全球导航系统无线电信号无法接收的原因？

坐在停车场，启动导航系统，等待小时玻璃停下来并获得卫星定位可能是一件令人沮丧的事情。
游戏的名称是首次定位时间（TTFF），其中无线电接收器可以从视野中的卫星（视线）获得信号，并对信号进行三角测量。
考虑到视线，全球导航系统无线电信号受到大型建筑物等障碍物的阻碍，通常称为“城市峡谷”，森林檐篷，停车场/室内和嘈杂的射频环境。
所有这些都可以使导航接收器不能接收这些信号或显着延迟接收。
进入意法半导体的Teseo-LIV3F全球导航卫星系统（GNSS）模块及其相关评估板。
对于在给定时间接收的卫星数量，情况总是更好。
较新的GNSS系统可以从许多全球导航系统接收卫星系统。
意法半导体的Teseo-LIV3F模块从人群中脱颖而出，因为它正在吸引来自众多全球标准的并发卫星信号：GPS，Glonass，Galileo，QZSS和BeiDou。
STMicroelectronics的Teseo-Suite PC软件，用于Teseo GNSS系列的可视化和开发。
这是一种称为同时多星座的功能，与仅使用GPS等系统或者可以同时接收的系统数量有限的模块相比，这是一个极大的优势。
还有其他方法可以减轻弱信号或部分信号接收的低数量卫星。
Teseo-LIV3F允许自主辅助GPS。
因此，对于提供移动GSM等网络可用性的设备，能够利用公共数据获取卫星位置和预测未来位置意味着能够获取前几个可用信号并根据可用信息推断当前位置。
这需要大量的三角测量数学处理工作，并等待设备进一步接收信号。
这转化为快速首次修复时间。
这几乎是火箭科学，但开发人员无需担心，ST的模块和开发环境为您做了所有繁重的工作。
随着用户对手持设备需求越来越多的功能，移动设备市场和飞行器的重量空间占据了极高的空间。
在非常紧凑的9.7 x 10.1毫米（0.38 x 0.39英寸）处，这是该设备突出的另一个区域。
由于物理限制，无法接收是不可避免的。
隧道，室内，以前描述的城市峡谷，以及在嘈杂的射频环境中，这就是“航位推算”的来源。
看了ST的图书馆和开发环境后，我注意到它们可以轻松点击它们的陀螺仪，加速度计和惯性测量单元，以便测量设备相对于空间的物理位置，从而允许设备
在无线电停电时保持地图移动。
为了便于开发，ST正在与Nucleo生态系统开发扩展板同时启动该模块，该扩展板采用Arduino外形屏蔽兼容插头连接器。
建议将此扩展板与STM32 Nucleo系列开发板的NUCLEO-F401RE，NUCLEO-L476RG或NUCLEO-L073RZ板一起使用。
ST的X-Cube-GNSS1软件扩展适用于STM32Cube，也可用于此开发屏蔽的方便的开箱即用成功。
STMicroelectronics的GNSS PC开发工具TESEO-SUITE是该开发板的重点，它有助于导航接收器的可视化，管理，配置和评估，从而实现固件重配置和未来固件升级等功能。
至于移动市场快速开发的工具，ST拥有AndroidHAL-Teseo，这是一款用于TESEO GNSS解决方案的Android硬件抽象层设备驱动程序。
成为手机，平板电脑，自动驾驶飞行器或车队追踪设计师是一个激动人心的时刻;
或者就此而言，这些设备的用户。



以下为原文


Sitting in a parking lot, booting up a navigation system and waiting for the ol’ hour glass to stop and get a fix on the satellites can be a frustrating thing. The name of the game is Time to First Fix (TTFF) where the radio receiver can get a signal from the satellites in view (line-of-sight), and triangulate the signal.
With line-of-sight in mind, global navigation systems radio signals are impeded by obstructions like large buildings, commonly referred in navigation parlance as ‘urban canyons’, forest canopies, parking garages/indoors, and noisy RF environments. All of these can keep a navigation receiver from being able to receive these signals or significantly delay reception.
Enter STMicroelectronics’ Teseo-LIV3F Global Navigation Satellite System (GNSS) module and its associated evaluation board.
More is always better is the case for the number of satellites being received at a given time.
Newer GNSS systems can receive satellite systems from a number of global navigation systems.
ST’s Teseo-LIV3F module is standing out from the crowd as it’s pulling in concurrent satellite signals from an impressive number of global standards: GPS, Glonass, Galileo, QZSS, and BeiDou.
STMicroelectronics’ Teseo-Suite PC software for visualization and development of Teseo GNSS family. (Image source: STMicroelectronics)
This is a feature called simultaneous multiconstellation, and this is an extreme advantage over modules that only utilize a system like GPS or have a limited number of systems they can receive concurrently.
There are other ways to mitigate a low number of satellites reception from weak or partial signals.
The Teseo-LIV3F allows for Autonomous Assisted GPS. So, for devices that offer network availability such as mobile GSM, the ability to tap into publicly available databases for satellite positions and predicted future positions means the ability to take the first few available signals and extrapolate current position based on the information available. This takes much of the processing work of triangulation math and waiting for further signal reception off the device. This translates to fast Time to First Fix. This IS pretty much rocket science, but developers need not be concerned, ST’s module and development environment do all the heavy lifting for you.
As users demand more and more features from their handhelds, space is at an extreme premium in the mobile device market, and for aerial vehicles, weight. At an extremely compact 9.7 x 10.1 mm (0.38 x 0.39 in.) this is another area where this device is standing out.
There are inevitable times when reception isn’t possible due to physical limitations. Tunnels, indoors, previously described urban canyons, and in noisy RF environments, that’s where ‘dead reckoning’ comes in.
Having taken a look under the hood of ST’s libraries and development environments, I noticed they allow for ease of tapping into their line of gyros, accelerometers, and Inertial Measurement Units to enable the measurement of the device’s physical positioning relative to space, allowing the device to keep the map moving in times of radio blackouts.
(Image source: STMicroelectronics)
Along the lines of ease of development, ST is hitting the ground running launching this module simultaneously with a Nucleo ecosystem development expansion board, featuring the Arduino form factor shield compatible header connectors.
This expansion board is recommended for use with NUCLEO-F401RE, NUCLEO-L476RG or NUCLEO-L073RZ boards from the STM32 Nucleo family of development boards.
Also available for expedient out-of-box success for this development shield is ST’s X-Cube-GNSS1 software expansion for STM32Cube.
Accenting this development board is STMicroelectronics’ GNSS PC development tool, TESEO-SUITE, that assists in visualization, management, configuration and evaluation of the navigation receivers, which allows for features like firmware reconfiguration and future firmware upgrades.
As for the mobile market’s tools for rapid development, ST has AndroidHAL-Teseo, an Android Hardware Abstraction Layer device driver for TESEO GNSS solutions.
It's an exciting time to be a mobile phone, tablet, autonomous aerial vehicle, or fleet tracking designer; or for that matter, a user of these devices.