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差分GPS水下立体定位系统 总被引:15,自引:3,他引:15
差分GPS水下立体定位系统包括GPS差分基准站、GPS浮标、水下收发机、船基控制中心四部分。差分基准站提供GPS差分改正,实现浮标内置GPS高精度实时定位。GPS浮标完成水上和水下的集成,检测水下收发机发射的定位信号并测量信号到达的时间,同时将各种数据发送到船基控制中心。船基控制中心接收各个浮标的数据后实时解算水下收发机的位置,同时将结果发送给水下收发机。本文首先对系统的总体构成和各个部分的功能进行了介绍,然后详细推导了系统定位算法,最后结合系统试验情况给出了系统试验精度统计结果。 相似文献
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差分GPS水下立体定位系统所有数据都是通过无线电台发送到船基控制中心,船基控制中心通过一个多通道浮标接收机同时接收所有浮标数据,并将所收到的数据通过串口发送控制中心的计算机。合理、高效地从接收到的数据中分离出各个浮标的数据,并从单浮标数据中分离各个数据语句是实现系统稳定工作的关键。本文提出基于链表、队列数据结构的多通道浮标接收机的数据分离和同步数据提取算法,实现了多通道GPS浮标接收机数据管理,软件运行的结果显示该算法高效地为水下GPS定位系统的状态监视和定位解算提供了正确的数据。 相似文献
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针对水下机器人在浅海工作时定位误差大的问题,在浅海电磁波信号衰减不大的情况下,文中重点介绍一种基于GPS/BDS双模组合定位技术的浅海水下机器人高精度定位导航系统,为了比较双模定位系统的定位性能,设置了GPS和BDS单模定位系统作对比,提出了使用中值滤波算法和卡尔曼滤波算法相结合的定位数据处理方法,通过对双模定位系统测试数据的滤波处理,得出系统的定位性能。测试结果表明,双模定位系统的定位精度要高于单模定位系统;中值滤波和卡尔曼滤波相结合算法的应用能够明显提高双模定位系统的定位精度。 相似文献
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针对城市环境中GPS动态定位系统的特点,提出了一种基于粒子滤波的GPS动态定位算法。与传统卡尔曼滤波算法相比,该算法利用观测伪距误差分布建立重要的密度函数,能够处理噪声符合非高斯分布的情况,且无需对观测方程线性化,提高了GPS动态定位的精度。通过实际算例分析,验证了该算法的有效性。 相似文献
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A combined algorithm of improving INS error modeling and sensor measurements for accurate INS/GPS navigation 总被引:1,自引:1,他引:1
Although the integrated system of a differential global positioning system (DGPS) and an inertial navigation system (INS)
had been widely used in many geodetic navigation applications, it has sometimes a major limitation. This limitation is associated
with the frequent occurrence of DGPS outages caused by GPS signal blockages in certain situations (urban areas, high trees,
tunnels, etc.). In the standard mechanization of INS/DGPS navigation, the DGPS is used for positioning while the INS is used
for attitude determination. In case of GPS signal blockages, positioning is provided using the INS instead of the GPS until
satellite signals are obtained again with sufficient accuracy. Since the INS has a very short-time accuracy, the accuracy
of the provided INS navigation parameters during these periods decreases with time. However, the obtained accuracy in these
cases is totally dependent on the INS error model and on the quality of the INS sensor data. Therefore, enhanced navigation
parameters could be obtained during DGPS outages if better inertial error models are implemented and better quality inertial
measurements are used. In this paper, it will be shown that better INS error models are obtained using autoregressive processes
for modeling inertial sensor errors instead of Gauss–Markov processes that are implemented in most of the current inertial
systems and, on the other hand, that the quality of inertial data is improved using wavelet multi-resolution techniques. The
above two methods are discussed and then a combined algorithm of both techniques is applied. The performance of each method
as well as of the combined algorithm is analyzed using land-vehicle INS/DGPS data with induced DGPS outage periods. In addition
to the considerable navigation accuracy improvement obtained from each single method, the results showed that the combined
algorithm is better than both methods by more than 30%. 相似文献
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X. X. Jin 《Journal of Geodesy》1997,71(7):411-422
This paper derives a DGPS positioning algorithm, referred to as the algorithm for carrier-adjusted DGPS positioning. This
algorithm can be applied by a DGPS user when code and carrier observations are available and when the dynamic behaviours of
both mobile positions and receiver-clock biases can and cannot be modelled. Since the algorithm directly uses code and carrier
observations, the stochastic model of observations has a simple structure and can be easily specified. When the dynamic behaviour
of mobile positions can be modelled, the algorithm can provide recursive solutions of the positions, on the other hand, when
the behaviour cannot be modelled, it can provide their instantaneous solutions. Furthermore, the algorithm can integrate with
a real-time quality-control procedure so that the quality of the position estimates can be guaranteed with a certain probability.
Since in the use of the algorithm there always exist redundant observations unless the position parameters are inestimable,
the quality control can even be performed when only four satellites are tracked. Using the algorithm and real GPS data collected
at a 100-km baseline, this contribution investigates how DGPS positioning accuracies vary with the type of observables used
at reference and mobile stations, and how important it is to choose an elevation-dependent standard deviation for code observations
in DGPS data reduction. It was found that using carrier observations along with code observations is more important at the
reference station than at the mobile station. Choosing an elevation-dependent standard deviation for code observations can
result in better positioning accuracy than choosing a constant standard deviation for code observations. For the 100-km baseline,
half-metre single-epoch positioning accuracy was achieved when dual-frequency data was used at both reference and mobile stations.
The positioning accuracy became better than 0.75m when the types of observable used at the mobile station were replaced by
L1 code and carrier.
Received: 9 April 1996 / Accepted: 6 February 1997 相似文献
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针对GNSS卫星导航中的伪距单点定位,提出一种不需要测站坐标近似值的非迭代算法。该算法将GNSS伪距导航定位方程转化为空间双曲定位方程,给出具体的解算步骤,研究了空间双曲定位方程的解(有两解),利用GNSS伪距导航定位的特点可消除多值性,从而实现无初值GNSS伪距单点定位。该算法与Bancroft算法相比,通过星间单差,与测站有关的公共误差项被消去,提高了定位精度;与传统的迭代算法相比,提高了计算效率,而且不需要测站坐标初值。最后通过IGS监测站实测数据对3种算法进行比较,验证了算法的有效性。 相似文献
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JIN Xinxiang 《地球空间信息科学学报》2000,3(2):65-73,78
1 IntroductionCurrently ,therealreadyexistseveralalgorithmsforthegenerationofdifferentialcorrections,forin stance ,thealgorithmbasedoncarrierfilteredcodeobservations (vanDierendonck ,1 993 ;Landau ,1 993 )andthealgorithmbasedoncodeobservationsandsequentialdiffere… 相似文献
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Jin Xinxiang 《地球空间信息科学学报》2013,16(2):65-73
The DGPS technique can provide considerably better relative positioning accuracy than the stand-alone GPS positioning, but the improvement depends on the distance between the user and the reference station (spatial correlation), the latency of differential corrections (temporal correlation), and the quality of differential corrections. Therefore, how to correctly generate differential corrections as well as their pricision is very important to the DGPS positioning technique. This paper presents a new algorithm for generating differential GPS corrections. This algorithm directly uses code and carrier observations in the measurement model of a Kalman filter, so that it is possible to use a simple stochastic model and to use the standard algorithm of the Kalman filter. The algorithm accounts for biases like multipath errors and instrumental delays in code observations and it shows how differential corrections are differently affected by code biases when dual or single frequency data is used. In addition, the algorithm can be integrated with a real time quality control procedure. As a result, the quality of differential corrections can be guaranteed with a certain probability. 相似文献
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DGPS services are provided in support of land and marine applications by many government agencies worldwide. Horizontal positioning accuracies in the order of several metres are typically achieved for these systems. Under high levels of ionospheric activity, however, significant degradations in DGPS positioning accuracies can occur. In particular, gradients of up to 50 ppm are associated with a feature known as storm-enhanced density (SED). This feature is a localized enhancement of total electron content (TEC) extending north through the mid-latitudes into the polar region. DGPS positioning errors of 20 m or more can persist for hours during such events. In this paper, archived IGS data from GPS reference stations are used to derive high-resolution TEC maps for two SED events. The impact of SED effects on DGPS horizontal positioning accuracies is then quantified using data from select IGS reference stations in North America and Europe. Results indicate that positioning accuracies may be degraded by factors as large as 10–20 during such events. 相似文献