SiRFInstantFixII is an autonomous version of SiRF (Nasdaq: SIRF) original SiRFInstantFix technology that is designed to significantly improve the start-up times of portable navigation devices (PNDs) and other mobile navigation devices without needing any network connectivity for assistance or updates. Available now for both SiRFstarIII GPS receivers and SiRFatlas and SiRFtitan multifunction SoC navigation processors, SiRFInstantFixII achieves GPS start-ups in as little as five seconds. As a result, consumers can begin navigating as soon as they’re ready to drive. SiRFInstantFixII is available now and works with all SiRF multifunction SoC navigation processors and SiRFstarIII-based products.
SiRFInstantFixII can reduce warm starts, the typical PND start-up mode, from over half a minute to as little as five seconds. The difference in urban canyons can be even more significant. SiRFInstantFixII does this while demonstrating excellent positional accuracy, an important attribute for navigation devices. SiRFInstantFixII accomplishes this using sophisticated, patent-pending algorithms that enable the PND to model the behavior of visible GPS satellites during the day and predict their position in the sky for up to three days in the future. SiRFInstantFixII continuously refines its calculations based on the latest data it receives from the satellites being tracked every time the PND is used. SiRFInstantFixII performs these calculations completely autonomously, without ever needing updates of any kind from a network.
The new SiRFInstantFixII has been specifically designed to meet the needs of mass-market consumers using non-connected devices where a network-based update would be cumbersome or otherwise undesirable. Manufacturers already using SiRF’s original SiRFInstantFix will find it continues to provide consistently high performance for network-connected devices and for products where updates can be performed seamlessly with little or no user interaction. SiRF offers manufacturers the greatest flexibility to choose between the new “unplugged” SiRFInstantFixII (with three days of satellite predictions) for PND type devices, which may have no connectivity, and the “classic” SiRFInstantFix (with up to seven days of satellite predictions) for connected devices to best meet their end customer requirements.
While in theory determining location using GPS satellites is a simple process of triangulation, the reality is much more complex. First, the GPS receiver needs to find and “lock” onto enough satellites to be able to calculate its location, a process called acquisition. With its 200,000 correlators, SiRF’s innovative SiRFstarIII architecture made the acquisition of satellites very fast. To calculate accurate position, however, the GPS receiver needs to know where each of these GPS satellites is in the sky with a very high degree of accuracy.
Every satellite requires 30 seconds to broadcast its precise location, and the GPS receiver must be able to download this data from each satellite it needs for a fix. This data is typically valid only for two to three hours. If anything interrupts the signal while receiving this data, such as a building or tree, the receiver has to wait another 30 seconds to completely download the data from the satellite. In real-world conditions, where the GPS receiver is usually moving, it can take up to several minutes to obtain all the data the receiver needs to perform its calculations and obtain a fix, resulting in a long period with a great deal of location uncertainty before navigation can begin.
Using SiRFInstantFixII, affordable PNDs can not only start tracking satellites and navigating more quickly, they can do it using signals much weaker than those needed to obtain satellite position data the traditional way, removing the barrier that often stands in the way of successfully navigating under tough GPS signal conditions.
More info: SiRF Technology