Kabushiki Kaisha Toyota Chuo Kenkyusho

Toyota Jidosha Kabushiki Kaisha

Tomohisa Harada

Toshiaki Watanabe

Kunitoshi Nishikawa

Masaru Ogawa

Shigeki Aoshima

Hiroaki Hayashi

Hisanori Uda

Noriyoshi Suzuki

Yoshikazu Asano

Tsutayuki Shibata

Eiji Teramoto

Nobuo Itoh

A receiver configured to receive a plurality of signals k (k=1, 2, . . . , M) allocated in a first frequency band. The receiver includes a frequency conversion section for reallocating the signals k in a second frequency band for sampling by a single AD converter at a sampling frequency fsuch that digital data of the sampled signals k are obtained in a third frequency band extending from zero Hz to a frequency represented by f/2; and a signal extraction section for extracting a target base band signal k from the digital data obtained by the AD conversion section. The frequency conversion section performs the reallocation in such a manner that at least a frequency represented by Jf/2 (J is an integer) is located between the frequencies of at least two of the signals k and that the sampled signals do not overlap.

Receiver apparatus

High-frequency signals from an oscillator (,) are transmitted, through a power divider (,) and a switch (,), from transmission antennas (T,, T,, T,). Reflection waves reflected by targets are received by reception antennas (R,, R,) to thereafter be fed via a switch (,) to a mixer (,). The mixer (,) is supplied with transmission high-frequency signals from the power divider (,) to retrieve beat-signal components therefrom, which in turn are converted into digital signals for the processing in a signal processing circuit,. The transmission antennas (T,to T,) and the reception antennas (R,, R,) are switched in sequence whereby it is possible to acquire signals equivalent to ones obtained in radars having a single transmission antenna and six reception antennas.

Holographic radar

A vehicle-mounted satellite signal receiving system adopting a satellite tracking system combining gyro tracking and hybrid tracking is disclosed which can correct a sensitivity coefficient for correcting a gyro sensor output signal to make up for a sensitivity error, even when a drift is produced in the sensitivity error. In this system, gyro tracking is caused when the received power level is above a threshold power level. The gyro tracking is done by determining the angular velocity .omega. of an antenna as .omega.=-(.omega.G.times..DELTA.SB+.omega.G from a value obtained by inverting the sign of the product of a gyro tracking angular velocity .omega.G and a sensitivity coefficient .DELTA.SB for dealing with the sensitivity error and a predetermined offset error correction value .omega.G and setting the antenna to .omega.. When .DELTA.SB is inaccurate and a sensitivity error is generated in the gyro sensor output signal, the received power level is reduced. When the received power level becomes lower than a threshold power level LB, the sensitivity coefficient is corrected on the basis of the sense of the angular velocity .omega.S in the hybrid tracking (step tracking) and in the gyro tracking.

Vehicle-mounted satellite signal receiving system

A directional beam antenna device includes: an antenna supporting member which is supported on a base in such a manner as to be rotatable about a first rotational axis; an antenna portion which is supported on the antenna supporting member in such a manner as to be rotatable about a second rotational axis which is perpendicular to an antenna aperture and is inclined at a first angle with respect to the first rotational axis, the direction of an antenna beam being inclined at a second angle with respect to the second rotational axis; a first driving unit for rotating the antenna supporting member about the first rotational axis with respect to the base; and a second driving unit for rotating the antenna portion about the second rotational axis with respect to the antenna supporting member. A directional beam controlling apparatus is provided with a controlling unit for controlling an elevation angle of the antenna beam to a target value by causing the second driving unit to rotate the antenna portion with respect to the antenna supporting member, and for controlling an azimuth angle of the antenna beam to a target value by causing the first driving unit to rotate the antenna supporting member with respect to the base.

Directional beam antenna device and directional beam controlling

A control portion performs gyro control at control intervals of .DELTA.t, by using -.omega.G, which is obtained by inverting the polarity of an angular rate .omega.G outputted from an angular rate sensor portion. On the other hand, a receiving level is detected at constant control intervals of .DELTA.T (=M.DELTA.t: M is an integer). The rotation of an antenna portion is controlled by using .omega.s, if the receiving level has increased, or by using -.omega.s, if the receiving level has decreased, i.e. by step track control. By accumulating the control amount .+-..omega.s for a predetermined long time period of N.DELTA.T, accumulation of an error contained in each angular rate .omega.G is obtained. The accumulated value is then divided by N to calculate an error .DELTA..omega.G contained in .omega.G. This error .DELTA..omega.G is used to compensate the actual error, so that the gyro control can be made more accurate.

Tracking antenna system

In a vehicle mounted satellite signal receiving apparatus which adopts a satellite tracking system combining a gyro tracking with a hybrid tracking, there is provided a device which can revise an offset error correction value of a gyro sensor, even if there is a drift in the offset error. In this device, gyro tracking is performed when a reception level is a threshold value L.sub.C or more. The gyro tracking is performed by setting an antenna at an angular velocity .omega., which is derived from an equation,.omega.=-.omega.G+.DELTA..omega.G, where -.omega.G is a value resulted from conversion of sign for gyro angular velocity .omega.G, and .DELTA..omega.G is a prescribed offset error correction value. A reception level declines if the offset error correction value .DELTA..omega.G deviates and therefore an apparent offset error arises in the gyro sensor. When the reception level declines below a threshold value L.sub.B, the aforementioned offset error correction value .DELTA..omega.G is revised, basing on the direction of an angular velocity .omega.S which is used in the hybrid tracking (or step tracking).

Vehicle-mounted satellite signal receiving apparatus

In an annular microstrip antenna element, an annular radiant conductor plate is mounted on a ground conductor plate via a dielectric layer. A coaxial transmission line is provided, whose external conductor is connected to the ground conductor plate, and whose central conductor is connected to the radiant conductor plate, via a feeding point, with a pair of microstrip lines. The pair of microstrip lines extend from the feeding point to two connecting points on the radiant conductor plate, forming an angle between them like a V shape. By varying the angle, it is possible to adjust the input impedance of the annular microstrip antenna element at the feeding point, so that impedance matching with the coaxial transmission line is achieved. In a radial line antenna system comprising a plurality of the antenna elements, the antenna elements are mounted on concentric circles with a constant space between the adjacent antenna elements, thereby reducing undesirable electromagnetic coupling.

Growing community of inventors

Aichi-ken, Japan

Tomohisa Harada