GPS Principles from GPS entry - Your entry point to GPS technologies

GPS Principle

1	How many GPS satellites are there around the earth?
	The space segment currently consists of 28 operational satellites orbiting the earth. They orbit at a height of almost 21,000 km above the earth's surface. Any one satellite completes its orbit in around 12 hours. Due to the rotation of the earth, a satellite will be at its initial starting position after approx. 24 hours.

What are WAAS and EGNOS?

WAAS (Wide Area Augmentation System) is a network of approx. 25 reference station (WRS, Wide Area Ground Reference Station) that receive GPS signals. They have been surveyed exactly in terms of their position. Each reference station determines actual and target pseudo-range deviation. The precisely processed DGPS correction values are transmitted to two geo-stationary satellites (Inmarsat) and beamed back to earth on the GPS L1 frequency. The WAAS signals are received by GPS receivers equipped for this task and further processed. Currently, WAAS satellite coverage is only available in North America. There are no ground reference stations in South America, so even though GPS users there can receive WAAS, the signal has not been corrected and thus would not improve the accuracy of their unit.
EGNOS (European GEO-stationary Navigation Overlay System) is satellite-based augmentation system for existing GPS and Glonass satellite navigation systems. A European network of GPS/Glonass receivers has been built up to receive the corresponding satellite signals and relay these to central data processing stations. The signals received at these data processing are evaluated taking into account the exact known position of receiving stations. In this way, correction data can be determined that is ultimately broadcast to users via geo-stationary communications satellites. With the help of these corrections positional accuracy of around 7 m can initially be achieved.

3	Will GPS work in any country on the earth?
	Yes, GPS can work in any country on the earth.

4	What is DGPS?
	A technique used to improve positioning or navigation accuracy by determining the positioning error at a known location and subsequently incorporating a corrective factor into the position calculations of another receiver operating in the same area and simultaneously tracking the same satellites. Also a system of beacons which broadcasts signals to help increase the accuracy of GPS positioning.

5	What is NMEA 0183?
	NMEA stands for National Marine Electronics Association, a US standards committee that defines data message structure, contents and protocols to allow the GPS receiver to communicate with other pieces of electronic equipment. NMEA 0183 is a standard data communication protocol used by GPS receivers.

6	What is Acquisition Time?
	The time it takes for a GPS receiver to acquire satellite signals and determine the initial position.

7	How is GPS used?
	GPS receivers collect signals from satellites in view. They display the user's position, velocity, and time, as needed for their marine, terrestrial, or aeronautical applications. Some display additional data, such as distance and bearing to selected waypoints or digital charts.

GPS Engine Board

1	Is there any evaluation board of the GPS module?
	Yes, you can contact with Gtop sales.

2	Is it possible to connect USB port or RS232 port to Gtop evaluation board?
	Yes. The Gtop evaluation board is provided both USB port and RS232 port for customer.

3	What is the difference between FGPSMOSL1 and FGPMMOSL1?
	The FGPSMOSL1 is used SiRF StarIII chipset solution and the FGPMMOSL1 is used MediaTek chipset solution. The backup power voltage for keeping RTC clock is 3.0V±10% in the FGPSMOSL1, but 1.5V±10% in the FGPMMOSL1. Please download both datasheet for detail difference between these two modules.

4	How to test the TTFF (Time to First Fix) for the GPS Engine Board?
	The TTFF that we test our modules is under such circumstances: In the chamber for avoiding Noise interference Use multi-channel GPS simulator for 12 channels satellite view and broadcast RF signals The RF Power is -130 dBm Test almost 1000 times

5	How to test the tracking sensitivity?
	The Tracking Sensitivity is testing under such conditions: In the chamber for avoiding Noise interference Use single channel GPS simulator With the external LNA

6	How to use the 5Hz update rate function in the FGPMMOSL1?
	We suggest customers if you need to test 5Hz update rate function, it is much better to be done by GTop Co., not by the end user, in case avoiding some potential risk and problems.

HUD GPS

1	Where can I find the procedure to install HG100 step by step?
	Please click here for Quick Installation Guide in detail.

2	Where is the suggested place to locate HG100 and Reflection layer film?
	The suggested place is at the right corner of the windshield windows without obstructing your view. Please click here for Quick Installation Guide in detail.

3	What is the button definition of HG100?
	Please refer to our user manual for detail configuration.

4	What is the speed range?
	The speed range can be set as following: Please refer to our user manual for detail configuration.

5	What is the baud rate of HG100?
	The baud rate of HG100 is 38400 bps.

6	What is the difference between 5Hz and 1 Hz?
	5Hz means that the GPS receiver output five GPS data for position every second. If you desire to obtain the more precise & accurate position GPS data, then you are recommended to own this 5Hz feathure on GPS solution.

7	How to adjust the best angle of car holder?
	Please refer to the picture which typically demostrate this installation. Because of the dashboard geography difference, please adjust the optimum angle of car holder with the reflection layer film which make sure you can get the best clear view of HUD information.

BT GPS receiver

I have purchased the BT GPS receiver. Is there a driver for the Palm or Windows operating system?

All of our BT-GPS receiver model do not need driver when use on OS(WINDOWS/PALM/Symbian...)system device,
Example---

G55 use on Windows OS device(HP iPAQ rw6828 GSM PDA phone, on board BT function)
1. Pair G55 & HP6828(do not need driver)
2. Run navigator software to fixed or navigation(do not need driver)
G55 use on PALM OS device(Palm Treo 650 GSM PDA phone, on board BT function)
1. Pair G55 & Treo 650 (do not need driver)
2. Run navigator software to fixed or navigation(do not need driver)

2	I wait for long time but position is not fixed.
	It could be satellite receiving problem, Please make sure gps signal reception level is good .One possible way to reset device by reloading battery and do the position fixed under open sky for almanac update!

3	How to connect BT GPS receiver with my computer?
	You can pair BT GPS receiver and your computer if the computer on board BT receiver function. or else, you need to add BT dongle on your computer.

4	What's different from NMEA & SiRF Binary protocol?
	NMEA: stands for National Marine Electronics Association, a US standards committee that defines data message structure. SiRF Binary protocol: SiRF company definition by oneself.

5	How Can I Reset BT GPS Receiver?
	You can take off battery and reload it again! This process will push device into cold start condition. For almanac update with this reset condition, we suggest you locate the gps device under open sky circumstance.

6	What does the lights means when using Gtop BT-Series products?

7	Why use NOKIA N70 mobile phone with GTOP G22 and TOMTOM 5, a half of hour of connection it disconnect 2 or 3 times, often but not ever.
	If have this problem, please try to do some procedure as below--- Check N70 internal memory whether enough. In TOMTOM5 software setting mode, the GPS receiver must select "other GPS" (when your GPS receiver is not TOMTOM provide) There is incoming a phone call, then map software will be closed and disconnect. You need to connection GPS again.

touch GPS G66

If I were occasionally to activate the touch switch of G66, does the device have any smart design to avoid the battery power waste dramatically?

Talented G66 with smart design to identify and response on these unexpected conditions which are without intention of navigation purpose such as:

On with un-intended long touch: Unexpected long contacting on the touch pad of G66, which like collision inside your pocket or closely contacting between stuffs physically.
- Device actions: G66 will automatically shut-down when been detected over 10 seconds at this abnormal switching condition.
On with non-BT hosted: While device is on but NOT case of above mentioned.
- Device actions: At once 10 minutes failure to get BT host connected continuously, G66 CPU will automatically shut-down for power saving.

2	How many battery hours of G66 can be lasted under normal state of using?
	When battery full charge and under the normal state of using, the battery power can be operated for 7 hours continuously.

3	Does G66 need to use Driver for my smartphone?
	G66 does not need to use additional Driver. Only BT function is required on your smart-phone to receive the location data.

4	What function of the aperture near G66 USB Port?
	This is reset function. You can press the reset button to cold start G66 device while hard to get position fix.

5	What functions does mini USB Port of G66 have?
	Mini USB Port of G66 is only featured for power charging not for data transfer.

G-Mouse receiver

1	Why G-mouse can't working with Microsoft Autoroute 2006(13.00.09.0100)
	Because Microsoft autoroute 2006(13.00.09.0100) only accept baud rate at 4800bps. And G-mouse default baud rate is 9600bps, also will not auto adjust the baud rate. That is why G-mouse can not run with autoroute 2006(13.00.09.0100).

2	Does G-Mouse receiver need any driver?
	Yes, G-Mouse receiver need to install driver when working on PC&NB.

3	Does G-Mouse work fine in Windows XP OS?
	Yes, it's can work fine in Windows XP.

4	Could I use G-Mouse on Microsoft Windows VISTA?
	It can't operating on VISTA Currently, but expect to support VISTA on Q2-2007.

5	Does Gmouse Type GPS Receiver water proof? How long the cable?
	Yes! It's waterproof. The cable length in standard is 5 meters.

External antenna

1	Does External antenna exist with magnet?
	Yes! You can stick antenna on the roof of car.

2	How many type of external antenna?
	Connector: MMCX/MCX/SMA Cable length: 2m/5m

3	When I need to add external antenna on GPS receiver?
	When your signal reception conditions are poor, like in car or indoor, you may use this.

4	Does your external antenna waterproof?
	Yes! It is.

Navigator

1	My touch panel not clever.
	You can redo the calibration function from main menu.

2	I can't enter navigation function.
	Please double check your SD card, and reinsert SD card into SD slot.

3	I can't turn on the navigator.
	There exist one rechargeable battery inside. Please charge your battery and turn on to check functionality.

4	How to update map?
	You can download the new map from http://www.navi-plugins.com. You need to key in your authorization number to download any information.

5	My map data was broken, and how to restore my SD card ?
	You can reinstall your map in SD card from DVD disk.

6	My navigator was broken, and how to repair it ?
	Please contact your distributor, and they will pre-overhaul your navigator. If your navigator need to change any parts, they will send us to repair.

Lightning switch

1	How to install my receiver?
	You can refer to our installation guide from website.

2	How does it work without batteries?
	The transmitter converts the mechanical displacement of pushing its button into enough electricity to send a coded radio frequency signal to the receiver.

3	How can I have two or more Transmitters (TX)to control the same Receiver(RX)? For example, lighting in living room could be controlled from different area.
	All you have to do is to let the receiver learned on the codes of transmitters individually. By going through the learning process with one transmitter after another, the one receiver can be learned to respond with commands from up to 30 different transmitters.

4	How can I have one transmitter(TX) to control many Receivers(RX)?
	Just use one transmitter to train(Teach) all of the receivers. There's no limit on the number of receivers that a transmitter can command, as long as the receivers are within broadcast range of the transmitter.

5	How can I do if I wish to eliminate control of RX from one Transmitter?
	A transmitter's ID code can be erased from the memory of a receiver by using the Erase button on the receiver. Press the Erase button and the yellow Erase light will glow. While glowing, press the transmitter button that you want the receiver to "forget". The yellow light will go out after the transmitter's ID code has been erased from the receiver's memory.

6	Can I use Lightning Switch products outdoors?
	Yes. If the products (especially the receivers) are protected in standard weatherproof boxes available for a few dollars at home supply stores.

7	What is a Toggle Transmitter?
	The "Toggle" means RX ON/OFF status will be switched consequentially.

8	What is a Double Toggle Transmitter?
	The Double Toggle Transmitter is the Transmitter with two buttons to control two different Receivers from the same Transmitter.

9	What is a Main (On/Off) Transmitter?
	This is the Transmitter to use simultaneously "Turn On" or "Turn Off" two or more Receivers as a group.

10	What is the Plug-In Receiver?
	This Receiver (in the United States and Canada) is designed to plug into any 110 volt, three-prong outlet. The Receiver receives commands from Lightning Transmitters and "Turns On" or "Turns Off" the light or appliance (up to 500 watts) that's plugged into it. Plug-in Receivers are typically used to control floor or table lamps, holiday window candles and Christmas trees.

What is the Wire-In Receiver?

Wire-In Receivers are currently available for 110 volt AC and 120 volt DC applications.These Receivers are wired into your electrical system between the power supply & the light fixture or device that you want to control. Typically, the 110V Receiver is wired into a junction box and remains in or adjacent to the box after installation. These Receivers receive commands from Lightning Transmitters and "Turn On" or "Turn Off" the light or appliance (up to 500 watts for the 110V Receiver) that's wired into them.