RU217382U1 - Stand for testing the electromagnetic compatibility of onboard equipment as part of CubeSat satellites - Google Patents

Abstract

The utility model relates to rocket and space technology, namely to devices for testing the electromagnetic compatibility of on-board equipment as part of CubeSat satellites. The technical result of the utility model is the development of an easy-to-use mobile test stand for determining the characteristics of the electromagnetic compatibility of radio communications and on-board equipment as part of CubeSat satellites. The stand for testing the electromagnetic compatibility of onboard equipment as part of CubeSat satellites is a chamber, which is a Faraday cage, having a cubic shape and a folding accordion-type structure. The walls of the chamber are covered with radio-absorbing material from the inside. The camera has a two-axis motorized satellite mount and two antenna mounts for connection to a transceiver and an interference simulator. 3 ill.

Description

The utility model relates to rocket and space technology, namely to devices for testing the electromagnetic compatibility of onboard equipment as part of CubeSat satellites.

A known method of testing and ensuring the electromagnetic compatibility of radio communications on a moving object, presented in the utility model patent RU 119963 U1. A test bench for measuring the electromagnetic compatibility characteristics of radio receivers, consisting of a high-frequency standard signal generator, a radio receiver under test and a non-linear distortion meter connected in series, as well as a radio transmitter under test loaded with an antenna dummy. The tests are carried out by successively switching on sources of radio interference with the frequency of the radio receiving equipment being adjusted until the coefficient of non-linear distortion is equal to the permissible value for the radio receiver under test. The parameters of the electromagnetic environment obtained on the simulation stand using the control device are used to ensure the electromagnetic compatibility of radio communications at the facility and to improve the quality of communication based on the choice of frequencies for communication channels with the maximum signal-to-noise ratio. The described method requires access to the radio transmitter of the device to connect the equivalent of the antenna with the measuring equipment, which is not always possible in the case of testing the entire MCA.

There is a known method for assessing the electromagnetic compatibility of onboard equipment in an aircraft, described in the patent for invention RU 2497282 C9, which consists in the sequential inclusion and exposure of the tested onboard equipment to sources of electromagnetic interference. After turning on the source of radio interference, the interference currents induced in the electrical circuits of the equipment under test are measured, for which an inductive current sensor is used, located at a distance of five centimeters from the input connector on the electrical circuit of the equipment under test. The operability of onboard equipment is evaluated before and after the inclusion of radio interference, and the interference current is compared with the maximum permissible interference current. This method makes it possible to increase the reliability of tests by measuring the radio interference current, however, it requires partial disassembly of the device to access the boards of the onboard equipment, which can be very difficult for small spacecraft.

The closest analogue of our proposed utility model is the method for assessing the electromagnetic compatibility of on-board radio-electronic equipment described in the patent for invention RU 2697810 C9. This method involves the assessment of electromagnetic compatibility without partial disassembly of the tested avionics. The method for assessing the electromagnetic compatibility of onboard equipment is based on the transmission of radiograms from a table of sounds or words and the sequential inclusion of radio interference sources. The received radiograms analyze and determine the ratio of the speech intelligibility value calculated under radio interference conditions and the speech intelligibility value calculated in the absence of radio interference, expressed as a percentage. From the test results obtained, a conclusion is made about the successful passing of the onboard equipment electromagnetic compatibility test, if the result did not exceed the specified allowable value. This method is mainly focused on vehicles using the transmission of voice radiograms, which is rare on small spacecraft, which makes the described method suboptimal for testing small spacecraft.

The purpose of the proposed technical solution is to develop an easy-to-use mobile test bench for determining the characteristics of the electromagnetic compatibility of radio communications and onboard equipment as part of CubeSat satellites.

The need to solve the described technical problem is associated with a growing number of developments of small spacecraft - satellites of the CubeSat standard and the need to simplify and reduce the cost of conducting ground tests for electromagnetic compatibility of onboard equipment in their composition, which will reduce the cost and reduce the development time of satellites.

The technical result is achieved by placing the tested satellite of the CubeSat standard inside the chamber, which has a folding structure and is a Faraday cage, the walls of which are covered with radio-absorbing material from the inside, while the satellite inside the chamber is mounted on a two-axis motorized suspension. The camera has two antenna mounts for connection to a transceiver and a jamming simulator.

The difference from the closest analogue lies in the use of:

an anechoic chamber placed in a Faraday cage, excluding both reflections of electromagnetic radiation inside and its penetration from the outside for testing in small enclosed spaces;

folding design of the camera, made in the form of an "accordion", making it mobile due to its compactness when folded;

a two-axis motorized suspension for fixing the small spacecraft, which allows testing in various orientations relative to the transceiver antenna;

high-frequency switch with electronic control to automate the test process.

The stand for testing and ensuring electromagnetic compatibility on satellites of the CubeSat standard is shown in the following drawings:

fig. 1 - general view of the assembled stand;

fig. 2 - view of the stages of folding the body;

fig. 3 - block diagram of the stand.

The general view of the stand is shown in Fig. 1. The stand is a metal chamber 1 of a cubic shape with a side of two meters, which is grounded, forming a Faraday cage, which makes it possible to exclude the influence of external electronic interference. From the inside, the walls of the chamber have a radio-absorbing coating to prevent reflections of electromagnetic waves inside the chamber - the so-called anechoic chamber. The camera is made of sectors mounted on special folding fittings 2; the folding design ensures compactness and mobility.

Inside the camera, a mount is provided for a transceiver antenna 3, which is connected to a radio station. A two-axis motorized gimbal 4 is installed at the bottom of the camera to fix the CubeSat 5 satellite. An antenna is also placed in the chamber, connected to an interference simulator (not shown in the figures), which is a radio equipment that allows you to create electromagnetic interference in the VHF band, the place and location is selected based on the test setting.

In FIG. 2. shows the stages of folding the construction of an anechoic chamber. First, the two-axis suspension and the transceiver antenna are dismantled. Then the top panel is folded, after which the structure is compressed according to the accordion principle. Then the bottom wall is detached, after which the structure is ready for transportation.

In FIG. 3 shows the block diagram of the test bench. A CubeSat 1 satellite located in a Faraday cage can interact with a transceiver antenna connected to a high-frequency attenuator 2, which allows you to adjust the strength of the output and input signals, which is connected to a high-frequency switch 3, which allows you to switch the signal source between the VHF generator 4 and the radio station 5, controlled personal computer 6. An antenna is also placed in the camera, connected to the interference simulator 7, which allows creating electromagnetic interference in the VHF range of various power.

Complex testing of the satellite for electromagnetic compatibility includes:

1. Testing on-board equipment for fault tolerance under the influence of electromagnetic radiation in the VHF range.

2. Tests of onboard transceiver equipment for radio channel noise immunity.

The device is used as follows.

When testing the fault tolerance of onboard equipment, a successive irradiation of a functioning satellite is carried out in the following sequence:

1. A VHF generator is connected to the transceiver antenna.

2. The radiation power is set.

3. The tilt angle of the satellite on a two-axis suspension is set.

4. The functioning of all satellite nodes is checked without irradiation.

5. Irradiation of the satellite begins in a predetermined frequency range, starting from the extreme value.

6. The functioning of all satellite nodes during irradiation will be checked.

7. The frequency of the electromagnetic channel is increased by a given step.

8. Steps 4 and 5 are repeated until the limit value of the set frequency range is reached.

After the end of the test, the data is analyzed, if no failures are detected in any of the satellite nodes, the test wanders successfully passed.

Testing of onboard transceiver equipment for noise immunity is carried out in the following sequence:

1. A radio station is connected to the transceiver antenna.

2. The radiation power is set.

3. The tilt angle of the satellite on a two-axis suspension is set.

4. The functioning of all satellite nodes and the radio channel with the receiving radio station are checked.

5. The radiation power of the interference simulator is set.

6. The interference simulator is turned on.

7. The transmission of a test sequence of data packets from the MCA to the receiving radio station is initiated.

8. The transmission of a test sequence of packets from the radio station to the satellite is initiated.

After the end of the test, the number of errors or missing data is determined for the receive and transmit sessions separately. If the amount of lost data is less than some predetermined value, then a conclusion is made about the successful completion of this test.

List of sources used:

1. Patent RU 119963 U1.

2. Patent RU 2497282 C9.

3. Patent RU 2697810 C9.

Claims (1)

Stand for testing the electromagnetic compatibility of on-board equipment as part of CubeSat satellites, which is a chamber, which is a Faraday cage, having a cubic shape and a folding accordion-type structure, the walls of which are covered with radio-absorbing material from the inside, while the chamber is provided with a two-axis motorized suspension for mounting satellite and two antenna mounts for connection to the transceiver and jamming simulator.

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