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摘要当接收机天线被建筑物遮挡或信号被强噪声淹没时,接收机为正常捕获信号,需进行长时间相干积分和多次非相干积分以提取全球卫星导航(GNSS)弱信号,但长时间相干积分会因为导航数据位跳变导致积分后信号能量衰减影响捕获,且多次非相干积分会带来平方损耗限制了对弱信号的捕获能力。针对这一问题,该文在非相干积分基础上提出以最大能量为准则估计最优导航数据位方法,消除导航数据跳变对积分时间长度限制,从而提高弱信号的捕获能力。捕获仿真结果表明: 该方法能大幅提高增益,可捕获到20 dBHz的弱信号。
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| 关键词 ：非相干积分,弱信号,最优导航数据位,捕获能力 |
Abstract：When antennae are blocked by buildings or the signals are drowned by strong noise, global navigation satellite system (GNSS) receivers require both long coherent integration times and a large number of non-coherent integration operations to acquire the signal. However, navigation data bit transition during the long coherent integration results in integrator signal energy attenuation and non-coherent integration will have squared losses that limit the ability to acquire weak signals. A signal acquisition algorithm is given here based on non-coherent integration that estimates the optimal combination of navigation data bits with the maximum energy criterion to eliminate the length limit and improve the ability to acquire weak signals. Tests demonstrate that these techniques greatly increase the gain such that low signal to noise ratio (SNR) signals as low as 20 dBHz can be successfully acquired.
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| Key words：non-coherent integrationweak signaloptimal navigation dataacquisition capability |
| 收稿日期: 2013-09-09 出版日期: 2015-03-17 |
| 基金资助:国家“八六三”高技术项目(2013AA122601) |
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