surveying iii (topographic and geodetic surveys) - Modern Prepper

More documents

Recommendations

Info

5-7. Pseudorange. A pseudorange is the time delay between the satellite clock and the receiver clock,as determined from C/A- or P-code pulses. This time difference equates to the range measurement but iscalled a pseudorange since at the time of the measurement, the receiver clock is not synchronized to thesatellite clock. In most cases, an absolute 3D real-time navigation position can be obtained by observingat least four simultaneous pseudoranges.5-8. Carrier Phase Measurements. Carrier frequency tracking measures the phase differencesbetween the Doppler-shifted satellite and receiver frequencies. The phase differences are continuouslychanging due to the changing satellite earth orbit geometry. However, such effects are resolved in thereceiver and subsequent data postprocessing. When carrier phase measurements are observed andcompared between two stations (differential mode), 3D baseline vector accuracy between the stationsbelow the centimeter level is attainable. New receiver technology and processing techniques haveallowed for carrier phase measurements to be used in real-time centimeter positioning.5-9. Broadcast Messages and Ephemeris Data. Each NAVSTAR GPS satellite periodicallybroadcasts data concerning clock corrections, system and satellite status and, most critically, position orephemeris data. There are two basic types of ephemeris data--broadcast and precise.a. Broadcast Ephemerides. Broadcast ephemerides are predicted satellite positions broadcast withinnavigation messages (transmitted from satellites in real time). The ephemerides can be acquired in realtime through a receiver capable of acquiring either a C/A- or P-code. Broadcast ephemerides arecomputed using the past tracking data of satellites. The satellites are continuously tracked by themonitor stations to obtain current data for use in orbit predictions. The data are analyzed by the mastercontrol station, and new parameters for the satellite orbits are transmitted back to the satellites. Thisupload is performed daily, and the new predicted orbital elements are transmitted every hour by thenavigation message.b. Precise Ephemerides. Precise ephemerides are based on actual tracking data that arepostprocessed to obtain more accurate satellite positions. These ephemerides are delayed for processingbut are more accurate than the broadcast ephemerides because they are based on actual tracking data andnot predicted data. Nonmilitary users can obtain this information from the NGS or private sources thatmaintain their own tracking networks. For most survey applications, broadcast ephemerides areadequate to obtain needed accuracies.EN0593 5-4
PART B - ABSOLUTE PRECISE POSITIONING5-10. General. Absolute positioning involves the use of a single passive receiver at one station locationto collect data from multiple satellites to determine the station's location. It is not sufficiently accuratefor precise surveying and positioning uses. It is, however, the most widely used GPS positioningmethod for real-time navigation and location.5-11. Accuracy. The accuracy of absolute positioning is dependent on the user's authorization. TheSPS user can obtain real-time point-positional accuracy of 100 meters. The lower level accuracy usingSPS is due to intentional degradation of the GPS signal by DOD selective availability (S/A). The PPSuser (usually a DOD-approved user) can use a decryption device to achieve a 3D accuracy in the range of10 to 16 meters with a single-frequency receiver. Accuracy to less than one meter can be obtained fromabsolute GPS measurements when special equipment and postprocessing techniques are employed.5-12. Ephemerides. By using broadcast ephemerides, the user is able to use pseudorange values in realtime to determine absolute point positions with an accuracy of between 3 meters in the best of conditionsto 80 meters in the worst of conditions. Using postprocessed ephemerides (precise), the user can expectabsolute point positions with the accuracy of near 1 meter in the best of conditions and 40 meters in theworst of conditions.5-13. Pseudorange. When a GPS user performs a GPS navigation solution, only an approximate rangeor pseudorange to selected satellites is measured. In order to determine the user's precise GPS location,the known range to the satellite and the position of those satellites must be known. Usingpseudoranging, the GPS user can measure an approximate distance between the antenna and the satellitethrough correlation of a satellite-transmitted code and a reference code created by the receiver. It is notnecessary to factor in corrections for errors in synchronization between the clock of the transmitter andthe receiver. The distance the signal travels is equal to the velocity of the transmission of the satellitemultiplied by the elapsed time of transmission. Satellite signal velocity changes due to tropospheric andionospheric conditions are also considered.5-14. Accuracy. The accuracy of the positioned point is a function of the range-measurement accuracyand the geometry of the satellites, reduced to spherical intersections with the earth's surface. Thedilution of precision (DOP) is a description of the geometrical magnification of uncertainty in a GPSdeterminedpoint position. Repeated and redundant range observations will generally improve rangeaccuracy; however, the DOP remains the same. In a static mode (where the GPS antenna remainsstationary), range measurements to each satellite can be continuously remeasured over varying orbitallocations of the satellites. The varying satellite orbits cause varying positional intersection geometry.Additionally, simultaneous range observations to numerous satellites can be adjusted using weightingtechniques based on the reliability of the elevation and pseudorange measurements.5-5 EN0593
Page 1 and 2:
SUBCOURSEEN0593EDITIONAUNITED STATE
Page 3 and 4:
TERMINAL LEARNING OBJECTIVE:ACTION:
Page 6 and 7:
Part G: Adjusting Precise-Positioni
Page 8 and 9:
PART A - FIGURES OF THE EARTH1-1. T
Page 10 and 11:
Figure 1-2. Flattening Fractiona. T
Page 12 and 13:
1-3. Geoid. In geodesy, precise com
Page 15 and 16:
point in the survey to provide the
Page 18 and 19:
one side of a triangle and all of t
Page 20 and 21:
Figure 1-10. Simple Triangulation N
Page 22 and 23:
observation, contains a light sourc
Page 24 and 25:
of a horizontal rod with a small sp
Page 26 and 27:
The Airy theory, announced by G. B.
Page 28 and 29:
Figure 1-15. Products of the Gravim
Page 30 and 31:
a. If the shape of the earth was ex
Page 32 and 33:
Figure 1-16. Single Astronomic Stat
Page 34 and 35:
Figure 1-17. Astro-Geodetic Deflect
Page 36 and 37:
Figure 1-19. Astro-Geodetic Datum O
Page 38 and 39:
(c) The significance of a gravity-o
Page 40 and 41:
absolute deflections of the vertica
Page 42 and 43:
Figure 1-23. Preferred Datumsa. The
Page 44 and 45:
1-17. The World Geodetic System. Be
Page 46 and 47:
Figure 1-25. Using the Same Referen
Page 48 and 49:
LESSON 1PRACTICE EXERCISEThe follow
Page 50 and 51:
12. Which of the following is assum
Page 52 and 53:
LESSON 1PRACTICE EXERCISEANSWER KEY
Page 54 and 55:
THIS PAGE IS INTENTIONALLY LEFT BLA
Page 56 and 57:
for all military and civilian activ
Page 58 and 59:
i. Additional support for other top
Page 60 and 61:
2-7. Status. At present, topographi
Page 62 and 63:
in both. (North American Datum of 1
Page 64 and 65:
water can impede leveling operation
Page 66 and 67:
A field recording booklet. A single
Page 68 and 69:
PART I - OFFICE WORK2-24. General.
Page 70 and 71:
PART J - SURVEY COMMUNICATION2-28.
Page 72 and 73:
length or side is known, and all th
Page 74 and 75:
second-order, Class I net. The leng
Page 76 and 77:
The number of observations required
Page 78 and 79:
to perform the reconnaissance. Fail
Page 80 and 81:
and cultivated, or fields may have
Page 82 and 83:
e an alphanumeric symbol that is st
Page 84 and 85:
2-53. Intervisibility of Stations.
Page 86 and 87:
station is (K/2) 2 x 0.0676, or one
Page 88 and 89:
Figure 2-8. Similar Triangles Solut
Page 90 and 91:
2-54. Height of Obstructions. It is
Page 92 and 93:
authorized to change the name, it s
Page 94 and 95:
Figure 2-12. Cells Connected in Par
Page 96 and 97:
added as the cells weaken. Three un
Page 98 and 99:
Figure 2-16. Construction Details f
Page 100 and 101:
2-60. Wooden Towers. When it become
Page 102 and 103:
Page 104 and 105:
11. The face of the 5-inch signal l
Page 106 and 107:
Page 108 and 109:
average line in a triangulation sys
Page 110 and 111:
3-4. Slope Measurements. The slope
Page 112 and 113:
strip as close as possible to its f
Page 114 and 115:
. Sight along the tops of both of t
Page 116 and 117:
Column 1. Record the station number
Page 118 and 119:
stake to steady it. With the back o
Page 120 and 121:
Figure 3-3. DA Form 4446 (Sample of
Page 122 and 123:
micrometer in this optical system i
Page 124 and 125:
laterally across the front of the e
Page 126 and 127:
Figure 3-7. Horizontal Circle and M
Page 128 and 129:
out of adjustment. If the index mar
Page 130 and 131:
(1) In order to avoid instrumental
Page 132 and 133:
location of the vertical circle on
Page 134 and 135:
Figure 3-13. Open Traversec. Closed
Page 136 and 137:
designate the exact point of refere
Page 138 and 139:
example, a line with an azimuth of
Page 140 and 141: When adjusting a traverse that star
Page 142 and 143: LESSON 3PRACTICE EXERCISEThe follow
Page 144 and 145: 11. The unit of graduation on a hor
Page 146 and 147: LESSON 3PRACTICE EXERCISEANSWER KEY
Page 148 and 149: THIS PAGE IS INTENTIONALLY LEFT BLA
Page 150 and 151: differential leveling. The theodoli
Page 152 and 153: additional runs are made due to exc
Page 154 and 155: Figure 4-2. Wild N-3 Precision Leve
Page 156 and 157: (8) Loosen the azimuth clamp (13),
Page 158 and 159: 4.7. Miscellaneous Equipment. In ad
Page 160 and 161: (2) To check for gross errors in th
Page 162 and 163: (a) (1) Begin by completing the inf
Page 164 and 165: Set up and level the instrument. Re
Page 166 and 167: Figure 4-8. Sun and Wind Code(5) Th
Page 168 and 169: (10) Enter the interval between the
Page 170 and 171: Figure 4-9. Closed-Circuit River Cr
Page 172 and 173: Figure 4-11. Sample DA Form 5820 (R
Page 174 and 175: is 0. When the telescope is pointed
Page 176 and 177: stations. However, since all statio
Page 178 and 179: a. Complete the heading, as shown.b
Page 180 and 181: a. (1) Enter the date, as in the sa
Page 184 and 185: 11. The maximum length of site to o
Page 186 and 187: LESSON 4PRACTICE EXERCISEANSWER KEY
Page 188 and 189: PART A - GLOBAL POSITIONING SYSTEM
Page 192 and 193: 5-15. Number of Pseudorange Observa
Page 194 and 195: i. Probable Error Measures. The acc
Page 196 and 197: Table 5-1. Representative GPS Error
Page 198 and 199: Table 5-2. Carrier Phase Trackinga.
Page 200 and 201: exercise extreme caution in applyin
Page 202 and 203: not be designed or performed to ach
Page 204 and 205: Table 5-3. GPS-S Design, Geometry,
Page 206 and 207: f. Multiple/Repeat Baseline Connect
Page 208 and 209: possible ionospheric and tropospher
Page 210 and 211: Figures 5-4. PDOP Versus Time PlotP
Page 212 and 213: e. Field Processing and Verificatio
Page 214 and 215: All carrier phase relative-surveyin
Page 216 and 217: time spent and the cost of conducti
Page 218 and 219: movement between occupation sites,
Page 220 and 221: 5-37. General. GPS baseline solutio
Page 222 and 223: (1) Receiver Time. This technique u
Page 224 and 225: NOTE: Repeated baselines should be
Page 226 and 227: 5-43. Loop Closure Checks. Postproc
Page 228 and 229: necessary to determine approximate
Page 230 and 231: This will ensure that future work w
Page 232 and 233: may (and usually does) far exceed t
Page 234 and 235: important in evaluating the overall
Page 236 and 237: i. Relative GPS baseline standard e
Page 240 and 241:
12. When the networking method is s
Page 242 and 243:
Page 244 and 245:
THIS PAGE IS INTENTIONALLY LEFT BLA
Page 246 and 247:
FAR-77 obstructions. Aircraft-movem
Page 248 and 249:
Figure 6-1. Imaginary SurfacesEN059
Page 250 and 251:
Figure 6-3. Approach Surfacesa. Fed
Page 252 and 253:
. Federal Aviation Regulation-77, S
Page 254 and 255:
Table 6-4. Airport Obstruction Accu
Page 256 and 257:
A horizontal scale of 1:12,000 and
Page 258 and 259:
Figure 6-4. Sample DA Form 5821 (Ai
Page 260 and 261:
Figure 6-5. Sample DA Form 5822 (PA
Page 262 and 263:
Page 264:
show all

surveying iii (topographic and geodetic surveys) - Modern Prepper

You also want an ePaper? Increase the reach of your titles

Delete template?

Save as template?