98:
thereby bring a zero mark on the attachment into coincidence with the gyroscope spin axis. By tracking the spin axis as it oscillates about the meridian, a record of the azimuth of a series of the extreme stationary points of that oscillation may be determined by reading the theodolite azimuth circle. A midpoint can later be computed from these records that represents a refined estimate of the meridian. Careful setup and repeated observations can give an estimate that is within about 10 arc seconds of the true meridian. This estimate of the meridian contains errors due to the zero torque of the suspension not being aligned precisely with the true meridian and to measurement errors of the slightly damped extremes of oscillation. These errors can be moderated by refining the initial estimate of the meridian to within a few arc minutes and correctly aligning the zero torque of the suspension.
20:
127:. For example, where a conduit must pass under a river, a vertical shaft on each side of the river might be connected by a horizontal tunnel. A gyro-theodolite can be operated at the surface and then again at the foot of the shafts to identify the directions needed to tunnel between the base of the two shafts. During the construction of the
97:
to reduce magnetic influence, connected by a spindle to the vertical axis of the theodolite. The battery-powered gyro wheel is rotated at 20,000 rpm or more, until it acts as a north-seeking gyroscope. A separate optical system within the attachment permits the operator to rotate the theodolite and
106:
of the spinner axis about the meridian repeats with a period of a few minutes. In practice the amplitude of oscillation will only gradually reduce as energy is lost due to the minimal damping present. Gyro-theodolites employ an undamped oscillating system because a determination can be obtained in
101:
When the spinner is released from restraint with its axis of rotation aligned close to the meridian, the gyroscopic reaction of spin and Earth's rotation results in precession of the spin axis in the direction of alignment with the plane of the meridian. This is because the daily rotation of the
110:
When not in operation, the gyroscope assembly is anchored within the instrument. The electrically powered gyroscope is started while restrained and then released for operation. During operation the gyroscope is supported within the instrument assembly, typically on a thin vertical tape that
170:
When available, astronomical star sights are able to give the meridian bearing to better than one hundred times the accuracy of the gyro-theodolite. Where this extra precision is not required, the gyro-theodolite is able to produce a result quickly without the need for night observations.
102:
Earth is in effect continuously tilting the east–west axis of the station. The spinner axis then accelerates towards and overshoots the meridian, it then slows to a halt at an extreme point before similarly swinging back towards the initial point of release. This oscillation in
111:
constrains the gyroscope spinner axis to remain horizontal. The alignment of the spin axis is permitted to rotate in azimuth by only the small amount required during operation. An initial approximate estimate of the meridian is needed. This might be determined with a magnetic
79:
in 1921 to build the first surveying gyro. In 1949, the gyro-theodolite – at that time called a "meridian pointer" or "meridian indicator" – was first used by the
Clausthal Mining Academy underground. Several years later it was improved with the addition of
159:
to the horizontal axis of the spinner and the meridian is undefined. Gyro-theodolites are not normally used within about 15 degrees of the pole where the angle between the earth's rotation and the direction of gravity is too small for it to work reliably.
84:
telescopes. In 1960, the Fennel Kassel company produced the first of the KT1 series of gyro-theodolites. Fennel Kassel and others later produced gyro attachments that can be mounted on normal theodolites.
107:
less than about 20 minutes, while the asymptotic settling of a damped gyro-compass would take many times that before any reasonable determination of meridian could possibly be made.
361:
N. Korittke; H. Klapperich (1998), "Application of high precision gyro-theodolites in tunneling", in
Arsenio Negro; Argimiro A. Ferreira (eds.),
364:
Tunnels and metropolises: proceedings of the World Tunnel
Congress'98 on tunnels and metropolises : Sao Paulo, Brazil, 25-30 april 1998
55:. It is the main instrument for orientation in mine surveying and in tunnel engineering, where astronomical star sights are not visible and
346:
398:
372:
320:
294:
265:
239:
419:
72:
167:, a gyro-theodolite cannot be relocated while it is operating. It must be restarted again at each site.
164:
115:, from an existing survey network or by the use of the gyro-theodolite in an extended tracking mode.
362:
336:
310:
284:
229:
388:
255:
8:
429:
208:
394:
368:
342:
316:
290:
261:
235:
212:
424:
200:
147:
and in both the northern and southern hemispheres, it cannot be used at either the
123:
Gyro-theodolites are primarily used in the absence of astronomical star sights and
68:
132:
81:
191:
Wang Hong-lan (September 1987), "Analysis of the motion of a gyro-theodolite",
128:
24:
413:
156:
76:
44:
19:
135:
from France to the UK, gyro-theodolites were used to align the tunnels.
204:
152:
148:
52:
48:
32:
312:
Introduction to geodesy: the history and concepts of modern geodesy
94:
144:
112:
103:
334:
282:
124:
56:
360:
411:
27:GAK gyroscope mounted on a Wild T-16 theodolite.
234:, Stanford University Press, pp. 169–170,
93:A gyroscope is mounted in a sphere, lined with
190:
51:. It is used to determine the orientation of
143:Although a gyro-theodolite functions at the
75:points north. This principle was adapted by
341:, Butterworth-Heinemann, pp. 519–533,
367:, Taylor & Francis, pp. 823–827,
186:
184:
393:, Taylor & Francis, pp. 55–56,
386:
278:
276:
253:
223:
221:
18:
335:Wilfred Schofield, Mark Breach (2007),
289:, Walter de Gruyter, pp. 112–116,
283:Heribert Kahmen, Wolfgang Faig (1988),
181:
412:
227:
155:, where the Earth's axis is precisely
308:
273:
218:
13:
14:
441:
260:, Walter de Gruyter, p. 18,
193:Applied Mathematics and Mechanics
43:) is an instrument composed of a
163:Unlike an artificial horizon or
71:discovered that a gyro with two
228:Staley, William Wesley (1964),
390:Engineering the Channel Tunnel
380:
354:
328:
302:
247:
231:Introduction to mine surveying
138:
67:In 1852, the French physicist
1:
309:Smith, James Raymond (1997),
174:
88:
7:
387:Kirkland, Colin J. (1995),
315:, Wiley-IEEE, p. 174,
10:
446:
165:inertial navigation system
62:
254:Deumlich, Fritz (1982),
131:, which runs under the
118:
28:
420:Surveying instruments
338:Engineering surveying
257:Surveying instruments
22:
16:Surveying instrument
205:10.1007/BF02019527
73:degrees of freedom
29:
348:978-0-7506-6949-8
437:
404:
403:
384:
378:
377:
358:
352:
351:
332:
326:
325:
306:
300:
299:
280:
271:
270:
251:
245:
244:
225:
216:
215:
188:
445:
444:
440:
439:
438:
436:
435:
434:
410:
409:
408:
407:
401:
385:
381:
375:
359:
355:
349:
333:
329:
323:
307:
303:
297:
281:
274:
268:
252:
248:
242:
226:
219:
189:
182:
177:
141:
133:English Channel
121:
91:
82:autocollimation
65:
59:does not work.
17:
12:
11:
5:
443:
433:
432:
427:
422:
406:
405:
399:
379:
373:
353:
347:
327:
321:
301:
295:
272:
266:
246:
240:
217:
199:(9): 889–900,
179:
178:
176:
173:
140:
137:
129:Channel Tunnel
120:
117:
90:
87:
64:
61:
41:surveying gyro
37:gyrotheodolite
15:
9:
6:
4:
3:
2:
442:
431:
428:
426:
423:
421:
418:
417:
415:
402:
400:0-419-17920-8
396:
392:
391:
383:
376:
374:90-5410-936-X
370:
366:
365:
357:
350:
344:
340:
339:
331:
324:
322:0-471-16660-X
318:
314:
313:
305:
298:
296:3-11-008303-5
292:
288:
287:
279:
277:
269:
267:3-11-007765-5
263:
259:
258:
250:
243:
241:0-8047-0361-2
237:
233:
232:
224:
222:
214:
210:
206:
202:
198:
194:
187:
185:
180:
172:
168:
166:
161:
158:
157:perpendicular
154:
150:
146:
136:
134:
130:
126:
116:
114:
108:
105:
99:
96:
86:
83:
78:
74:
70:
69:Léon Foucault
60:
58:
54:
50:
47:mounted to a
46:
42:
38:
34:
26:
21:
389:
382:
363:
356:
337:
330:
311:
304:
285:
256:
249:
230:
196:
192:
169:
162:
142:
122:
109:
100:
92:
66:
40:
36:
30:
139:Limitations
77:Max Schuler
45:gyrocompass
430:Gyroscopes
414:Categories
175:References
153:South Pole
149:North Pole
53:true north
49:theodolite
286:Surveying
213:121190508
89:Operation
33:surveying
95:Mu-metal
425:Geodesy
145:equator
113:compass
104:azimuth
63:History
39:(also:
397:
371:
345:
319:
293:
264:
238:
211:
209:S2CID
395:ISBN
369:ISBN
343:ISBN
317:ISBN
291:ISBN
262:ISBN
236:ISBN
119:Uses
35:, a
25:Wild
201:doi
151:or
125:GPS
57:GPS
31:In
416::
275:^
220:^
207:,
195:,
183:^
23:A
203::
197:8
Text is available under the Creative Commons Attribution-ShareAlike License. Additional terms may apply.
