Development direction of portable GPS technology: small size and low power consumption

GPS is an indispensable technology for modern security. The data shows that the three major GPS vendors account for more than 80% of global portable GPS devices. Since the installation of GPS is primarily a mobile device, the small size becomes the future direction for the development of portable GPS. Industry insiders agree that low power consumption and small size design have become necessary conditions for mobile phones, PMPs, and even portable products like watches to install portable GPS.

Choose the solution that suits yours The GPS scheme can be roughly divided into three kinds: Independent of the main processor, all signal processing and algorithm implementation all run on the GPS chip set; Some GPS software runs on the main processor of the system; GPS baseband deals with And all algorithms are implemented by software running on the main processor, the so-called software solution. These solutions have differences in performance, system resource requirements, cost, and design difficulty. Design engineers need to choose according to their specific products.

“Before choosing a solution, understanding the needs of the end user and the platform to which the GPS solution will be integrated is very important.” Kanwar Chadha, Founder and Vice President of Marketing at SiRF stated, “Navigation performance is a key consideration for automotive applications. Factors, for portable systems, supporting value-added services and a good combination of features are the main concerns.”

The choice of MCU is one of the core of the entire solution. "The requirements for the MCU depend on what kind of navigation software and operating system is used. The complex navigation software requires the operating frequency of the MCU to exceed 200MHz. The current hardware platform used by ordinary mobile phones is difficult to support such a high processing capacity." Shenzhen Xing Liang Electronic GPS product manager Liu Yong pointed out. Typically system design companies or solution providers work with navigation software companies to customize a navigation software version that is appropriate to meet specific needs.

To further reduce size and cost, many GPS providers have introduced software solutions in which the baseband chip is integrated into the DSPxpfzxzjqtd_67615.html'target='_blank'>DSP chip. "But this solution is not yet mature, and the performance of the MCU will be affected when performing partial GPS processing, especially in the search stage." CEO-Homax Seiler of u-blox pointed out, "Integrating GPS baseband software to multimedia DSP It also increases the risk of development, delays the launch of the product and increases the overall cost."

Zhou Qinghua, manager of automotive electronics at Shanghai Fengbao Electronic Technology Co., Ltd., said: "Compared with software solutions, hardware solutions run faster and do not increase the burden on the host processor, but software solutions have significant cost advantages."

Stability is the industry's biggest concern for software solutions. "If the software algorithm is not good, the system will take a lot of time to calculate the useful data, it will increase the power consumption and increase the probability of system error. Therefore, how to make the system more stable is the biggest challenge." Serfo Asia Pacific President Lin Acer points out.

There are more and more options available on the market. How do you choose a product that meets your needs? "You can't just choose from the specification of your program, but you must use actual drive tests to test the same conditions and time. Comparison of items." Lin Hongzheng said. "A lot of times there is no problem with individual module testing. Once the overall performance test is conducted, due to interference and other factors, it may show problems such as unstable performance and poor anti-interference performance." Hu Bo, Marketing Manager of Xi'an Huaxun Microelectronics also pointed out .

Design Challenge Analysis “Developing GPS systems and integrating GPS into the system are very challenging. Design engineers must be aware of possible problems,” Chadha pointed out. Since the GPS signal is very weak, any interference can seriously affect its performance. This interference may come from other radio devices, display screens, or other processors, and therefore requires engineers in the design team who are very familiar with RF design.

In addition, the GPS signal is also very sensitive, and replacement of any device may cause performance problems. Therefore, it is very important to pay attention to the RF sensitivity of the GPS system during development and manufacturing.

At present, some portable GPS devices are faced with the problem of long time for first positioning. “This is mainly related to the irrational structural design of the product and inappropriate antenna selection. In addition, excessive power supply, grounding, and white noise and RF interference will make it difficult to quickly locate.” Liu Yong pointed out. Although the use of modular solutions can avoid the design challenges of GPS circuits, the impact of power on the system design cannot be ignored.

Joel M.Alber, Atmel’s senior marketing manager, said: “A lot of designers still prefer to adopt a modular solution to avoid the design risks that may arise from their own use of the chipset.” But he also pointed out that the current single-chip solution and The reference design also allows some designers to choose to directly use chipset solutions to reduce additional module costs.

Liu Yong believes that the modular approach can meet the shorter and shorter design cycle requirements of portable products such as mobile phones, because the module has integrated radio frequency and peripheral components, and the design of these circuits is one of the most challenging parts. He suggested that designers need to consider taking up more PCB area for the antenna and even put more cost budget on the high-performance GPS antenna.

With the intensification of market competition, how to reduce system costs is one of the major considerations of manufacturers. The map engine usually accounts for about 40% of the total cost of the project, so this part of the cost pressure.

"At present, the world's top five PND manufacturers have all developed their own engines." Lin Hongzheng pointed out. However, for most companies, this must take into account their design capabilities, product integration capabilities, cost control, and volume. There are similar problems for system software design. "For software design, the usual question is how to integrate the software with the design platform." Chadha pointed out.

Technology Trends With the increasing use of GPS in mobile phones, PMPs, and even portable products like watches, the low power consumption and small size of the solution have become one of the important factors for design considerations.

“At present, we have adopted a 90-nm semiconductor process. In the future, we will use 65-nanometer technology to produce our chips, which will further increase the efficiency and reduce the size of the chips.” said Lin Hongzheng. "Higher semiconductor integration and lower power consumption will enable GPS to be used in a wider range of consumer devices," Chadha said. "With the continuous development of technological innovation, the new silicon technology and hardware architecture will further reduce costs," Seiler said.

"We are also developing some new technologies to achieve a similar performance of the portable navigation system and automotive systems," said Chadha. The development of semiconductor technology will also bring about changes in the solution. With the continuous improvement of processor processing capabilities, future software solutions will probably get more applications.

The Galileo system including the China Beidou system and Europe will be put into practical use in the next few years. The emergence of these systems will improve the reliability and accuracy of positioning. Major global GPS solution providers have already or will soon introduce systems that can support multiple systems simultaneously. solution.

For example, u-blox's fifth-generation solution, u-blox5, to be launched in the fourth quarter will support the European Galileo system. "The advent of multiple satellite systems will improve the reliability of positioning technology," said Chadha.

In addition, the combination with multiple wireless communication technologies will certainly promote the development of positioning technology. Servo and Skyhook Wireless, based on the company's multi-mode positioning platform, introduced wireless hybrid positioning technology that can provide GPS-WiFi hybrid positioning. This technology can speed up the deployment of certain positioning-based services and increase the coverage of positioning. "Combining GPS with other sensors and signals will enable location information to be obtained in a timely and accurate manner at any location," said Chadha.

Currently, some GPSs have combined wireless communication and positioning technologies, such as quick positioning by downloading ephemeris data. Obviously, the combination of positioning technology and communication has more room for imagination. Operators and terminal developers and a large number of third-party developers can realize more creative and profitable businesses based on the existing infrastructure. Features and applications, such as location-based games, information services, advertising, etc. Undoubtedly, the deployment of the third-generation mobile communications network will bring such development opportunities to GPS mobile terminals.