HomeMy WebLinkAbout06/16/1998, C9 - GLOBAL POSITIONING SYSTEM EQUIPMENT ACQUISITION 4 7,
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CITY OF SAN LUIS OBISPO
FROM: Michael D.McCluskey,Public Works DirecW"�J
Prepared By: Allen Hopkins,GIS Manager
David Elliott,Administrative Analys
SUBJECT: Global Positioning System Equipment cquisition
CAO RECOMMENDATIONS:
• Authorize the Public Works Director to approve a purchase order in the amount of$61,584.52
to Trimble Navigation Ltd. for global position system equipment
• Approve transferring$24,200 from other project accounts to cover the full cost of buying and
implementing the global positioning system equipment
DISCUSSION
In the 1997-98 budget the Council approved the Storm Sewer Improvements project, which
included buying global positioning system(GPS)equipment to locate all of the City's rock guards,
catch basins, and storm sewers and map them onto the City's geographic information system(GIS).
Heavy flooding in the 1995 storms showed that many of the City's storm drainage facilities were
not working well. Preliminary inspection of a small sample of facilities revealed areas where
rock guards, catch basins, and storm sewers were too small or had deteriorated to the point of
near failure. A typical example was a section of corrugated metal pipe where the entire bottom
section of pipe had corroded away and left the pipe vulnerable to collapse and failure.
The City's storm drainage facilities have not been completely and accurately inventoried. Also,
the extent of damage or deterioration is not documented. Before any reconstruction work can
proceed, the location and condition of all storm drainage facilities must be precisely determined.
Interns have already entered attribute data on about 90% of the storm drainage system but cannot
perform the final data entry of physical location until the GPS equipment is purchased. In the
future, all attribute entry will occur simultaneously with the GPS equipment. This equipment will
include:
• A base station to be installed on the top of the South Street Hill. This station will receive
satellite information and transmit the data via a low-power transmitter to a rover receiver.
• A rover receiver to be used in the field. The rover will be placed on or adjacent to a feature
such as a manhole or culvert. It will receive location information from the satellite and the
base station and will compare the data to determine the precise location to within two
centimeters. While the receiver calculates its precise coordinates, information about the
feature will be entered into a hand-held computer connected to the receiver. This information
may include data such as serial number, description, material, size,or condition.
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Council Agenda Report- GPS Equipment Acquisition
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• A repeater receiver to be used for re-transmitting data from the base station to locations
where the radio signal cannot be received directly from the transmitter because of intervening
terrain or structures.
• Software to convert the data from GPS format into the City's GIS.
After the storm sewers have been located and mapped, this equipment will be available to locate
and map other City infrastructure features such as water lines, wastewater lines, street trees, or
street lights. Although the equipment will be configured for GIS mapping and data collection,
additional hardware and software purchased in the future would allow it to be used for land
surveying.
For the following reasons Public Works is recommending a single source procurement for the
GPS equipment from Trimble Navigation Ltd:
• Most local professional land surveyors use Trimble equipment.
• Caltrans uses Trimble equipment.
• The California Conservation Corps is buying Trimble equipment for its GPS operations.
• Cal Poly uses Trimble equipment to teach its students GPS technology.
• Because of this extensive local use, there is a significant local user group to share support and
information about Trimble equipment.
• Because Public Works will be using Cal Poly interns and CCC workers for data collection,
training and specification will be minimized if they are familiar with Trimble equipment.
• Trimble requires that the City buy from the dealer who serves the territory we're in.
• No significant cost savings would be available by purchasing from another manufacturer.
FISCAL IMPACT
Status of the GPS equipment budget:
GPS Equipment (from Trimble) $61,600
Pen-based computer 3,000
FCC radio license 1,000
Deep cycle battery for the transmitter 100
Surveying services to precisely locate the base station antenna 2,500
Training 6,000
Total Cost to Implement GPS Equipment $74,200
Amount Currently Budgeted * 50,000
Additional Amount Needed $24,200
*$67,000 was budgeted to purchase equipment needed for the Storm Sewer Improvements
project $17,000 of this amount was allocated for a video inspection camera.
There are budget savings available from two related sources as shown on the next page.
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Council Agenda Report- GPS Equipment Acquisition
Page 3
Amount Budgeted for a High Speed GIS Plotter $20,000
Actual Plotter Cost 9,700
Savings Available $10,300
Amount Budgeted for Interns to Locate and Map .$40,000
Revised Estimate of Amount Needed for Interns 25,000
Savings Available $15,000
Public Works recommends using the entire$10,300 savings available from the plotter account and
$13,900 of the savings available from the intern labor account.
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