公开(公告)号：US20070076788A1

公开(公告)日：2007-04-05

申请号：US11244305

申请日：2005-10-04

Applicant: Zhike Jia ,  Chi-Shin Wang

Inventor： Zhike Jia ,  Chi-Shin Wang

IPC: H04B1/00

CPC classification number: G01S19/30 ,  G01S19/24

Abstract: Methods to achieve data bit synchronization from weak navigational satellite signals are based on a maximum likelihood criterion. The bit synchronization technique may be implemented by calculating a normalized dot product of two consecutive one-millisecond correlation values. Similar normalized dot products are calculated at intervals separated by one bit duration, and these dot products are summed and compared with pre-computed thresholds to declare bit edge detection. In another implementation, the normalized dot product of adjacent correlation values is replaced by a coherent integration powers of adjacent correlation values.

Abstract translation: 从弱导航卫星信号实现数据位同步的方法是基于最大似然准则。 比特同步技术可以通过计算两个连续的1毫秒相关值的归一化点积来实现。 以间隔一位持续时间的间隔计算相似的归一化点积，并将这些点积相加并与预先计算的阈值进行比较以声明位边缘检测。 在另一实现中，相邻相关值的归一化积积由相邻相关值的相干积分能量代替。

公开(公告)号：US20070046536A1

公开(公告)日：2007-03-01

申请号：US11218298

申请日：2005-08-31

Applicant: Zhike Jia ,  Chi-Shin Wang

Inventor： Zhike Jia ,  Chi-Shin Wang

IPC: G01S5/14 ,  H04B1/707

CPC classification number: G01S19/24 ,  G01S19/246 ,  G01S19/29 ,  G01S19/35 ,  H04B1/7085

Abstract: A method and device to track navigational satellite signals, are claimed. In this invention, a combination of down-sampling and frequency domain transformation are used to track the navigational satellite signals under dynamic environment. A Fast Fourier Transform (FFT) with long coherent integration has been employed to determine the varying frequency components with high resolution. By representing a number of correlation values with their average value, it is possible to represent a long sequence of input values by a smaller number of values and a relatively short length FFT can reveal the low frequency components that are present in the signal during tracking operation. A large reduction in the computational load may be achieved using this down-sampling method without compromising on the frequency resolution.

Abstract translation: 声称用于跟踪导航卫星信号的方法和装置。 在本发明中，使用下采样和频域变换的组合来跟踪在动态环境下的导航卫星信号。 已经采用具有长相干积分的快速傅里叶变换（FFT）来确定具有高分辨率的变化频率分量。 通过用其平均值表示多个相关值，可以通过较小数量的值表示输入值的长序列，并且相对较短的长度可以显示在跟踪操作期间在信号中存在的低频分量 。 使用这种下采样方法可以在不影响频率分辨率的情况下实现计算负荷的大幅度减小。

公开(公告)号：US20060267703A1

公开(公告)日：2006-11-30

申请号：US11140492

申请日：2005-05-26

Applicant: Chi-Shin Wang ,  Kudrethaya Shridhara ,  Jun Mo ,  Shaowei Han ,  Hansheng Wang

Inventor： Chi-Shin Wang ,  Kudrethaya Shridhara ,  Jun Mo ,  Shaowei Han ,  Hansheng Wang

IPC: H03L1/00

CPC classification number: H03L1/026 ,  G01S19/235

Abstract: The invention provides a method and apparatus to optimally estimate and adaptively compensate the temperature-induced frequency drift of a crystal oscillator in a navigational signal receiver. A Read-Write memory encodes two tables, one for looking up frequency drift values versus temperature readings and another one for valid data confirmation on the first table. The initially empty look-up table is gradually populated with frequency drift values while the receiver computes the frequency drift along with its position. During initial start of the receiver or re-acquisition of satellite signals, the stored frequency drift value corresponding to the current temperature is used. If no valid frequency drift value is available, the frequency drift value is computed based on the existing frequency drift values in the table. This invention reduces the Time-To-First-Fix (TTFF) of the receiver and enables the receiver to self-calibrate, thus no additional factory calibration would be necessary.

Abstract translation: 本发明提供了一种方法和装置，用于对导航信号接收机中的晶体振荡器的温度感应频率漂移进行最佳估计和自适应补偿。 读写存储器编码两个表，一个用于查找频率漂移值与温度读数，另一个用于在第一个表上进行有效数据确认。 初始空的查找表逐渐填充频率漂移值，而接收器计算频率漂移及其位置。 在接收机初始启动或重新采集卫星信号时，使用与当前温度对应的存储频率漂移值。 如果没有有效的频率漂移值可用，则基于表中现有的频率漂移值来计算频率漂移值。 本发明减少了接收机的首次定时（TTFF），使得接收机能够自校准，因此不需要额外的工厂校准。

公开(公告)号：US20060250304A1

公开(公告)日：2006-11-09

申请号：US11124413

申请日：2005-05-06

Applicant: Jun Mo ,  Hansheng Wang ,  Chi-Shin Wang ,  Shaowei Han ,  Kudrethaya Shridhara

Inventor： Jun Mo ,  Hansheng Wang ,  Chi-Shin Wang ,  Shaowei Han ,  Kudrethaya Shridhara

IPC: G01S5/14

CPC classification number: G01S19/28

Abstract: The present invention provides a method and apparatus for a satellite navigation receiver to lock onto satellite signals in the cold start mode with no information on the receiver position, the satellite position, or time estimates stored in the receiver's memory. All satellites in a positioning system are divided into groups based on the satellite constellation structure. In an embodiment, the positioning system is the Global Positioning System (GPS) and all GPS satellites are divided into three groups. During initialization of the receiver, the satellites are searched per group to lock onto at least one satellite signal. Other satellites are then searched in a given order based on their respective distance or proximity to the first satellite acquired. This method reduces the Time-to-First-Fix (TTFF) ordinarily required by conventional receivers in the cold start mode.

Abstract translation: 本发明提供了一种用于卫星导航接收机在冷启动模式下锁定卫星信号的方法和装置，其中没有关于存储在接收机的存储器中的接收机位置，卫星位置或时间估计的信息。 基于卫星星座结构将定位系统中的所有卫星分成几组。 在一个实施例中，定位系统是全球定位系统（GPS），所有GPS卫星分为三组。 在接收机的初始化期间，每组搜索卫星以锁定至少一个卫星信号。 然后根据其相应的距离或与所获取的第一卫星的距离，以给定的顺序搜索其他卫星。 这种方法减少了常规接收机在冷启动模式下通常要求的首次固定时间（TTFF）。

公开(公告)号：US08094758B2

公开(公告)日：2012-01-10

申请号：US11612426

申请日：2006-12-18

Applicant: Chi-Shin Wang ,  Yue-Meng Chen ,  Zhike Jia ,  EnYuan Tu

Inventor： Chi-Shin Wang ,  Yue-Meng Chen ,  Zhike Jia ,  EnYuan Tu

IPC: H04B1/00

CPC classification number: G01S19/13 ,  G01S19/24

Abstract: The present invention provides systems and methods for downloading navigation data to a satellite receiver under weak signal conditions. In an embodiment, the receiver uses a tracking algorithm to estimate the Doppler frequency and rate of change of the Doppler frequency to compensate the phases of the I/Q samples from the received signal to reduce the effect of the Doppler frequency. In an embodiment, differential detection based data bit decoding is provided. In another embodiment, phase compensation based data bit decoding is provided, in which the phase of samples are rotated to compensate for phase error. In an embodiment, a multiple frame strategy is provided to increase signal-to-noise ratio (SNR) and improve sensitivity, in which similar placed samples in consecutive frames are coherently summed over the consecutive frames. In an embodiment, the samples are weighted to reduce the impact of noise in the multiple frame strategy.

Abstract translation: 本发明提供了在弱信号条件下将导航数据下载到卫星接收机的系统和方法。 在一个实施例中，接收机使用跟踪算法来估计多普勒频率的多普勒频率和变化率，以便从接收信号补偿I / Q采样的相位，以减少多普勒频率的影响。 在一个实施例中，提供了基于差分检测的数据比特解码。 在另一个实施例中，提供了基于相位补偿的数据比特解码，其中样本的相位被旋转以补偿相位误差。 在一个实施例中，提供多帧策略以增加信噪比（SNR）并提高灵敏度，其中连续帧中的类似放置样本在连续帧上相干相加。 在一个实施例中，加权样本以减少多帧策略中噪声的影响。

公开(公告)号：US07778311B2

公开(公告)日：2010-08-17

申请号：US11244305

申请日：2005-10-04

Applicant: Zhike Jia ,  Chi-Shin Wang

Inventor： Zhike Jia ,  Chi-Shin Wang

IPC: H04B1/00

CPC classification number: G01S19/30 ,  G01S19/24

Abstract: Methods to achieve data bit synchronization from weak navigational satellite signals are based on a maximum likelihood criterion. The bit synchronization technique may be implemented by calculating a normalized dot product of two consecutive one-millisecond correlation values. Similar normalized dot products are calculated at intervals separated by one bit duration, and these dot products are summed and compared with pre-computed thresholds to declare bit edge detection. In another implementation, the normalized dot product of adjacent correlation values is replaced by a coherent integration powers of adjacent correlation values.

Abstract translation: 从弱导航卫星信号实现数据位同步的方法是基于最大似然准则。 比特同步技术可以通过计算两个连续的1毫秒相关值的归一化点积来实现。 以间隔一位持续时间的间隔计算相似的归一化点积，并将这些点积相加并与预先计算的阈值进行比较以声明位边缘检测。 在另一实现中，相邻相关值的归一化积积由相邻相关值的相干积分能量代替。

公开(公告)号：US20090168851A1

公开(公告)日：2009-07-02

申请号：US11428800

申请日：2006-07-05

Applicant: Chi-Shin Wang ,  Jian Cheng ,  Zhike Jia ,  Shridhara A. Kudrethaya

Inventor： Chi-Shin Wang ,  Jian Cheng ,  Zhike Jia ,  Shridhara A. Kudrethaya

IPC: H04B1/707

CPC classification number: H04B1/7075 ,  H04B1/7085 ,  H04B1/7095 ,  H04B2201/70715

Abstract: The present invention provides systems and methods for faster acquisition and more stable tracking of spread spectrum signals with lower computational load requirements. Instead of the present day practice of using only the Prompt correlator, the systems and methods of the invention use the sum of the powers of all the correlators of a channel to determine the acquisition or tracking of the signal. These systems and methods improve the signal acquisition speed resulting in a reduced Time-To-First-Fix (TTFF). Further, these systems and methods improve the acquisition and tracking sensitivity of the receiver.

Abstract translation: 本发明提供了具有较低计算负荷要求的用于更快速采集和更稳定地跟踪扩频信号的系统和方法。 代替现在仅使用Prompt相关器的做法，本发明的系统和方法使用信道的所有相关器的功率之和来确定信号的采集或跟踪。 这些系统和方法提高了信号采集速度，从而缩短了首次固定时间（TTFF）。 此外，这些系统和方法提高了接收机的采集和跟踪灵敏度。

公开(公告)号：US07459984B2

公开(公告)日：2008-12-02

申请号：US11140492

申请日：2005-05-26

Applicant: Chi-Shin Wang ,  Kudrethaya A. Shridhara ,  Jun Mo ,  Shaowei Han ,  Hansheng Wang

Inventor： Chi-Shin Wang ,  Kudrethaya A. Shridhara ,  Jun Mo ,  Shaowei Han ,  Hansheng Wang

IPC: H03L1/00 ,  G01S1/00

CPC classification number: H03L1/026 ,  G01S19/235

Abstract: The invention provides a method and apparatus to optimally estimate and adaptively compensate the temperature-induced frequency drift of a crystal oscillator in a navigational signal receiver. A Read-Write memory encodes two tables, one for looking up frequency drift values versus temperature readings and another one for valid data confirmation on the first table. The initially empty look-up table is gradually populated with frequency drift values while the receiver computes the frequency drift along with its position. During initial start of the receiver or re-acquisition of satellite signals, the stored frequency drift value corresponding to the current temperature is used. If no valid frequency drift value is available, the frequency drift value is computed based on the existing frequency drift values in the table. This invention reduces the Time-To-First-Fix (TTFF) of the receiver and enables the receiver to self-calibrate, thus no additional factory calibration would be necessary.

Abstract translation: 本发明提供了一种方法和装置，用于对导航信号接收机中的晶体振荡器的温度感应频率漂移进行最佳估计和自适应补偿。 读写存储器编码两个表，一个用于查找频率漂移值与温度读数，另一个用于在第一个表上进行有效数据确认。 初始空的查找表逐渐填充频率漂移值，而接收器计算频率漂移及其位置。 在接收机初始启动或重新采集卫星信号时，使用与当前温度对应的存储频率漂移值。 如果没有有效的频率漂移值可用，则基于表中现有的频率漂移值来计算频率漂移值。 本发明减少了接收机的首次定时（TTFF），使得接收机能够自校准，因此不需要额外的工厂校准。

公开(公告)号：US07436357B2

公开(公告)日：2008-10-14

申请号：US11561749

申请日：2006-11-20

Applicant: Chi-Shin Wang ,  David Wang ,  Zongde Qiu

Inventor： Chi-Shin Wang ,  David Wang ,  Zongde Qiu

IPC: G01S5/14 ,  G01S1/02

CPC classification number: G01S19/34 ,  G01S19/258

Abstract: The present invention provides methods and systems for keeping the ephemeris in a navigational receiver current to achieve fast TTFF without the need for connecting to an aiding network or remote server. In an embodiment, the receiver keeps the ephemeris current by downloading the ephemeris in the background. In the preferred embodiment, the receiver uses a background sleep/wake up process to download current ephemeris with minimal power drain. In this embodiment, the receiver alternates between a sleep mode and a wake up mode. During the wake up mode, the receiver attempts to download current ephemeris. The receiver then goes back to the sleep mode until the next wake up to conserve power. The receiver may wake up from the sleep mode to download the ephemeris when the stored ephemeris is no longer current or the ephemeris broadcasted from a satellite has been updated or based on receiver usage patterns.

Abstract translation: 本发明提供了用于将星历保持在导航接收机当中以在不需要连接到辅助网络或远程服务器的情况下实现快速TTFF的方法和系统。 在一个实施例中，接收器通过在背景中下载星历来保持星历当前的状态。 在优选实施例中，接收机使用背景睡眠/唤醒过程以最小的功率耗散来下载当前星历。 在该实施例中，接收器在睡眠模式和唤醒模式之间交替显示。 在唤醒模式下，接收端尝试下载当前星历。 接收器然后回到睡眠模式，直到下一次唤醒以节省电量。 当存储的星历不再是当前的或者从卫星广播的星历表已被更新或基于接收机使用模式时，接收机可以从休眠模式唤醒以下载星历。

公开(公告)号：US20080143594A1

公开(公告)日：2008-06-19

申请号：US11612421

申请日：2006-12-18

Applicant: Chi-Shin Wang ,  Yue-Meng Chen ,  Zhike Jia ,  Enyuan Tu

Inventor： Chi-Shin Wang ,  Yue-Meng Chen ,  Zhike Jia ,  Enyuan Tu

IPC: H04B7/185

CPC classification number: H04B7/18589 ,  G01S19/243 ,  G01S19/246 ,  G01S19/27

Abstract: The present invention provides systems and methods for downloading navigation data to a satellite receiver under weak signal conditions. In an embodiment, the receiver uses a tracking algorithm to estimate the Doppler frequency and rate of change of the Doppler frequency to compensate the phases of the I/Q samples from the received signal to reduce the effect of the Doppler frequency. In an embodiment, differential detection based data bit decoding is provided. In another embodiment, phase compensation based data bit decoding is provided, in which the phase of samples are rotated to compensate for phase error. In an embodiment, a multiple frame strategy is provided to increase signal-to-noise ratio (SNR) and improve sensitivity, in which similar placed samples in consecutive frames are coherently summed over the consecutive frames. In an embodiment, the samples are weighted to reduce the impact of noise in the multiple frame strategy.

Abstract translation: 本发明提供了在弱信号条件下将导航数据下载到卫星接收机的系统和方法。 在一个实施例中，接收机使用跟踪算法来估计多普勒频率的多普勒频率和变化率，以便从接收信号中补偿I / Q采样的相位，以减少多普勒频率的影响。 在一个实施例中，提供了基于差分检测的数据比特解码。 在另一个实施例中，提供了基于相位补偿的数据比特解码，其中样本的相位被旋转以补偿相位误差。 在一个实施例中，提供多帧策略以增加信噪比（SNR）并提高灵敏度，其中连续帧中的类似放置样本在连续帧上相干相加。 在一个实施例中，加权样本以减少多帧策略中噪声的影响。