10.5 Testing and Verification
359
tests, special tests such as compact field test and interface test between spacecraft
and ground system should also be conducted.
10.5.1 Compact Field Test
In recent years, various antenna measurement technologies had been widely used.
Generally, the electrical test was a general term that studies the radiation performance
of the antenna by means of experiments with source and probe when the antenna
was regarded as an unknown space radiation [13].
The radiation measurement of the antenna could be classified into near field
measurement, far field measurement and compact field measurement according to
the position of spacecraft. The probe was located near the antenna to be measured
so as to sample field data in the near field measurement, and the far field parameters
were acquired by transformation. According to the sampling method, it was classified
into plane near-field measurement, cylindrical near-field measurement and spherical
near-field measurement, which were suitable for antennas with different radiation
characteristics. The far field measurement was a direct measurement of the parameters such as the antenna pattern, gain, electric axis, phase center, polarization and
etc., when the test distance satisfied the far-field free space condition. The compact
field measurement was a method for the intermediate distance between the near
field and far field measurements. Generally, the compaction field was classified into
single reflective surface compaction field, double reflective surface compaction field,
and triple reflective surface compaction field. The double reflective compaction field
was classified into cylinder-shaped compaction fields and Cassegrain-compensated
compaction fields. The triple reflective compaction field was classified into double
Cassegrain, Cassegrain-Gregorian, Gregory Cassegrain and double Gregorian.
When the antenna was installed, its electrical performance such as the gain pattern
would be degraded to some extent compared with the unit antenna because of
the influence of surface status of spacecraft. In particular, along with the increase
of spacecraft function, the surface status of spacecraft became more sophisticate.
Therefore, the performance of the antenna installed on spacecraft was an important
specification to check compliance of the antenna.
The basic principle of the compaction field was to convert the spherical wave
emitted by the test feed into a plane wave by large aperture hyperboloid and parabolic
reflector to provide an ideal plane wave test environment within a short distance. The
antenna to be tested or the spacecraft was located in the quiet zone of the plane
test wave to acquire the ideal and accurate test results. In an indoor environment,
real-time measurements of the entire spacecraft’s radiation characteristics could be
conducted fast with high accuracy.
In the compact field test, the transmitting or receiving antenna and the spacecraft
were mounted on the turntable and located in the test quiet zone in the center of
compaction field. In the operation status of continuous wave, the continuous wave
signal was transmitted from the source of compact field and the antenna to be tested
359
tests, special tests such as compact field test and interface test between spacecraft
and ground system should also be conducted.
10.5.1 Compact Field Test
In recent years, various antenna measurement technologies had been widely used.
Generally, the electrical test was a general term that studies the radiation performance
of the antenna by means of experiments with source and probe when the antenna
was regarded as an unknown space radiation [13].
The radiation measurement of the antenna could be classified into near field
measurement, far field measurement and compact field measurement according to
the position of spacecraft. The probe was located near the antenna to be measured
so as to sample field data in the near field measurement, and the far field parameters
were acquired by transformation. According to the sampling method, it was classified
into plane near-field measurement, cylindrical near-field measurement and spherical
near-field measurement, which were suitable for antennas with different radiation
characteristics. The far field measurement was a direct measurement of the parameters such as the antenna pattern, gain, electric axis, phase center, polarization and
etc., when the test distance satisfied the far-field free space condition. The compact
field measurement was a method for the intermediate distance between the near
field and far field measurements. Generally, the compaction field was classified into
single reflective surface compaction field, double reflective surface compaction field,
and triple reflective surface compaction field. The double reflective compaction field
was classified into cylinder-shaped compaction fields and Cassegrain-compensated
compaction fields. The triple reflective compaction field was classified into double
Cassegrain, Cassegrain-Gregorian, Gregory Cassegrain and double Gregorian.
When the antenna was installed, its electrical performance such as the gain pattern
would be degraded to some extent compared with the unit antenna because of
the influence of surface status of spacecraft. In particular, along with the increase
of spacecraft function, the surface status of spacecraft became more sophisticate.
Therefore, the performance of the antenna installed on spacecraft was an important
specification to check compliance of the antenna.
The basic principle of the compaction field was to convert the spherical wave
emitted by the test feed into a plane wave by large aperture hyperboloid and parabolic
reflector to provide an ideal plane wave test environment within a short distance. The
antenna to be tested or the spacecraft was located in the quiet zone of the plane
test wave to acquire the ideal and accurate test results. In an indoor environment,
real-time measurements of the entire spacecraft’s radiation characteristics could be
conducted fast with high accuracy.
In the compact field test, the transmitting or receiving antenna and the spacecraft
were mounted on the turntable and located in the test quiet zone in the center of
compaction field. In the operation status of continuous wave, the continuous wave
signal was transmitted from the source of compact field and the antenna to be tested