Development and prospects of GPS chips _What are the mainstream GPS chips?

Introduction to GPS knowledge-Features-Classification: Introduction to the basic knowledge of GPS core chips. The following content is organized by BuyBuy.com. Provide you with a reference.

Here we introduce some basic knowledge of the GPS core chip, I hope to help you.

After 2003, the GPS chip industry has sprung up like a booming situation. At present, there are more than 10 manufacturers of GPS chips, including US SiRF, Garmin, Motorola, Sony, Fujitsu, Philips, Nemerix, uNav, and uBlox.

In 2005, SiRF acquired Motorola's GPS chip business and will cooperate in integrating GPS functions in Motorola's smartphones in the future. Coincidentally, Qualcomm has also designed an integrated GPS function in the enhanced 3G mobile phone chip CDMA2000 EV-DO. Nextel is also using SiRF technology to implement GPS functions in its mobile phones.

The United States has passed laws requiring mobile phone manufacturers to integrate GPS receivers into products in 2007 to provide location and emergency call capabilities. 2007 is already the 3G era. It can be seen that although the mobile phone with integrated GPS function has not yet entered the mainstream market, in the future, the high-end models of 3G mobile phones will generally integrate GPS functions.

In July 2005, Xi'an Huaxun, which was founded by five overseas scholars with Dr. Zhou Wenyi as the core of the country, also launched the first GPS chip in China.

Despite the manufacturers, the status of SiRF in the field of non-independent GPS is like that of Intel in the PC industry. The mainstream products use almost all SiRF chips. Therefore, readers can understand the core technology differences of non-independent GPS by knowing several major models of SiRF chips.

In addition, Garmin occupies half of the independent GPS device market, mainly using Garmin's own chip products. Garmin is much like IBM in the IT field, from map software to GPS devices to core chips, a vertically integrated company. In some non-independent GPS applications, Garmin also uses SiRF chips.

Emerging GPS chip companies have difficulty in having a foothold in the original market. They are focusing on various IT devices that integrate GPS in the future, such as mobile phones, digital cameras, PDAs, notebook computers, and even USB flash drives.

If integrated with computing devices, many of the features of the GPS chip can be done in software, and the cost can be further reduced. As early as 2004, SiRF has already launched such a simplified product? ? Software GPS. Recently, Philips has also released similar products, which can support ARM processors, Xscale processors, and x86 processors to complete various GPS processing tasks. The integrated software GPS costs only $4 to $5.

The GPS chip is mainly composed of three parts: RF circuit, software (firmware), memory and processor.

Since the main use of laptops is non-independent GPS, we will focus on SiRF's chip products.

(1) SiRFstarIII

The SiRF chip released the latest third-generation chip SiRFstarIII (GSW 3.0/3.1) in 2004, making the civilian GPS chip a peak in performance, and the sensitivity is much higher than previous products. The chip improves sensitivity by using 200,000 times/frequency correlators (Correlators), and the cold boot/warm boot/hot boot time is 42s/38s/8s, respectively, and can track 20 satellite channels simultaneously. Many of the latest non-independent GPS receivers introduced in 2005 have adopted this chip.

We strongly recommend that users purchase products equipped with this chip. Some of the products using this chip are as follows:

- Fortuna SlimGPS - Bluetooth

- Globalsat BR-355 USB

- Globalsat BT-338-Bluetooth

- Globalsat SD-502 SDIO

- Guidetek GS-R238 (Holux sub-brand) - Bluetooth + USB

- Haicom 303iii CF

- Haicom 305iii CF

- Haicom BT405iii - Bluetooth

- Holux GR-213 USB

- Holux GPSlim 236 - Bluetooth + USB

- Leadtek 9553/L/X - Bluetooth

- Leadtek 9825 - Bluetooth

- Royaltek RBT-2001-Bluetooth

(2) SiRFstarIIe and SiRFstarIIe/LP

SiRFstarIIe is the first high performance GPS chip released in 2002. SiRFstarIIe/LP (GSW2.3) is a low power version of SiRFstarIIe. Both use 1920/frequency correlators, and the cold boot/warm boot/hot boot time is 45s/35s/8s respectively, which can track 12 satellite channels simultaneously. It should be said that the indicators of these two chips can meet the needs of daily applications. The non-independent GPS products launched from 2003 to 2004 use these two kinds of chips.

Some of the products currently using this chip are as follows:

- Fortuna ClipOn Bluetooth

- Fortuna PocketXtrack CF

- Globalsat BR-305 (Semsons iTrek)

- Globalsat BT-308 (Dell/HP) Bluetooth

- Haicom HI303MMF CF

- Holux GM210 USB

- Holux GR230 - Bluetooth

- Royaltek RBT-1000 Bluetooth

- Royaltek RBT-3000 - Bluetooth

(3) SiRF XT2 and Xtrac

The SiRF XT2 chip adds a software function called Xtrac to the SiRFstarIIe/LP. It can enhance the positioning capability by tracking and analyzing weak satellite signals, and it has a certain effect in indoor and indoor signals where the signal is weak.

In the case of weak signals, Xtrac can enhance the positioning ability of GPS. However, Xtrac sometimes causes the positioning error to increase due to the judgment of weak signal errors, and may even lead to incorrect positioning information, which is obvious in high-speed driving.

All in all, Xtrac is a technology that combines strengths and weaknesses, is neither as powerful as SiRF's promotion, and does not cause many problems.

Some of the products currently using this chip are as follows:

- Fortuna ClipOn Bluetooth

- Globalsat SD-501 - SDIO

- Haicom HI303S - CF

- Holux GR231 - Bluetooth

- Holux GM270U CF

- Royaltek RBT-1000 v2 - Bluetooth

The difference in performance between different GPS products depends mainly on the core chip. The technical indicators you see when you purchase GPS are determined by the GPS chip. The future development of GPS is also determined by the core chip technology.