Johnny Appleseed G P S - Garmin DGPS and WAAS

Differential GPS (DGPS) Products from Garmin Check the latest Garmin price.	Garmin GBR23 Low power consumption, automatic tuning, integral design. Price	Garmin GBR21Lightweight, using wire antenna This unit now superceded.
Garmin Solutions The DGPS solutions from Garmin can be applied for field or marine use. For field use, the DGPS receiver is mounted professionally in a backpack with battery and charger. Any Garmin hand-held GPS can be used for GPS functions such as waypoints, tracks, or locating points to 2-3 metres. Any computing device can also be connected, for more powerful mapping functions. The back-pack battery powers both GPS and beacon receiver, and also powers a laptop computer or PDA if required. For marine use, the GBR is mounted in a suitable location, and the wiring intergrated with the GPS. Garmin beacon receivers take advantage of the free to air service from the Australian Maritime Safety Authority. This AMSA service is active over the length of the Queensland coast, and also in the Sydney, Melbourne, Albany (WA), Perth, Adelaide and Port Hedland (WA) areas. You get the signal free, even inland for hundreds of kilometres. - all you need to do, is ask Johnny Appleseed GPS to rig up a suitable receiver for the GPS unit of your choice. AMSA beacon signal- more information	The GBR 23 is a remote, auto-tuning, differential beacon receiver with a built-in H-field antenna. The perfect companion to any GARMIN GPS receiver, the GBR 23 provides position correction data to all GARMIN differential-ready, marine, and recreational GPS receivers, including select products made by other manufacturers. The GBR23 can be mounted many ways, including a car-top magnetic base. The GBR-23 is a replacement product for the GBR-21. Backpack configuration Specification: DGPS frequency: 283.5 to 325.0 kHz Data rates: 200/100/50/25 BPS Sensitivity: 10 uV/m (200 Hz BW) Size: 112mm diameter, 128mm high Waterproof: IEC-529, IPX7 (Ð1m for 30 minutes) Tuning: Automatic with manual override Input commands: Binary, $PSLIB, $--MSK at 4800 baud Output data: RTCM SC-104 (6 of 8 bit format) at 4800 baud Interface connector: 7-pin bayonet latch at receiver Cable options: 30' 7-conductor standard, 60' optional Supply voltage: 8 to 35 VDC Supply current: 95 mA at 12 VDC OEM intergrated GPS/DGPS version is also available. Model DGPS53. Please phone me on 1800 666477.	This small, remote-mounted, black box-style receiver links to all GARMIN differential-ready receivers and is in use only when turned on. The GBR 21 is waterproof, weighs less than 250grams, and measures only 128mmL x 80mmW x 37mmH. All tuning and operating functions are controlled by the GPS unit while the GBR 21 is being used, including beacon receiver setup and beacon logging. The GBR 21 decodes the AMSA beacon signal information for use by a GARMIN GPS receiver, providing the improved repeatability and accuracy required for commercial applications and precision navigation. Frequency: 283.5--325 KHz Demodulation: MSK (Minimum Shift Keying) MSK Bit Rates: 25, 50, 100, 200. Selectable at the GPS receiver Data Format: RTCM 104 version 2.0, RS-232, 6 of 8 format, 4800/9600 baud Remote Tuning: Via auxiliary page menu on GARMIN marine GPS receivers  Antenna Requirements Rec. Antenna: 18" stainless antenna (included) Antenna Coupler: 1.6" base diameter, .6" top diameter, 4.8" height Coupler Cable: 30' RG-58 coaxial   Power/Physical Specifications The GARMIN GBR 21 is controlled from an on/off power switch (not included). The receiver may be mounted remotely, but a location that allows easy viewing of the LED status light is recommended. Size: 5.2"L x 3.6"W x 1.5"H (13.2 x 9.1 x 3.8 cm) Weight: 6.8 ounces (193g) Voltage: 10-18vDC Current Draw: 130 ma  LED Status Indicator Off: Power to receiver off Flashing: Power to receiver on Constant: Power on, receiving data

Some of the new Garmin receivers are WAAS capable for 2-3 metre accuracy. WAAS capable receivers do not require addition of any external DGPS device. The WAAS is NOT operating viably in Australia. Look for this symbol. US Aviation authorities have been experimenting with LAAN, which is a localised version of WAAS. This will give better than metre accuracies, aid reliability, and will enable precision aircraft instrument approaches and landings.

WAAS- Wide Area Augmentation System As you know, position on earth is calculated by triangulation of intersecting radio signals at the GPS receiver. The signals emanate from earth orbiting satellites of the US Defence Department GPS constellation. It is possible to "augment" these signals from other satellites or ground transmitters of known position, thereby increasing reliability, or accuracy, or both. WAAS is currently available over US, some northern Pacific areas, and Europe (EGNOS). WAAS is still in Beta (test) mode. WAAS does not work in Australia; in fact if you enable WAAS on your GPS, it will probably have the opposite effect; your accuracy will be worse.

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