EVA: GPS-based extended velocity and acceleration determination
EVA: GPS-based extended velocity and acceleration determination
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DOI：
10.1007/s00190-010-0439-6
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发表时间：
2011-01
影响因子：
4.4
通讯作者：
D. Salazar;M. Hernández‐Pajares;J. M. Juan-Zornoza;J. Sanz-Subirana;À. Aragón‐Àngel
中科院分区：
文献类型：
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作者：
D. Salazar;M. Hernández‐Pajares;J. M. Juan-Zornoza;J. Sanz-Subirana;À. Aragón‐Àngel
本文提出了一种新的基于载波相位的GPS速度和加速度测量方法，扩展了已有技术的有效范围。这种方法被命名为EVA，当崎岖的地形或水体使在附近建立GPS参考接收器变得困难或不切实际时，该方法可能会在航空重力测量等领域得到应用。EVA方法类似于Kennedy(根据载波相位测量精确确定加速度)等方法。见：航海研究所卫星分部第十五届国际技术会议记录。Ion GPS 2002，Portland pp962-972,2002b)，因为它使用L1载波相位观测值来确定速度和加速度。然而，它引入了一个广泛的站点网络，而且它不依赖于精确的时钟信息，因为它估计卫星的时钟漂移和漂移率“在运行中”，只需要足够高质量的轨道数据。此外，EVA的解算速率仅受数据速率的限制，而不受可用的精确卫星时钟数据速率的限制。对于长基线，所得结果比用参考肯尼迪方法得到的结果更稳健。独立于精确时钟信息的优点在于，除了IGS最终产品之外，还可以使用快速、超快速(观测)和超快速(预测)产品。此外，EVA技术还可以使用无电离层的无差载波相位组合(LC)，在电离层梯度可能是一个问题并且需要非常低的偏置的情况下克服基线限制。在这项工作的开展过程中，发现了肯尼迪方法在速度估计过程中存在的一些问题。确定了问题的根源，并将肯尼迪方法的改进版本用于这项研究工作。使用一架飞越比利牛斯山脉的轻型飞机进行的一项实验表明，EVA和改进的肯尼迪方法都能够应对山地飞行的动态。还生成了RTK派生的解，当将这三种方法与已知的零速度参考进行比较时，结果产生了相似的性能。在本实验中，EVA方法和改进的肯尼迪方法优于RTK方法，其中EVA方法的效果最好。最后，将改进的肯尼迪方法和EVA方法应用于南美洲赤道地区一个基线超过1,770公里的网络，并在当地中午期间进行了计算。在这种艰难的情况下，EVA方法在速度和加速度的所有分量上都显示出明显的优势，产生了更好和更稳健的结果。
In this work, a new GPS carrier phase-based velocity and acceleration determination method is presented that extends the effective range of previous techniques. The method is named ‘EVA’, and may find applications in fields such as airborne gravimetry when rough terrain orwater bodies make difficult or impractical to set up nearby GPS reference receivers. The EVA method is similar to methods such as Kennedy (Precise acceleration determination from carrier phase measurements. In: Proceedings of the 15th international technical meeting of the satellite division of the Institute of Navigation. ION GPS 2002, Portland pp 962–972, 2002b) since it uses L1 carrier phase observables for velocity and acceleration determination. However, it introduces a wide network of stations and it is independent of precise clock information because it estimates satellite clock drifts and drift rates ‘on-the-fly’, requiring only orbit data of sufficient quality. Moreover, with EVA the solution rate is only limited by data rate, and not by the available precise satellite clocks data rate. The results obtained are more robust for long baselines than the results obtained with the reference Kennedy method. An advantage of being independent of precise clock information is that, beside IGS Final products, also the Rapid, Ultra-Rapid (observed) and Ultra- Rapid (predicted) products may be used. Moreover, the EVA technique may also use the undifferenced ionosphere-free carrier phase combination (LC), overcoming baseline limitations in cases where ionosphere gradients may be an issue and very low biases are required. During the development of this work, some problems were found in the velocity estimation process of the Kennedy method. The sources of the problems were identified, and an improved version of the Kennedy method was used for this research work. An experiment was performed using a light aircraft flying over the Pyrenees, showing that both EVA and the improved Kennedy methods are able to cope with the dynamics of mountainous flight. A RTK-derived solution was also generated, and when comparing the three methods to a known zero-velocity reference the results yielded similar performance. The EVA and the improved-Kennedy methods outperformed the RTK solutions, and the EVA method provided the best results in this experiment. Finally, both the improved version of the Kennedy method and the EVA method were applied to a network in equatorial South America with baselines of more than 1,770 km, and during local noon. Under this tough scenario, the EVAmethod showed a clear advantage for all components of velocity and acceleration, yielding better and more robust results.