Dyadic wavelet analysis of PDA signals

The dyadic wavelet transform is used to analyze PDA measured signals in order to identify the CASE-damping factor, which may be directly calculated from the dyadic wavelet analysis, not from the correlation study; accordingly, the pile capacity may be more exactly estimated by the CASE method. The dyadic wavelet transform can decompose a PDA measured signal into an incident impact wave and a reflected impulse wave at the certain scale that are clearly shown on the wavelet transform graph. The relation between the incidence and the reflection has been established by a transfer function based on the dyadic wavelet transform and the one-dimensional wave equation, whose phase is the time delay between the incident and the reflected and whose magnitude is a function of the CASE-damping factor. An autocorrelation function analysis method is proposed to determine the time delay and to estimate the magnitude of the transfer function that is determined by the ratio of the maximum of the autocorrelation function to the second peak value represented the reflected wave on the autocorrelation function graph. Thus, the damping factor is finally determined. An analog signal, a PIT signal and five PDA signals demonstrate the proposed methods, by which the time delay, the CASE-damping factor, and pile capacity are determined. The damping factors and pile capacity are good agreement with those by CAPWAP.     

基于PDA形变台站电子手簿系统的设计与开发

地壳形变测量是地震预报的一项重要基础工作,PDA的轻便、电池持久耐用,WinCe操作简单等特点,为形变台站野外观测记录提供基本平台。本文按照有关规范及标准的要求,采用PDA硬件平台,在windows CE软件支持下,利用Microsofte Mbedded Visual Basic编程环境,通过wince sdk工具模块,实现基于PDA的形变台站电子手簿系统(CaisBook PDA1.0)。采用电子数据防伪技术,建立了完善形变台站水准电子记簿软件,可代替手工记录。     

GNSS软件无线电接收机及典型案例

介绍了GNSS软件无线电接收机和它与传统接收机相比的优缺点，并引述了典型的GNSS软件接收机及其应用。     

基于 PDA 的 CPⅢ轨道控制网数据采集系统的设计与实现

为了提高C PⅢ轨道控制测量数据采集的效率,结合PD A 与测量机器人联合作业的技术特点,以Visual studio 2008和Visual C＃．NET 为开发平台和开发语言,采用串口通信和多线程技术,设计了基于PD A的C PⅢ轨道控制网数据采集系统。系统解决了国内外同类软件彼此间平台不统一、数据不兼容的问题,实现了在任意一款基于Windows Mobile操作系统的手簿上进行项目管理、数据通信、自动测量、质量控制和成果输出的功能。     

基于J2ME的PDA GIS开发

PDA是移动GIS的重要载体,现在的GIS多是针对微机或工作站,不适用于硬件条件较低的PDA平台。基于J2ME技术在PDA平台上开发GIS,探讨基于PDA的GIS软件开发具体技术,介绍笔者在PDA中实现的一个地理信息系统软件。