WO2017066836A1

WO2017066836A1 - A survey staff

Info

Publication number: WO2017066836A1
Application number: PCT/AU2016/050987
Authority: WO
Inventors: David Cramer; Nicholas DEEGAN
Original assignee: David Cramer; Deegan Nicholas
Priority date: 2015-10-20
Filing date: 2016-10-20
Publication date: 2017-04-27

Abstract

A survey staff includes a plurality of elongate staff sections. A connecting mechanism is operatively arranged on at least two consecutive staff sections to permit the consecutive staff sections to be connected or disconnected between extended and retracted conditions, respectively. A laser receiver is arranged on each of the at least two consecutive staff sections and is configured to detect a laser signal and to generate a signal related to an impingement location on one of the staff sections at which the laser signal impinges the receiver. A processor is operatively connected to the laser receiver and is configured to receive the signal generated by the laser receiver and to generate a signal carrying data related to the impingement location.

Description

A SURVEY STAFF

FIELD OF THE INVENTION

[0001 ] The present description relates to a survey staff and to a survey system. Survey staffs are also sometimes referred to as measuring poles, measuring rods, survey sticks, measuring sticks, levelling staff, or stadia.

BACKGROUND OF THE INVENTION

[0002] Survey systems can use a laser level and a laser receiver clamped to a staff. A laser level is set up to project a laser beam in a horizontal plane. The height of the plane can be calculated relative to a known benchmark height. The laser-receiving staff is positioned upright at a particular point on a site where a height measurement is to be taken. The laser beam intersects the survey staff to provide a height reading at the point where the survey staff stands.

[0003] The survey staff can have a graduated height scale. The height at which the laser beam strikes the staff is visible as a line on the staff and can be read directly from the staff.

[0004] The survey staff can be equipped with a moveable laser detector, which can detect the laser beam and gives a signal when the laser detector is in line with the laser beam. The position of the laser detector on the graduated staff indicates a height measurement on the staff where the laser beam intersects the staff.

SUMMARY OF THE INVENTION

[0005] In one aspect, a length-adjustable survey staff is described which includes a plurality of slidably connected sections. At least two adjacent sections each include a longitudinally extending laser receiver. The longitudinally extending laser receivers of the two adjacent sections may together form a substantially continuous linear laser receiver arrangement when the two adjacent sections are extended relative to each other. The laser receiver includes a linear array of opto- electric elements.

[0006] The survey staff may include a detector which is operable to detect whether one of the sections is moved to an extended position relative to an adjacent section. The detector may be one or more switches which are activated when one section is moved to an extended position relative to an adjacent section.

[0007] The survey staff may include a detection circuit connected to the laser receiver arrangement. The detection circuit may output distance data relating to a position at which the laser receiver arrangement is intersected by a laser beam, measured from an end of the survey staff. The detection circuit may include a microprocessor. The survey staff may include a wireless communications module for wirelessly communicating the distance data to a mobile electronic device.

[0008] The survey staff may be configured for the laser receiver of one of the sections to become active only after the section is moved to an extended position relative to an adjacent section.

[0009] The opto-electric elements forming each laser receiver may be photodiodes, phototransistors, light-dependent resistors, or semiconductor diodes.

[0010] The laser receiver arrangement of the survey staff may be at least 1 m long. The laser receivers making up the laser receiver arrangement may be at least 0.5m long. The opto-electric elements making up the laser receivers may be no more than 10mm wide, for example no more than 5mm wide.

[001 1 ] The laser receiver may be configured to detect a red laser beam with a wavelength of between 635nm and 650nm, or a green laser beam with a wavelength of approximately 532mm. The laser receiver may be configured to detect a laser beam of any colour, including blue laser beams with a wavelength of approximately 473nm, violet laser beams with a wavelength of approximately 405nm, and yellow laser beams with a wavelength of approximately 593nm.

[0012] The survey staff may include a lock mechanism to releasably lock one of the sections in an extended position relative to an adjacent section.

[0013] The survey staff may include a display connected to the detection circuit.

[0014] The survey staff may include extension sections which do not include a laser receiver, but which may be extended to increase the length of the survey staff.

[0015] In another aspect, a survey system is described including a survey staff, mobile communications device, and a software application executed on the mobile communications device.

[0016] The survey staff of the survey system has a longitudinally extending laser receiver arrangement operable to detect a laser beam intersecting the survey staff. The survey staff includes a wireless communications module. The mobile communications device has a wireless communications module for wirelessly communicating with the survey staff. The mobile communications device includes a screen, a memory and a processor. The mobile communications device may be a smartphone, a tablet or a laptop.

[0017] The survey staff may be configured to transmit distance data of where the laser receiver arrangement is intersected by the laser beam, measured from an end of the survey staff, to said mobile communications device. The software application may be configured to calculate an elevation of the end of the survey staff using the height data.

[0018] In yet another aspect, a method of surveying is described. The method includes placing a laser level at a site and activating the laser level to emit a level laser beam. The method includes standing a survey staff, having a linear laser receiver arrangement extending along a length of at least a section of the survey staff and operable to detect the laser beam, on a benchmark surface of a known elevation at the site. The method includes detecting a height measured from an end of the survey staff at which the laser beam intersects the laser receiver arrangement while standing on the benchmark surface. The method includes storing the detected height at the benchmark surface in a memory of an electronic device. The method includes moving the survey staff to stand at a survey location to be surveyed. The method includes detecting a height from the end of the survey staff at which the laser beam intersects the survey staff while standing at the survey location. The method includes calculating, with the electronic device, a relative height difference between the height detected at the benchmark surface and the height detected at the survey location.

[0019] The method may include storing the elevation of the benchmark surface in the electronic device and adding the elevation of the benchmark surface to the height at which the laser beam intersects the survey staff standing on the benchmark surface, thereby to calculate a laser beam level height saved in the electronic device.

[0020] The method may include storing a required elevation for the survey location in the electronic device and calculating a difference between the required elevation at the survey location and a surveyed elevation of the survey location.

[0021 ] In another aspect, a survey staff comprises

a plurality of elongate staff sections;

a connecting mechanism that is operatively arranged on at least two consecutive staff sections to permit the consecutive staff sections to be connected or disconnected between extended and retracted conditions, respectively; a laser receiver arranged on each of the at least two consecutive staff sections and configured to detect a laser signal and to generate a signal related to an impingement location on one of the staff sections at which the laser signal impinges the receiver; and

a processor operatively connected to the laser receiver and configured to receive the signal generated by the laser receiver and to generate a signal carrying data related to the impingement location.

[0022] A detector may be operatively connected to the at least two staff sections and to the processor, and is operable to generate a signal, to be received by the processor, when the staff sections are connected or disconnected.

[0023] A switch mechanism may be arranged between consecutive staff sections and is configured to connect, electrically, the laser receiver of one of the consecutive staff sections to the laser receiver of the other staff section when the staff sections are connected and to disconnect, electrically, the laser receivers from each other when the staff sections are disconnected.

[0024] The processor may be configured to determine whether or not the staff sections are connected together as a result of the state of the switch mechanisms.

[0025] A communications device or module may be operatively connected to the processor and may be configured to receive the signal from the processor and to transmit the signal to a signal receiver.

[0026] The communications device may be configured to generate a wireless communications signal for receipt by a wireless communications apparatus having the signal receiver.

[0027] The connecting mechanism may be a sliding mechanism interposed between the staff sections so that the staff sections can slide relative to each other between the extended and retracted conditions while being retained together.

[0028] The staff sections may have consecutively decreasing cross-sectional areas from a narrowest staff section to a broadest staff section and at least the broadest staff section defines an internal passage in which a narrower staff section can be received so that the staff sections can extend or retract, telescopically.

[0029] Each staff section may include an elongate housing, the dimensions of which define its cross-sectional area and the laser receiver is positioned in the housing. [0030] Each laser receiver may include a linear array of laser detectors positioned on the staff section and extending between ends of the staff section, the laser detectors having a

predetermined spacing to establish a measurement resolution capacity of the survey staff.

[0031 ] Each laser receiver may include laser detection circuitry positioned in the housing and the array of laser detectors connected to the laser detection circuitry and mounted at a detection angle that is generally orthogonal to a longitudinal axis of the housing.

[0032] An electrical connector may be arranged on the laser detection circuitry for connecting the laser detection circuitry in one housing to the laser detection circuitry in a consecutive housing.

[0033] The electrical connectors may be positioned so that the laser detection circuitry of one staff section is connected to the laser detection circuitry of the consecutive staff section when the staff sections are in the extracted condition.

[0034] Each housing may include a protective structure that defines a series of detector openings in register with respective laser detectors.

[0035] The protective structure may define a series of windows at a facing surface and passageways between respective detector openings and windows, the windows being spaced outwardly from the detector openings.

[0036] The protective structure may include a series of spaced, parallel partitions and passage walls, the partitions and passage walls defining the passageways and the passage walls diverging from each other from the detector openings to the windows.

[0037] In each staff section, the housing may include a back wall and a pair of sidewalls, the protective structure being mounted between the sidewalls with the laser detection circuitry being interposed between the back wall and the protective structure.

[0038] The protective structure and the sidewalls may include complementary engaging formations so that the protective structure can engage the sidewalls and be retained in position by the engaging formations.

[0039] A translucent screen is mounted on each staff section to cover the windows. The translucent screen may be an optical filter.

[0040] The communications device and the processor may be mounted in a control housing that is fastened to one of the staff sections. The processor may include a microcontroller that is operatively connected to the laser detection circuitry in the staff section on which the control housing is mounted, and to the laser detection circuitry in the consecutive staff section, when the staff section and the consecutive staff section are in the extended condition.

[0041 ] The microcontroller may be operatively connected to the laser detection circuitry with multiplexer circuitry so that the microcontroller can receive signals from the laser detection circuitry of one or more staff sections, depending on whether or not the staff sections are in the extended condition.

[0042] The communications device may include a wireless communications module that is configured to generate a wireless signal according to a standard communications protocol, the communications module being connected to the microcontroller, the microcontroller being configured to control operation of the communications module to transmit signals relating to the impingement location on the relevant staff section.

[0043] A GPS module may be operatively connected to the microcontroller to provide a location signal to the microcontroller.

[0044] A user interface may be connected to the microcontroller, the user interface including a display and an actuating mechanism configured to permit an operator to actuate the laser receivers and the microcontroller.

[0045] A level sensing device may be connected to the microcontroller and may be configured to generate a signal corresponding to an orientation of the survey staff, the microcontroller being configured to display information relating to the orientation on the display of the user interface.

[0046] The processor may be configured to be connected to a wireless communications device to relay the signal to the wireless communications device.

[0047] Each laser detector may include a polarized lens. Instead, each laser detector may include a polarized film positioned on a lens of the laser detector.

[0048] Each laser detector may include an optical filter.

[0049] An aspect of a survey system comprises:

a survey staff, the survey staff including a plurality of elongate staff sections, a connecting mechanism that is operatively arranged on at least two consecutive staff sections to permit the consecutive staff sections to be connected or disconnected between extended and retracted conditions, respectively, a laser receiver arranged on each of the at least two consecutive staff sections and configured to detect a laser signal and to generate a signal related to an impingement location on one of the staff sections at which the laser signal impinges the receiver, and a processor operatively connected to the laser receiver and configured to receive the signal generated by the laser receiver and to generate a signal carrying data related to the impingement location; and

a wireless communications device that is configured to receive the signal generated by the processor.

[0050] An aspect of a method of surveying comprises the steps of:

positioning a survey staff on a predetermined location, the survey staff including a plurality of elongate staff sections, a connecting mechanism that is operatively arranged on at least two consecutive staff sections to permit the consecutive staff sections to be connected or disconnected between extended and retracted conditions, respectively, a laser receiver arranged on each of the at least two consecutive staff sections and configured to detect a laser signal and to generate a signal related to an impingement location on one of the staff sections at which the laser signal impinges the receiver and a processor operatively connected to the laser receiver and configured to receive the signal generated by the laser receiver and to generate a signal carrying data related to the impingement location; and

operating a laser level so that a laser beam emitted by the laser lever strikes one of the staff sections.

BRIEF DESCRIPTION OF THE DRAWINGS

[0051 ] Figure 1 is a front view of an embodiment of a survey staff with staff sections in a retracted condition.

[0052] Figure 2 is a front view of the survey staff of figure 1 , with two consecutive staff sections showing one of the sections of the staff extended.

[0053] Figure 3 is a front view of the survey staff of figure 1 , showing two of the staff sections extended.

[0054] Figure 4 is a front view of the survey staff of figure 1 , showing three of the sections extended.

[0055] Figure 5 is a front view of the length-adjustable staff of figure 1 , showing all of the sections extended.

[0056] Figure 6 is a layout diagram of electronic components of the survey staff of figure 1 . [0057] Figure 7 is a front view of a survey system including the survey staff of figure 1 and a wireless communications device mounted on to the survey staff with a bracket.

[0058] Figure 8 is a side view of a survey system including the survey staff of figure 1 , in use.

[0059] Figure 9 is a side view of the survey system of figure 8, used for surveying an elevation of an excavation.

[0060] Figure 10 is a wireless communications device used with or forming part of the survey system of figure 8.

[0061 ] Figures 1 1 to 14 show sections of a building plan that is surveyed by the survey system of figure 8.

[0062] Figure 15 shows a side view of the survey system of figure 8 being used to survey a grade between two points on a site.

[0063] Figure 16 shows a side view of the survey system of figure 8 being used to survey an overhead ceiling height relative to a floor.

[0064] Figure 17 shows a three dimensional view of a further embodiment of a survey staff with two consecutive staff sections retracted and disconnected from a bottom staff section.

[0065] Figure 18 shows a three dimensional view of the survey staff of figure 17 with a bottom staff section connected to an intermediate, extended staff section and a top, retracted, staff section disconnected from the intermediate and bottom staff sections.

[0066] Figure 19 shows a three-dimensional view of the survey staff of figure 17 with all three of the staff sections connected to each other and extended.

[0067] Figure 20 shows a three-dimensional view of part of the survey staff of figure 17 having an extension assembly connected to a lower end of the bottom staff section.

[0068] Figure 21 shows a three-dimensional view of the extension assembly in an extended condition.

[0069] Figure 22 shows a top plan view of the survey staff of figure 17.

[0070] Figure 23 shows a connecting assembly for connecting the bottom staff section to the extension assembly. [0071 ] Figure 24 shows another view of the connecting assembly of figure 23.

[0072] Figure 25 shows a sectioned view of the connecting assembly of figure 23.

[0073] Figure 26 shows a locking assembly for releasably locking extension members of the extension assembly together.

[0074] Figure 27 shows part of a laser receiver of any of the staff sections.

[0075] Figure 28 shows a sectioned, cut-away view of part of the top staff section.

[0076] Figure 29 shows another sectioned, cut-away view of the part of the top staff section.

[0077] Figure 30 shows another sectioned, cut-away view of the part of the top staff section with a screen in position.

[0078] Figure 31 shows a connection between the intermediate and top staff sections.

[0079] Figure 32 shows a sectioned view of a region in which the intermediate and top staff sections are connected together.

[0080] Figure 33 shows a sectioned view of the intermediate and top staff sections, illustrating an electrical connection between laser detector circuitry of the intermediate and top staff sections.

[0081 ] Figure 34 shows a sectioned view of a region in which the first and second staff sections are connected together, with the second staff section in a condition prior to detachment from the first staff section.

[0082] Figure 35 shows a sectioned view of the region of figure 33 with the bottom and intermediate staff sections attached to each other.

[0083] Figure 36 shows a sectioned view of a region in which the intermediate and top staff sections are connected together.

[0084] Figure 37 shows a sectioned view of a region in which the intermediate and top staff sections are disconnected.

[0085] Figure 38 shows an electronic circuit layout diagram of the survey staff. [0086] Figure 39 shows a schematic layout of the survey staff.

Detailed Description of the Drawings [0087] In figures 1 to 5, reference numeral 10 generally indicates an embodiment of a survey staff. The survey staff includes five stages, segments or staff sections 12.1 to 12.5. The sections 12.1 to 12.5 are collectively referred as sections 12 for ease of reference. However, where a reference numeral with a suffix of either .1 , .2, .3, .4, .5, is used to indicate a component, that reference numeral is intended to indicate the component on the respective staff section 12.1 to 12.5.

[0088] The survey staff 10 is length-adjustable to be in different configurations or states of extension as shown in figures 1 to 5. The sections 12 are configured so that they can slide relative to each other in a telescopic manner. The sections 12 are each approximately 1 metre long, making the staff 10 approximately 5 metres long when all the sections 12 are fully extended, as shown in Fig. 5. It will be appreciated that the lengths mentioned herein are exemplary only, and that different lengths may be used as desired.

[0089] Each section 12 is a hollow member 13 formed from a rigid material such as extruded aluminium, plastic material or a composite material. The section 12.1 is an operatively top-most section of the survey staff 10 and the section 12.5 is an operatively bottom-most section. A base 14 of the survey staff 10 is defined by the underside of the bottom-most section 12.5. A top 16 of the survey staff 10 is defined at the top of the top-most section 12.1 . The survey staff 10 is lengthened by extending the sections 12, and the survey staff 10 is shortened by collapsing the sections 12.

[0090] The widths of the sections 12 are different to each other in a stepped arrangement in which the sections 12 are received one within the other in telescopic fashion. In another embodiment, the sections 12 are connected in an arrangement in which the sections are one behind the other and relatively displaceable between collapsed and extended states of the survey staff 10. In this entire description, other methods of connection are envisaged. These can include connecting sections together which were previously discreet sections, stored discreetly as opposed to being in a telescopic or mounted arrangement.

[0091 ] The sections 12 each include a longitudinally extending laser receiver 20 in the form of a linear array of photodiodes 24. The different laser receivers 20 together form a substantially continuous linear laser receiver arrangement 22. In one embodiment, not shown, the bottom-most section 12.5 may not have a laser receiver 20. [0092] Photodiodes 24 are mentioned as one example of opto-electric elements which can detect a laser beam, but the laser receivers 20 can also be a linear array of phototransistors, light- dependent resistors, or semiconductor diodes.

[0093] Each section 12 has a collar 18 at its upper end. The survey staff 10 can include photodiodes 24 on the collars 18, which align with the laser receivers 20 of adjacent sections 12. The photodiodes 24 on the collars 18 ensure that the laser receiver arrangement 22 is continuous along the length of the survey staff 10. Figure 5 shows an embodiment of the survey staff 10 including photodiodes 24 on the collars 18 to avoid any photodiode gap between the laser receivers 20 of the adjacent sections 12.

[0094] The photodiodes 24 are photodetectors with a spectral response to output a voltage signal when struck by a laser beam in a particular wavelength range. The wavelength range may be a range for a red laser beam and/or a range for a green laser beam, or laser beams of any other suitable wavelength. The photodiodes 24 may be sensitive to red and/or green laser beams, or any other laser beam colour as discussed with reference to the laser level. The photodiodes 24 are between 0.5mm and 3mm wide, for example about 2mm wide. It will be appreciated that the widths mentioned herein are exemplary only, and that different widths may be used as desired. The width of the photodiodes 24 is measured in a longitudinal direction of the laser receiver 20. The photodiodes 24 are packed one against the other in a linear array along each section 12 to form the laser receivers 20. The detection resolution of the laser receivers 20 is a function of the width of the photodiodes 24. In the present example of a linear array of 2mm wide photodiodes 24, the resolution or height accuracy of the survey staff 10 is about 2mm. In the example where the laser receivers 20 are each approximately 1 m long, each laser receiver 20 can include a linear array of approximately five hundred photodiodes 24. The photodiodes 24 can be arranged on the respective members 13 in a staggered formation bringing them closer together and increasing the resolution or accuracy of the height measurements.

[0095] The photodiodes 24 are connected to a laser detector circuit as discussed in more detail below with reference to figure 6.

[0096] The sections 12 lock together when extended. The sections 12 may lock together with clip locks 26. The clip locks 26 are spring-activated and lock into holes in the side of an adjacent section 12. The sections 12 can lock together in their extended positions by other means such as clamps or screws or ratchets. In an embodiment in which the sections 12 are round poles, the sections 12 can include twist-lock mechanisms so that the sections 12 can be locked together by twisting the sections 12 relative to each other. [0097] The survey staff 10 includes detectors in the form of a number of switches or sensors which change status when one section 12 moves to an extended position relative to an adjacent section 12. For example, one of the switches activates upon the section 12.4 being extended from section 12.5. The switches may form part of the clip locks 26, such that the switch is activated upon the clip locks 26 locking sections 12 in the extended position.

[0098] The switches are connected to a microcontroller, as discussed in more detail with reference to figure 6. The status of the switches is an input to the microcontroller of the current configuration or extension state of the survey staff 10. For example, if the switch between section 12.4 and section 12.5 is activated, but no other switches are activated, then only the second section 12.4 from the bottom is extended. When all the switches are activated then all the sections 12 are extended, as shown in figure 5. When the switch between section 12.4 and section 12.5 is activated, and the switch between section 12.3 and section 12.4 is also activated, but no other switches are activated, then only the second and third sections 12.3 and 12.4 are extended, as shown in figure 3.

[0099] The switches may include a pin in one section 12 which plugs into a plug of an adjacent section 12. When the pin and plug connect, a circuit is closed which is an input to the

microcontroller. The switches may be contact pairs with a switch including a contact at the bottom of one section 12 which contacts a contact at the top of an adjacent section 12 when the two sections 12 are extended relative to each other. The contact pair closes a circuit when in contact, which sends a signal to the microcontroller.

[0100] Referring to figure 6, a layout diagram of electronic components of the survey staff 10 is shown. The electronic components can be housed in one of the sections 12, for example, the bottom-most section 12.5. The electronic components can, instead, be housed in a casing secured to one of sections 12.

[0101 ] The survey staff 10 includes a processor or control circuitry in the form of a

microprocessor or microcontroller 30. A multiplexer circuit 32 is an input to the microcontroller 30. The multiplexer circuit 32 is connected to the respective photodiodes 24 of the linear laser receiver arrangement 22. The multiplexer circuit 32 combines many signals into a single transmission circuit or channel to the microcontroller 30.

[0102] The microcontroller 30 can be configured to activate only the laser receivers 20 of the sections 12 which are extended and visible. Alternatively, only the laser receivers 20 which are visible may be electrically connected to the multiplexer circuit 32. [0103] The survey staff 10 includes a GPS module 36, which provides a location signal to the microcontroller 30. The GPS module 36 can be any module for receiving signals from a global navigation satellite system, for example the Global Positioning System.

[0104] The microcontroller 30 is configured to communicate with a wireless communications device using a wireless communications module 38. The communications module 38 can include a Bluetooth module 40 and/or a Wi-Fi module 42 and/or an RF module.

[0105] The survey staff 10 includes a user interface 44 connected to the microcontroller 30. The user interface 44 includes an LED or LCD screen 46, and a switch or power button 48.

Survey staff 10 is powered up or down using the power button 48.

[0106] The switches that indicate the extension configuration of the staff 10 are indicated in figure 6 by reference numeral 50. The switches 50 are an input to the microcontroller 30 to determine the extension configuration of the staff 10, as discussed. The length of the staff 10, measured between the base 14 and the top 16, differs depending on the extension configuration of the sections 12.

[0107] The survey staff 10 optionally includes a Level Sensor or Gyro 52 that indicates the vertical attitude or orientation of the survey staff 10. The vertical attitude or orientation can be displayed on the screen 46 of the staff 10 and/or be transmitted to be displayed on a screen of the wireless communications device.

[0108] When a laser beam strikes one of the photodiodes 24, a signal from the multiplexer circuit 32 indicates to the microcontroller 30 which photodiode 24 was struck. The microcontroller 30 includes a memory with data representing the distance of each photodiode 24 from the base 14 and the top 16 of the staff 10 for different extension configurations of staff 10. Taking into account the specific extension configuration of the staff 10, and the particular photodiode 24 which has been struck by the laser beam, the microcontroller 30 is able to calculate a distance between the base 14 or the top 16 and the photodiode 24 being struck. The distance is referred to as the Staff Strike Height. The Staff Strike Height for each photodiode 24 is known and stored in a lookup table in the memory of the microcontroller 30.

[0109] The microcontroller 30 is operable to have the Staff Strike Height displayed on the screen 46. The microcontroller 30 is operable to transmit the Staff Strike Height as data to a mobile wireless communications device via the communications module 38. The microcontroller 30 can be configured so that the screen 46 can display additional information on the operational status of the staff 10, including battery charge status, wireless connection status of the communications module 38, how many sections 12 are detected as being extended, and a current extended length of the staff 10.

[01 10] A battery 34 of the survey staff 10 energises the different electronic components shown in figure 6. The battery 34 can be replaceable alkaline batteries or rechargeable batteries. In the embodiment in which the battery 34 is rechargeable, the staff 10 can be provided with a plug-in charger to recharge the battery 34.

[01 1 1 ] Figure 7 shows a wireless communications device, for example a cell phone or smartphone 56, mounted to the survey staff 10. The smartphone 56 communicates with the survey staff 10 as discussed in more detail below. The smartphone 56 is mounted to the survey staff 10 using an adjustable bracket 55. The bracket 55 clamps onto any section 12 of the survey staff 10 and is adjustable up and down the length of the staff 10. The bracket 55 includes a clamp 57. The bracket 55 is a universal holder able to receive and support different sizes, makes and models of phone.

[01 12] Referring to figures 8 and 9, the survey staff 10 is shown communicating with a mobile wireless communications device in the form of the smartphone 56 held by an operator 58. The smartphone 56 can also be held in the bracket 55, clamped to the staff 10, as described with reference to figure 7. A software application, hereinafter referred to as a "Survey App", is run or executed by the smart phone 56.

[01 13] A survey system 60 includes the survey staff 10 and the smart phone 56 on which the Survey App is executed. The survey system 60 includes a laser level 62 supported on a tripod 66.

[01 14] The smartphone 56 is preferably a commercially available, conventional smartphone. Some of the basic functions the smartphone 56 preferably includes are: a touch sensitive graphical screen interface 54; a wireless communications receiver such as a Bluetooth module and/or a Wi-Fi module; a cellular radio transceiver; a Global Navigation Satellite System (GNSS) radio or receiver in the form of a GPS receiver; and the ability to run or execute a software application.

[01 15] In the examples that follow, specific coding for the Survey App has been omitted for simplicity as a person of ordinary skill in the art would be able to understand and reproduce the functionality of the described embodiments without the need for discussion on particular coding. Although a smartphone is described as an example of a mobile communications device, the mobile communications device may be a PDA, a laptop, a tablet, or any similar mobile device capable of wireless communication. [01 16] The location for download of the Survey App can depend on the operating system of the smartphone 56. In one embodiment, the smartphone 56 is an iPhone®, manufactured and sold by Apple, Inc. and running the iOS operating system. For phones running the Android ® operating system the Survey App may be downloaded from the Google Play ® store and similarly for phones running the Windows ® operating system the Survey App may also be downloaded.

[01 17] The Survey App is typically used in combination with one or more processors of the smartphone 56, and, where it is hosted, configures what might otherwise be a general purpose processor into a special purpose processor according to the functions and parameters of the Survey App. Preferably, the Survey App is downloaded to a computer-readable medium such as a memory in the smartphone 56, or a non-transitory computer-readable medium.

[01 18] For ease of description, functions of the smartphone 56 described below should be regarded as functions that are facilitated when the smartphone 56 executes the Survey App.

[01 19] The operator 58 downloads the Survey App to the smartphone 56. The Survey App is installed on the smartphone 56 and can be launched in the conventional manner known for launching installed applications for the operating system of the smartphone 56.

[0120] Launching the Survey App establishes a wireless communications link between the smartphone 56 and the staff 10. The wireless communications link between the smartphone 50 and the staff 10 can be established using Bluetooth and/or a Wi-Fi and/or any other suitable wireless communications protocol, for example a conventional wireless communications protocol.

[0121 ] In use, the staff 10 is struck by a laser beam 64 which is projected or emitted from the laser level 62 and intersects or impinges on the laser receiver arrangement 22. The laser level 62 can be self-levelling so that the laser beam 64 is in a generally horizontal plane.

[0122] The laser level 62 can be any commercially available laser level, such as a Rotary Laser Level, Dot Laser Level or Line Laser Level available from Johnson Level & Tool Mfg. Co., Inc. Other examples of commercially available laser levels include the DeWalt Brand of Self Levelling Line Lasers, Self-Levelling Rotary Lasers and Spot Lasers. The laser level 62 may typically emit or project a green-beam laser, or a red-beam laser, as is known in the art of laser levels. Other laser beam colours of laser beam emitters that are available include: blue laser beams with a wavelength of approximately 473nm; violet laser beams with a wavelength of approximately 405nm; and yellow laser beams with a wavelength of approximately 593.5nm. Laser level 62 may emit or project a rotary laser beam, a spinning laser beam, a fanned laser or a straight-line laser beam. The laser beam 64 may be a constant beam or may be pulsed. [0123] The Survey App, when executed on the smartphone 56, configures the smartphone 56 and the survey staff 10 to enable the features and modes described below.

[0124] The "Bench Mark Height" is a term used to describe a height value or elevation of a local datum point, the bench mark, established on or near a building or construction site to be surveyed. The Bench Mark Height and the location of the bench mark is known. Bench marks are sometimes small disks, pins or bolts that are permanently attached to a stable foundation, such as posts, kerb stones, footings, buildings, or concrete blocks. The bench mark may be marked with the elevation of the bench mark relative to a National Datum such as the Australian Height Datum.

[0125] In figures 8 and 9, the bench mark is a bench mark surface 70 at the top of a mound. The Bench Mark Height, being the elevation of the bench mark surface 70 relative to the Australian Height Datum, is known. The Bench Mark Height is marked on the bench mark surface 70 and/or indicated on a construction site map.

[0126] The operator 58 enters the Bench Mark Height into a field in the Survey App. The Survey App can prompt the operator 58 to enter the Bench Mark Height. The Bench Mark Height is stored in the memory of the smartphone 56 and can be recalled to be displayed on the screen 54.

[0127] The laser level 62 can be placed at a location where points to be measured on site have line-of-sight to the laser level 62. The laser level 62 is then switched on and given time to self- level. The laser level 62 can stand on a tripod 66 or can be placed on some other structure or level surface.

[0128] The base 14 of the staff 10 is placed on the benchmark surface 70. The staff 10 is stood vertically upright with the required number of sections 12 extended so that the staff 10 stands taller than the laser level 62. The laser beam 64 intersects the survey staff 10.

[0129] The staff 10 continuously measures and transmits the vertical distance relative to the base 14 at which the laser beam 64 strikes the staff 10. The vertical distance relative to the base 14 at which laser beam 64 strikes staff 10 is referred to as the "Staff Strike Height". Data representing the Staff Strike Height is wirelessly transmitted to the smartphone 56. The Staff Strike Height can also be displayed on screen 46 of staff 10.

[0130] The operator 58 stores the Staff Strike Height with the Survey App once he or she is satisfied that the staff 10 and the laser level 62 are functioning properly and the staff 10 is correctly positioned on the bench mark surface 70. [0131 ] The smartphone 56 calculates what is referred to as a "Laser Beam Level Height", being the sum of the Bench Mark Height and the Staff Strike Height. For example, if the Bench Mark Height of the bench mark surface 70 is 3.14m and the Staff Strike Height when standing the staff 10 on the bench mark surface 70 is 1 .50m, then the Laser Beam Level Height is 4.64m. The Smartphone 56 displays the calculated Laser Beam Level Height on the screen 54 of the smartphone 56. The Laser Beam Level Height can also be displayed on the screen 46 of the staff 10. The Laser Beam Level Height remains current for as long as the laser level 62 is supported at the same elevation on site. In the present example, the Laser Beam Level Height is the elevation of the laser beam 64 relative to the National Datum.

[0132] What is referred to as "Reduced Level" points are commonly shown on a site map or drawing and indicate the required height or elevation of a point on the site. The height or elevation of a Reduced Level point is measured relative to the National Datum or a local datum. For example, if the Bench Mark Height for a bench mark surface 70 is 3.14m and the height of a Reduced Level point on the construction site is 2.00m, then the Reduced Level point is 1 .14m below the bench mark surface 70.

[0133] In what is referred to as "Reduced Level Mode", the Laser Beam Level Height is calculated and stored in the Smartphone 56 as described above. For example, the staff 10 is stood upright on the bench mark surface 70 with a known height of 3.14m. The photodiode 24 which is struck with the laser beam 64 while the staff 10 is standing on the bench mark surface 70 is "assigned" the height of 3.14m by the Smartphone 56. The photodiodes 24 of the laser receiver arrangement 22 above the photodiode 24 struck while standing on the bench mark surface 70 represent heights less than 3.14m by the distance they are spaced from the photodiode 24 assigned the 3.14m height. For example, if the staff 10 is moved to a position on site where the laser beam 64 strikes the staff 10 a distance of 0.5m above the photodiode assigned the 3.14m height, then the base 14 of the staff 10 is standing at a height of 2.64m. That is because the base 14 of the staff 10 has moved downwardly 0.5m in the vertical direction. The alternate applies for photodiodes 24 below the photodiode 24 assigned the 3.14m height. Photodiodes 24 below the photodiode 24 struck while standing on the bench mark surface 70 represent heights more than 3.14m by the distance they are spaced from the photodiode assigned the 3.14m height. The staff 10 may be placed vertically upright on any Reduced Level point on site and the Smartphone 56 will display the current elevation of the Reduced Level point, which is the height of the base 14 when the staff 10 stands on the Reduced Level point. The smartphone 56 can request the operator 58 to confirm that the staff 10 is standing on a Reduced Level point to be measured and requires the height as measured at the bottom of the base 14 to be displayed. [0134] Referring to figure 9, a Reduced Level point RLi is indicated by a broken line. The Reduced Level point RLi is below the bench mark surface 70. RLi indicates the desired level of excavation at that point, for example the level of a sub grade or trench 72.

[0135] In what is referred to as a "Cut/Fill Mode", the RLi value is known to the operator 58 and is entered into the smartphone 56. The RLi value can, for example, be 2.00m, purely for illustrative purposes.

[0136] In use, the smartphone 56 requests that the operator 58 place the staff 10 at the current elevation of the surface above or below point RLi. The staff 10 is positioned vertically above or below the point RLi with the base 14 at the current level of excavation. The Staff Strike Height of the staff 10 is transmitted to the smartphone 56.

[0137] The operator 58 inputs an indication to the smartphone 56, that the current elevation at RLi is being measured. The smartphone 56 displays the difference between the current elevation being measured and the RLi height.

[0138] Referring to figure 9, the staff 10 is stood in the trench 72 with the base 14 vertically above the point RLi . The staff 10 transmits a Staff Strike Height of 1 .75m to the smartphone 56. The smartphone 56 can calculate the current height at which the base 14 is located as the difference between the Laser Beam Level Height (4.64m) and the Staff Strike Height of 1 .75m. The smartphone 56 calculates that the base 14 stands at a height of 2.89m. The height of the base 14 at the current elevation can be displayed on the screen 54 of the smartphone 56 and can be displayed on the screen 46 of staff 10.

[0139] The smartphone 56 displays the elevation difference between the current elevation above/below point RLi and the desired level of RLi . In the example above where the current level above point RLi, as indicated by the height of base 14, is 2.89m, and the required level of RLi as saved in the smartphone 56 is 2.00m, the difference displayed to the operator 48 is 0.89m by which a depth of a trench 72 needs to be increased.

[0140] Figure 10 shows the screen 54 of the smartphone 56 with a user interface during Cut/Fill Mode. The Current Elevation of 2.89m as measured by the staff 10 is displayed. The desired level of RLi as input into the smartphone 56 is displayed. The vertical "CUT" distance which is required to be excavated to reach RLi is displayed as 0.89m.

[0141 ] In the instances where the current excavation level is below RLi , the Survey App will display "FILL", and by how far/deep the excavation is to be filled to get to RLi . [0142] Bench Mark Mode can be used when the height to a bench mark needs to be measured for multiple points on a terrain. An example is where a house is to be built on undulating terrain and the required column heights supporting a horizontal floor is required at various places on the terrain.

[0143] In Bench Mark Mode, the Laser Beam Level Height is calculated by the smartphone 56 executing the Survey App as discussed. The smartphone 56 requests an RL height to be entered, which is a desired height for a building structure(s). For example, the RL height may be the top of a column for supporting a floor.

[0144] The staff 10 can then be stood at various locations on site and the smartphone 56 displays the vertical height from the base 14 of the staff 10 to the required RL height.

[0145] An example use case of Bench Mark Mode is described below with reference to figures 1 1 to 14.

[0146] Referring to figure 1 1 , a floor surface 80 of a ground floor 82 of a house is required to be at RL height 25.665m as indicated on the building plan.

[0147] Referring to figure 12, the floor 82 has a thickness of 320mm, such that the top of a column 84 supporting the floor 82 is required to be at an RL height of 25.345m. The required RL height of 25.345m is entered into the smartphone 56, executing the Survey App, being the required height at the top of all of the columns supporting floor 82.

[0148] Floor 82 is to be supported by a number of columns at locations marked P1 on the building plan of figure 13. The different locations P1 are at different elevations due to the undulating terrain on which the house is to be built. The columns at each of the locations P1 thus each have a different length or vertical extension so that the tops of all of the columns are all at the same RL height.

[0149] Referring to figure 14, the top of a concrete base 86 at a P1 location for a column is at 23.5m as measured by the survey system 60. Placing the staff 10 upright on the base 86 in Bench Mark Mode will result in the smartphone 56 indicating that the column at this location needs to be built 1 .845m tall to reach the required RL height of 25.345m. The smartphone 56 calculates the height of the column to be built relative to the top of the base 86 as the required RL height at the top of the column (25.345m), less the 23.5m measured by staff 10 as the top of the base 86.

[0150] The procedure is repeated for all the P1 locations where a column is to be built and the smartphone 56 instantaneously displays the required column height for the different P1 locations. The different heights for the different columns can be stored by the smartphone 56 and overlayed onto the construction drawing shown in figure 13.

[0151 ] The smartphone 56 can operate in what is referred to as "Grade Mode" when the operator 58 requires a grade to be calculated between two points.

[0152] Referring to figure 15, in Grade Mode the smartphone 56 requests the operator 58 to place the staff 10 at a first point 90. The operator 58 inputs an indication to the smartphone 56 that the staff 10 is at the first point 90. The smartphone 56 can prompt the operator 58 to indicate that the staff 10 is at the first point 90. The smartphone 56 stores the Staff Strike Height at the first point 90. The smartphone 56 also stores the GPS coordinates of the first point 90 as provided by the GPS module 36 of the staff 10.

[0153] The operator 58 is then instructed by the smartphone 56 to move the staff 10 to a second point 92. The operator 58 inputs an indication to the smartphone 56 that the staff 10 is at the second point 92. The smartphone 56 can prompt the operator to indicate when the staff 10 is at the second point 92. The smartphone 56 stores the Staff Strike Height at the second point 92. The Survey App also stores the GPS coordinates at the second point 92.

[0154] The smartphone 56 can calculate the vertical elevation difference between the first point 90 and the second point 92, by calculating the difference between the Staff Strike Height at the first point 90 and the Staff Strike Height at the second point 90.

[0155] The smartphone 56 calculates the horizontal distance "D" between the first point 90 and the second point 92, by using the GPS coordinates at the first and second points. The horizontal distance between the two points 90 and 92 may also be measured using conventional means or may be known from a site map.

[0156] The grade between the two points 90 and 92 is calculated by the smartphone 56 using the elevation difference between the points 90, 92 and the horizontal distance between the points 90, 92. As an example, the elevation difference between the two points 90, 92 may be measured as 1 .00m. The horizontal distance between the two points 90, 92 may be measured as 25m using the GPS function. The smartphone 56 displays the grade between the two points as 4%, being (1 .00m/25m) x 100.

[0157] The GPS capability of the staff 10 renders the survey system 60 useful to take horizontal measurements between points on a site and for setting out point locations on a site. [01 58] In what is referred to as inverted Level Mode", the top 1 6 of the staff 10 is the reference on the staff 1 0 for surveying an overhead point. The Inverted Level Mode may be used to set or survey a ceiling height, a bulkhead height, or a soffit height, for example.

[01 59] Referring to figure 1 6, the survey system 60 is used in Inverted Level Mode to measure the height of a ceiling 94. A floor 96 may be a bench mark surface with a bench mark value of 0m. Staff 1 0 is stood on the floor 96 with the base 14 of the staff 1 0 resting on the floor 96. The Staff Strike Height when the staff 10 is standing on the floor 96 is measured and automatically entered into the smartphone 56. The Staff Strike Height is the Laser Beam Level Height in the instance where the staff 1 0 stands on the bench mark surface and the bench mark surface height is 0m.

[01 60] It may be necessary to survey the height of the ceiling 94 as measured relative to the floor 96. The smartphone 56 is operated in Inverted Level Mode, meaning the smartphone requests the top 1 6 of the staff 10 to be placed against the surface to be surveyed. The staff 1 0 is raised so that the top 1 6 buts against the ceiling 94. The operator 58 inputs an indication to the smartphone 56 that the top of the staff 1 0 is against the ceiling 94 and the smartphone 56 records the distance from the top 1 6 at which the laser beam 64 strikes the staff 1 0. The smartphone 56 can calculate the height of ceiling 94 relative to floor 96, being the sum of the Laser Beam Level Height and the distance measured from the top 1 6 to where the laser beam 64 strikes the staff 1 0.

[01 61 ] In what is referred to as "Averages Mode", the smartphone 56 requests that multiple points be surveyed on the terrain of a site. The smartphone 56 is configured to calculate an average height of the terrain by calculating the average of the heights of the surveyed points.

[01 62] Knowing the average height of the terrain is useful for calculate the expected amount of material to be removed or brought in to bring the terrain to a required height.

[01 63] The terrain boundary dimensions can be stored in the smartphone 56 and the smartphone 56 can calculate the amount of material to be removed or brought in based on the surveyed average height of the terrain.

[01 64] The Averages Mode can also be used by the smartphone 56 to create a 2D or 3D landscape using the multiple points surveyed in Averaged Mode. The 2D or 3D landscape may be saved as a digital plan or map.

[01 65] The surveyed points may be overlaid by the Survey App onto a map of the terrain. [0166] Drawings and plans of a site can be uploaded to the smartphone 56. The drawings and plans include height data of points on the site. The height data can be automatically imported from the plans for the different points, or the operator can enter the height data separately.

[0167] The smartphone 56 can allow the operator 58 to add notes to the drawings prior to surveying heights on site with the staff 10 or subsequent to the survey. The smartphone 56 can permit the operator to enter height data onto the displayed map automatically as points are surveyed.

[0168] It is sometimes useful to mark increments of height, for example for setting brick course height or stair heights.

[0169] The smartphone 56 can operate in what is referred to as an "Increment Mode" in which the survey system 60 indicates to an operator 58 every time the staff 10 is moved a set vertical increment distance. The vertical increment distance is selected by the operator 58 and input into the smartphone 56.

[0170] The increment distance may, for example, be 85mm or 86mm or 87mm or 88 mm for standard brickwork. The increment distance may, for example, be 200mm for standard blocks. The increment distance may be any selected vertical height being the difference in height between two stairs.

[0171 ] The smartphone 56 can generate a discernible signal, such as an audible or visual signal every time the staff 10 is raised or lowered the increment distance relative to a previous increment point.

[0172] In one embodiment, the microcontroller 30 can be configured to actuate a discernible signal mechanism such as an audible signal mechanism, every time the staff 10 is raised or lowered the increment distance relative to a previous increment point.

[0173] In what is referred to as "True Height Mode", the smartphone 56 displays the Staff Strike Height. That is to say that the smartphone 56 displays the distance from the base 14 at which the laser beam 64 strikes the staff 10 along the length of the staff 10. The Staff Strike Height is usually converted to a relative height with respect to a site datum as described for the Reduced Level Mode, Cut/Fill Mode and Bench Mark Mode. In True Height Mode only the distance between the base 14 and where a laser beam strikes the staff 10 is recorded and displayed.

[0174] The Survey App can also be executed by the microcontroller 30 of the survey staff 10, so that the functionality described above with reference to the smartphone 56 is available directly on the survey staff 10 without the need for the smartphone 56. The screen 46 of the survey staff 10 can then, for example, be a touchscreen.

[0175] In another embodiment, the smartphone 56 can dock with the survey staff 10. The survey staff 10 can include a docking station which receives the smartphone 56. Communication between the smartphone 56 and the survey staff 10 can then be via the docking station rather than via wireless communication. The docking station may form part of the bracket 55 clamped to the staff 10.

[0176] Although the survey staff 10 is described as being handheld, the staff 10 may also be mounted on excavation equipment such as graders or loaders.

[0177] In figure 17, reference numeral 100 generally indicates a further embodiment of a survey staff. With reference to the preceding drawings, like reference numerals refer to like parts, unless otherwise specified. The use of such common reference numerals is not intended to indicate that the use of common components is essential. Rather, the use of the common reference numerals is for the purposes of convenience only. Furthermore, where practical and/or feasible, the components described above with reference to the survey staff 10 are interchangeable with the components described below with reference to the survey staff 100, and vice versa.

[0178] The survey staff 100 can be used in the same way as the survey staff 10. It follows that any methods of use of the survey staff 10, described above, apply equally to the survey staff 100, unless clearly indicated, explicitly or implicitly, otherwise. Furthermore, the survey staff 100 can be used together with the smartphone 56, in the same way as the survey staff 10 is used with the smartphone 56 executing the Survey App. Thus, the survey staff 100 can form part of a survey system, together with the smartphone 56.

[0179] The survey staff 100 includes a plurality of elongate staff sections 102. In this embodiment, there are three staff sections, namely an operatively bottom staff section 102.1 , an intermediate staff section 102.2 and an operatively top staff section 102.3. In the following description, where reference numerals are used together with the suffix, .1 , .2, .3, the reference numerals are intended to indicate the components located on the staff section 102.1 , 102.2, and 102.3, respectively.

[0180] A connecting mechanism is arranged on consecutive staff sections to permit the consecutive staff sections 102 to be connected or disconnected. The connecting mechanism will be described in further detail below. [0181 ] A laser receiver 104 is arranged on each of the consecutive staff sections 102 and is numbered, accordingly. The laser receivers 104 are configured to detect a laser signal and to generate a signal related to an impingement location on one of the staff sections 102 at which the laser signal impinges the receiver 104. A processor or microcontroller 232 (figures 38 and 39) is operatively connected to at least one of the laser receivers 104 and is configured to receive the signal generated by the laser receiver 104 and to generate a signal carrying data related to the impingement location.

[0182] In one example, a detector is operatively connected to the staff sections 102 and to the microcontroller 232. The detector is operatively connected to the staff sections 102 to generate a signal, to be received by the microcontroller 232, when two or all three of the staff sections 102 are connected together. The detector can be a proximity sensor or some other form of sensing arrangement interposed between the staff sections 102.1 and 102.2 and between the staff sections 102.2 and 102.3.

[0183] In another example, or in addition to the above example, a switch mechanism is arranged between the staff sections 102.1 and 102.2 and between the staff sections 102.2 and 102.3. One of the switch mechanisms is configured to connect, electrically, the laser receiver 104.2 to the microcontroller 232 when the intermediate staff section 102.2 is connected to the bottom staff section 102.1 . Another of the switch mechanisms is configured to connect, electrically, the laser receiver 104.3 to the microcontroller 232 when the top staff section 102.3 is connected to the intermediate staff section 102.2, which is connected to the bottom staff section 102.1 . Thus, the switch mechanisms can serve to actuate or power up the laser receivers 104 depending on the state of extension or connection of the sections 102 to each other. Furthermore, it will be appreciated that the microcontroller 232 can be configured to determine whether or not the staff sections 102 are connected together and the extent of such connection.

[0184] A communications device or module 234 (figure 38) is operatively connected to the microcontroller 232 and is configured to receive the signal from the microcontroller 232 and to transmit the signal to a signal receiver. The communications module 234 is configured to generate a wireless communications signal for receipt by a wireless communications apparatus, such as a cell phone or smart phone, having a receiver suitable for receiving the wireless communications signal. For example, as mentioned above, the communications module 234 is configured to communicate with the smartphone 56 programmed with the Survey App.

[0185] The connection mechanism is a sliding mechanism. Thus, the staff sections 102 are configured so that the staff section 102.2 can slide relative to the staff section 102.1 from a retracted position in which the staff sections 102.1 and 102.2 are disconnected and an extended condition in which the staff sections 102.1 and 102.2 are connected to each other. Similarly, the staff section 102.3 can slide relative to the staff section 102.2 from a retracted position in which the staff sections 102.3 and 102.2 are disconnected and an extended condition in which the staff sections 102.2 and 102.3 are connected to each other. As described in further detail below, the connections are electrical and not necessarily physical. As described above, with reference to the survey staff 10, various other connecting mechanisms are also possible to connect the staff sections in various ways.

[0186] As can be seen in figures 17 to 19, the staff sections 102 have consecutively decreasing cross-sectional areas from the bottom staff section 102.1 , which is the broadest, to the top staff section 102.3 which is the narrowest. Both the bottom staff section 102.1 and the intermediate staff section 102.2 define internal passages 106. The internal passage 106.1 (figure 34) of the bottom staff section 102.1 has a cross-sectional area which is sufficient to permit the intermediate staff section 102.2 to be received in the internal passage 106.1 . Likewise, the internal passage 106.2 (figure 33) has a cross-sectional area which is sufficient to permit the top staff section 102.3 to be received in the internal passage 106.2. Thus, the staff sections 106 can be displaced so that the survey staff 100 can be in a retracted condition (figure 17), an intermediate condition (figure 18) and an extended condition (figure 19).

[0187] Each staff section 102 includes an elongate housing 108. The dimensions of the elongate housing 108 define the cross-sectional area of the associated staff section 102. The laser receivers 104 are positioned within the respective housings 108.

[0188] Each laser receiver 104 includes a linear array of laser detectors 1 10 positioned in the housing 108 and extending between ends of the housing 108. The laser detectors 1 10 have a predetermined spacing relative to each other to establish a measurement resolution capacity of the survey staff 100.

[0189] Each laser receiver 104 includes laser detection circuitry 1 12 positioned in the housing 108. The array of laser detectors 1 10 is connected to the laser detection circuitry 1 12 and is mounted at a detection angle that is generally orthogonal to a longitudinal axis of the housing 108.

[0190] An electrical connector 1 14 is arranged on the laser detection circuitry 1 12 for connecting the laser detection circuitry 1 12 in one housing 108 to the laser detection circuitry in a consecutive housing 108. The electrical connectors 1 14 are positioned so that the laser detection circuitry 1 12 of one staff section 102 is connected to the laser detection circuitry 1 12 of the consecutive staff section 102 when the staff sections 102 are in the extended condition.

[0191 ] Each housing 108 includes a protective structure 1 16 (figures 29, 30) that defines a series of detector openings 1 18 in register with respective laser detectors 1 10.

[0192] The protective structure 1 16 also defines a series of windows 120 at a facing surface 122 and passageways 1 24 between respective detector openings 1 18 and windows 120. The windows 120 are thus spaced outwardly from the detector openings 1 18.

[0193] The protective structure 1 16 includes a series of spaced, parallel partitions 126 and passage walls 128 diverging from each other from the detector openings 1 18 to the windows 120.

[0194] In each staff section 102, the housing 108 includes a back wall 130 and a pair of sidewalls 132, the protective structure 1 16 being mounted between the sidewalls 132 with the laser detection circuitry 1 12 being interposed between the back wall 130 and the protective structure 1 16.

[0195] As can be seen in figures 17 to 19, each housing 108 has a generally square or rectangular cross-section. In the staff sections 102.1 and 102.2, the housings 108.1 and 108.2 are dimensioned so that the staff section 102.2 is offset towards the back wall 130.1 of the staff section 102.1 and the staff section 102.3 is offset towards the back wall 130.2 of the staff section 102.2. Thus, the protective structure 1 16 and the laser detection circuitry 1 12 is accommodated in the staff sections 102.1 and 102.2.

[0196] The protective structure 1 16 and the sidewalls 132 include complementary engaging formations so that the protective structure 1 16 can engage the sidewalls 132 and be retained in position by the engaging formations 134.

[0197] A translucent screen 136 is mounted on each staff section 102 to cover the windows 120. The translucent screen 136 can be a polarized screen so that the detectors 1 10 receive polarized light. This can alleviate problems associated with optical "noise" generated by other sources of light.

[0198] The communications module 234 and the microcontroller 232 are mounted in a control housing 138 that is fastened to one of the staff sections 102, in this example, the bottom staff section 102.1 . [0199] The microcontroller 232 is operatively connected to the laser detection circuitry 1 12.1 in the staff section 102.1 . The microcontroller 232 is operatively connected to the laser detection circuitry 1 12.2 in the staff section 102.2 when the staff section 102.2 is in the extracted condition relative to the staff section 102.1 . Likewise, the microcontroller 232 is operatively connected to the laser detection circuitry 1 12.3 when the staff section 102.3 is in the extracted condition relative to the staff section 102.2 and the staff section 102.2 is in the extracted condition relative to the staff section 102.1 .

[0200] The microcontroller 232 is operatively connected to the laser detection circuitry 1 12 with multiplexer circuitry so that the microcontroller 232 can receive signals from the laser detection circuitry 1 12 of one or more staff sections 102, in addition to the staff section 102.1 , depending on whether or not the one or more staff sections 102 are in the extended condition.

[0201 ] A cap 141 is mounted on an operatively top end of the housing 108.1 of the bottom staff section 102.1 . A sliding collar 140 is mounted on the housing 108.2 of the intermediate staff section

102.2. The sliding collar 140 is configured to slide along the housing 108.2 and can be positioned to abut the cap 141 , which closes off the bottom staff section 102.1 to protect the internal mechanisms and circuitry of the staff section 102.1 . Likewise, a cap 143 is mounted on an operatively top end of the housing 108.2. A sliding collar 145 is mounted on the housing 108.3 of the top staff section

102.3. The sliding collar 145 is configured to slide along the housing 108.3 and can be positioned to abut the cap 143 to close the intermediate staff section 102.2 to protect the internal mechanisms and circuitry of the staff section 102.2. A cap 107 is mounted on top of the housing 108.3 to protect the internal mechanisms and circuitry of the staff section 102.3.

[0202] As can be seen in figures 17 to 19, a display 142 is mounted or arranged on the control housing 138. The display 142 is connected to the microcontroller 232 to display information to an operator. That information can be the same as information displayed on the screen 46 of the staff 10, or, as envisaged with the staff 10, the same as the information displayed by the smartphone 56.

[0203] In figures 20 and 21 , there is shown an extension assembly 144 for use with the staff 100. The extension assembly 144 includes an operatively lower extension piece 146 and an upper extension piece 148. It will be appreciated that use of the words "lower" and "upper" are only used with reference to the orientation on the figures. It is envisaged that the extension assembly 144 can be used extending upwardly from the survey staff 100, with the survey staff 100 inverted. The extension assembly 144 can also be used with the staff 10 in the manner described below with suitable modifications. [0204] A coupling assembly 150 is mounted on a top end of the upper extension piece 148. The coupling assembly 150 is detachably engageable with a bottom end of the bottom staff section 102.1 .

[0205] The extension pieces 146, 148 are telescopically arranged with respect to each other so that they can be displaced between a retracted condition (figure 20) and an extended condition (figure 21 ). The extension assembly 144 includes a releasable locking assembly 152 mounted on a bottom end of the extension piece 148 and engageable, in a releasable manner, with the extension piece 146 so that the extension pieces 146, 148 can be locked in the extended condition. A further bottom extension piece 154 can be detachably connected to a bottom of the extension piece 146 to further extend the extension assembly 144.

[0206] Further detail of the coupling assembly 150 is shown in figures 23 to 25. The coupling assembly 150 includes a receptacle 156 that is fastened to the top end of the upper extension piece 148. The receptacle 156 defines a recess 158 into which the bottom end of the staff section 102.1 can be positioned. The receptacle 156 has a pair of sidewalls 160 and a back wall 162 that correspond generally with the sidewalls 132.1 and the back wall 130.1 of the staff section 102.1 . Furthermore, the relative dimensions of the receptacle 156 and the staff section 102.1 are such that the bottom end can be a sliding fit within the receptacle 156. The receptacle 156 is open at the front to accommodate the screen 136. Free ends of the sidewalls 160 define retaining formations 164 to engage front ends of the sidewalls 132 to retain the staff section 102.1 in position.

[0207] A locking pin 166 has a shank 168 that is received through an opening 170 in the back wall 162 and into a passageway 172 defined in the back wall 130.1 . Thus, the pin 166 can serve to lock the staff section 102.1 to the receptacle 156.

[0208] The switch mechanism referred to above for detecting connection or disconnection of the staff sections 102 can include an electrical contact assembly 174 mounted internally on the back wall 162 of the receptacle 156. A complementary electrical contact assembly 176 is mounted on the staff section 102.1 and is positioned to engage the contact assembly 174 when the staff section 102.1 is positioned in the receptacle 156, as shown in figure 25. The electrical contact assembly 176 is connected to the microcontroller 232 so that the microcontroller 232 can detect engagement and disengagement of the extension assembly to and from the staff 100.

[0209] Figure 26 shows detail of the manner in which the upper extension piece 148 engages the bottom extension piece 146 with the releasable locking assembly 152. A collar 178 is fastened to a lower end of the extension piece 148. The releasable locking assembly 152 includes an actuator 180 that is mechanically connected to a latch 182 that can engage a recess 184 defined in a passage 186 of the upper extension piece 148. The latch 182 is pivotally mounted on an upper end of the extension piece 146. When the extension piece 146 is extended, the actuator 180 can engage the latch 182 to be operable to displace the latch 182 between a released condition, as shown in figure 26 and an engaged condition in which the latch 182 is received in the recess 184 to lock the extension pieces 146, 148 together in the extended condition. In the released condition, the extension piece 146 can slide along the passage 186.

[0210] Figures 27 to 30 show detail of the laser detectors 1 10 and the laser detection circuitry 1 12, together with the protective structure 1 16 and the back and side walls 130, 132.

[021 1 ] The laser detection circuitry 1 12 includes a printed circuit board (PCB) 188 mounted in each housing 108, between the sidewalls 132. It is envisaged that more than one PCB 188 can be mounted in each housing 108, depending on the application. The laser detectors 1 10 are mounted, in series, on the PCB 188 and in connection with the laser detection circuitry 1 12. The laser detectors 1 10 can be the same as the opto-electric elements or photodiodes 24 or can be in other forms, as described above, with reference to the survey staff 10. Each laser detector 1 10 can be covered by an optical filter 1 1 1 to limit the wavelength of light detected by the detector 1 10 to that of the laser beam 64. For example, the optical filter is a red filter. Each laser detector 1 10 includes a lens 1 13 and a polarized film 1 15 positioned on the lens 1 13. Instead, the lens 1 13 can be polarized. The polarized film 1 15 or the lens 1 13 can be oriented so that the wavelength of the light being detected is horizontally oriented. This can be in correspondence with the orientation of the wavelength of the laser beam 64. Thus, the effects of optical "noise" can be ameliorated with this arrangement. The lens 1 13 can be of a plastics material. The lens 1 13 can itself be an optical filter.

[0212] In one embodiment, each of the housings 102 is about one metre long. Four of the PCB's 188 are mounted in each housing 108. Each PCB 188 includes one microprocessor 189. Fifty laser detectors 1 10 are mounted on each PCB 188 and are spaced about 5 mm apart. Thus, the windows 120 have a similar spacing. The microprocessors 189 are configured to process and the signals from the detectors 1 10, to provide a resolution of about 2.5 mm. It will be appreciated that the thickness of the partitions 126 can vary depending on the application. However, in one embodiment, the thickness can be selected to set the spacing of the laser detectors 1 10. The partitions 126 have planar, internal surfaces 127 that define roofs and floors of the passageways 124. These internal surfaces can be parallel. However, they can also diverge slightly from the detector openings 1 18 to the windows 120 in each passageway 124 to accommodate fabrication restrictions. [0213] Each PCB 188 includes an electronic amplifier. The amplifier is configured to convert an analogue signal to a digital signal. The PCB 188 is configured so that the digital output from each amplifier is multiplexed. For example, the PCB 188 can be configured to reduce fifty digital outputs to fifteen digital address lines, five common address lines and ten common cluster address lines. The address lines are connected to the microprocessor 189.

[0214] In use, the external laser level device emits a continuous rotating beam from a central location, such as the laser beam 64 described above. The beam intersects or impinges upon the relevant staff section 102. Thus, one or two of the laser detectors 1 10 detect light as the beam rotates past, over a few seconds. The microprocessor 189 thus receives a multiplexed signal from the laser detectors 1 10 and decodes the signal to determine which of the laser detectors 1 10 is impinged by the laser beam. As a result, the microprocessor 189 can accumulate an electronic buffer.

[0215] The microprocessor 189 is configured to process the data in the electronic buffer. For example, in order to ensure that the correct signals are processed, the microprocessor 189 only communicates a relevant data signal to the microcontroller 232 once a signal or pulse has been received from a particular laser detector 1 10 or one or two laser detectors 1 10 a predetermined number of times, for example, between twenty and fifty times. The microprocessor 189 can also be configured so as to carry out various signal processing operations, such as electronic filtering, on the data in the electronic buffer. This can allow transfer of data via an l²C bus 236 to the microcontroller 232 for further processing for example into human-readable information.

[0216] The complementary engaging formations include opposite internal engagement formations 190 (figures 29 and 30) that depend from opposite sides of the facing surface 122. Each of the formations 190 defines an outwardly facing recess 192. Each sidewall 132 includes a projection 194 that is received in one of the respective recesses 192. Furthermore, free ends of the sidewalls 132 define inwardly projecting retaining formations 196 that can engage the protective structure 1 16 at opposite sides of the facing surface 122. Thus, the protective structure 1 16 is retained in position between the sidewalls 132.

[0217] Figures 31 and 32 show detail of the manner in which the staff section 102.2 and staff section 102.3 engage each other.

[0218] The collar 140.2 includes a roof portion 192, a side wall 193 and a rear wall 195. The roof portion 192 defines an opening 198 that accommodates the housing 108.3. The roof portion 192 serves to prevent the ingress of detritus into the housing 108.2. [0219] Figure 33 shows detail of an electrical connection between the laser detection circuitry of the staff section 102.3 and the staff section 102.2.

[0220] The electrical connectors 1 14 extend from the PCB 188.2 at an upper end portion 202 of the PCB 188.2. Where there are more PCBs 188.2, the connectors 1 14 are arranged on a topmost PCB 188.2. The connectors 1 14 are in the form of a pair of electrical contacts. The housing 108.3 includes a contact support structure 200 below the PCBs 188.3. The contact support structure 200 is positioned so that when the housing 108.3 is extended from the housing 108.2, the contact support structure 200 overlies or overlaps the upper end portion 202. Two electrical contact members 204 are mounted on the contact support structure 200 to engage respective connectors 1 14 when the housing 108.3 is extended from the housing 108.2. The electrical contact members 204 are electrically connected to the PCB 188.3 so that, when the housing 108.3 is extended from the housing 108.2, the PCB 188.2 and the PCB 188.3 are electrically connected to each other. It is to be understood that the PCB 188.1 is releasably electrically connectable to the PCB 188.2, in the same way, as the housing 108.2 is displaced relative to the housing 108.1 .

[0221 ] The microcontroller 38 and the laser detection circuity 1 12.3 and 1 12.2 are configured so that the microcontroller 38 can communicate with the laser detectors 1 10 on the PCB 188.3.

[0222] The laser detection circuitry 1 12.1 and 1 12.2 of the staff sections 102.1 and 102.2 are connected and disconnected in a similar manner.

[0223] Figure 34 shows a sectioned view of the staff section 102.1 connected to the staff section 102.2. Figure 35 shows a sectioned view of the staff section 102.1 disconnected from the staff section 102.2.

[0224] A push button mechanism 206 is mounted in the control housing 138. The mechanism 206 includes a plunger 208 that extends through the back wall 130.1 and is displaceable between an extended condition (figure 34) in which the plunger 208 extends through an opening 210 in the back wall 130.2 of the housing 108.2 to lock the staff sections 102.1 and 102.3 to each other.

[0225] The mechanism 206 includes a push-button 21 1 that is connected to the plunger 208 with a lever arrangement 212 that is configured so that, as the button 21 1 is depressed, the lever arrangement 212 serves to drive the plunger 208 out of the opening 210. A spring 214 is interposed between the plunger 208 and a wall 216 of the control housing 138 to bias the plunger 208 towards the back wall 130.2. Thus, as the housing 108.2 is extracted or moved from the position shown in figure 35 to the position shown in figure 34, the plunger 208 can be driven into the opening 210 when the plunger 208 and the opening 210 are in register with each other. The push-button 21 1 can be depressed to release the housings 108.2 and 108.3 from each other.

[0226] Figure 36 shows a sectioned view of the staff section 102.2 connected to the staff section 102.3. Figure 37 shows a sectioned view of the staff section 102.2 disconnected from the staff section 102.3.

[0227] The staff section 102.3 has a front wall 216 and a rear wall 218 that is an extension of the back wall 130 below the contact support structure 200. A push-button mechanism 220 is mounted between the walls 216, 218. The mechanism 220 includes a plunger 222. The plunger 222 is hollow with one open end and an annular stop formation 224 extending from a body 226 of the plunger 222. An opposite end 221 of the plunger 222 is closed so that an operator can push against the plunger 222. A hollow cylindrical spring retainer 228 is mounted or arranged on an internal surface of the wall 216 and opens into the plunger 222. A spring 230 is positioned in the retainer 228 to bear against the wall 216 and the closed end of the plunger 222. The spring 230 is configured to bias the plunger 222 away from the wall 216 so that the stop formation 224 can bear against the wall 218 (figure 36).

[0228] The closed end 221 of the plunger 222 can be received in an opening 232 defined in the back wall 130.2 to lock the sections 102.2 and 102.3 together, as shown in figure 36. The operator can press against the plunger 222 so that the plunger 222 moves, against a bias of the spring 230 out of the opening 232 to disconnect the sections 102.2 and 102.3, as shown in figure 37.

[0229] Figure 38 shows an electronic circuit layout of the staff 100. A master printed circuit board (PCB) 238 is mounted in the control housing 138. The PCB 238 carries the microcontroller 232. The microcontroller 232 receives power from voltage regulators 240. The voltage regulators 240 are connected to a battery 242 that can be recharged by a mains battery charger indicated at 244.

[0230] The display 142 is shown in figure 38. In this example, the display 142 is an LCD display. The PCB 238 also carries a number of status LEDs indicated at 246. The microcontroller 232 is connected to the LEDs 246 so that the LEDs can show, for example, low battery, ambient light level, a Bluetooth connection, modes of operation (for example, see the modes described with reference to the survey staff 10) and whether or not the staff sections are connected.

[0231 ] The PCB 238 also carries various pushbuttons indicated at 248 and connected to the microcontroller 232. These can include a button for powering up or powering off the survey staff 100. Further buttons can be used for muting the system, selecting a mode of operation, carrying out a measurement, setting a reading, or clearing the settings.

[0232] The PCB 238 carries the wireless communications module 234 that is connected to the microcontroller 232. The module 234 is configured to communicate via Bluetooth or some other wireless protocol, for example, as described with reference to the communication module 38. The communications module 234 is also connected to the voltage regulators 240 so that it can be powered.

[0233] The PCB 238 carries an I2C communications module 248. The module 248 is connected to the microcontroller 232. The module 248 is also connected to complementary modules 250 on the PCBs 188, depending on the connection state of the associated staff section 102.

[0234] Figure 38 also shows one of the PCBs 188 that would be connected to the PCB 238 in the event that the associated staff section 102 was connected to the staff section 102.1 , in the manner described above. The PCB 188 also includes a voltage regulator 252 that can be connected to the voltage regulators 240, again depending on the connection state of the associated staff section 102. It will be appreciated that the voltage regulator 252 and the communications module 250 are both connected to the PCB 238 via the connectors 1 14 and the electrical contact members 204, as described above, when the associated staff section 102 is connected to the staff section 102.1 .

[0235] It has been found by the inventor that operation of the laser detectors 1 10 can be disrupted or the sensitivity can be reduced in the event of optical "noise" or ambient light. For example, on a work site, that optical noise could be the result of flashing warning lights, or other indicating lights. Also, during the later parts of the day, when the sun is low, the sunlight can strike the staff sections and angle relatively close to an orthogonal angle.

[0236] These potential problems are ameliorated by the protective structure 1 16 and the translucent screen 136.

[0237] For example, a depth of the passageways 124 is selected so that only light that impinges on the translucent screen 136 at an angle within a particular range will reach the laser detectors 1 10. For example, the depth of the passageways 124 can vary from about 4mm to 20mm for the spacing of the laser detectors 1 10 described above. However, it will be appreciated that the depth will be selected based on the intended application of the staff 100. For example, it will be appreciated that the deeper the passageways 124, the closer the strike or impingement angle to horizontal will be required in order for light to enter the passageways 124. Thus, the depth can be selected to suit the anticipated conditions.

[0238] In addition to being an optical filter, the screen 136 can be polarized. The polarization can be horizontal. This helps to ensure that the wavelength of light entering the passageways 124 is substantially limited to that having a horizontal orientation. This would correspond with the wavelength orientation of the scanning or rotating laser beam generated by the laser level, for example the laser level 62.

[0239] A further mechanism for filtering out the unwanted optical noise is the optical filter 1 1 1 . The optical filter 1 1 1 is selected to allow only light having a wavelength of the laser beam to strike the detector 1 10.

[0240] In addition, the polarized filter 1 15 can be oriented so that the polarization is horizontal. This can also serve to ensure that the wavelength of light entering the passageways 124 is substantially limited to that having a horizontal orientation.

[0241 ] In more general terms, use of the survey staff 10, 100 obviates the need for an operator to obtain a visual reading of a laser mark. It also obviates the need for an operator to move a laser detector relative to a staff. Both the visual recognition and the moving of the detector can be difficult in locations where the survey staff is in a position in which part of the survey staff is difficult to reach. For example, if an extension assembly, similar to the one described above, is used, the operational part zone of the survey staff may simply not be reachable or visible to the operator. The survey staff 10, 100 detects the laser beam without the need for such visual recognition or the manipulation of a detector into a strike zone. The survey staff 10, 100 allows an operator simply to operate the laser level and then carry on the survey operation using, primarily, the smartphone 56, for example.

[0242] Alternative embodiments of the invention will be apparent to those of ordinary skill in the art from consideration of the specification and practice of the invention disclosed herein. It is intended that the specification and examples be considered as exemplary only, with a true scope and spirit of the invention being indicated by the claims which follow.

[0243] It will be understood that the term "comprising" is intended to have a broad, open meaning and not limited to a particular embodiment. [0244] The features described with respect to one embodiment may be applied to other embodiments, or combined with or interchanged with the features of other embodiments, as appropriate, without departing from the scope of the present invention.

[0245] The claims as filed and attached with this specification are hereby incorporated by reference into the text of the present description.

[0246] Any words indicating an orientation are used solely for the purpose of convenience and are not intended to be limiting.

[0247] Other embodiments of the invention will be apparent to those skilled in the art from consideration of the specification and practice of the invention disclosed herein. It is intended that the specification and examples be considered as exemplary only, with a true scope and spirit of the invention being indicated by the following claims.

Claims

What is claimed is:

1 . A survey staff that comprises

a plurality of elongate staff sections;

a connecting mechanism that is operatively arranged on at least two consecutive staff sections to permit the consecutive staff sections to be connected or disconnected between extended and retracted conditions, respectively;

a laser receiver arranged on each of the at least two consecutive staff sections and configured to detect a laser signal and to generate a signal related to an impingement location on one of the staff sections at which the laser signal impinges the receiver; and

2. The survey staff as claimed in claim 1 , in which a detector is operatively connected to the at least two staff sections and to the processor, and is operable to generate a signal, to be received by the processor, when the staff sections are connected or disconnected.

3. The survey staff as claimed in claim 1 , which includes a switch mechanism that is arranged between consecutive staff sections and is configured to connect, electrically, the laser receiver of one of the consecutive staff sections to the laser receiver of the other staff section when the staff sections are connected and to disconnect, electrically, the laser receivers from each other when the staff sections are disconnected.

3. The survey staff as claimed in claim 3, in which the processor is configured to determine whether or not the staff sections are connected together as a result of the state of the switch mechanisms.

4. The survey staff as claimed in claim 1 , in which a communications device is operatively connected to the processor and is configured to receive the signal from the processor and to transmit the signal to a signal receiver.

5. The survey staff as claimed in claim 4, in which the communications device is configured to generate a wireless communications signal for receipt by a wireless communications apparatus having the signal receiver.

6. The survey staff as claimed in claim 1 , in which the connecting mechanism is a sliding mechanism interposed between the staff sections so that the staff sections can slide relative to each other between the extended and retracted conditions while being retained together.

7. The survey staff as claimed in claim 6, in which the staff sections have consecutively decreasing cross-sectional areas from a narrowest staff section to a broadest staff section and at least the broadest staff section defines an internal passage in which a narrower staff section can be received so that the staff sections can extend or retract, telescopically.

8. The survey staff as claimed in claim 7, in which each staff section includes an elongate housing, the dimensions of which define its cross-sectional area and the laser receiver is positioned in the housing.

9. The survey staff as claimed in claim 1 , in which each laser receiver includes a linear array of laser detectors positioned on the staff section and extending between ends of the staff section, the laser detectors having a predetermined spacing to establish a measurement resolution capacity of the survey staff.

10. The survey staff as claimed in claim 9, in which each laser receiver includes

laser detection circuitry positioned in the housing; and

the array of laser detectors connected to the laser detection circuitry and mounted at a detection angle that is generally orthogonal to a longitudinal axis of the housing.

1 1 . The survey staff as claimed in claim 10, in which an electrical connector is arranged on the laser detection circuitry for connecting the laser detection circuitry in one housing to the laser detection circuitry in a consecutive housing.

12. The survey staff as claimed in claim 1 1 , in which the electrical connectors are positioned so that the laser detection circuitry of one staff section is connected to the laser detection circuitry of the consecutive staff section when the staff sections are in the extracted condition.

13. The survey staff as claimed in claim 10, in which each housing includes a protective structure that defines a series of detector openings in register with respective laser detectors.

14. The survey staff as claimed in claim 13, in which the protective structure defines a series of windows at a facing surface and passageways between respective detector openings and windows, the windows being spaced outwardly from the detector openings.

15. The survey staff as claimed in claim 14, in which the protective structure includes a series of spaced, parallel partitions and passage walls, the partitions and passage walls defining the passageways and the passage walls diverging from each other from the detector openings to the windows.

16. The survey staff as claimed in claim 15, in which, in each staff section, the housing includes a back wall and a pair of sidewalls, the protective structure being mounted between the sidewalls with the laser detection circuitry being interposed between the back wall and the protective structure.

17. The survey staff as claimed in claim 16, in which the protective structure and the sidewalls include complementary engaging formations so that the protective structure can engage the sidewalls and be retained in position by the engaging formations.

18. The survey staff as claimed in claim 16, in which a translucent screen is mounted on each staff section to cover the windows.

19. The survey staff as claimed in claim 17, in which the translucent screen is an optical filter.

20. The survey staff as claimed in claim 4, in which the communications device and the processor are mounted in a control housing that is fastened to one of the staff sections.

21 . The survey staff as claimed in claim 20, in which the processor includes a microcontroller that is operatively connected to the laser detection circuitry in the staff section on which the control housing is mounted, and to the laser detection circuitry in the consecutive staff section, when the staff section and the consecutive staff section are in the extended condition.

22. The survey staff as claimed in claim 21 , in which the microcontroller is operatively connected to the laser detection circuitry with multiplexer circuitry so that the microcontroller can receive signals from the laser detection circuitry of one or more staff sections, depending on whether or not the staff sections are in the extended condition.

23. The survey staff as claimed in claim 21 , in which the communications device includes a wireless communications module that is configured to generate a wireless signal according to a standard communications protocol, the communications module being connected to the

microcontroller, the microcontroller being configured to control operation of the communications module to transmit signals relating to the impingement location on the relevant staff section.

24. The survey staff as claimed in claim 21 , in which a GPS module is operatively connected to the microcontroller to provide a location signal to the microcontroller.

25. The survey staff as claimed in claim 21 , in which a user interface is connected to the microcontroller, the user interface including a display and an actuating mechanism configured to permit an operator to actuate the laser receivers and the microcontroller.

26. The survey staff as claimed in claim 25, in which a level sensing device is connected to the microcontroller and is configured to generate a signal corresponding to an orientation of the survey staff, the microcontroller being configured to display information relating to the orientation on the display of the user interface.

27. The survey staff as claimed in claim 1 , in which the processor is configured to be connected to a wireless communications device to relay the signal to the wireless communications device.

28. The survey staff as claimed in claim 9, in which each laser detector includes a polarized lens.

29. The survey staff as claimed in claim 9, in which each laser detector includes a polarized film positioned on a lens of the laser detector.

29. The survey staff as claimed in claim 9, in which each laser detector includes an optical filter.

30. A survey system, comprising:

a survey staff, the survey staff including

a plurality of elongate staff sections;

a laser receiver arranged on each of the at least two consecutive staff sections and configured to detect a laser signal and to generate a signal related to an impingement location on one of the staff sections at which the laser signal impinges the receiver; and a processor operatively connected to the laser receiver and configured to receive the signal generated by the laser receiver and to generate a signal carrying data related to the impingement location; and

31 . A method of surveying, the method comprising the steps of: