Abstract:
An apparatus for measuring a two-dimensional displacement is disclosed and includes a laser light source, a collimator lens, a beam splitter, a plurality of staggered conjugate optic lens and a plurality of interference optical dephasing modules. The laser light source provides a laser light incident on the collimator lens to generate collimated laser beams. Each of the collimated laser beams are incident on the beam splitter to be separated into two incident beams and incident on a two-dimensional diffraction unit to generate a plurality of first diffracted beams and a plurality of second-order diffracted beams. The staggered conjugate optic lens are used to reflect the first diffracted beams so that the first diffracted beams return to the two-dimensional diffraction unit to generate a plurality of second diffracted beams where the second diffracted beams and the second-order diffracted beams generated as a result of the first diffraction of the beams stagger.
Abstract:
An interruption free navigator includes an inertial measurement unit, a north finder, a velocity producer, a positioning assistant, a navigation processor, an altitude measurement, an object detection system, a wireless communication device, and a display device and map database. Output signals of the inertial measurement unit, the velocity producer, the positioning assistant, the altitude measurement, the object detection system, and the north finder are processed to obtain highly accurate position measurements of the person. The user's position information can be exchanged with other users through the wireless communication device, and the location and surrounding information can be displayed on the display device by accessing a map database with the person position information.
Abstract:
A improved positioning and navigation method and system thereof can substantially solve the problems encountered in global positioning system-only and inertial navigation system-only, such as loss of global positioning satellite signal, sensibility to jamming and spoofing, and inertial solution's drift over time, in which the velocity and acceleration from an inertial navigation processor and an attitude and heading solution from an AHRS processor are used to aid the code and carrier phase tracking of the global positioning system satellite signals, so as to enhance the performance of the global positioning and inertial integration system, even in heavy jamming and high dynamic environments and when the GPS satellite signals are not available.
Abstract:
An efficient approach to exploit hyperspectral imagery and detect target of interest is disclosed. This approach uses proximity pixels as reference signatures to detect potential discontinuity that represents material of unknown existing on the terrain. By incorporating signature of a chosen material of interest, this approach provides an effective way for target detection and identification. An evolutionary algorithm is employed to estimate the abundance of material of interest.
Abstract:
The design of the low cost GPS/IMU positioning and data integrating method, which employs integrated global positioning system/inertial measurement unit enhanced with dual antenna GPS carrier phase measurements to initialize and stabilize the azimuth of the low cost GPS/IMU integrated system, is performed. The utilization of the raw carrier phase measurement for the integration speeds up the ambiguity search.
Abstract:
An improved positioning and data integrating process and system can substantially solve the problems encountered in system integration for personal hand-held applications, air, land, and water vehicles, wherein an integrated global positioning system/inertial measurement unit, enhanced with optional other devices to derive user position, velocity, attitude, and body acceleration and rotation information, and distributes these data to other onboard systems, for example, in case of aircraft application, flight management system, flight control system, automatic dependent surveillance, cockpit display, enhanced ground proximity warning system, weather radar, and satellite communication system.
Abstract:
A passive ranging/tracking processing method provides information from passive sensors and associated tracking control devices and GPS/IMU integrated navigation system, so as to produce three dimensional position and velocity information of a target. The passive ranging/tracking processing method includes the procedure of producing two or more sets of direction measurements of a target with respect to a carrier, such as sets of elevation and azimuth angles, from two or more synchronized sets of passive sensors and associated tracking control devices, installed on different locations of the carrier, computing the range vector measurement of the target with respect to the carrier using the two or more sets of direction measurements, and filtering the range vector measurement to estimate the three-dimensional position and velocity information of the target.
Abstract:
A positioning and proximity warning method for vehicle includes the steps of outputting global positioning system signals to an integrated positioning/ground proximity warning system processor; outputting an inertial navigation solution to an integrated positioning/ground proximity warning processor; measuring air pressure, and computing barometric measurements which is output to the integrated positioning/ground proximity warning processor; measuring time delay between transmission and reception a radio signal from a terrain surface, and computing radio altitude measurement which is output to the integrated positioning/ground proximity warning processor; accessing a terrain database for obtaining current vehicle position and surrounding terrain height data which is output to the integrated positioning/ground proximity warning processor; and receiving the position, velocity and time information or said pseudorange and delta range measurements of said global positioning system, the inertial navigation solution, the radio altitude measurement, the radio altitude measurement, and the current vehicle position and surrounding terrain height data, and computing optimal positioning solution data and optimal ground proximity warning solution data. Furthermore, a positioning and proximity warning method for vehicles further includes the steps of outputting the optimal positioning solution data and position data of near objects to an object tracking and collision avoidance processor to determine a potential collision threat with the near object.
Abstract:
An integrated Global Positioning System (GPS)/Inertial Measurement Unit (IMU) method and MicroSystem is disclosed, wherein data from an IMU, a MEMS IMU preferred, a GPS chipset, and an earth magnetic field detector are mixed in a mixed GPS/IMU/Magnetic Data microprocessor to achieve a low cost, micro size, and low power consumption mixed GPS/IMU/magnetic position, velocity, and attitude solution. Furthermore, to deal with sensitivity of the MEMS inertial sensors to environment temperature, a temperature based scheduler, error estimator, and a current acting error estimator are co-operated to minimize the mismatching between the filter system modules and the actual ones due to change of environment temperature, so that the system of the present invention can provide high performance and stable navigation solution over a wide range of environment temperature.
Abstract:
A real time simulation method for jamming and anti-jamming evaluation of GPS systems and GPS/IMU integrated systems includes the steps of receiving real time trajectory data from a 6DOF trajectory generator and generating jamming signals, global positioning system simulated measurements, and inertial measurement unit simulated electronic signals which are injected into an on-board integrated global positioning system/inertial measurement unit system. When the on-board integrated global positioning system/inertial measurement unit system is excited in dynamic operation, a performance under various jamming conditions is able to be tested and evaluated as if carrying a real transportation test under a real jamming environment.