| CPC H04B 17/18 (2015.01) [H04B 17/102 (2015.01); H04B 17/203 (2023.05); H04B 17/296 (2023.05); H04B 17/347 (2023.05)] | 9 Claims |
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1. An over the air (OTA) test method for a vehicle antenna system, applied to an OTA test system, wherein the OTA test system comprises a reflecting surface, a reflecting surface bracket, a feed antenna, a feed turntable, a feed fixing bracket, a feed lifting apparatus, a feed sliding track, a feed switcher, a feed bracket controller, a rotary table, a left lifting arm, a right lifting arm, a vehicle fixing turntable, a rotating shaft, a driving motor, a vehicle attitude controller and a measuring device; the feed turntable is configured to mounting a plurality of probes of the feed antenna; the feed switcher is configured to control the feed turntable to rotate; the feed antenna required to be used is rotated to a focus of the reflecting surface; the rotary table rotates along an X axis in a vehicle head direction; the vehicle fixing turntable rotates along a Z axis in a vehicle top direction; the rotating shaft rotates along a Y axis in a lateral direction of the vehicle; the measuring device comprises a feed connecting port and an antenna system connecting port; the feed connecting port is connected to the feed turntable; the antenna system connecting port is connected to the vehicle antenna system;
the method comprises:
controlling, by the vehicle attitude controller, a rotating angle of the rotary table, a rotating angle of the vehicle fixing turntable and a rotating angle of the rotating shaft to obtain a current vehicle body attitude of the vehicle to be tested and placed on the vehicle fixing turntable;
controlling the vehicle antenna system in the vehicle to be tested to transmit a first test signal to enable the first test signal to pass through the reflecting surface and the feed antenna and arrive at the measuring device, obtaining an average carrier power, and determining the antenna system radiated power of the vehicle antenna system in the current vehicle body attitude based on the average carrier power; and
controlling the feed antenna to transmit a second test signal to enable the second test signal to pass through the reflecting surface and arrive at the vehicle antenna system, adjusting the transmitting power of the second test signal by the measuring device until the packet loss rate of the vehicle antenna system reaches a preset value, recording a current transmitting power, and determining a receiving sensitivity of the vehicle antenna system in the current vehicle body attitude based on the current transmitting power;
wherein the method further comprises:
measuring, by the measuring device, the reflection coefficient of a reference antenna placed on the vehicle fixing turntable;
measuring, by the measuring device, a cable loss from the feed connecting port to the reference antenna, and obtaining a first path loss from the feed connecting port to the antenna position corresponding to the reference antenna based on the reflection coefficient and the cable loss;
connecting a cable between the reference antenna and the antenna system connecting port, and measuring, by the measuring device, an OTA path loss from the feed connecting port to the antenna system connecting port; and
obtaining a second path loss from the antenna position corresponding to the reference antenna to the antenna system connecting port based on the OTA path loss and the first path loss.
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