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Description  |
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The system at issue has been studied to be of great use in the field of
topographical, cadastral and any other kind of ground surveys, including
the measurement and the mapping of interiors.
By means of electromagnetic waves and barometric sensors, the
above-mentioned system allows the measurement both of distances between
points and of their heights, even when the points to be surveyed are not
visible from the survey stations.
Most of the systems employed in this field use high precision optical and
mechanical-optical instruments. The application of electronics in this
field is relatively recent and it integrates traditional optical devices
such as tacheometers, theodolites etc. This is due both to the increased
potentiality of the instruments and to the reduction of the risk of
errors. Electronic devices allow more accurate measurements, they save
time in the processing of the data, while their accessories are lighter,
less bulky and easy to carry. All these advantages obviously influence the
price, which is sensibly higher than that of the traditional instruments.
Data registers that, once connected to an electronic unit, can
automatically record all the surveyed data descriptions of the targets
surveyed and additional notes of various kind, have been recently put on
the market. When connected to a computer, such registers transfer the
surveyed data to it, producing tabulations and/or graphics with no need of
the operator's presence. This completely prevents any possibility of
mistake both in the transcriptions and in the conversion computation of
the surveyed data.
Since all the instruments currently employed, both traditional and
electronic, are basically optical, they all need the points to survey to
be visible to the operator working on the instrumental unit. The European
Patent n. A-0 051 913 filed on Aug. 14th 1981 must be mentioned in
connection with this. This Patent describes a method and an apparatus for
remote control surveying of distances, the method comprises the steps of
positioning electronic distance measuring and rotating reflector units in
spaced relation, of energizing the reflector unit from adjacent the
measuring device in order to create a sight line between the devices, ad
of measuring the distance-between the devices-with the electronic distance
measuring device.
The surveying apparatus comprises a reflector unit, a motor for rotating
said unit, a radio receiver energizing said motor and a portable radio
transmitter controlling said receiver.
Both the presence of reflector units and the repeated statement that the
devices must be reciprocally visible to each other in order to create a
sight line indicate that such a method of surveying distances is based on
the employment of electromagnetic waves whose wavelength ranges between
300.mu. and 100 .ANG.--namely light waves--as vectors. In case of poor
visibility, when the vegetation is thick, or in the middle of conurbation,
the devices described in this Patent and the optical instruments used
nowadays in general are often unusable if not supplemented by survey
methods alternative to direct measurement such as, for instance, by
referring to a traverse measured at a series of instrument stations from
which the points to survey are visible.
While such devices are generally effective and ingenious, they require the
use of heavy and complex equipments due to the presence of accumulators,
of strong and sturdy tripods, of reflector units, of motors, of radio
receiver, etc. A bigger problem is then represented by the necessity of
positioning the devices over reciprocally visible points and on an even
plane, since the devices can only rotate on an horizontal plane; it is
therefore impossible to collimate points located outside such a plane.
The SU Patent A-802 783 must be mentioned as far as the use of barometers
is concerned. This Patent describes an altitude measuring system which has
two fixed and one movable barometers and includes one unit to determine
the difference between information from pressure converters. The signals
from the two atmosphere converters pass to two radio transmitters and then
to two radio receivers, the radio receivers pass them to two units which
fix both the difference between the signals and the value of the
difference in pressure between one of the fixed stations and the movable
station. The transmission of information among the various stations thus
occurs by means of radio waves. The radio waves are however used only for
the data transmission.
The invention at issue, a system to measure distances and heights of any
kind, is based on radio ranging electromagnetic waves and barometric
sensors. Its purpose is to help the measurement of both distances and
heights of points even when the latter are not visible, thus allowing any
kind ground survey (be it topographical, cadastral, of either buildings or
roads) also in poor visibility. Another purpose of the above-mentioned
device is to make very easy the measurement work needed in a ground
survey. The device shortens the time needed for measurements, reduces the
minimum number of operators from two to one while increasing the accuracy
of the measurements; finally, it is equipped with light and handy
accessories. Its additional advantage is to be produced at a rather
interesting cost.
The device at issue basically consists of two portable stationary units and
one portable mobile unit. This is the lowest possible number of elements
needed to survey through trilateration.
By increasing the number of the portable stationary units it is possible to
survey a wider number of measures in order to determine the sides of a
triangle for a possible verification. On the other hand, by setting out a
grid of permanent stationary units on a chosen area, surveys with a common
system of orientation can be carried out by numberless operators. By
increasing the number of the portable mobile units it is in fact possible
to perform a survey employing several operators at the same time, thus
reducing the total length or time required by the measurements themselves.
The above-mentioned portable units can for instance be built--this,
however, is not binding--as rods of insulating material (for instance,
three rods about one meter long and about 3,5 centimeters wide). While
their lower ends are pointed, on the upper ends--under a spherical
level--is the housing for the barometric sensor.
The feeding elements of the electronic system, the electronic circuits, the
transceiver, the aerial and the barometric sensor, together with the
spherical level are to be found inside each rod.
Such units are very easy to carry even on rough terrains and it is possible
to plumb set them up quickly by means of, for instance, tripods with
ball-point pliers (already commonly used to support stadia rods and
reflecting prism stands).
It is important to underline that this device does not employ optical,
mechanical-optical, mechanical-electronic elements nor precision
instruments, which are on the contrary present both in the traditional and
in the electronic-optical instruments. Finally, it has to be underlined
the good resistance of such a device to collisions and accidental drop
impacts.
The whole system contained in the rods has a watertight protection against
rain and even against immersion, the only exception being the housing of
the barometric sensor which, though itself watertight, must be in contact
with the outside (for instance through holes on the sides of the rod) in
order to work properly.
The electronic elements of the portable stationary units are: a circuit
measuring the height by means of a barometric sensor, a receiver of the
inquiries sent by the portable mobile unit, and a transmitter of the
electromagnetic echo.
Inquiries are used to determine the distances and the differences in level
both between the portable mobile unit and the portable stationary units,
and between the portable stationary units themselves. Apart from measuring
height and distance, the portable mobile unit works out the data received
by the portable stationary units and supplies the required measures.
An electronic control keyboard is housed in a portable container connected
to the portable mobile unit either through a cable or through
electromagnetic waves.
The invention at issue is meant to be used as follows:
Plumb set the portable stationary units on the extremities of a base line
chosen in advance.
Turn on both the portable stationary units (through switches) and the
portable mobile unit (by portable control keyboard input).
Begin the measurements for the trilateration by plumb setting the portable
mobile unit.
Put either at zero or at a known altitude one of the units through portable
control keyboard. By being interrogated, the portable control keyboard
displays the distances measured on the incline, the differences in level,
the distances on the horizontal related to the space between the portable
stationary units and to the space between each portable stationary unit
and the portable mobile unit.
Data can be recorded into a suitable peripheral, possibly incorporated in
the portable control keyboard.
In FIG. 1, for instance, A and B are the extremities of a chosen base line
where the portable stationary units are to be set. C is a point to be
surveyed according to the trilateration method, and the portable mobile
unit is set on it. B' and C' are the projections of B and C on an
horizontal plane set at the altitude of .+-.0.00 and passing through A
(the datum point in this example).
Once all the units have been set up and as a result of the operator's
request by portable control keyboard input, data similar to the following
ones appear on the control unit display (all the measures are only an
example concerning FIG. 1):
______________________________________
AB = 538,456 m CA = 774,786 m
AB' = 537,859 m CB = 555,140 m
hA = 0,000 m C'A = 773,410 m
hB = 25,347 m C'B' = 554,750 m
hC = 46,143 m
______________________________________
The data of the second column change during the measurements of the
subsequent points (DA, DB, D'A, hD-EA, EB, B'A, B'B, hB etc.). On the
contrary, the first column, which refers to the base line AB, does not
change. It could therefore appear on the display only after a request from
the operator, unless the two portable stationary units were accidentally
moved by the wind, by animals etc. In such a case an error message would
appear on the display, and it would be necessary to set up the portable
stationary units again in order to continue the survey. In this way it is
possible to measure as many triangles as are the points to be surveyed,
all of which having in common the chosen base line AB.
All the measures resulting from such data (for instance: Cartesian
coordinates of the points, area delimited by the surveyed targets, etc.)
could obviously be displayed at the operator's request. To such a purpose
the portable control keyboard should contain also a calculator with
built-in coordinate-geometry functions. This would be useless when the
portable control keyboard incorporates a data register which can compute
such functions by employing its own microcomputer. It is possible to note
further features and advantages of the device at issue when built in the
above-mentioned shape which, even if more convenient is not binding, as
shown in the enclosed drawings, that is to say:
FIG. 1: Schematic tridimentional representation of the three portable units
while in use.
FIG. 2: Frontal view of the portable mobile unit as a whole. It is possible
to note both the knurled parts that can be unscrewed to open the unit, and
the cable to connect the portable control keyboard.
FIG. 3: View from above of the portable mobile unit. The spherical level is
clearly visible here.
FIG. 4: Transverse section (indicated in FIG. 2) of the portable mobile
unit, where the internal space is clearly visible.
FIG. 5: Longitudinal section (indicated in FIG. 3 and in FIG. 4) from which
it is possible to see the internal space, the location of the different
elements, the water-tight system (near the barometric sensor and near the
accumulators), and the system to open the different sections.
FIG. 6: Portable control keyboard.
FIG. 7: Frontal view of the portable stationary unit as a whole. It is
possible to note both the knurled parts that can be unscrewed to open the
unit and the on/off switch.
FIG. 8: View from above of the portable stationary unit. The spherical
level is clearly visible.
FIG. 9: Transverse section (indicated in FIG. 7) of the portable stationary
unit.
FIG. 10: View from below of the portable stationary unit.
FIG. 11: Longitudinal section (indicated in FIG. 8 and in FIG. 9) from
which it is possible to see the internal space, the location of the
different elements, the water-tight system (near the barometric sensor and
near the accumulators), and the system to open the internal sections.
FIG. 12: Block diagram of the electromagnetic waves transceiver connected
to the first portable stationary unit.
FIG. 13: Block diagram of the electromagnetic waves transceiver connected
to the second portable stationary unit.
FIG. 14: Block diagram of the electromagnetic waves transceiver and of the
electronic parts which process the data, both connected to the portable
mobile unit.
The main feature of the device at issue is the use of the transmission of
electromagnetic waves in the measurement of distances. In detail:
The portable mobile unit 1, built as a tube in watertight and insulating
material, includes one spherical level 2, one barometric sensor 3, one
electromagnetic waves transceiver 4, one electronic circuit to process the
surveyed data 5, a series of accumulators 6, one multiple cable socket 7
and one portable control keyboard 8. The portable stationary unit 9
differs from the portable mobile unit 1 only for the lack of the portable
control keyboard 8, for the different electronic circuits which process
the surveyed data 10 and for the on/off switch 11.
Both the unit 9 and the unit 1 consist of a tube 12 of insulating material
as supporting frame, which has a pointed lower end in order to allow an
accurate positioning. The accumulators 6 providing the necessary energy to
all the electric and electronic circuits are housed in the lower part of
the tube 12. Both the electronic circuits 10 and the circuits of the
transceiver 4 are housed in the central part of the tube 12, while the
aerial 15 is directly above them. The barometric sensor 3 and the
spherical level 2 above it are located in the upper part of the tube 12.
The electronic elements of the portable stationary unit 9 consist of a
circuit which measures the height by means of a barometric sensor 3 and
one receiver 4 of the inquiries sent by the portable mobile unit 1 to the
portable stationary units 9. Such elements are necessary to compute the
distances between the two above-mentioned units as well as between two
different portable stationary units 9.
Apart from measuring the relative height, the portable mobile unit 1
processes the data received from the portable stationary units 9 and,
subsequently, supplies the requested measures.
The portable control keyboard 8 is connected to the portable mobile unit 1
by means of a cable plugged in the socket 7.
The device at issue, in order to survey by means of electromagnetic waves
and barometric sensors, has to be used in the following way:
Plumb setting of the portable stationary units 9 on the extremities of the
chosen base line;
Turning on of both the portable stationary units 9 (by means of the
switches 11) and of the portable mobile unit 1 (by portable control
keyboard 8 input);
Plumb setting of the portable mobile unit 1 and beginning of the survey for
the trilateration;
On request of the operator by keyboard 14 input, the portable control unit
8 displays the distances measured on the incline, the differences in level
and the distances on the horizontal related to the space between the
portable stationary units 9 and the portable mobile unit 1.
It is possible to connect the device to a peripheral, on which the surveyed
data are continually recorded for a later processing.
To complete the description, it is for instance worth mentioning the
electronic block diagrams of the instruments.
The transceiver of the first portable stationary unit, shown in FIG. 12,
employs a modulated electromagnetic waves transmitter (17) both for the
transmission of data and for telemetering distances through the electronic
circuit (19). It also employs a receiver (18) synchronised with the
transmitter in order to receive both the interrogations sent by the
portable mobile unit and the data sent by the other portable stationary
unit. An electronic aerial change-over switch (16) automatically switches
over the aerial from the transmitter to the receiver and vice-versa.
The electronic system of the first portable stationary unit, shown in FIG.
12, consists of a microprocessor (20) with its interfaces which carries
out the following tasks:
it receives the inquiries--sent by the portable mobile unit--through the
receiver (18);
it measures the distance between the two portable stationary units by means
of the transceiver system (17 and 18), using one of the radiotelemetering
methods;
on request by the portable mobile unit, it transmits the data referring
both to the first portable stationary unit's absolute height and to the
distance between the two portable stationary units;
it records in and reads from its own memory (22);
it cyclically repeats the telemetering between the first and the second
portable stationery unit.
A barometric sensor (3) is employed to measure the absolute height. The
signal of the barometric sensor is amplified by an amplifier (21), while
also the temperature compensation, as well as the conversion of the signal
from analog to digital, take place in the sensor itself.
The transceiver of the second portable stationary unit, shown in FIG. 13,
employs a modulated electromagnetic waves transmitter (17) for the
transmission of data. It also uses a receiver (18) synchronised with the
transmitter for the reception both of the inquiries sent from the portable
mobile unit and of the data sent by the other portable stationary unit.
The electronic aerial change-over switch (16) automatically switches over
the aerial from the transmitter to the receiver and vice-versa. The
electronic system of the second portable stationary unit, shown in FIG.
13, consists of a microprocessor (23) with its interfaces which carries
out the following tasks:
it receives the inquiries--sent from the portable mobile unit--about its
absolute height through the receiver (18);
it transmits the data of its absolute height to the portable mobile unit
through the transmitter (17);
it reflects the telemetric signals after request of either the other
portable stationary unit or the portable mobile unit;
it records in and reads from its own memory (24).
A barometric sensor (3) is employed in order to measure the absolute
height. The signal of the barometric sensor is amplified by an amplifier
(21), while also the temperature compensation, as well as the conversion
of the signal from analog to digital, take place in the sensor itself.
The transceiver of the portable mobile unit, shown in FIG. 14, employs a
modulated electromagnetic waves transmitter (17) both for the transmission
of inquiries and for telemetering distances by means of the electronic
circuit (19). It also employs receiver (18) synchronised with the
transmitter for the reception both or the data referring to the chosen
base line--sent by the first portable stationary unit (FIG. 12)--and of
the data sent by the second portable stationary unit.
The electronic aerial change-over switch (16) automatically switches over
the aerial from the transmitter to the receiver and vice-versa.
The electronic system o f the portable mobile unit, shown in FIG. 14,
consists of a microprocessor (25) with its interfaces which carries out
the following tasks:
it interrogates the first portable stationary unit, shown in FIG. 12, by
means of the transmitter (17), in order to receive data about both the
stationary unit's absolute height and the distance between the portable
stationary units, which are recorded in the stationary unit's memory (22);
it interrogates the second portable stationary unit, shown in FIG. 13, by
means of the transmitter (17) in order to receive data recorded in the
stationary unit's memory (24) about the same unit's absolute height;
it receives the data recorded in the memories (22) and (24) by means of the
receiver (18);
by employing one of the radiotelemetering methods through the transceiver
(17 and 18), it measures the distance between itself and the two portable
stationary units;
it codifies the instruction sent by keyboard (14) input and controls the
alphanumeric display (26);
it sends the data to be recorded to the possible peripheral (27);
it records in and reads from its own memory (28);
it processes the data about all three units' absolute heights and
calculates the relative heights by referring them to a datum in order to
obtain the measures of the differences in level between the units. Such
data will be used to calculate the projection on the horizontal plane of
the distances surveyed on the incline;
it cyclically repeats the inquiries to the two portable stationary units in
order to verify the uniformity of the position data and to signal any
possible change.
A barometric sensor (3) is employed in order to measure the absolute
height. The signal of the barometric sensor is amplified by the amplifier
(21), while also the temperature compensation as well as the conversion of
the signal from analog to digital take place in the sensor itself.
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