How accuracy is GPS?
With SA (Selective Availability) on, the basic GPS signal is accurate to within approximately 100 meters lateral and 140 meters vertical everywhere on earth. With SA off, the accuracy is within approximately 30 meters lateral. Now, our GPS receiver supports WAAS/EGNOS to improve accuracy. In the region under the coverage of WAAS/EGNOS system, you can get an accurate position fix within approximately 3 meters lateral error.
Top How much bandwidth is GPS receiver able to provide?
GPS receiver is not used for communication, but just signal receiving. There is no bandwidth issue in ordinary GPS products, including our products. At least, we have no need to consider that. GPS signal is broadcasted by satellites on the channel, L1 frequency of 1575.42MHz. The bandwidth for transmission is arranged in advance, and enough to transmit simple data. Anyone with the GPS receiver can get the signal, just like you listen to radio (FM/AM). Therefore, we don’t have to share it with someone.
Top Top Can I use GPS inside a building?
Satellite navigation receivers must operate by line of sight with global positioning satellites. Though the radio signals of navigation satellites will pass through clouds, glass, plastic and other lightweight materials, satellite navigation receivers will not work underground or in other enclosed spaces such as a building.
Top What affects GPS accuracy?
Many factors affect how accurate your GPS receiver is. The atmosphere, the ionosphere and the position of your receiver could all affect GPS accuracy. Any buildings, natural structures or heavy foliage that obstruct the view of the sky may decrease the position accuracy. Your GPS accuracy will also depend on your level of clearance with the US DOD. There are two available radio signals that receivers can use: the Standard Positioning Service (SPS) for civilians and the Precise Positioning Service (PPS) for military and authorized personnel. The DOD occasionally jams the GPS signals for civilians on a short-term basis.
Top What is the Standard Positioning Service?
GPS provides two levels of service: A Standard Positioning Service (SPS) for general civil use and an encoded Precise Positioning Service (PPS) primarily intended for use by the Department of Defense and U.S. allies. The SPS is the standard specified level of positioning and timing accuracy that is available, without restrictions, to any user on a continuous worldwide basis.
SPS provides accuracies (for position, the accuracy with respect to geographic or geodetic coordinates of the Earth) within: 100 meters (2 drms) horizontal, 156 meters (2 Sigma) vertical, 300 meters (99.99% prob.) horizontal, 340 nanoseconds time (95% prob.). SPS Coverage is continuous and worldwide, with a position dilution of precision (PDOP) of 6 or less.
These accuracy´s reflect the last signal specification in the Federal Radionavigation Plan, the signal specification is in the process of being revised to reflect the accuracy obtained with Selective Availability (SA) turned off.
Top If I find my PC´s mouse cursor is in panic after I connect SP3150 with my PC, what can I do for it?
Please fellow the Steps below to fix this problem:
1. Please disconnect the SP3150 with your USB slot.
2. Right click [My Computer] and choose [Properties]. (Refer to Photo 1)
3. When the System Properties screen appears, press [Hardware] tab and click [Device Manager] bottom. (Refer to Photo 2)
4. When the Device Manger screen show up. Please connect your SP3150 into USB slot again, and you will find device like [Microsoft Serial BallPoint] under the [Mice and other pointing devices] node appearing. (Refer to Photo 3)
5. Your mouse will become uncontrollable again. Please use “Tab” or “Alt+Tab” key on your keyboard to control the screen and press “Enter” key on the [Microsoft Serial BallPoint] item.
6. Then the screen below will show up, please choose [Do not use this device (disable)] in the [Device usage] item and press Enter key on the [ok] bottom. (Refer to Photo 4)
Note: The Mouse properties below is just a example for your reference.
7. After disable the [Microsoft Serial BallPoint] device. The mouse will back to work normally now.
Top Top Why the USB ports of SP204 providing 500mA only?
Follow USB standard, the electric current of each USB port is 500mA. We have found some USB products in market that do not obey this rule. If so, the device and your PC will be destroyed in the long run. For this issue, we develop SP204 providing 500mA only.
Top How many USB peripherals can be connected at once?
Technically, you can connect up to 127 individual USB peripherals at one time. Due to the fact that some devices reserve USB bandwidth, the practical maximum of devices is less than the theoretical maximum.
Top Top How does USB compare to IEEE-1394?
While the two serial buses seem similar, they are intended to fulfill different bandwidth and cost needs. 1394 can move more data in a given amount of time, but is considerably more expensive than USB due to its more complex protocol and signaling rate. Applications that are best suited for 1394 are disk drives, high quality video streams and other high bandwidth applications; all higher end consumer devices. USB is appropriate for middle and low bandwidth applications such as audio, scanners, printers, keyboards, and mice.
USB and 1394 are complimentary technologies. 1394 is for devices where high performance is a priority and price is not, while USB is for devices where price is a priority and high performance is not.
Top What´s the difference between USB 1.1 and USB 2.0?
USB 2.0 is designed to work at up to 480Mb per second. It is fully backward compatible with USB 1.1. USB1.1 supports two speeds, 1.5 and 12 Mbps. USB 2.0 supports 1.5, 12 (making it backward compatible), and 480Mbps.
Top Top Why USB modem can not be installed properly on USB 2.0 port?
The problem is due to USB 2.0 does not fully compatible with USB 1.1. In general case, USB modem compliant with USB 1.1. Most of motherboard providers have released new firmware for solving this problem. Please upgrade your motherboard then test again.
Top Do USB 2.0 & USB 1.1 hardware work interchangeably?
You may have heard that USB 2.0 is "backward-compatible" with USB 1.0/1.1 (Full-Speed USB). While that´s true, USB 1.1 is also forward-compatible with USB 2.0. Whenever a system has USB 2.0 ports, you´ll find the "Enhanced" USB controller in Device Manager, but you will also find two other USB controllers. These two to maintain backward compatibility to USB 1.1 devices. Each USB 2.0 host actually has 3 chips onboard. The USB controller routes signals to the correct controller chip depending on how a device is recognized. Where a device is physically plugged in has no bearing on how it is routed. All ports on a USB 2.0 motherboard can host any USB devices at all as long as the system and devices are healthy.
The vast majority of USB 2.0 devices will work on older PCs and Macs. None should flat-out fail unless there are other issues with the system. Hi-Speed USB devices will revert to Full-Speed operation when connected this way. Understand that Hi-Speed is at least ten times faster than Full-Speed in actual operation, so the speed difference is quite noticeable – unless you have never experienced Hi-Speed, of course.
When it comes to USB hub compatibility between USB 2.0 and USB 1.1, here some facts:
(1) A powered hub is always preferable to unpowered.
(2) USB hub ports are not as capable or flexible as real PC ports so it´s best not to expect the world of them.
(3) USB 1.1 (obsolete) hubs will work fine on USB 2.0 ports, but they cannot utilize USB 2.0 capabilities. They will default to slower speeds.
(4) Hi-Speed and Full/Low-Speed USB devices can coexist nicely on USB 2.0 hubs. Connecting such a hub to a USB 2.0 port is recommended.
(5) USB 2.0 hubs can be used on older USB 1.1 computers.
(6) Although it is said that you can "cascade" up to 4 hubs, problems may start to arise after two hubs, it´s best to minimize hub usage if possible.
(7) Many USB devices don´t work well on hubs. Cameras, scanners and especially USB drives are known to have problems with hub connectivity.
(8) Remember that "active USB extensions" are really just one-port hubs.
As you can see, there are very few issues (if any) to be concerned about when mixing USB types. If the system and devices are healthy, it should be a "no-brainer" to connect any USB device – provided that you follow manufacturer´s instructions.
Top Top Top Top Top What is Bluetooth Specification Version 1.2?
In addition to Adaptive Frequency Hopping(AFH), the Bluetooth Core Specification Version 1.2 introduced a host of new features intended to make Bluetooth wireless technology easier and more reliable to use:
1.Enhanced Voice Processing -- This feature is designed to improve the quality of voice connections, particularly in noisy environments, using error detection methodologies.
2. Faster Connection Setup -- This version of the wireless technology allows for even faster connections to other Bluetooth wireless devices, thus improving the user experience.
3.Backward Compatible -- As a core feature, the new version of the Bluetooth Core Specification is backward compatible with 1.1 Bluetooth Core Specification Version 1.1 products, allowing users of nearly all existing Bluetooth equipped devices to easily work with products built to the new Specification.
Top Top How to fix SP935A and SP936 Bluetooth Dogle in Windows XP SP2 unofficially?
1.Don´t plug in the Bluetooth device yet.
2.If you have any Bluetooth software apart from the included Windows drivers installed, uninstall them and reboot.
3.Install the WIDCOMM BTW 1.4.2.10 Bluetooth software. When it asks you to plug in the Bluetooth device and click OK, don´t, and click Cancel instead.
4.When the WIDCOMM setup has finished, plug in your Bluetooth device and let Windows install the driver (there should be two Bluetooth icons in the system tray; one blue-white: this is the Windows driver - and one blue-red: this is the WIDCOMM driver which is deactivated).
5.Now go to the Device Manager, right click on the "Generic Bluetooth Radio" and select "Update driver". Don´t let Windows XP connect to the Internet, then select "Choose software from a list or specified location". In the next window, select "Don´t search, but select the driver to install".
6.In the next window, activate "Show compatible hardware" (if it isn´t activated already) and select your manufacturer´s driver instead of the "Generic Bluetooth Radio" driver. Click next until the new driver is installed. Now the WIDCOMM system tray icon should be blue-white as well, activated and ready to use. If you now double click on "My Bluetooth Places" (e.g. on the desktop), the WIDCOMM software installation will be continued and finished.
(Note: Please take your own risk)
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