spirent.cn
Posts Tagged "Multi-GNSS"

CNAV is the name for the civilian navigation message that will be carried by the modernized GPS system. And while the CNAV message will carry similar data to the existing NAV message, its structure will be completely different, with a packetised format that will increase message bandwidth to allow for greater information density and pave the way for future system expansion. To this end, the system is designed to support 63 satellites, compared with 32 for the L1 NAV message. Each packe...

Read full post 0 Comments

Although satellite-based navigation systems are the preferred means for establishing location in “open” terrain, they do suffer shortcomings in areas where the satellites are obscured from the receiver, particularly by man-made structures such as buildings. In short, the performance of GNSS receivers cannot be guaranteed indoors or in densely populated “urban canyon” environments. Wi-Fi positioning is a technique that has been developed to overcome these limitations and augment GNSS-based po...

Read full post 0 Comments

CNSS is the Compass Navigation Satellite System, which will eventually comprise up to 30 medium-earth-orbit satellites and five geosynchronous satellites to provide true global coverage. This Chinese system is distinct from that country's existing Beidou I satellite system, which has been operating since 2003 but provides only domestic coverage using three geosynchronous satellites. Like other systems, the CNSS will provide two levels of service. The free service for civilian users will offer p...

Read full post 0 Comments

In the wider world, an almanac is an annual publication dedicated to information such as weather forecasts, tide tables, lunar cycles etc. A typical almanac will contain tabular information covering a particular field or fields, and will be arranged according to the calendar. However, in the world of satellite navigation systems, the almanac is a regularly updated digital schedule of satellite orbital parameters for use by GNSS receivers. The almanac for any g...

Read full post 0 Comments

L2C is the name given to one of the new signals to be broadcast from the satellites in the modernised GPS constellation. This new signal is intended for civilian use (hence the “C”), and will be broadcast on the L2 frequency at 1227.6MHz by all satellites from block IIR-M onwards. The L2C signal is one of the key means by which the modernized GPS will offer improved accuracy and availability for civilian applications based on dual-frequency receivers. Not only is the signal intended to...

Read full post 0 Comments

In addition to the new signals to be broadcast under the GPS modernization project, there are to be two significant changes to the existing civilian signals, both designed to improve the performance of GPS receivers. The first is an additional data-free pilot signal and the second is the addition of forward error correction (FEC) encoding to the navigation message. The new data-free signal will be broadcast alongside the normal data signal, acting as an easy-to-acquire pilot signal. On...

Read full post 0 Comments

The official opening on 20th December 2010 of the Fucino Galileo Control Centre, 130km east of Rome, has brought the Galileo global navigation satellite system one step closer to fruition. However, a continuing shortage of funding for the project suggests that while Galileo will be available by 2014, the service will initially be limited. Earlier in 2010, the European Commission confirmed that funding was available to launch four in-orbit validation (IOV) satellites by 2014, with the f...

Read full post 0 Comments

In a recent post I explained the concept behind QZSS (What is QZSS) – Since the publication of that post and to further help in the development of the Quazi-Zenith Satellite System (QZSS) programme, the Japanese Aerospace Exploration Agency (JAXA) has selected Spirent’s GSS8000 Multi-GNSS Constellation Simulator to verify QZSS receivers. The highly elliptical orbits of QZSS allow satellites to dwell at high elevations, improving coverage in urban canyons and providing additional overhead ran...

Read full post 0 Comments

The core requirement of any GNSS receiver test, whether for development, integration or production purposes, is for a controlled, repeatable signal. For many tests, the signal control includes flexibility over test case, or scenario, conditions that enable performance testing at nominal and extreme or error-state conditions. Real-world, live-sky testing has significant drawbacks which, in practice, preclude controlled testing. These drawbacks of live-sky testing include: ...

Read full post 0 Comments

In the past, designers of satellite-based navigation systems have been mostly restricted to using a single system and service, the GPS C/A code. The current revolution in the industry is giving rise to not only new GNSS systems, some GNSS systems, notably GPS and Galileo, have multiple services available to the commercial GNSS designer. The question of which system or blend of systems a GNSS designer should consider, along with the potential for multiple services is thus an entirely ne...

Read full post 0 Comments
By Andy Walker On September 7, 2010
定位
GLONASS, multi-GNSS

With global coverage of the GLONASS constellation now scheduled before the end of 2010, Russian Prime Minister Vladimir Putin has announced plans for a major expansion in its use on the nation's roads. In announcing the deadline for total coverage, Mr Putin revealed that all new vehicles sold in the Russian market from 2012 will be required to include GLONASS receivers. GLONASS tracking devices are already routinely installed in commercial and emergency services vehicles throug...

Read full post 0 Comments

As new GNSS systems appear, it becomes more apparent that you need a Multi-GNSS test solution. Here at Spirent we’ve been advocating Multi-GNSS for quite some time but now someone else has taken up the mantle. If you haven’t already done so, check out this comprehensive article in Inside GNSS magazine. Three receiver designers and researchers explain how they view Multi-GNSS simulators as an essential tool throughout the entire receiver development cycle: from research, development, de...

Read full post 0 Comments

GPS/GLONASS - You may not be working on it, but many of your competitors are Work continues apace on the GLONASS constellation, with the commencement of a headquarters building that will also house an office of the United Nations IT and satellite navigation agency. And the head of the Russian Space Agency, Anatoli Perminov, took the opportunity of laying the foundation stone of the new building to confirm that the GLONASS constellation would achieve full global coverage before January 2011. He ...

Read full post 0 Comments

Today, navigation and positioning technology is no longer just about GPS L1 C/A code. GPS is being modernized, the GLONASS constellation is nearly complete, new systems including QZSS, IRNSS, Galileo and Compass are on the way. Multi-GNSS offers significant opportunities and challenges to GNSS technology, system and application developers. Spirent multi-GNSS simulation systems are now being purchased by customers developing commercial systems and most chipset manufacturer...

Read full post 0 Comments

A new US national space policy document unveiled recently by President Obama marks a major change of direction on the relationship between the country's GPS system and other GNSS systems around the world. And the change can only accelerate the development and interoperability of systems such as GLONASS, Compass and Galileo. Whereas US policy as affirmed in a December 2004 national security directive was focused on maintaining the country's lead in GNSS on a unilateral basis, the new in...

Read full post 0 Comments

Despite continuing delays in its introduction, when the new European Union funded Galileo constellation goes live in 2014 it will provide a number of novel services. Designers of next-generation Multi-GNSS systems need to factor in these new capabilities in order to keep their equipment ahead of the competition. Importantly, Galileo is designed provide more precise location data from that provided by GPS or GLONASS, and will be accurate down to the one-meter range. The data will also i...

Read full post 0 Comments

It goes without saying that any RF device as sensitive as a GPS receiver will be inherently vulnerable to interference. Clearly, care needs to be taken at both the design and integration stages to minimise interference effects. But what interference sources need to be considered? And how do you know if your receiver can deal with them? Most potential sources of interference are obvious and predictable: The effects of fixed-frequency transmitters for TV, radio and the like can easily be modelle...

Read full post 0 Comments

The Russian Deputy Prime Minister Sergei Ivanov has confirmed that the country's GLONASS system will have 100% global availability before the end of 2010. The news follows the launch of three new satellites during March 2010, bringing the GLONASS constellation up to 19 operational satellites of the 24 required for full service. GLONASS, or Global'naya Navigatsionnaya Sputnikovaya Sistema (literally Global Navigation Satellite System) had fallen into severe disrepair after the f...

Read full post 0 Comments

If you're a GNSS technology, system or application developer involved in the design and implementation of a GNSS project today, you need to take into account the full range of satellite systems and signals that will be available in the near future and understand the challenges and opportunities you face. Using satellites from more than one system brings special challenges and design choices for receiver design and evaluation. But what exactly is the timescale before these new systems are operati...

Read full post 0 Comments

A few years ago the Sat Nav system in your car was considered a luxury now almost every PDA, mobile phone and PC has built-in GPS technology. However, navigation and positioning technology is no longer just about GPS L1 C/A code. The GPS constellation is being modernized, the GLONASS constellation is nearly complete with 19 satellites transmitting as you read, new systems including the Japanese QZSS, the European Galileo and the Chinese Compass constellations are on the way. GPS, the ba...

Read full post 0 Comments

我们上一篇博文 (权衡各种选择:测试真实世界中A-GPS性能的三种方法) 中讨论了测试真实世界中A-GPS性能的方法,最终的建议是采用基于实验室的模拟方法。实验室模拟具有环境可重复、设置简便、测试时间短、自动采集结果和增强手机性能基准能力等特点,因此似乎是最理想的方法。但事实上,在我们讨论的三种方法中,实验室模拟并不是使用最广泛的方法。原因是什么呢? 对于测试新手而言,要想正确地实现真实的实验室模拟是非常困难的。精确模拟多个运动状态下的卫星,而且这些卫星还要以无线方式向运动中的接收机发送信号,同时还要存在信号扭曲、反射和受移动物体阻挡,再加上大气条件的变化,整个模拟过程将变得极为复杂。事实上,思博伦在过去的20年中一直致力于此项业务,因此思博伦对此了如指掌,这一切都是通过思博伦的巨大努力才得以实现! 然而,如果您同意,我们认为实验室模拟不需要在呈现真实世界时达到完美的程度,而只需要“足够好”即可,并将达到这一标准的实验室模拟作为A-GNSS设计和验证的一个基本组成部分。在本文的讨论中,我们将“足够好”的意义定义为: ...

Read full post 0 Comments
× Spirent.com uses cookies to enhance and streamline your experience. By continuing to browse our site, you are agreeing to the use of cookies. If you would like to learn more about how we use cookies