System level solutions for GPS tracker

When access to the GPS first became available for military and commercial use, only a few companies had the technology and expertise to develop reliable, accurate GPS Tracking Device . Application developers who needed GPS services would simply purchase a board level solution from a GPS supplier, and integrate it into their design. In the past, GPS correlators were designed with a single channel, which was multiplexed between each SV signal being received. This resulted in a very slow process for calculating a position solution. Today, systems come with up to 12 channels, allowing the correlator to process multiple SV signals in parallel, achieving a position solution in a fraction of the time. Also, while the correlator functionality is sometimes performed in software using a high-performance digital signal processor (DSP), the real-time processing requirements and repetitive high rate signals involved make a hardware correlator solution ideal, from both a cost and throughput standpoint.

More recently, the demand for putting GPS capabilities into customized packaging has grown dramatically. To meet that demand a variety of solutions are now available, ranging from traditional board-level solutions that connect to an application via a serial interface, to integrated circuit (IC) chip sets, which application developers can embed directly into their designs. The sections below will give a brief overview of the types of solutions available on the market today.

The first commercially available GPS tracker were designed as either standalone units with connectors for power, an antenna, and a serial interface to a computer or other device, or as more basic board-level solutions, which could be integrated into an application enclosure, but which still required an external antenna connection and serial network interface. These units were entirely self-contained, with the RF interface, downconverter and baseband processing done entirely independent of the application. With this type of solution, the PVT information was transmitted out of the serial port, to be displayed or used as appropriate depending upon the application. In some cases, the user could provide some configuration data to the system, such as the choice of a local datum, and in that way ‘customize’ the resulting positioning information for their needs. This type of solution is still widely available, and for many applications provides a cost-effective way of adding GPS positioning or timing services to an existing design.

One variation of the board-level solution that is becoming more popular today is to supply the RF section of the GPS receiver, including the discrete RF interface and downconverter, as a self-contained module, along with a standalone correlator ASIC or an MCU with an integrated correlator and software to perform the baseband processing of the IF signal. Typically, the RF section of a GPS receiver is the most challenging portion of the design because of the sensitivity to component layout and extraneous signals, and many of the RF circuits that exist today were designed with a combination of technical know-how and trial-and-error experience that few application developers can afford. By comparison, designing the hardware layout for the baseband processor and interface to the RF module is a relatively minor task, which is what has made this an attractive solution for application developers who want to integrate GPS into their designs, but cannot afford the cost or space necessary for a board-level solution.

More GPS tracking solutions at http://www.jimilab.com/ .