GPS - Hệ thống định vị toàn cầu

Khi bắt tay vào làm cái tóp bích này, tớ đâu có biết ai quan tâm cái gì đâu. Lúc đó tớ cũng chẳng biết gì về GPS. Cứ tìm hiểu tới đâu, post bài lên tới đó. Hy vọng bạn cũng cứ mạnh dạn trình bày những gì bạn biết, theo kiểu bạn thích. Tớ đỡ phải bỏ công ra tìm hiểu .

Giá Garmin 76S chỉ vào khoảng 400$ tại Mỹ thôi. Không biết tiền vận chuyển, thuế má là bao nhiêu mà lên tới gấp đôi !!!. Thôi, chuyện cơ quan mua đừng nói vào nói ra làm gì, coi chừng mang hoạ đó. Chừng nào mình mua cho mình thì hãy lo sau.

Nhưng nếu cẩn thận hơn thì nên khéo léo tìm cách cho người có trách nhiệm mua biết là trên Net giá thế thế ... (froogle.google.com chẳng hạn) vì bây giờ có việc gì giấu được đâu, nhất là những thông tin phổ thông như vậy ?! Tóm lại là không biết là cơ quan có mua gì là hay nhất ! Vì hắc cũng chết mà bạch cũng không thoát đâu nếu có việc mờ ám!
Chúc may mắn và mau có GPS xịn để dùng!

khổ thân cho em rồi
vì người lấy báo giá và hướng dẫn sử dụng cái 76S sau này là em ,vì trong cơ quan chỉ có mình em là hay dùng GPS nhất
còn nếu mà không vì cái hoá đơn VAT và em toàn quyền Quyết định thì giá có lẽ đã down nhiều rồi
hic hic
đúng là "hắc" cũng chết mà "bạch" cũng chết

Improved GPS Receiver Provides Increased Benefits To Warfighters
Perhaps the most important improvement over PLGR and commercial receivers is DAGRâ?Ts Selective Availability Anti-Spoofing Module. This module allows DAGR to be securely encrypted without the risk that unfriendly forces could capture a DAGR and discover its encryption code. The Navstar GPS Joint Program Office pioneered Global Position Systems more than 11 years ago with its PLGR â?" Precision Lightweight GPS Receiver. At the time, PLGR was "state-of-the-art," providing warfighters with position, velocity, navigation and time.

Now the Joint Program Office has improved upon its original GPS and is prepared to field the Defense Advanced GPS Receiver. DAGR will give the warfighter a number of improvements over PLGR, to include many capabilities not found on any commercial receiver.
Whereas PLGR is large and weighs 2.75 pounds, DAGR is just under one pound and fits easily into a battle dress uniform pocket or a standard ammo pouch. The external antenna on PLGR, and on many commercial receivers, is always in the way and is the source of most maintenance problems. DAGRâ?Ts antenna is internal.
PLGR requires the large and expensive BA5800, military-only, battery at a cost of $25.13, or eight AA batteries, which last only 13 hours under continuous use. DAGR, however, operates on only 4 AA batteries, that last 19 hours under continuous use or for up to 200 hours obtaining four "fixes" per hour.
Life cycle expenses are the greatest part of all military equipment costs. With the much lower cost of batteries, operating DAGR will be much more economical throughout its expected life of operation. Ad***ionally, expected repairs, known as Mean Time Between Failure, are much lower for DAGR.
Both PLGR and DAGR can give accurate direction while on the move or when tracking satellites. However, DAGR also offers a magnetic compass. Both receivers can store up to 999 Way Points, which can be used for route planning, targeting or situational awareness.
PLGR uses four single channel satellite signals to compute its PVNT solution and state-of-the-art commercial receivers use "all in view," which is up to 12 single channel satellite signals, while DAGR uses up to 12 dual channel, two frequencies, satellite signals.
DAGR is far more accurate, correcting sources of error known as Doppler, multipath, ionospheric bending and ambient noise.
Perhaps the most important improvement over PLGR and commercial receivers is DAGRâ?Ts Selective Availability Anti-Spoofing Module. This module allows DAGR to be securely encrypted without the risk that unfriendly forces could capture a DAGR and discover its encryption code.
Ad***ionally, while commercial receivers use only Standard Positioning System, DAGR uses Precise Positioning System, which is much more accurate. If satellite signals are jammed, commercial receivers will be unable to receive and decode the signals, while DAGR will continue to operate through a considerable amount of jamming.
Enemy forces may also be able to rebroadcast a satellite signal at a higher level. This signal, known as spoofing, gives a false location. Commercial receivers and PLGR are not able to detect that a signal, if being spoofed, will calculate incorrect PVNT.
However, DAGR will detect the spoofed signal and will reject it, while continuing to provide highly accurate navigational information.
While PLGR has a simple textual-based screen, DAGR uses a modern Graphical User Interface, which is menu driven. It provides numerous graphics, which aid in situational awareness and ease of use.
DAGR can use a wide variety of maps, which can be downloaded from a computer. Ad***ionally, information, mission planning and reprogramming can be performed from one DAGR to another or from PLGR to DAGR by using available cables.
DAGR was designed to be backward compatible with PLGR. Wherever a PLGR has been integrated into a vehicle or weapons system, it can be replaced by DAGR without modification to the vehicle or weapons system. In fact, the mount for DAGR will fit the same hole pattern as the PLGR mount. All data and power cables, as well as antennas, mounts and other accessories for DAGR are available.
DAGR was also designed for special military requirements, such as integration with Laser Range Finders. An LRF will tell you how far away a distant object or target is and its direction â?" but when attached to DAGR, DAGR will give you the instantaneous location of any target within the range of the LRF, as well as the distance and direction. DAGR was also designed to enhance the emplacement of weapons systems, known as "Gun Laying."
DAGR is smaller, lighter and cheaper than PLGR. It has far more capabilities and is more accurate and reliable than PLGR or commercial receivers. DAGR is the right answer for todayâ?Ts and tomorrowâ?Ts warfighter, bringing highly reliable position, velocity, navigation and time to handheld users, weapons systems and vehicles.
In November 2004, the Army plans to begin New Equipment Training and fielding DAGR to Special Operations Units.
Within the first six months of fielding, the Army plans to field at total of 8,725 DAGRS to three Divisions, one Regiment, three Brigades and one Training Center. The Air Force is also working on a fielding plan for units supporting the Global War on Terrorism.

Hôm thấy có 1 cty ở HN bán cái này

http://www.leadtek.com.tw/eng/gps/overview.asp?lineid=8&pronameid=105 . Các bác nhiều kinh nghiệm review hộ em cái.
Được Digicams sửa chữa / chuyển vào 13:27 ngày 16/10/2004

Nói chung thì chắc cũng không đến nỗi tệ, chỉ có giá thì cực bèo.
Mà sao tớ không thích CF GPS cho lắm! Tớ cho rằng, những thiết bị dùng nhiều mà thực hiện qua CF thì chết nguồn ! Nuôi riêng cái PDA đã mệt rồi, nay gánh thêm cái CF nữa thì ngóm là cái chắc! (Ấy vậy mà tớ nhất định không chọn PDA nào chỉ có 1 slot với lý do không sử dụng được thiết bị ngoại vi!).
Được lytoet12 sửa chữa / chuyển vào 06:51 ngày 16/10/2004

Nghe là thấy khoái rồi! Có 1 chiếc DAGR mà chơi nhỉ ?!
Chỉ không biết upload bản đồ thế nào thôi!?

Góp chút "thèm" cho tớ và các pác"
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May 20, 2003
Microsoft''''s Windows CE operating system and InHand''''s low-power hardware/software reference platform technology have been licensed by Raytheon''''s Precision Guidance Systems (PGS) Division for use in a new handheld GPS receiver being developed for the US Army, according to an announcement this week from InHand Electronics (Rockville, MD). The Army''''s "Defense Advanced GPS Receiver" (DAGR) is the replacement for PLGR ("Precision Lightweight GPS Receiver"), and is expected to become the positioning device of choice for next-generation US and allied soldiers, the company said.
An enlarged photo of the Raytheon DAGR is available here.
"In ad***ion to incorporating Raytheon''''s advanced anti-jamming technology, Raytheon''''s DAGR adds Intel''''s StrongARM/XScale microprocessor and Microsoft''''s Windows CE operating system, thus offering advanced computing capabilities on top of basic navigation functions," commented Mike Fleenor, director of business development for Raytheon''''s PGS Division. "InHand''''s low-power technology helped us meet our aggressive performance and battery life goals," Fleenor added.
What''''s a DAGR?
From the U.S. Army''''s description . . .
The Defense Advanced Global Positioning System (GPS) Receiver (DAGR) program will provide authorized DoD, Federal Civilian and Foreign Military Sales (FMS) users of GPS User Equipment (UE) a lightweight (less than 2 pounds), hand-held, dual frequency (L1/L2), Selective Availability Anti-Spoofing Module (SAASM) based, Precise Positioning Service (PPS) receiver. The DAGR will have a ten-year service life. The DAGR will be an easy to use, highly reliable, multiple-use device that can accommodate, with minimal training, a wide range of user skill levels. The DAGR will replace the Precision Lightweight GPS Receiver (PLGR) and be interoperable with PLGR integrated platforms (adapters permissible). Fielding is anticipated to begin in 4QFY04 at a target unit price of $2,000 or less (including a five-year warranty). Similar to the PLGR, the DAGR will be maintained by the developer with field service limited to battery change out and self-test.
DAGR provides real-time position, velocity, navigation, and timing (PVNT) information in a standalone receiver configuration. The DAGR program will take advantage of the availability of a broad industry product line of hand-held GPS receivers and the results of GPS program sponsored Program Research & Development Announcement (PRDA) contracts for advanced security devices. The program maximizes flexibility in ordering of products to accommodate a broad customer base with diverse funding and ordering requirements. This will allow DoD, Federal Civilian agencies (approximately 10) and Allied countries (approximately 31) to order and receive identical products at DoD quantity pricing with value added functionality and performance characteristics.
The primary operational mission of the DAGR is to provide Precise Positioning Service support to missions that involve land-based war fighting operations and operations other than war. These include ground personnel, indirect fire weapon systems, and armored vehicles. The DAGR can also be used as a secondary or supplemental aid to aviation-based missions, which involve operations in low-dynamic aircraft, such as helicopters, and as an aid to navigation in water-borne operations, such as for combat swimmers, submarines, and watercraft.
Raytheon is scheduled to deliver the first DAGR units to the US government this spring, InHand said.
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http://gps.losangeles.af.mil/user/products/dagr/
Được lytoet12 sửa chữa / chuyển vào 06:51 ngày 16/10/2004