosure aims to increase measurement accuracy of a height level of a liquid propellant by considering a degree of latency of a transfer time of propagated power passing through a liquid propellant in a tank together with the degree of attenuation. An embodiment of the present disclosure aims to enable accurate level measurement and flow calculation while a launch vehicle moves by identifying movement of a liquid propellant in response to movement of the launch vehicle using a measured value of propagated power received by multiple points of a propellant tank through a plurality of reception antennas. An embodiment of the present disclosure aims to miniaturize and produce a transmission antenna generating propagated power inside a tank by using broadband propagated power when measuring a level of a propellant tank, a reception antenna receiving propagated power passing through a liquid propellant in the tank, and a transceiver module controlling the transmission antenna and the reception antenna to be installed in a propellant tank provided in a small launch vehicle. According to an aspect, there is provided a method of measuring a level for calculating a flow of a propellant tank including, in response to an instruction to measure a level in a propellant tank storing a liquid fuel, generating propagated power for level measurement at a specified generation intensity inside the propellant tank through a transmission antenna, receiving the propagated power for level measurement passing through the liquid fuel through a reception antenna, calculating a degree of attenuation between the generation intensity and a reception intensity of the propagated power for level measurement, and measuring a height level of the liquid fuel by considering the degree of attenuation. In addition, there is provided an apparatus for measuring a level for calculating a flow of a propellant tank including, in response to an instruction to measure a level in a propellant tank storing a liquid fuel, a transmitter configured to generate propagated power for level measurement at a specified generation intensity inside the propellant tank through a transmission antenna, a receiver configured to receive the propagated power for level measurement passing through the liquid fuel through a reception antenna, a calculator configured to calculate a degree of attenuation between the generation intensity and a reception intensity of the propagated power for level measurement, and a measurement unit configured to measure a height level of the liquid fuel by considering the degree of attenuation. According to the present disclosure, a height level of a liquid propellant may be accurately measured in a simple method based on a degree of attenuat