GISCAD-OV developed an integrated Service Chain Architecture based on PPP-RTK and Galileo HAS for providing innovative affordable services for Cadastral Surveying and Infrastructural Monitoring. An extensive, Real-Time Testing Campaign on seven Countries has been carried out in order to validate the proposed SSR approaches in operative surveying scenarios. Hundreds of Cadastral Surveying was carried out following single NMCA rules. An Augmentation System was developed, creating a network of more than 120 Reference Station over the 7 Countries. A GNSS surveying receiver was designed and developed:
A low-cost GNSS COTS receiver, able to provide at least double frequency real-time code and phase measurements and to decode Galileo HAS on E6B in real-time
A GISCAD-OV PPP Client App, able to guarantee backward compatibility, converting any SSR message to OSR messages to be provided to the receiver or to apply HAS corrections to raw measurements for deriving PPP-like solutions
A GISCAD-OV Result Adapter, able to transform NMEA GGA and GBS (or proprietary format) sentences to Cadastral Point survey output to be inserted into the Cadastral elaborate
Comparable performance is achieved through the global, local, and mixed products, as all three solutions achieve centimeter-level positioning instantaneously.
In case of the absence of precise atmospheric corrections, the global solution relies on the use of many frequency (up to four) on many constellations (four) to achieve NRTK-like performance. T
Furthermore, for the first time a mixed solution (e.g. orbit and clock corrections from one source and ionospheric and tropospheric corrections from another) has been designed and demonstrated the possibility of deriving a solution from different sources. This has a relevant impact in national boundaries.
The Galileo HAS solution is able to achieve sub-two decimeter accuracy within 6 minutes in nominal conditions. The HAS performance has been assessed with test signals, and with only Galileo and GPS orbit, clock, and code bias corrections. It is expected that the availability of phase bias corrections in the future can further reduce the convergence time by allowing for ambiguity resolution. Integrity monitoring and Galileo HAS carried out an extensive analysis for PPP-RTK multiconstellation solutions in several situations. The Cadastral Survey carried out during Pilot Projects revealed that GISCAD-OV services can be applied to different operations:
GISCAD-OV SL3 (e.g. PPP-RTK) meets NMCA requirements in most of the Countries and allows a quick convergence for Cadastral Survey operations.
GISCAD-OV SL2 (e.g. PPP-AR) has not been tested, being comparable to PPP-RTK solution with a longer convergence time.
GISCAD-OV SL1 (e.g. Galileo HAS) is considered useful only for surveys in remote areas and in absence of communication link. The impact of multipath and shadowing on the final performances has been recognized as relevant. Furthermore, Galileo HAS can be used as an Integrity monitoring tool backup for corrections validation and integrity monitoring.
Concerning the Infrastructural Monitoring, the carried out analysis demonstrated how GISCAD-OV SSR services can be applied for reducing the number of accelerometers to be installed and provide a more affordable tool. Through a real operative validation on a bridge, with three GISCAD-OV terminals operating at 50 Hz, load peaks on the road due to the passage of heavy trucks have been recognized in real-time. An analysis of the impact of RTCM SC-104 for the development of GISCAD-OV solution was carried out. Integrity Monitoring messages, derived and updated from RTCM SC-134 draft, has was used for implementing external Integrity Monitoring Service Providers has been developed. Furthermore, Open SSR standard (e.g. SSRZ) are used for implementing a full PPP-RTK solution, waiting for the full RTCM SC-104 SSR standard. Furthermore, a survey model has been derived and proposed to ISO 19152, the Land Administration Domain Model (LADM).
The Business Models has been drafted, based on the feedback of all the Value Chain stakeholders, An analysis Country by Country has been carried out-
