ST Engineering iDirect

Skew Angle

Efficient waveforms are critical for offering a bandwidth efficient and cost-effective service, but satellite transmissions to fast moving antenna are a challenge. Doppler compensation and skew angle mitigation capabilities can help overcome the challenges of antennas on a fast moving platform such as an airplane. Fast beam switching and fast (re)aquisition are additional capabilities that help maintain a seamless connectivity onboard an airplane.

advanced mobility

  • The Doppler Effect is the change in the frequency of a wave, as perceived by a receiving station, as either the transmitter or the receiver moves. Historically, the Doppler Effect in satellite transmission has been a secondary consideration arising from the satellite’s motion in its station-keeping box. With aircraft, however, the Doppler Effect has a great impact on the effectiveness of antennas. We have developed a technology to manage the Doppler Effects caused by aircraft movements. Another antenna consideration is skew angle support which refers to the angle at which a beam hits the satellite. This is primarily dependent on the location of the antenna on the Earth. Due to the oval shape of some antennas, for example, the beam will leave an aircraft in a wide direction vertically and a narrow direction horizontally and with a wider beam hitting the adjacent satellites with more power. Our platform includes Skew Angle Mitigation to help adapt to the skew angles of such antennas. This allows a terminal to take advantage of high skew situations while ensuring compliance with the adjacent satellite interference limits. In addition, our platform incorporates enhanced frequency and phase tracking of waveforms on inbound channels to offer efficient MODCODs.

    Skew angle refers to the angle at which a beam from a terminal location hits the satellite. Skew angle mitigation allows a terminal to take advantage of high skew situations while ensuring compliance with adjacent satellite interference limits.

    Mounted antennas, such as those on the fuselage of an aircraft or the roof of a vehicle, require special provisions in order to comply with regulatory off-axis limits. Skew angle support is needed for proper and efficient operation of terminals with radiation patterns that are not circularly symmetric.

    Depending on the location of the antenna and the oval shape of some antennas, the beam will leave a vehicle or aircraft in a wide direction vertically and a narrow direction horizontally and with a wider beam hitting the adjacent satellites with more power. The ST Engineering iDirect platform includes Skew Angle Mitigation to help adapt to the skew angles of such antennas. This allows a terminal to take advantage of high skew situations while ensuring compliance with the adjacent satellite interference limits.

  • Benefits of Skew Angle

    • Compliance with adjacent satellite interference regulations
    • Efficient operation of mobile terminals subject to high skew situations