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SURV18
Final Test
| Question | Answer |
|---|---|
| It is a system of satellites that can give a position/location on the earth’s surface, often using trilateration | Global Positioning System |
| The accuracy of GPS varies depending on the technology and the type of equipment, but precision can be as close as | 0.001 m. |
| Points can be given as symbols, features, attributes, and points can be listed in tables and databases. | Global Positioning System |
| GPS points and their themes become part of the | GIS. |
| When a point lies on the surfaces of three spheres, then the centers of the three spheres along with their radii provide sufficient information to narrow the possible locations down to no more than two (unless the centers lie on a straight line). | Trilateration |
| It works in a similar way to pinpointing your position on a map knowing the precise distance from three different landmarks using a pair of compasses. | Trilateration |
| It is a network of satellites that transmits high-frequency radio signals. | Global Navigation Satellite Systems (GNSS) |
| Contains time and distance data that can be picked up by a receiver, allowing user to pinpoint their precise location anywhere around the globe. | Global Navigation Satellite Systems (GNSS) |
| There are currently two full GNSS systems in operation: | USGPS and GLONASS |
| GPS constellation system of satellites that consists of 24 satellites. | GLONASS and USGPS |
| There are at least four satellites above the horizon for every point on earth 24 hours a day. | satellites in the USGPS |
| Satellites are in six orbital planes with 34 satellites in each plane. | satellites in the USGPS |
| The planes are inclined at 55° to the equatorial plane, and rotated by 60° with respect to each other. | satellites in the USGPS |
| Revolves around the earth every 12 hours. | satellites in the USGPS |
| Satellites are situated 20,200 km above the Earth. | satellites in the USGPS |
| GLONASS owned and operated by | Russia |
| There are three parts of a GPS: | Satellites (space segment); Control stations; Receivers (user segment) |
| Two files are updated at the control stations: | ephemeris and almanac |
| Files that include information about the state (health) of the entire GPS satellite constellation, and course data on every satellites orbit. | Almanac Files |
| A GPS unit must have a recent _______ each time it is used in the field. | almanac |
| Because of these needed files, it may require receiving satellite positions for a few minutes or up to a half an hour or more if the technician is far from the previous fieldwork. | Almanac Files |
| This data contains precise orbital parameters that permit the receiver to predict the exact position of the satellite at any time. | Ephemeris files |
| Gives the distance of the satellite from the geo-center of the earth. | Ephemeris files |
| This file is accurate for about a week, so does not usually require so long to update every time. | Ephemeris files |
| Time of signal on the satellite is measured with the | atomic clocks |
| Time in the receiver is measured with a | quartz clock. |
| The error between the clocks is resolved when | four satellites are observed. |
| Selective Availability (SA) was a means to | scramble the signal and limit accuracy. |
| An encrypted P code is called | anti-spoofing (AS) |
| The satellite transmits | electromagnetic radio waves. |
| There are ____ atomic clocks in each satellite. | four |
| Measure to the billions of a second (nano second). | Atomic clock |
| There are two carrier frequencies: | L1 (cheap) and L2 (good). |
| There is a precision code called | precise positioning service, or PPS. |
| It is modulated onto the L1 and L2 carriers, and these allow for the removal of the first order effects of the ionosphere. | precise positioning service, or PPS. |
| Each satellite is assigned a unique | course acquisition code (C/A-Code). |
| On this device in GPS, position is calculated in real-world coordinate system of latitude and longitude. | Receivers |
| Can display the position in any coordinate systems, i.e. UTM, NAD 27 or NAD 83. | Receivers |
| Survey-level and sub-meter level receivers calculate with the number of channels available, and can observe both | L1 and L2 frequencies. |
| Receivers are classified according to receiving capabilities. These are | Single frequency receivers which access the L1 frequency only and Dual frequency receivers which access both the L1 and L2 frequencies. |
| Receivers are also classified according to the | number of channels it can receive |
| Each channel is dedicated to tracking a particular satellite; this is | the multichannel feature |
| Simpler, low precision receiver types accurate 5 to 15 m are known as | orienteering and hiking receivers. |
| More complex, precise and expensive receivers. These are accurate within 2 to 5 m. | marine and aerial navigation receivers |
| These receivers are very accurate and very expensive and are categorized as sub-meter accuracy feature mapping devices. | Mapping and geographic information system (GIS) receivers |
| Receivers that measure to the nearest millimeter | Survey-level receivers |
| For GPS measurement, the distance from the receiver to a satellite is measured using the | C/A code. |
| For GPS measurement, the time difference of the signal, from when it leaves a satellite to when it is received in the receiver is used to determine | the position on the planet. |
| For GPS measurement, it requires at least ____ satellites to get a direction and a position. | 3 |
| For GPS measurement, ____ satellites are even more accurate, and the ___ satellites there are in the measurement the more precise it is. | Four/more |
| For GPS measurement, the position is given using ______ and the _______. | trilateration/ ephemeris file |
| For GPS measurement, the ephemeris file gives the distance of the satellite from the | geocenter of the earth. |
| For GPS measurement, the file that originated at the control station is | the ephemeris file |
| For GPS measurement, the file that originated at the control station was transmitted to the satellite and then transmitted to the receiver. | The ephemeris file |
| To eliminate clock errors in the quartz clock in the receiver | the position of fourth satellite is required. |
| There are several types of ___ and ___ that will cause a GPS signal and receiver to calculate an incorrect position. | errors and biases |
| Ephemeris error result from improper prediction of __________. | satellite position |
| This error is identical to all users. | Ephemeris error |
| Intentional denial of GPS accuracy by Department of Defense to ensure US national security. | Selective Availability (SA) |
| Satellite clock dithering and slowly varying orbital errors are. | SA introduced to errors |
| A correction that usually overcame effect of selective availability. | Differential GPS correction |
| Errors that are common to all users and can be removed through differencing between receivers. | Satellite Clock Error |
| Errors that can be removed through differencing between satellites, i.e. differential GPS. | Receiver clock errors |
| Error that occurs when satellite signal arrives at antenna through different paths | Multipath Error |
| Similar to “ghosting” that can be seen on old TV sets | Multipath Error |
| Good receivers use sophisticated signal rejection techniques to minimize this problem. | Multipath Error |
| Careful site and antenna selections are essential. | Multipath Error |
| These errors occur near water bodies, in urban areas between buildings, or in field conditions under tree canopies. | Multipath Error |
| Error that results from the limitations of receivers electronics. | System Noise |
| Antenna phase centre is the point at which a signal is ____. | Received |
| An error when antenna phase centre does not coincide with physical center of antenna. | Antenna Phase Centre Variations |
| The region of the atmosphere which extends from a height of 50 km 2000 km above the Earth’s surface and can exceed 2000 km. | ionosphere |
| Signal travel error that speeds up carrier phase beyond the speed of light while it delays pseudo-range by the same amount. | Ionospheric Delay |
| Signal travel error that causes a refraction and diffraction of signal altering speed and to a lesser extent, direction of the signal. | Ionospheric Delay |
| Signal travel error that is of the order 5 to 15 m, but can reach over 100 m depending on the time of day, time of year the 11 year solar cycle, and the geographic location. | Ionosphere delay |
| Signal travel error that is at its maximum in March and November and can be minimal effect at mid latitude but greater above 60° north latitude. | Ionosphere delay |
| Signal travel error that is associated with sunspot activities and Northern lights. | Ionosphere delay |
| It is the region of the atmosphere extending from 0 to 50 km from the earth surface. | The troposphere |
| Signal travel error that has reported values of 3 m at zenith and 10 m for 15° elevation angle. | Tropospheric Delay |
| Signal travel error that affects height component error more than horizontal component. | Tropospheric Delay |
| Satellites are continuously moving in their orbits, so their position in the sky and their position relative to each other are______ | not fixed. |
| Satellite geometry refers to the position of satellites to each other from the view of the_____ | receiver. |
| Ideal satellite geometry exists on the satellites that are located at _________ relative to each other. | wide angles |
| If satellites are located in a line or in a tight grouping, the results are called | Poor geometry |
| Satellites are positioned at _________to each other, from the view of the receiver | wide angles (approximately 90°) |
| PDOP means | Position Dilution of Precision |
| A dimensionless number that represents contribution of satellite geometry to positioning accuracy. | Position Dilution of Precision (PDOP) |
| The ____ value of PDOP, the ______ the geometry and the results. | lower/ better |
| A PDOP of less than ____is usually preferred for most applications. | four |
| VDOP is | vertical position component of Position Dilution of Precision (PDOP). |
| HDOP is | horizontal position component of Position Dilution of Precision (PDOP). |
| Due to high inclination of GLONASS, users in higher latitude areas, such as Canada, obtain ____ GLONASS derived dilution of precision than users of Navstar GPS. | better |
| A clear view to the sky is required, signal is not received through buildings and trees is considered a | A Disadvantage of GPS Measurement |
| Interference to the signal as it travels through space and the atmosphere. | A Disadvantage of GPS Measurement |
| Can receive the same signal twice, similar to ghosting of signals. | A Disadvantage of GPS Measurement |
| Satellite geometry, the position of the satellites in a poor triangulation configuration. | A Disadvantage of GPS Measurement |
| Inter-visibility is not required to determine a line between points | An Advantage of GPS Measurement |
| The measurement can be made in any weather, whether independent. | An Advantage of GPS Measurement |
| Geodedic accuracy, takes into account the curvature of the earth. | An Advantage of GPS Measurement |
| 24 hour operation, can measure day and night. | An Advantage of GPS Measurement |
| Economic advantage, often just one person can get the measurements. | An Advantage of GPS Measurement |
| An independent network of points is not required, site selection of points. | An Advantage of GPS Measurement |
| A GPS accuracy improvement where the accuracy of the receiver is enhanced by adding a local reference station (receiver) to augment the information available from the satellites. | Differential GPS (DGPS) |
| A GPS accuracy improvement that also improves the integrity of the whole GPS system by identifying certain errors. | Differential GPS (DGPS) |
| A GPS accuracy improvement that involves the use of two receivers, and the signals that reach both receivers will have virtually the same errors (to eliminate discrepencies) | Differential GPS (DGPS) |
| A GPS accuracy improvement that involves a stationary base station set at a known location, and another roving around making position measurements | Differential GPS (DGPS) |
| A GPS accuracy improvement where one receiver measures the timing errors and then provides correction information to the other receiver that is roving around | Differential GPS (DGPS) |
| A GPS accuracy improvement where a reference receiver is placed on a very accurately surveyed point. The station receives the same GPS signals as the roving receiver, then calculates timing and errors between locations of two receivers. | Differential GPS (DGPS) |
| A GPS accuracy improvement where it figures out what the travel time of the GPS signals should be, and compares it with what they actually are. The difference is an “error correction” factor. | Differential GPS (DGPS) |
| A GPS accuracy improvement that provides better accuracy from the GPS constellation, and a second receiver is not required. | Wide Area Augmentation System (WAAS) |
| A GPS accuracy improvement where the correction data is sent via a geostationary satellite and is decoded by one of the regular channels already present in the GPS receiver. | Wide Area Augmentation System (WAAS) |
| A GPS accuracy improvement where the system of satellites and ground stations provide GPS signal corrections giving an average of up to five times better position accuracy. | Wide Area Augmentation System (WAAS) |
| Most good GPS units are receivers that can give you a position accuracy of better than 3 m 95% of the time are | A WAAS capable receiver |
| A GPS accuracy improvement that requires no additional equipment or service fees | Wide Area Augmentation System (WAAS) |
| A GPS accuracy improvement program that was developed for use in precision flight approaches. | Wide Area Augmentation System (WAAS) |
| A GPS accuracy improvement that corrects for GPS signal errors caused by ionosphere disturbances, timing, and satellite orbit errors, and it provides vital integrity information regarding the health of each GPS satellite. | Wide Area Augmentation System (WAAS) |
| A GPS accuracy improvement that involves approximately 25 ground reference stations positioned across the US that monitor GPS satellite data. | Wide Area Augmentation System (WAAS) |
| A GPS accuracy improvement that has two master stations on either coast, collecting data from the reference stations and create a GPS correction message which accounts for GPS satellite orbit and clock drift plus signal delays | Wide Area Augmentation System (WAAS) |
| A GPS accuracy improvement that has a corrected differential message that is then broadcast through one of two geostationary satellites that have a fixed position over the equator. | Wide Area Augmentation System (WAAS) |
| A GPS accuracy improvement that supports wide-area or regional augmentation through the use of additional satellite-broadcast messages. | Satellite-based Augmentation System (SBAS) |
| A GPS accuracy improvement where systems are commonly composed of multiple ground stations, located at accurately-surveyed points. | Satellite-based Augmentation System (SBAS) |
| A GPS accuracy improvement where the ground stations take measurements of one or more of the GNSS satellites, satellite signals, or other environmental factors which may impact the signal received by the users. | Satellite-based Augmentation System (SBAS) |
| Developed by the MTO and the MNR, it is a database that contains horizontal and vertical Geodedic control survey data for the province of Ontario. Includes reference sketch image files which give details on finding monumented stations. | Control Survey Information Exchange (COSINE) |
| It is a mobile GIS and mapping unit, and uses a location-based services (LBS) and applications. | ArcPad |
| Software provides database access, mobile mapping, GIS, and GPS integration to users out in the field via a handheld and mobile device. | ArcPad |
| Allows for fast, easy data collection. | ArcPad |
| Provides immediate data validation and availability. | ArcPad |
| Is the integration four technologies: GPS GIS wireless communications lightweight hardware | ArcPad |
| Provides real-time mobile mapping and GIS field software that is coupled with GPS technology. | ArcPad |
| It can capture locations with GPS, create new data, add attributes, edit existing features, query information and navigate to locations. It is also used to create maps, browse data, find features, create data and edit existing features. | ArcPad |
| When a technician wants to create a new layer in ArcPad, they are essentially creating a | new shape file. |
| There is a variety of shape files that can be created depending on the information that will be inputted into ArcPad, i.e. | points or polylines, etc. |
| Once the new layer is created, the technician ensures that it is editable and you can create a new point or line feature from the | editing toolbar. |
| This option exists in the Editing tools, where the technician chooses a Polyline, and enter vertices. After adding the final vertex, to finish the sketch tap the polyline button. Tap the proceed button which is a ________ to complete the feature. | green arrow |
| Concerning accuracy, the VDOP is almost always ________ then the HDOP. | less accurate |
| It is a computer-based system used to store, manipulate and analyze information about geographic features. | GIS |
| Uses combined digital maps and databases to analyze spatial problems and present new information. | GIS |
| It addresses spatial, locational and positional questions/queries. | GIS |
| It is a powerful tool that can create and overlay many maps, each layer produced shows only specific data of interest. | GIS |
| It has the ability to store data on feature-unique layers which permit the production of thematic maps. | GIS |
| Features on the map can be attached to attribute tables (non-spatial), i.e. Feature characteristics can be “queried” and linked to other tables | GIS |
| GIS applications for hydrological modeling typically uses | DEMs |
| GIS applications for hydrological modeling to calculate flow direction and flow accumulation; delineate watershed boundaries and extract streamlines use? | hydrology raster functions |
| Data bases, existing topographic maps and plans; conventional field surveying data; data collected using GPS surveying techniques (lidar is becoming an important source of data); remote-sensing imagery including aerial photographs; census Data are? | GIS Information Sources |
| It is the most important aspect of creating GIS? | Accuracy and level of collected data certified as appropriate for intended use |
| It describes spatial location, such as geographic/map coordinates, street addresses, postal codes. | Spatial Data |
| It describes the different aspects of the entity being collected, such as population of towns, ground/crop cover, number of occupants in a dwelling, soil type, conductivity of wells, etc. | Attribute Data |
| Linking feature and attribute data to a specific geographic location (e.g. taking an address or postal code and turning it into a point feature on a map). | Geocoding |
| GIS programs usually use an ordered set of attribute data grouped in two-dimensional tables, linked by a primary key or unique identifier (e.g sin number, driver’s license, watershed ID, etc.) | relational database |
| GIS uses two data models/structures called? | raster and vector models. |
| In this GIS data model, it looks like points, lines and areas (like your GPS waypoint shape file). | Vector Model |
| Is used when the data has been accessed by coordinated consistent fieldwork (e.g. GPS shape files) or digitized map. | Vector Model |
| In this GIS data model, the point is described by a set of X/Y or East/North coordinates. | Vector Model |
| In this GIS data model, the line or arc is a spatial entity having two points and can be a sequence of connected lines or arc segments called a string (e.g. could be a polyline). | Vector Model |
| In this GIS data model, the area is called a polygon and is made up of a string of lines/arcs that close back to the starting point. | Vector Model |
| In this GIS data model, attributes for polygons would be whole areas such as tree cover, land zoning, contaminant plume, etc. | Vector Model |
| In this GIS data model, it looks “pixelated” like digital camera image. | Raster Model |
| This GIS data model is used with data from scanned maps or remotely sensed imagery (satellite imagery), where the smallest identifiable area is a pixel or cell. | Raster Model |
| This GIS data model is made up of grid cells and is described by grid column and row. | Raster Model |
| In this GIS data model, the size of the grid cell/pixel (resolution) defines the size of a point. | Raster Model |
| In this GIS data model, the point is a single grid cell, the line arc a series of adjoining grid cells, and the area is the adjoining grid cells called a matrix with the same attribute values. | Raster Model |
| This GIS data model could consist of oil or pollution spill, for stand, flooded area, etc. | Raster Model |
| In the related field of remote-sensing and aerial/satellite imagery, the raster pixels have | an image color and tone. |
| A component of GIS, where spatial relationships that geographic feature (polygon/lines, and points) have with each other. | Topology |
| A component of GIS where the relationships may be spatial in nature such as proximity, adjacency and connectivity. | Topology |
| A component of GIS, where the relationships may also be based on entity attributes such as tree specimen, planted or harvested, and time frames. | Topology |
| A component of GIS, which gives GIS its ability to analyze geospatial data, to ask “where” questions. | Topology |
| Component of topology that determines where (e.g. at which lines are connected and give a sense of direction among connected lines such as streams and rivers). | Connectivity |
| Component of topology that determines what spatial features (points, lines, and areas) are adjacent to lines and polygons (how close is the fire hydrant to the fire and which fire station is closest). | Adjacency |
| Component of topology that determines determines which spatial feature (points, lines, and smaller polygons) are enclosed within a specific polygon. | Containment |
Created by:
ctherria