Synchronization method for multi-station data of dynamic coordinate measurement by workshop measuring and positioning network

Abstract

The present invention discloses a synchronization method for multi-station data of dynamic coordinate measurement by a workshop measuring and positioning network. The method comprises the following steps of: determining a measuring and positioning space according to the in-situ measurement dimension, selecting locations for placing several transmitters, calibrating external parameters of the transmitters by a reference ruler, and establishing a measurement field; in a communication data packet of a signal processor, attaching local clock information into the angle information of each transmitter; and setting fixed time nodes on a time axis, and synchronizing data of different transmitters to corresponding time nodes so as to realize data synchronization. The present invention improves the conventional static measurement function of the wMPS to a certain dynamic measurement function for expanding the application ranges of the wMPS, and provides a technical support for realization of real-time, high-accuracy and large-scale in-situ industrial coordinate measurement based on wMPS.

Claims

1. A synchronization method for multi-station data of dynamic coordinate measurement by a workshop measuring and positioning network, comprising the following steps of: determining a measuring and positioning space according to the in-situ measurement dimension, selecting locations for placing a plurality of transmitters, calibrating external parameters of the transmitters by a reference ruler, and establishing a measurement field; In a communication data packet of a signal processor, attaching local clock information into the angle information of each transmitting station; and Setting fixed time nodes on a time axis, and synchronizing data of different transmitters to corresponding time nodes so as to realize data synchronization.

2. The synchronization method for multi-station data of dynamic coordinate measurement by a workshop measuring and positioning network according to claim 1, wherein the step of In a communication data packet of a signal processor, attaching local clock information into the angle information of each transmitter specifically comprises the steps of: 1) Receiving, by a receiver, synchronous light pulse signals and scanning light pulse signals transmitted by the transmitters, converting the synchronous light pulse signals and scanning light pulse signals into electrical pulses, and transmitting the electrical pulses to the signal processor; 2) Matching, by the signal process and by using internal crystal oscillator as a timing standard, the timing on the electrical pulses of different transmitters according to the period of rotation of the transmitters; and 3) Packing, by the signal processor, the angle information of different transmitters and corresponding timestamps received by a same receiver to form data frames, and uploading the data frames to a computing workstation.

3. The synchronization method for multi-station data of dynamic coordinate measurement by a workshop measuring and positioning network according to claim 1, wherein the step of Setting fixed time nodes on a time axis, and synchronizing data of different transmitters to corresponding time nodes so as to realize data synchronization specifically comprises the steps of: 1) Selecting the timestamp t.sub.on of the latest moment from the receiver, and extracting the timestamp t.sub.on-1 of the previous moment adjacent to the latest moment, where the time mode corresponding to the timestamp of the latest moment is t.sub.pn; 2) Synchronizing data of the transmitting stations at a moment having a timestamp t.sub.on onto the time node t.sub.pn; and 3) Synchronizing data of all the transmitters onto corresponding time nodes, and obtaining coordinate values at this moment by an angle intersection principle, so as to realize data synchronization of multiple transmitters.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a schematic diagram of a wMPS;

(2) FIG. 2 is a schematic diagram of the operation principle of the wMPS;

(3) FIG. 3 is a schematic diagram of a coordinate measurement error resulted from data asynchronism of multiple transmitters;

(4) FIG. 4 is a schematic diagram of a time sequence of a system having two transmitters; and

(5) FIG. 5 is a flowchart of a synchronization method for multi-station data of dynamic coordinate measurement by a workshop measuring and positioning network.

DETAILED DESCRIPTION OF THE PRESENT INVENTION

(6) To make the objectives, technical solutions and advantages of the present invention clearer, the embodiments of the present invention will be further described below in detail.

(7) It can be known from the analysis of the background art that the error is determined by the system measurement principle, and ideally, it can be ensured that data synchronization of different transmitters can be compensated within the measured slowest period of rotation of the transmitters (for example, if the minimum rotation speed of multiple transmitting stations is 1800 rpm, the synchronization time error can be within 33.33 ms). Considering that the signal processor performs time stamping on light pulses received by a receiver by using single crystal oscillator, the present invention focuses on to the methods of synchronizing and compensating data from multiple transmitters by using the result of timing so as to improve the accuracy of dynamic coordinate measurement to the greatest extent.

(8) For this purpose, referring to FIG. 5, the technical solutions of an embodiment of the present invention are as follows:

(9) 101: Determining a measuring and positioning space according to the in-situ measurement dimension, selecting proper locations (e.g. having stable foundation, and the space without sheltering) for placing a plurality of transmitters, calibrating external parameters of the transmitting stations by a reference ruler, and establishing a measurement field;

(10) 102: In a communication data packet of a signal processor, attaching local clock information into the angle information of each transmitter (that is, adding a timestamp for the measured data).

(11) The step 102 specifically includes the following steps:

(12) 1) Receiving, by the receiver, synchronous light pulse signals and scanning light pulse signals emitted by the transmitters, converting the two signals into electrical pulses, and transmitting the electrical pulses to the signal processor;

(13) 2) Matching, by the signal processor and by using internal crystal oscillator as a timing standard, the timing on the electrical pulses of different transmitters according to the period of rotation of the transmitters;

(14) For example, if the receiver receives synchronous light pulse signals from the transmitters at the moment t.sub.0 and then continuously receives two scanning light pulse signals from the transmitters at the moment t.sub.1 and moment t.sub.2, the angles of rotation of the transmitters scanning the receiver within the period of rotation T are respectively:

(15) ${}_1=\frac{t_1-t_0}{T}$${}_2=\frac{t_2-t_0}{T}$

(16) Since the moment t.sub.0 of the synchronous light pulse signals marks the starting time point of signal transmission of the transmitters within this period, the moment t.sub.0 recorded by the signal processor is used as timestamps of the angles .sub.1 and .sub.2 of the transmitting stations;

(17) 3) Packing, by the signal processor, the angle information of different transmitters and corresponding timestamps received by a same receiver to form data frames, and uploading the data frames to a computing workstation;

(18) 103: Setting fixed time nodes on a time axis, and synchronizing data from different transmitters to corresponding time nodes so as to realize data synchronization;

(19) In practical applications, due to the asynchronism of data from multiple transmitters received by a same receiver, a synchronization error will be caused if direct calculation is employed. The angle information of different transmitters have timestamps, which can be synchronized to a same time axis according to the timestamps. On this basis, the present invention sets fixed time nodes on the time axis, and synchronizes data from different transmitters to corresponding time nodes so as to realize data synchronization.

(20) By taking a system having two transmitters as example, as shown in FIG. 4, t.sub.p1, t.sub.p2, t.sub.p3 . . . t.sub.pn denote the time nodes, t.sub.j1, t.sub.j2, t.sub.j3 . . . t.sub.jn denote the time when the signals from the corresponding transmitters are received, and j denotes the serial number of the transmitter. The synchronization of data from different transmitters requires the following conditions:

(21) 1) During the movement of the receiver, due to its limited movement conditions, the movement within a very short period of time (about dozens of milliseconds) can be approximately regarded as a forward movement in a certain direction at a constant speed of v.

(22) 2) In the measurement field, the data output of the signal processor is temporarily continuous, and the data of the transmitter at any moment within a short period of time can be inferred according to the data of the transmitters measured for two adjacent times.

(23) After the time sequence is set, the data from each transmitter is synchronized to the corresponding node of the time sequence. By taking one transmitter as example, the specific process of the data synchronization method is as follows:

(24) 1) Selecting the timestamp t.sub.0n of the latest moment from the receiver, and extracting the timestamp t.sub.0n-1 of the previous moment adjacent to the latest moment, where the time mode corresponding to the timestamp of the latest moment is t.sub.pn.

(25) 2) Synchronizing data of the transmitter at a moment having a timestamp t.sub.0n onto the time node t.sub.pn by the following formula:

(26) $t_{\mathrm{in}}^{}=t_{\mathrm{in}}+\frac{t_{\mathrm{pn}}-t_{0n}}{t_{0n}-t_{0n-1}}*\left(t_{\mathrm{in}}-t_{\mathrm{in}-1}\right),\left(i=1,2\right)$

(27) Where, i denotes the serial number of scanning light, t.sub.in denotes the value of the scanning angle of the scanning light i at the time node t.sub.pn, t.sub.in denotes the value of the scanning angle of the scanning light i at the timestamp t.sub.0n, and t.sub.in-1 denotes the value of the scanning angle of the scanning light i at the timestamp t.sub.in-1;

(28) 3) By the step 2), synchronizing all data of the transmitter to the corresponding time nodes.

(29) Thus, by performing the above steps, the present invention obtains data of multiple transmitters at the corresponding time nodes, and further obtains the coordinate value at this moment by an angle intersection principle, so as to realize data synchronization of multiple transmitters.

(30) In conclusion, the embodiment of the present invention fully utilizes the existing clock information inside a signal processor, to synchronize the information from multiple transmitters in a same processor to a same moment, so that the accuracy of in-situ dynamic coordinate measurement is improved. The embodiment of the present invention improves the conventional static measurement function of the wMPS to a certain dynamic measurement function, expands the application range of the wMPS, and provides a technical support for realization of real-time, high-accuracy and large-scale in-situ industrial coordinate measurement based on wMPS.

(31) In this embodiment of the present invention, unless the model numbers of devices are specified, the model numbers of other devices are not limited as long as the above functions can be realized.

(32) Those skilled in the art can understand that the accompanying drawings are schematic diagrams of a preferred embodiment, and the serial numbers of embodiments of the present invention are merely descriptive and do not indicate the priority of the embodiments.

(33) The forgoing description merely shows preferred embodiments of the present invention and is not intended to limit the present invention. Any modification, equivalent replacement and improvement made within the spirit and principle of the present invention shall fall into the protection scope of the present invention.