New stations and upgrades

Permit requests: We are in the process of permit agreement for the PTP1 site along the Hayward fault and the BDM site located in Black Diamond Mine Park. The permit for this site will be retrieved by the EBPARK board during the month of September 2007.

Three sites have been upgraded to 1Hz (BRIB, HOPB, PTRB). The sites BRIB and HOPB are colocated with a broad-band seismometer (BRIB, HOPS) belonging to the BDSN network. The upgrade of these sites is a important step leading to the comparison of the GPS data with seismic records in the Bay Area.

5Hz data in buffer. We started to experiment with the use of 5Hz GPS data during August 2007. Today, the telemetry cost is too high to allow the transmission of these data in real-time. However, some delayed use of these data can occur after manual download, using the existing telemetry for a selection of sites. The storage capacity of NETRS receivers allows storing two days of data recorded at 5Hz.

Real-Time Kinematic (RTK) service In the framework of the collaboration with EBPARK, BSL is distributing RTK corrections at some sites. This experimental project aims at developing collaborations with private actors or local institutions in northern California. We hope to densify the network and reduce monumentation and telemetry costs associated with the installation and operations of new sites.

Conversion of ten PBO sites: Ten sites (P181, P222, P224, P225, P227, P228, P229, P230, P262, P256) of the PBO network will be included in the high rate processing under development at Berkeley Seismological Lab. These operations are carried out in close collaboration with East Bay Regional Parks (EBPARK) and East Bay Municipal Water District (EBMUD). These 10 sites will be operated through a radio network (Freewaves or Wi-LAN) using the existing telemetry paths. The cost of the installation will be supported by EBPARK and BSL (the Wi-LAN radio for the site P224). All sites will feed a NTRIP server installed this year on the BSL network by Doug Neuhauser. This server is providing RTK corrections while the streamed data is being converted into RINEX format.

Upgrade of the EBMD site: This site, operated in collaboration with EBMUD, is streaming RTK messages to Berkeley via a Wi-LAN link to the Space Science Lab. telemetry facility (Figure 3.16). This site is a prototype of the system that will be used for the 10 PBO sites (see above). This system is reliable and has proven its efficiency in terms of real-time localization (Jim Swanson and Janine Hampton, personnal communication). The RTK system is not able to offer accurate displacements for basic science purposes. The RTK accuracy is estimated to 3 cm instantaneously. For this reason, all the RTK messages are converted by an NTRIP server at BSL.

Figure 3.16: Present BSL operations at EBMD site and planned operations between the PBO site P224 and BSL. Since its installation in 2003, the EBMD site had been sending data to BSL using an internet DSL connection. The data collected (Trimble 5700 receiver) are now sent to BSL using a WI-LAN radio connection. The connection represents an upgrade of the quality of the radio link. The data collected here are thus more safely sent to BSL in case of a large seismic event.
\epsfig{file=RTK_EBPARK.eps, width=8cm}\end{center}\end{figure}

Parkfield area: In February 2003, the BSL assumed responsibility for data telemetry from a 14-station GPS network in the Parkfield region, in addition to the BSL station PKDB. Most of these stations were constructed using mini-PBO funding with contributions from the USGS and SCIGN. This project was continued during the year 2006-2007. All the Parkfield GPS sites have been transferred to the PBO network except the PKDB site, which remains a BSL/BARD site, as it is collocated with a long-term BDSN station. The PKDB sites have not been upgraded to 1Hz, which limits the comparison of data with seismic data. Last year, the site HUNT at Parkfield was upgraded to a Trimble NETRS receiver. We appreciated the good coordination with PBO (Freddy Blume) and San Diego teams during this last upgrade. Today, BSL is still in charge of the creation of the RINEX format files. These files are then downloaded daily by the PBO team to be archived at the UNAVCO facility in Boulder. .3cm

Replacement and Upgrade of BARD and MPBO GPS receivers: During 2006-2007, geodetic GPS hardware receivers of the BARD and MPBO arrays failed at a number of sites (CMBB, HOPB). Typically these sites had a a crashed receiver that could not be rebooted. Electronics at these sites are twelve to 15 years old.

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