CN102710343B - Ground station equivalent isotropic radiated power (EIRP) value towerless coupling testing method - Google Patents

Abstract

The ground station EIRP value tower-free coupling test method proposed by the present invention aims to provide a method that is simple and reliable in operation, accurate in measurement, does not require any external system cooperation, gets rid of the dependence on the calibration tower, and has no influence on the antenna caliber and work of the measured station. There is no EIRP value test method with any restrictions on the frequency band. The present invention is realized through the following technical solutions: First, the single carrier signal output by the integrated baseband is connected to the entrance of the up-converter (U/C), and the high-power amplifier (HPA) is set to transmit a small power value of 1% to 2% of the rated power ; Then, extract the uplink signal from the directional coupler at the output of the HPA, and switch to the spectrum analyzer through the test switch network, and read the power level with the spectrum analyzer; finally, according to the known antenna transmission gain, feeder loss and directional coupler The coupling degree calculates the EIRPs value under the above low power, and the EIRP value under the rated power of the ground station can be deduced.

Description

Ground station EIRP value test method without tower coupling

technical field

The invention relates to a tower-free coupling test method for the effective transmission power (EIRP value) of a ground station in the fields of aircraft measurement and control and satellite communication. The "ground station" here includes ground fixed stations, vehicle-mounted stations, and ship-borne stations.

Background technique

The effective transmission power (EIRP value) of the ground station, also known as the equivalent isotropic radiated power of the transmission system, is an important indicator to measure the performance of the transmission system of the ground station, and is a mandatory test item for the system acceptance and network access verification of the ground station. The larger the EIRP value, the better the system launch effect. There are two main methods for testing the EIRP value of the ground station:

The first is the calibration tower method, that is, place a spectrum analyzer, calibration antenna, and joint test cable on the calibration tower, and the ground station antenna faces the tower. The spectrum analyzer on the tower receives the signal sent by the ground station through the calibration antenna, and uses the spectrum analyzer to measure The strength of the received signal is calculated through the link to obtain the EIRP value of the system.

The second is the tower-less comparison method, that is, the EIRP value is first measured by the calibration tower method and the output power P ₀ of the high power amplifier is recorded, and then the spectrum analyzer receives The downlink signal power value P _SPA0 . In the future, when using the comparison method with and without towers, set the output power of the high power amplifier to P ₀ , read the power value P _SPA1 measured by the spectrum analyzer, calculate the change of EIRP value from P _SPA1 -P _SPA0 , and obtain the current The EIRP value of the system.

There is following shortcoming in above-mentioned prior art:

First, the operation is cumbersome. The calibration tower method needs to manually transport the spectrum analyzer to the calibration tower for each test, operate the antenna to the tower, and establish a wireless link to the tower. The test involves many links and the steps are cumbersome;

Second, it is limited by the conditions of the calibration tower. Both the calibration tower method and the comparison method with and without a tower are based on the calibration tower as a prerequisite. If the calibration tower does not meet the far-field conditions, such as the antenna aperture is too large or the frequency band is too high, the test cannot be carried out.

When there is no local calibration tower or the calibration tower does not meet the far-field conditions, none of the existing methods can complete the EIRP value test. In particular, the new high-frequency band large-aperture antenna ground station system has been plagued by this problem in recent years.

Contents of the invention

In order to overcome the above-mentioned shortcomings of the existing test methods, improve the convenience of the test, and realize the EIRP value test of the large-aperture antenna ground station system in the high frequency band. The invention provides a simple and reliable operation, accurate measurement, does not need any external system and equipment cooperation, completely uses the equipment of the station under test, can get rid of the dependence on the calibration tower, and has no need for the antenna caliber and working frequency band of the station under test. Conditional EIRP value test method.

The above object of the present invention can be achieved by the following measures. First, connect the single-carrier signal output by the baseband to the entrance of the up-converter, and the high-power amplifier (HPA) sends out low power; then, extract the uplink signal from the directional coupler at the output of the HPA, and switch to the spectrum analyzer through the test switch network. Use a spectrum analyzer to read the power level; finally, calculate the EIRPs value under the above low power based on the known transmitting antenna gain, feeder loss and coupling degree, and derive the EIRP value under the rated power. The low power mentioned here is because the rated full power output will affect the service life of the HPA, so generally only a small power of 1% to 2% of the rated power is required for testing.

The beneficial effect of the present invention compared with prior art method is:

In the present invention, the single carrier signal output by the baseband is connected to the entrance of the up-converter, and the high-power amplifier (HPA) sends out low power; then, the uplink signal is coupled and extracted from the directional coupler at the output end of the HPA, and switched to the spectrum analyzer through the test switch network. Read the power level with a spectrum analyzer, and finally determine the EIRP value. It does not require the cooperation of any external systems and equipment, and completely uses the equipment of the station under test, completely getting rid of the dependence of the existing method on the calibration tower. There is no restriction on the antenna caliber and working frequency band of the station under test. precise.

The method will be further described below in conjunction with the accompanying drawings and specific implementation methods.

Description of drawings

Fig. 1 is a connection block diagram of the ground station EIRP value without tower coupling test equipment of the present invention.

Detailed ways

Referring to Figure 1, the test equipment includes the ground station working equipment composed of antennas, high-power amplifiers, up-converters and integrated basebands connected in series on the same link; and the test switch network and spectrum of directional couplers connected in series on the link instrument, the ground station is composed of supporting calibration and testing equipment. The antenna, high power amplifier, up-converter and integrated baseband are connected in series on the same link, and the baseband signal is sent to the high-power amplifier (high-power amplifier, HPA) through the up-converter, and the high-power amplifier amplifies the signal power and sends it to the antenna. On the link, a test switch network and a spectrum analyzer are connected in series from the directional coupler. The directional coupler extracts the uplink signal, which is switched to the spectrum analyzer through the test switch network to read the power level.

Before using the tower-free coupling method to test the EIRP value, the antenna transmission gain G, coupling degree C, and feeder loss L _t data are accurately calibrated in advance. The antenna transmission gain G and coupling degree C can be calibrated by antenna manufacturers and microwave device manufacturers, and the transmission and feeder loss L _t can be accurately calibrated by a spectrum analyzer or a vector network analyzer.

When using the EIRP value tower-free coupling method to test, first, connect the single-carrier signal output by the baseband to the inlet of the up-converter, and the high-power amplifier HPA sends out low power; then, the uplink signal coupled from the directional coupler at the output end of the HPA is tested Switch the network to the spectrum analyzer, and use the spectrum analyzer to read the power level; finally, calculate the EIRPs value at low power based on the known antenna transmission gain, feeder loss, and coupling degree, and then deduce the EIRPs value at the rated power of the ground station. EIRP value. The EIRP value of the measured station is calculated by the following formula

EIRP| _Measured ＝P+CL _t +G+(P _max -P _t ) (1)

The relationship between the rated power EIRP value and the small power EIRP value is

EIRP| _Measured ＝EIRP _s +(P _max -P _t ) (2)

In the formula: P is the transmission power of the high power amplifier measured by the spectrum analyzer, C is the coupling degree of the directional coupler, L _t is the loss of the transmitting and feeding line, G is the gain of the transmitting antenna, P _max is the rated output power of the high power amplifier, and P _t is the high The actual output power of the power amplifier. The specific test steps of EIRP value are:

a) The monitoring subsystem controls the baseband to send a single carrier;

b) The monitoring subsystem controls the output power of the high power amplifier;

c) The monitoring subsystem controls the test switch network to switch to the spectrum analyzer;

d) Control the test power of the spectrum analyzer manually or by the automated test subsystem;

e) Calculate the EIRP value under the rated power of the ground station according to the formulas (1), (2) and the pre-booked antenna transmission gain G, feeder loss L _t , and coupling degree C data.

Claims (3)

1. A ground station EIRP value without tower coupling test method is characterized in that the steps are as follows: first, the single carrier signal output by the integrated baseband is connected to the U/C entrance of the up-converter, and the high power amplifier HPA is set to emit 1% to 2% The small power value of the rated power is radiated by the antenna; then, the uplink signal is coupled and extracted from the directional coupler at the output end of the HPA, switched to the spectrum analyzer through the test switch network, and the power level is read by the spectrum analyzer; finally, according to the Calculate the equivalent isotropic radiated power EIRPs value of the ground station under the above low power based on the known antenna transmission gain, feeder loss and coupling degree of the directional coupler, and derive the EIRP value of the measured station under the rated power of the ground station; EIRP| _Measured =P+CL _t +G+(P _max -P _t ) =EIRP _s +(P _max -P _t ) In the formula: P is the transmission power of the high power amplifier measured by the spectrum analyzer, C is the coupling degree of the directional coupler, L _t is the loss of the transmission and feeder line, G is the antenna transmission gain, P _max is the rated output power of the high power amplifier, and P _t is the high The actual output power of the power amplifier. 2. ground station EIRP value according to claim 1 has no tower coupling test method, it is characterized in that, the test of measured station EIRP value comprises: a) The monitoring subsystem controls the baseband to send a single carrier; b) The monitoring subsystem controls the high power amplifier to output low power; c) The monitoring subsystem controls the test switch network to switch to the spectrum analyzer; d) Control the test power of the spectrum analyzer manually or by the automated test subsystem; e) From the power P value read by the spectrum analyzer and the known antenna transmission gain G, feeder loss L _t , and coupling degree C data, calculate the EIRP value at rated power according to the EIRP value formula. 3. ground station EIRP value according to claim 1 does not have tower coupling test method, it is characterized in that, participating equipment comprises, on the same link, the ground of antenna, high power amplifier, up-converter and integrated baseband formed in series Station working equipment, as well as the ground station supporting calibration test equipment consisting of a test switch network of series directional couplers on the link and a spectrum analyzer. the

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