International Business Machines Corporation

Shanghai Huace Navigation Technology Ltd

Rui Tu

Xuefeng Shen

Xiao Liang Hu

Bo Qu

Jiejun Wang

Qiang Ren

Guangyang Dong

Wending Dai

Xianghui Che

Si Shi

Guangjie Cao

Hai Tao Cao

Wenlong Zhao

Qiang Yue

Cui Li Chen

Qing Q L Li

The present invention discloses a GNSS-INS vehicle attitude determination method based on a single antenna, including the steps as below: mounting a GNSS antenna at a centroid and in the center of the vehicle, and mounting the IMU measuring unit of the MEMS sensor on the steering shaft of the vehicle; obtaining the position and velocity information of the vehicle by means of the GNSS antenna, obtaining the heading angular speed information of the vehicle by means of the IMU measuring unit; calculating the attitude angle of the vehicle by means of the combination with accelerometer and gyroscope; calculating the heading angle of the vehicle based on the position, velocity, and heading angular speed of the vehicle. The method combines the advantages of the short-term high precision of the IMU gyroscope and the long-term high stability of the GNSS single antenna, so as to avoid the divergence phenomenon.

Method of determining GNSS-INS vehicle attitude based on single antenna

A precision calibration method of attitude measuring systems is provided. The precision calibration method of attitude measuring systems includes the following steps: calibrating a zero-deviation, a scale coefficient, and a non-orthogonal angle between axes of an accelerometer to the attitude measuring system via an ellipsoid fitting model (S); compensating original data of the accelerometer using a calculated ellipsoid parameter (S); calibrating an electronic compass via the ellipsoid fitting model according to compensated accelerometer data (S); compensating original electronic compass data by the calculated ellipsoid parameter (S); calculating an attitude according to the compensated data of the accelerometer and compensated data of the electronic compass (S). The above steps of the method have a reliable calibration result and a high precision with a less time consumption of calibration.

Precision calibration method of attitude measuring system

A circuit and method for power gating is provided. The circuit includes a switch circuit and a modulation oscillator. The switch circuit is connected between a circuit module and a power network having a target level. The switch circuit receives a control signal at its control signal input terminal to gate a connection between the circuit module and the power network under the control of the control signal. The switch circuit is connected to the circuit module at a first node. A modulation oscillator enabling signal input terminal is connected to a gating signal for enabling the modulation oscillator, a modulation oscillator control signal input terminal is connected to the first node, and an modulation oscillator output terminal is connected to the control signal input terminal of the switch circuit. The oscillation signal outputted from the modulation oscillator is modulated by the level of the first node.

Power gating

Embodiments of the invention provide a sense amplifier, a SRAM chip comprising the sense amplifier and a method for conducting read operation on a SRAM cell. The sense amplifier according to an embodiment of the invention comprises a cross coupling circuit, a tail current transistor and an output stage, wherein source of the tail current transistor is connected to a negative level. With the scheme according to embodiments of the invention, speed of the sense amplifier can be enhanced, thereby increasing read speed of the SRAM chip.

Sense amplifier

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Shanghai, China

Rui Tu