General Article

ACCURACY STANDARDS OF TRIMBLE AND GARMIN MACHINES IN NATURAL RESOURCE MAPPING

Differential GPS Positioning of Garmin & Trimble Experimented in Working Plan Groundbreaking, Innovative and R

Survey and Demarcation has recently captured the market of number of global positioning machines of which Garmin and Trimble compete each other in terms of reduction of error in positioning by 15 to 5 meter and 3 to 1 meter respectively.

Post processing of the Trimble handheld is considered to be competitive over Garmin GPS Map Machines. Incorporating a high-sensitivity GPS receiver, Trimble claims to have been specifically designed to maximize yield of positions in hostile environments such as under forest canopy and up against mountains and rocks, under cloudy atmosphere, mist and fog. Trimble handheld can be used in real time with its integrated SBAS receiver to achieve 2 to 5 meter positional accuracy. When higher accuracy is required to meet the regulatory standards, the field data collected with the Trimble handheld can be

as compared to Garmin A K Singh

One of the most popular Machines used for measuring natural resources since almost more than two decades in Forest resources survey had been the Garmin. GPS tracking depends on Global Positioning System to determine the precise location of a way point, forest boundary stone, corner points of survey numbers, person, vehicle or any natural assets to record position at regular intervals in time. With the latest GPS machines -location-data can be stored in bulk. Large field data can be transmitted through internet connected computers, email, SMS, radio or satellites. This allows the assests location to be displayed against a map backdrop either in real time or when analyzing the track later using GPS tracking software like QGIS, ArcInfo etc. Advances in technology and new demands on the existing system have now led to efforts to modernize the

GPS system. GPS receiver calculates its position by precisely timing the signal sent by GPS satellites high above the earth.

Each satellite continually transmits messages that include the time the message was transmitted and the satellite position at

the time of message

transmission. The receiver uses the messages it receives

to determine the transit time of each message and computes the distance to each satellite using the speed of light. Changes in speed or direction can only be computed with delay and that derived direction becomes inaccurate when the distance travelled between two position drops below or near the random error of position measurement. To counter this effect, more advanced navigation systems use additional sensors like compass or

Measurement errors in a closed traverse can be quantified by summing the interior angles of the polygon formed by the traverse. The accuracy of a single angle measurement cannot be known, but since the sum of the interior angles of a polygon is always (n-2) 180, it's possible to evaluate the

traverse as a whole, and to distribute the accumulated errors among all the interior angles.

inertial navigation system to complement the GPS. In typical GPS operation, four or more satellites must be visible to obtain an accurate result. Four sphere surfaces reflected by four satellites do not intersect. We need to solve navigation equations to find a perfect intersection which can give position of the receiver along with the

-board clock and the true time-of-the-day. Very accurately computed time is used for display or not at all in

many GPS applications, which use only the location. Using at least four satellites if one variable is known, a receiver can determine its position, using better applications for accurate timing, precise traffic signal timing and synchronizing local base stations.

ACCURACY STANDARD TRIAL BETWEEN TRIMBLE & GARMIN:

The field data of waypoints from the forest boundary was taken from Arakera Reserve Forest of Davanagere

District in Karnataka. GPS coordinates were saved both in Trimble and Gamin GPS Handheld Machines

simultaneously.

Way points tracks

were plotted in

GIS Map Source

Software

converting into

GPX files to be

used in Quantum

GIS. Both the

layers taken from

the machines were

superimposed.

Trimble machine

provided data

both before

processing and

after processing

which can be seen

below in QGIS Software. Trimble red boundary line deflects 1.8 to 5.6 Meter to and fro before and after

processing. In Trimble total average error fluctuates from 3 to upto 5 meter at the most. Garmin boundary line

data fluctuated from 5 to 15 meters in different times domains of the same location. Both the machines were

found to have frequency of error ranging from 5 to 8 meters. In fact, Trimble machine requires very delicate

and sophisticated handling in data acquisition whereas Garmin is robust, stout and sturdy in hold and control.

Garmin is easy to use, ready to handle and gives relaxed and informal interface. Trimble require much of

attention, stress, care and thoughtfulness while using it in the field on hostile topographic conditions. Touch

typing and stylus in Trimble require amphidextrous skill and expertize whereas Garmin provides easy to use,

convenient and befitting style. Trimble machine handling seems to claim better data acquisition after post

GeoSpatial Model of Arkeraa Reserve Forest of Davanagere in Karnataka created by taking GPS coordinates of the boundary both by Garmin and Trimble GPS Machines. Green and Red

line boundary perceptively reduce the error upto 3 meter after post processing.

processing only. Garmin waypoint or track data was found to be adequate, though not so much precise, in

alignment of village survey number boundary lines in accordance with descriptions of the forest notifications.

Garmin handhelds were found to be quick to use, traditional and customary. Trimble handheld requires

training, teaching and regular working out exercise in the field. Trimble post processed data needed one to two

days to be ready and felt to be cumbersome until saved in the device properly. Preprocessed data of Trimble

was found to be as good as that of Garmin. Post processing of the data in Trimble again changes the readings of

almost all the waypoints and shifts the entire boundary track 3 to 5 meter away or near to from its field data

original track which require ground truthing verification again visiting the disputed boundary waypoint

locations. URAL RESOURCE MAPPING: The latest technology of Garmin GPSMAP handheld navigator features a 3-axis tilt-compensated compass, a

barometric altimeter and -

Eye-(subscription required) and photo navigation. Rugged and waterproof, GPSMAP handheld employs a quad helix antenna for unparalleled reception, has a high-speed USB connection, a sleek new design and connects wirelessly to compatible

Garmin handhelds.L

atest GPSMAP handheld

comes with built-in

worldwide base map with shaded relief, so we

can navigate anywhere with ease. With photo navigation, we can download pictures from Garmin Connect Photos and navigate to them. Latest Garmin Hand held has a built-in 3-axis tilt-compensated electronic compass, which shows heading even when we are standing still, without holding it level. Its barometric altimeter tracks changes in pressure to pinpoint your precise altitude, and we can even use it to plot barometric pressure over time, which can help

Forest Boundary of Arkera Reserve Forest in Davanagere opened in Quantum GIS Software.Green Garmin Line with adjoining Trimble Red Line visible giving pre processed and post processed position error from 1.826 upto 5.631 meters.

you keep an eye on changing weather conditions. With these latest Garmin handhelds we can share our waypoints, tracks, routes and geocaches wirelessly with other compatible Garmin device users. So now one handheld receiver can also enjoy favorite hike or cache--simply press "send" to transfer field data information to similar units and share the data among different users sitting world apart. With its quad helix antenna and high-sensitivity, WAAS-enabled GPS receiver and HotFix satellite prediction, GPSMAP 62s locates the GPS position quickly and precisely and maintains its GPS location even in heavy forest cover, in deep gorges and valleys. Adding more maps is easy with Garmin's wide array of detailed topographic, marine and road maps. With 1.7G of onboard memory, we can conveniently download 24K and 100K topo-sheet maps and hit the trail, plug in Blue Chart g2 preloaded cards for a great day on the water or City Navigator NT map data for turn-by-turn routing on forest boundaries (see maps tab for compatible maps). Garmin handheld also supports Birds-Eye Satellite Imagery (subscription required), that lets us download satellite images to the device and integrate them with maps. In addition, the machine is compatible with Custom Maps, free software that transforms paper and electronic maps into downloadable maps for your device. Garmin Handheld helps to store and analyze wide field activities. With a simple connection to the computer through Internet, we can get a detailed analysis of our activities and send tracks to different outdoor devices using Garmin Connect. This one-stop site offers an activity table and allows us to view our field navigation data on a map using Google Earth. Explore other routes uploaded by millions of Garmin Connect users and share experiences on Twitter and Facebook. Getting started is easy, so get out there, explore, and share. Latest Garmin handheld supports geocaching GPX files for downloading geocaches and details straight to the unit. By going paperless, it not only enables the environment but also helps improving efficiency. Garmin stores and displays key information, including location, terrain, difficulty, hints and

descriptions, which means no more manually entering coordinates and paper print outs ! Simply upload the GPX file to the unit and start hunting for caches.

TRIMBLE IN NATURAL RESOURCE MAPPING: Trimble Handheld serves as -field-computer that integrates a rich array of functionality, including photo capture and high-yield GPS receiver with 2 to 5 meter positioning accuracy in real time or 1 to 3 meter post processed. The Trimble Juno SB handheld claims to be the reasonable way to maximize the productivity of entire workforce while minimizing expenditure, without compromising on features or functionality. The Trimble handheld includes a 533 MHz processor, 3.5 inch display, and a 3 megapixel camera. The ability to augment their GPS information with photographs while performing GIS data collection, maintenance, and inspection activities. Standard wireless capabilities include built-in Bluetooth, cable-free connections to peripherals such as RFID readers and barcode scanners, and Wi-Fi wireless technology that enables to access secure network to get the latest data. In applications such as natural resource data collection, asset inspection, and mobile workforce management where high productivity is critical, the Trimble handheld is

considered to be competitive over Garmin GPS Map Machines. Incorporating a high-sensitivity GPS receiver, it claims to have been specifically designed to maximize yield of positions in hostile environments such as under forest canopy and up against buildings, under cloudy atmosphere, mist and fog. Trimble handheld can be used in real time with its integrated SBAS receiver to achieve 2 to 5 meter positional accuracy. When higher accuracy is required to meet company or regulatory standards, the field data collected with the Trimble handheld can be post

As part of the Trimble family of GPS solutions, the Trimble handheld is fully compatible with range of Mapping

& GIS software, giving a choice of field-proven different software solutions for professional GIS data collection

and maintenance. Applications help Asset Surveys, Disaster management, Incident and outage reporting, natural

asset inventory and inspection, weed management, wild life monitoring, pollution mapping, Environmental

incidental mapping, sample gathering and urban forest management.

Trimble has expanded coverage of its satellite-delivered Trimble RTX technology for surveyors to most of the

world. Trimble

has also

introduced post-

processing

capability for its

CenterPoint

RTX positioning

service for

farmers. Both

announcements

were made at the

Trimble

Dimensions 2012

conference held

in Las Vegas.

RTX technology

enables Trimble

xFill, a new

technique in

RTK and VRS

surveying that allows

surveyors to continue working in the event the primary RTK or VRS correction stream is not available.

Trimble RTX technology, first introduced in 2011, combines real-time data and positioning algorithms to

deliver centimeter accuracy around the world. While RTX technology is available worldwide via IP and cellular

delivery methods, Trimble RTX has been available via satellite L-Band only in North and South America. Now,

the expanded satellite coverage includes most of Europe, Russia, and the Commonwealth of Independent States

(CIS), Africa, Asia, and Australasia. Powered by Trimble RTX technology, Trimble xFill, a feature integrated into

the new Trimble R10 GNSS Receiver, enables a new and innovative technique in RTK surveying, according to

connection outage with the primary correction source. Minimizing downtime, Trimble xFill enables higher

productivity for field survey crews, allowing them to continue working until radio or cellular connectivity is

restored.

-delivered Trimble RTX technology further extends their commitment to

providing different ways of realizing high accuracy positioning solutions.

Point RTX service

3 D dynamic GeoSpatial Model of Sogi Reserve Forest of Davanagere in Karnataka was created by taking GPS coordinates of the boundary & superimposing geo-referenced layers of villages in

keyhole markup language zipped interface transmitting the data into Google Earth Pro.

http://www.trimblertx.com/