CN113949472B - Passive intermodulation test method suitable for whole star - Google Patents
Passive intermodulation test method suitable for whole star Download PDFInfo
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- CN113949472B CN113949472B CN202111012617.1A CN202111012617A CN113949472B CN 113949472 B CN113949472 B CN 113949472B CN 202111012617 A CN202111012617 A CN 202111012617A CN 113949472 B CN113949472 B CN 113949472B
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- 238000010998 test method Methods 0.000 title claims abstract description 11
- 238000002347 injection Methods 0.000 claims abstract description 50
- 239000007924 injection Substances 0.000 claims abstract description 50
- 238000000034 method Methods 0.000 claims abstract description 16
- 230000001965 increasing effect Effects 0.000 claims abstract description 11
- 238000012360 testing method Methods 0.000 claims description 47
- 238000005259 measurement Methods 0.000 claims description 18
- 230000005855 radiation Effects 0.000 claims description 5
- 238000011144 upstream manufacturing Methods 0.000 claims description 3
- 239000003550 marker Substances 0.000 claims description 2
- 238000009434 installation Methods 0.000 abstract description 10
- 238000012790 confirmation Methods 0.000 abstract description 5
- 238000010276 construction Methods 0.000 abstract 1
- 238000011161 development Methods 0.000 description 3
- 238000012986 modification Methods 0.000 description 3
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- 230000005540 biological transmission Effects 0.000 description 2
- 230000035945 sensitivity Effects 0.000 description 2
- 239000000243 solution Substances 0.000 description 2
- 239000011358 absorbing material Substances 0.000 description 1
- 230000000712 assembly Effects 0.000 description 1
- 238000000429 assembly Methods 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000005672 electromagnetic field Effects 0.000 description 1
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Classifications
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B17/00—Monitoring; Testing
- H04B17/30—Monitoring; Testing of propagation channels
- H04B17/309—Measuring or estimating channel quality parameters
- H04B17/336—Signal-to-interference ratio [SIR] or carrier-to-interference ratio [CIR]
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W24/00—Supervisory, monitoring or testing arrangements
- H04W24/06—Testing, supervising or monitoring using simulated traffic
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02D—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN INFORMATION AND COMMUNICATION TECHNOLOGIES [ICT], I.E. INFORMATION AND COMMUNICATION TECHNOLOGIES AIMING AT THE REDUCTION OF THEIR OWN ENERGY USE
- Y02D30/00—Reducing energy consumption in communication networks
- Y02D30/70—Reducing energy consumption in communication networks in wireless communication networks
Abstract
The invention relates to a passive intermodulation test method suitable for whole starsThe method comprises the following steps of: s1, powering up a whole satellite and a navigation subsystem; s2, uplink construction of a navigation subsystem; s3, adjusting the level of the uplink injection signal to enable the carrier-to-noise ratio zone bit of the telemetry return to be displayed as 0X10, and recording the level of the uplink signal as P at the moment 1 The method comprises the steps of carrying out a first treatment on the surface of the S4, powering on other radio frequency systems of the whole satellite, and switching on wireless signals, wherein the estimated value of the carrier-to-noise ratio is reduced; s5, by increasing the level of the uplink injection signal to P 2 The carrier-to-noise ratio of the uplink injection receiver is restored to the state 0X10 before other wireless signals are started; s6, navigating increment P of up injection level before and after starting up of downlink and other subsystem radio frequency channels 2 ‑P 1 To evaluate the final assembly state of the satellite. The invention can clearly determine the influence of the passive intermodulation products generated in the final installation state on the uplink, and provide data evidence for the confirmation of the final assembly technical state of the satellite and the delivery of the satellite.
Description
Technical Field
The invention relates to a passive intermodulation test method suitable for whole stars, which is suitable for the passive intermodulation test of whole stars in a microwave darkroom state, and belongs to the technical field of spacecraft test
Background
The uplink and downlink frequency bands of the navigation satellite are all in the L frequency band, the downlink RNSS (Radio Navigation Satellite system) signal has larger output power due to the requirement of the transmission EIRP (Effective Isotropic Radiated Power), and the satellite uplink receiver has higher sensitivity. The active intermodulation can eliminate the influence by configuring a reasonable filter, the amplitude of the passive intermodulation (Passive Intermodulation, PIM) products is far lower than the amplitude of the transmitted signal, the modulated signal passive intermodulation products are broadband signals with the same magnitude as the bandwidth of the transmitted signal, the power of the modulated signal passive intermodulation products is distributed in the whole frequency band, and the noise of the whole system is generally improved. Although the quality of RNSS signals is not affected by passive intermodulation products, the passive intermodulation products enter a high-sensitivity receiver of an uplink channel and can bring the effects of deteriorated carrier-to-noise ratio, improved bit error rate, deteriorated ranging accuracy and the like. The navigation satellite payload connects the amplified navigation signal with the antenna subsystem feed source after passing through triplexer, square coaxial, round coaxial, etc. The operations such as disassembly and installation of the link can influence the amplitude of passive intermodulation products, thereby influencing indexes such as the carrier-to-noise ratio, the sensitivity and the like of the uplink injection receiver.
PIM tests of spacecraft passive radio frequency components and equipment can be divided into non-radiative, radiative and re-radiative passive intermodulation tests. The non-radiative PIM test system is suitable for testing non-radiative single-port, dual-port and multi-port radio frequency components, such as cables, filters, diplexers and the like; the radiation PIM test system is suitable for testing radiation type radio frequency components, such as an antenna feed source assembly, a spiral antenna, a reflecting surface assembly and the like; the reradiating PIM test system is suitable for testing radio frequency components and equipment exposed to an electromagnetic field emitting radio frequency signals, such as antenna reflectors, reflector test samples, antenna support structures, reflector support arms, antenna thermal control multilayer assemblies, whole-satellite thermal insulation protection hardware, and the like.
According to the current existing patent and literature, the method for testing passive intermodulation of a spacecraft mainly aims at radio frequency parts or equipment, and a device or a method for testing passive intermodulation under the conditions of normal temperature and pressure, thermal test and the like and a device or equipment for inhibiting the generation of the passive intermodulation are researched. The passive intermodulation test method after the installation of all the devices of the whole satellite radio frequency link is few, the passive intermodulation test in the whole satellite state can confirm the installation integrity of all the radio frequency links, know the influence of passive intermodulation products generated in the final installation state on the uplink, discover, lock and exclude PIM sources generated by effective loads or other structures, and provide favorable data evidence for the confirmation of the final assembly technical state of the satellite and the delivery of the satellite.
Disclosure of Invention
The invention solves the technical problems that: the method for testing the passive intermodulation is suitable for the whole satellite, is based on an accurate carrier-to-noise ratio estimation function of an uplink injection receiver, can intuitively and rapidly test the influence of passive intermodulation products on the uplink injection receiver, and discovers, locks and eliminates PIM sources generated by effective loads or other structures, thereby confirming the installation integrity of a satellite radio frequency link and providing data evidence for the final assembly technical state confirmation of the satellite and the delivery of the satellite.
The solution of the invention is as follows:
a passive intermodulation test method suitable for whole stars specifically comprises the following steps:
s1, powering up a whole satellite and a navigation subsystem, wherein the whole satellite is wireless and only starts the navigation uplink injection load, and a navigation downlink amplifier and a modulator are not started;
s2, an uplink of the navigation subsystem is established, and the level signal is stepped to 1-3dB by adjusting the level of an uplink injection signal, so that a linear region of a carrier-to-noise ratio estimated value is obtained;
s3, when the estimated value of the carrier-to-noise ratio is confirmed to be 0X10, the level of the uplink injection signal is adjusted in a linear region of the estimated value of the carrier-to-noise ratio, so that the carrier-to-noise ratio marker bit of the telemetry return is displayed as 0X10, and the level of the uplink signal is recorded as P at the moment 1 ；
S4, powering on other radio frequency systems of the whole satellite, and switching on wireless signals, wherein the estimated value of the carrier-to-noise ratio is reduced;
s5, by increasing the level of the uplink injection signal to P 2 The carrier-to-noise ratio of the uplink injection receiver is restored to the state 0X10 before other wireless signals are started, and whether the error rate and the measurement accuracy of an uplink channel meet the index requirements is checked; if not, adjusting the level of the uplink injection signal to P 3 The error rate and the measurement precision of the uplink channel meet the index requirement, and the measurement result is P 3 -P 1 ；
S6, navigating increment P of up injection level before and after starting up of downlink and other subsystem radio frequency channels 2 -P 1 The influence of passive intermodulation on the uplink injection load signal is used for evaluating the final total assembly technical state of the satellite.
Further, in S2, the carrier-to-noise ratio estimate is the upstream fast-varying telemetry C/N0.
Further, the distance between the uplink ground test antenna and the satellite uplink antenna is 5-6 meters, and the distance is 3-8 degrees away from the radiation center of the satellite antenna.
Further, in S3, 0X10 is an estimate of the carrier-to-noise ratio of the satellite to the ground, and the corresponding actual carrier-to-noise ratio estimate is 59.
Further, in S4, the whole satellite other radio frequency systems include a measurement and control subsystem, an autonomous operation subsystem, a payload RNSS load, and an S navigation load.
Further, in S2, the ground signal level is increased by 1dB, and the uplink fast-change telemetry C/N0 is synchronously increased by 1dB, wherein C/N0 is a carrier-to-noise ratio estimated value, C is the power of a carrier wave, and N0 is the power of noise.
Compared with the prior art, the invention has the beneficial effects that:
(1) The invention can solve the passive intermodulation test in the whole satellite state, find, lock and exclude PIM sources generated by effective load or other structures, confirm the installation integrity of all radio frequency links, and clear the influence of passive intermodulation products generated in the final installation state on an uplink, thereby providing data evidence for the final assembly technical state confirmation of satellites and satellite delivery;
(2) The invention utilizes the accurate carrier-to-noise ratio estimation of the uplink injection receiver, can intuitively and rapidly measure the influence of the passive intermodulation products on the uplink injection receiver, and the test method directly utilizes the ground test antenna during wireless test without independently developing passive intermodulation measurement equipment;
(3) The invention is arranged to be carried out when the satellite carries out whole-satellite wireless test, utilizes the environment of the microwave darkroom to carry out passive intermodulation test, does not occupy the whole-satellite test flow independently, and saves the whole-satellite development time of the satellite.
Drawings
Fig. 1 is a basic flow chart of the passive intermodulation test of the present invention.
Detailed Description
The invention is further illustrated below with reference to examples.
As shown in fig. 1, the specific steps include:
s1, powering up a whole satellite and a navigation subsystem, wherein the whole satellite is wireless and only starts the navigation uplink injection load, and a navigation downlink amplifier and a modulator are not started;
s2, an uplink of the navigation subsystem is established, and the level signal is stepped to 1-3dB by adjusting the level of an uplink injection signal, so that a linear region of a carrier-to-noise ratio estimated value is obtained;
s3, when the estimated value of the carrier-to-noise ratio is confirmed to be 0X10, the level of the uplink injection signal is adjusted in a linear region of the estimated value of the carrier-to-noise ratio, so that the carrier-to-noise ratio zone bit of the telemetry return is displayed as 0X10At this moment, the level of the uplink signal is recorded as P 1 ；
S4, powering on other radio frequency systems of the whole satellite, and switching on wireless signals, wherein the estimated value of the carrier-to-noise ratio is reduced;
s5, by increasing the level of the uplink injection signal to P 2 The carrier-to-noise ratio of the uplink injection receiver is restored to the state 0X10 before other wireless signals are started, and whether the error rate and the measurement accuracy of an uplink channel meet the index requirements is checked; if not, adjusting the level of the uplink injection signal to P 3 The error rate and the measurement precision of the uplink channel meet the index requirement, and the measurement result is P 3 -P 1 ；
S6, navigating increment P of up injection level before and after starting up of downlink and other subsystem radio frequency channels 2 -P 1 The influence of passive intermodulation on the uplink injection load signal is used for evaluating the final total assembly technical state of the satellite.
The method can find and exclude PIM sources generated by effective loads or other structures, and provides data evidence for confirming the final assembly technical state of the satellite and satellite delivery.
The method is based on the accurate carrier-to-noise ratio estimation function of an uplink injection receiver, and the passive intermodulation test of the navigation satellite is carried out after the whole satellite wireless test. The requirements for the test environment are as follows:
and all the test antennas of other subsystems on the ground in the microwave darkroom are removed from the microwave darkroom, only the satellite and the uplink are reserved for injecting the test antennas, and the wave absorbing material is paved on the ground between the satellite uplink antenna and the wall surface of the microwave darkroom. The distance between the uplink ground test antenna and the satellite uplink antenna is about 5-6 meters, and the distance deviates from the radiation center of the satellite antenna by about 5 degrees.
The following describes the testing steps of the method by taking a satellite passive intermodulation testing step as an example.
1. The whole satellite is powered on, the navigation subsystem is powered on, the whole satellite is powered on only by the navigation uplink injection load, and the navigation downlink amplifier, the modulator and other radio frequency links are not powered on.
2. The navigation subsystem establishes a link on an uplink channel, and confirms that the carrier-to-noise ratio estimated value (uplink fast-change telemetry C/N0) is increased by 1dB in a linear region, namely the ground signal level is increased by 1dB, and the uplink fast-change telemetry C/N0 is synchronously increased by 1dB/Hz by adjusting the uplink injection signal level.
The change in the level of the up-injection signal is by adjusting an adjustable attenuator in the up-radio channel, the minimum step of the adjustable attenuator is 0.5dB, and the minimum unit of change in satellite carrier-to-noise ratio estimate telemetry is 1, so the ground signal change is changed in 1dB steps. The following are data during the test:
| sequence number | Level value of uplink injection signal | Satellite uplink C/N0 value | Level value of uplink injection signal | Satellite uplink C/N0 value |
| 1. | -125dBm | 2 | -115dBm | 11 |
| 2. | -124dBm | 3 | -114dBm | 12 |
| 3. | -123dBm | 3 | -113dBm | 13 |
| 4. | -122dBm | 4 | -112dBm | 14 |
| 5. | -121dBm | 5 | -111dBm | 15 |
| 6. | -120dBm | 6 | -110dBm | 16 |
| 7. | -119dBm | 7 | -109dBm | 17 |
| 8. | -118dBm | 8 | -108dBm | 18 |
| 9. | -117dBm | 9 | -107dBm | 19 |
| 10. | -116dBm | 10 | -106dBm | 20 |
Based on the above data, the carrier to noise ratio estimate is considered linear at 3 to 20. The receiver carrier-to-noise ratio estimate is selected to be in a linear operating range during testing.
3. At this time, when the estimated value of the carrier-to-noise ratio is confirmed to be 0X10 (C/N0=60 dB/Hz), the level of the uplink injection signal is adjusted in the linear region of the estimated value of the carrier-to-noise ratio, so that the carrier-to-noise ratio zone bit of the telemetry back transmission is displayed as 0X10 (C/N0=16, which means 60 dB/Hz), and the level of the uplink signal is recorded to be P1 to be-110 dBm at this moment.
4. And powering up other radio frequency systems of the whole satellite, including a measurement and control subsystem, an autonomous operation subsystem, a payload RNSS load and an S navigation load, and switching on wireless signals. The carrier-to-noise flag bit of the telemetry return is shown as "0X0E" (C/n0=14, 58 dB/Hz).
5. By enhancing the level of the uplink injection signal to the P2 of-108 dBm, the carrier-to-noise ratio of the uplink injection receiver is recovered to the state of 0X10 (C/N0=16, 60 dB/Hz) before other wireless signals are started, and the error rate and the measurement precision of the uplink channel are checked to meet the index requirements.
6. The increment P2-P1=2dBm of the uplink injection level before and after the start-up of the navigation downlink and other subsystem radio frequency channels is the influence of passive intermodulation on the uplink injection load signal.
The satellite uses the method to measure the influence of the passive intermodulation on the uplink injection load, has a good carrier-to-noise ratio estimation function based on the uplink injection receiver, can intuitively and rapidly measure the influence of the passive intermodulation product on the uplink injection receiver, and the test method directly uses a ground test antenna during wireless test without independently developing passive intermodulation measurement equipment. But the measurement accuracy of this method is limited, about 1dB.
The possible reasons for generating PIM by the navigation satellite are mainly that the triplexer, square coaxial and round coaxial after outputting the filter, and the measurement result of the method can be used as a partial reference basis for judging whether the triplexer, square coaxial and round coaxial are well installed or not, so that the passive intermodulation product of the downlink navigation signal is confirmed to not influence the normal operation of the uplink injection load. The passive intermodulation test of the navigation satellite is carried out in a wireless stage, and on one hand, a microwave darkroom in the wireless stage is used to meet the requirement of a test environment; on the other hand, the whole star testing process is not occupied independently, and the whole star development time is saved.
The invention can solve the passive intermodulation test in the whole satellite state, find, lock and exclude PIM sources generated by effective load or other structures, confirm the installation integrity of all radio frequency links, and clear the influence of passive intermodulation products generated in the final installation state on an uplink, thereby providing data evidence for the final assembly technical state confirmation of satellites and satellite delivery;
the invention utilizes the accurate carrier-to-noise ratio estimation of the uplink injection receiver, can intuitively and rapidly measure the influence of the passive intermodulation products on the uplink injection receiver, and the test method directly utilizes the ground test antenna during wireless test without independently developing passive intermodulation measurement equipment;
the invention is arranged to be carried out when the satellite carries out whole-satellite wireless test, utilizes the environment of the microwave darkroom to carry out passive intermodulation test, does not occupy the whole-satellite test flow independently, and saves the whole-satellite development time of the satellite.
Although the present invention has been described in terms of the preferred embodiments, it is not intended to be limited to the embodiments, and any person skilled in the art can make any possible variations and modifications to the technical solution of the present invention by using the methods and technical matters disclosed above without departing from the spirit and scope of the present invention, so any simple modifications, equivalent variations and modifications to the embodiments described above according to the technical matters of the present invention are within the scope of the technical matters of the present invention.
Claims (5)
1. The passive intermodulation test method suitable for the whole star is characterized by comprising the following specific steps:
s1, powering up a whole satellite and a navigation subsystem, wherein the whole satellite is wireless and only starts the navigation uplink injection load, and a navigation downlink amplifier and a modulator are not started;
s2, an uplink of the navigation subsystem is established, and the level signal is stepped to 1-3dB by adjusting the level of an uplink injection signal, so that a linear region of a carrier-to-noise ratio estimated value is obtained;
s3, when the estimated value of the carrier-to-noise ratio is confirmed to be 0X10, the level of the uplink injection signal is adjusted in a linear region of the estimated value of the carrier-to-noise ratio, so that the carrier-to-noise ratio marker bit of the telemetry return is displayed as 0X10, and the level of the uplink signal is recorded as P at the moment 1 ；
S4, powering on other radio frequency systems of the whole satellite, and switching on wireless signals, wherein the estimated value of the carrier-to-noise ratio is reduced;
s5, by increasing the level of the uplink injection signal to P 2 The carrier-to-noise ratio of the uplink injection receiver is restored to the state 0X10 before other wireless signals are started, and whether the error rate and the measurement accuracy of an uplink channel meet the index requirements is checked; if not, adjusting the level of the uplink injection signal to P 3 The error rate and the measurement precision of the uplink channel meet the index requirement, and the measurement result is P 3 -P 1 ；
S6, navigating increment P of up injection level before and after starting up of downlink and other subsystem radio frequency channels 2 -P 1 The influence of passive intermodulation on the uplink injection load signal is used for evaluating the final total assembly technical state of the satellite;
in S3, 0X10 is the estimated carrier-to-noise ratio of the satellite to the ground, and the corresponding actual estimated carrier-to-noise ratio is 59.
2. The method of claim 1, wherein in S2, the carrier-to-noise ratio estimate is an upstream fast-varying telemetry C/N0.
3. The passive intermodulation test method for whole satellite according to claim 1, wherein the distance between the uplink ground test antenna and the satellite uplink antenna is 5-6 meters, and the distance is 3-8 degrees away from the radiation center of the satellite antenna.
4. The method of claim 1, wherein in S4, the whole-satellite other radio frequency system includes a measurement and control subsystem, an autonomous operation subsystem, a payload RNSS load, and an S navigation load.
5. The method of claim 1, wherein in S2, the ground signal level is increased by 1dB, and the upstream fast-varying telemetry C/N0 is synchronously increased by 1dB, wherein C/N0 is a carrier-to-noise ratio estimate, C is the power of the carrier, and N0 is the power of the noise.
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN103033824A (en) * | 2012-12-18 | 2013-04-10 | 中国科学院国家授时中心 | High-performance navigational satellite space signal quality assessment method |
| CN112311483A (en) * | 2020-09-22 | 2021-02-02 | 中国空间技术研究院 | Passive intermodulation test evaluation method for satellite navigation signals |
| CN112615665A (en) * | 2020-12-14 | 2021-04-06 | 航天东方红卫星有限公司 | Whole satellite testing system and testing method for intelligent small satellite image processing function |
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| CA3024175A1 (en) * | 2016-06-01 | 2017-12-07 | Isco International, Llc | Method and apparatus for performing signal conditioning to mitigate interference detected in a communication system |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103033824A (en) * | 2012-12-18 | 2013-04-10 | 中国科学院国家授时中心 | High-performance navigational satellite space signal quality assessment method |
| CN112311483A (en) * | 2020-09-22 | 2021-02-02 | 中国空间技术研究院 | Passive intermodulation test evaluation method for satellite navigation signals |
| CN112615665A (en) * | 2020-12-14 | 2021-04-06 | 航天东方红卫星有限公司 | Whole satellite testing system and testing method for intelligent small satellite image processing function |
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