RESULTS OF THE ITALIAN GPS VALIDATION TEST FOR PARCEL MEASUREMENTS

RESULTS OF THE ITALIAN GPS VALIDATION TEST FOR PARCEL MEASUREMENTS

Introduction SIN s.r.l. and AGEA under the supervision of JRC, in May 2011 have held in Rome, tests for the certification and validation of GPS receivers for area parcel measurements in those cases where it is not possible to operate using remote sensing analysis. PURPOSE OF THE TEST Was to verify the capacity of GPS receiver to respect an accuracy <1.50m and to give a buffer tolerance for each device To give indications of a good methodology to the surveyors

Methodology The test has been done measuring 5 parcels in different conditions to reproduce the typical situations of the real life. The parcels were marked on the ground using pegs The parcels had different dimensions and shapes Each parcel had to be measured 32 times, 8 sets, 4 repetitions per set (2 CW, 2 ACW) The acquisition was in continuous, at 1sec, using EGNOS as Real Time correction source. Only internal antenna used

The parcels Areas from 0.2 ha to 1.6 ha

The choice of devices For JRC specifications and for our experience on the field, we think that a good GPS device for this activity must have: Integratated antenna Easy and intuitive software Long life battery (it is not nice to have low battery when you are measuring a big area) For this reasons we have tested TRIMBLE GEOXT 6000 TRIMBLE JUNO

TRIMBLE GEOXT6000 IN DETAILS

Forward facing camera GNSS receiver and antenna Ext. GNSS antenna port Auto brightness sensor Touch panel & display SIM card slot (3.5G edition handhelds) SD/SDHC card slot LED status panel Backlit keypad Stylus Microphone Mini-USB socket Speaker Removable battery

Computer system Windows Mobile 6.5 Professional Edition OMAP-35x series 600MHz ARM Cortex-A8 CPU Sunlight readable 4.2 inch VGA display 256 MB RAM 2 GB Non-volatile Flash storage SD/SDHC memory card slot (up to 32 GB) Bluetooth version 2.1 + EDR Wi-Fi 802.11b/g 3.5G cellular data modem (optional)

Trimble Floodlight Satellite Shadow Reduction Technology Increase satellite availability Multi-constellation positioning Stabilise acquisition and tracking Advanced tracking algorithms and filters Improve accuracy and limit position outages Altitude-constrained positioning * Standard on GeoXH, available as an optional upgrade on GeoXT

TRIMBLE JUNO IN DETAILS

Juno series handhelds A lightweight, compact field computer with integrated GPS Four versions: Juno SD handheld with integrated 3.5G Voice + Data modem Juno SC handheld with integrated 3.5G HSDPA Data modem Juno SB handheld without modem Juno SA handheld GPS only Cost-effective, fully integrated solution 3 megapixel camera High-sensitivity GPS receiver for 1 to 3 meter accuracy Real-time SBAS (EGNOS) or Post-Processed Bluetooth and 802.11b Wireless LAN connectivity Windows Mobile 6.1 operating system Long life battery for all-day use

Results All the data has been converted to Shape files in Rome 40 Gauss-Boaga est and UTM 32N WGS84 and submeted to JRC together with area and perimeter results for each measurement. JRC has applyed statistical analysis and given back the following results:

Trimble GEOXT 6000 A statistically significant bias at 1% level was noticed in the measurements taken by Trimble Geo XT for two out of five parcels, the highest bias being of 41m2 for parcel A; and therefore neglected. The analysis of variance showed that there is a significant difference between the measurements taken in the clockwise and anticlockwise directions for two parcels; the highest difference is 7cm (Parcel C) and therefore neglected. The mean reproducibility limit of the measurements (95% confidence level) of all parcels, expressed as a buffer width, was found to be 0.18m.

Trimble Juno A statistically significant bias at 1% level was noticed in the measurements taken by Trimble Juno for two out of five parcels, the highest bias being of 81m2 for parcel A; and therefore neglected. The analysis of variance showed that there is a significant difference between the measurements taken in the clockwise and anticlockwise directions for one parcel; the difference is 52cm (Parcel E) and therefore neglected. The mean reproducibility limit of the measurements (95% confidence level) of all parcels, expressed as a buffer width, was found to be 1.03m.

QUESTIONS?

CRISEL SRL clivo di cinna 196 00136 ROMA tel. +39 06 35498681 fax +39 06 35498686 e-mail: info@crisel.it