For the single-frequency GPS receiver, ionospheric delay is an important factor affecting the positioning performance. There are many kinds of ionospheric correction methods, common models are Bent model, IRI model, Klobuchar model, Ne Quick model and so on. The US Global Positioning System (GPS) uses the Klobuchar coefficients transmitted in the satellite signal to correct the ionospheric delay error for a single frequency GPS receiver, but this model can only reduce the ionospheric error of about 50% in the mid-latitudes. In the Beidou system, the accuracy of the correction delay is higher. Therefore, this paper proposes a method that using BD grid information to correct GPS ionospheric delay to improve the ionospheric delay for the BDS/GPS compatible positioning receiver. In this paper, the principle of ionospheric grid algorithm is introduced in detail, and the positioning accuracy of GPS system and BDS/GPS compatible positioning system is compared and analyzed by the real measured data. The results show that the method can effectively improve the positioning accuracy of the receiver in a more concise way.
With the development of 3-D imaging techniques, three dimensional point cloud partition becomes one of the key
research fields. In this paper, two data partition algorithms are proposed. Each algorithm includes two parts: data
re-organization and data classification. Two methods for data re-organization are proposed: dimension reduction and
triangle mesh reconstruction. The algorithm of data classification is based on edge detection of depth data. The edge
detection algorithms of gray images are improved for depth data partition. As to the triangulation method, the data
partition is realized by region growing. The simulation result shows that the two methods can achieve point cloud data
partition of standard template and real scene. The result of standard template shows the total error rates of the two
algorithms are both less than 3%.
Proc. SPIE. 8552, Semiconductor Lasers and Applications V
KEYWORDS: Data acquisition, Field programmable gate arrays, Data conversion, Signal processing, Data transmission, Laser development, Data processing, Radar signal processing, Telecommunications, Control systems
In this paper, a high-speed data acquisition system based on the technology of USB2.0 (Universal Serial Bus) is
designed, in which USB master logic is implemented in an FPGA (Field Programmable Gate Array). Firstly, the
hardware of data acquisition system is discussed, which includes chip selection, data acquisition and transmission circuit
and power conversion circuit. Secondly, the corresponding software including USB firmware program, USB device
driver and application program as well as its modifications have been described. The designed hardware and software
will help to achieve a data acquisition system with the characterstics of high speed and high accuracy, etc.