Method and system for determining position

Wireless systems for detecting hazardous conditions based on location

TECHNICAL FIELD

Field [0001] The present invention relates to a sensing device, and more particularly relates to a portable gas detector.

Background technique

[0002] In many environments, it is desirable to accumulate a dangerous situation is detected before the presence of potentially dangerous gases. For example, the factory floor will include the use of gas detection systems are distributed throughout the plant gas sensor. Such a system may also include one or more central stations, which receives signals from the gas sensor. For example, if one of the gas detector of dangerous gases to excess, then in the central station to trigger an alarm condition. Such gas detection systems can also alert the operator to take action to eliminate potential hazards of the results of this workshop.

[0003] Although such a system in a fixed position is valid, such as when being positioned in the vicinity of the factory floor industrial equipment, but these types of systems are not portable or can not be adapted to changing conditions. In addition, such conventional gas detection systems typically do not provide rapid centralized access to information about events of gas detection, the information includes the location (s) of events and historical information based gas detection location. In addition, if the conventional system does provide centralized access, then the need for expensive wiring to the gas detector connected to a central station.

[0004] In some prior art gas detection system, individual belt worn device may be utilized to detect gas concentration within a certain location. Such a gas detector may be provided with a concentration of gas in function of time related information. However, the central station operator can not access the location information, and the gas concentration as a function of time the information is not available until the daily log of the device is transmitted to a much later time until the personal computer.

[0005] Based on the above, the presence of wireless gas detection system and method for improved location-based needs. There is location information wirelessly detect hazardous gases associated with the event, along with requiring time information, as described in more detail herein.

BRIEF DESCRIPTION

[0006] FIG. 1 is a block diagram generally illustrating environmental sensing system according to the illustrated embodiment of the present invention.

detailed description

[0007] Figure 1 depicts an example of gas detection systems typically shown in accordance with the illustrated embodiment of the invention 250. Included in the gas detection system 250 may be a plurality of portable gas detectors (transceiver) 256. Also included within the gas detection system 250 is connected to more than one location location manager module 252 anchor (anchor) transceiver 276, 278.

[0008] It may be noted that not all the anchor position transceivers 276, 278 can be connected to the position of manager module 252. Anchor position transceivers 276, 278 may only be used to provide some of the probe in response to the position for the purpose, instead of being used to convey information to a location module 252 tube.

[0009] connected to the position location manager module 252 anchor transceiver 276, 278 can receive gas readings and location information from a portable gas detector 256 wirelessly. Anchor location transceiver may forward this information to the location manager. Location manager module 252 mainly uses this information to inform the central position and appear human operator of gas detection event. Location manager module 252 may also use gas readings and location information to create across a predetermined area of ​​the gas concentration profile 904.

[0010] Also located within the region 904 are a plurality of anchor position enhanced transceiver 900, 902. The enhanced location transceiver 900, 902 and the position of the anchor bolt transceiver 276, 278 - from the work, is mainly used to monitor the accuracy of portable gas detector 256 position estimate. Enhanced anchor location transceiver 900, 902 may also be a transceiver 276, 278 with the position of the anchor - operates to provide position information from the measuring device via a portable gas detector 256 is performed, location information is sent to the location manager to make positioning the portable gas detector 256 estimates convenience.

[0011] Gas detectors 256, 276, 278, and the position of the anchor transceiver enhanced anchoring location transceiver 900, 902 are operating to the appropriate wireless format (e.g., IEEE 802.11) exchange information wirelessly. At least some of the anchor position of the transceiver can be used as a gas detector wireless access point 256 and the enhanced position anchor transceiver 900, 902 276, 278 of which work.

[0012] anchor position detector 276, 278 and enhanced anchor position detector 900, 902 is provided at known locations in the region 904. Location manager module 252 using the position detectors 276, 278 and the anchor position of the anchor enhanced detector 900, 902 of the known locations, the location information is provided by the combination of the gas detector 256 to estimate the portable gas detector 256 location. The location manager also can work performed by collecting, diary and shows the estimated position of the portable device.

[0013] portable gas detector 256 can be worn by 904 in the entire area of ​​the mobile personnel. With the wear of the portable gas detector 256 people to move from position to position within the region 904, the gas detector 256 may periodically measure the gas concentration at those locations. Gas detector 256 may be a gas composition measurements to measure the position information packets and the data packets 276, 278 to wirelessly transmit location manager module 252 supported by the position of the anchor access point transceiver functions.

[0014] gas detector location information collected by the position of the anchor 256 may be a transceiver 276, 278 and enhanced the position of the anchor 900, 902 transceiver transmitted by the gas detector 256 detects (or via a probe response (such as MAC address ) obtained) parameter signals. In order to collect location information and transmission of gas measurements to the location manager module 252, during a request from the anchor position of the transceiver 276, 278 and enhanced the position of the anchor transceiver 900, 902 response, as the first step in a gas detector 256 may be transmitted first probe request.

[0015] detected anywhere anchor transceiver from the portable gas detector probe requests 276, 278 and 256 of the enhanced position of the anchor 900, 902 transceiver can transmit a probe response. Anywhere anchor transceiver 256 measures the portable gas detector probe response transmitted from the position of the anchor 276, 278 and enhanced transceiver 900, 902 received the probe response signal parameters.

[0016] The parameter signals from the portable gas detector 256 may be any suitable measure of the distance indicator (e.g., received signal strength indicator (received signal strength indicator, RSSI), transit time, etc.). Based on the measured signal parameters, the portable gas detector 256 may select the location of anchor one transceiver 276, 278 as an access point to associate and send data. The portable gas detector 256 can select optimal measurement signal parameters with a probe response of the position of the anchor transceiver 276, 278 (for example, if you use RSSI, is the largest relative RSSI, if you are using the time of flight, it is the shortest relative transit time, etc.).

[0017] Once the position of the anchor transceiver 276, 278, 256 of the portable gas detector on the preparation of data packets for transmission to the location manager module 252 through the selected access point 276, 278. In this case, the write data packet includes at least three parts. The first and second portions including portable gas detectors and gas measurement system identifier. The third part includes a signal measured parameters and provides a probe response anywhere anchor transceiver system identifier 276, 278 and enhanced the position of the pin 900, 902 transceiver.

[0018] Once the packet has been prepared and has been selected access point, the portable gas detector 256 to transmit the packet to the selected access point 276, 278. The selected access point and then the transmitted data packet is forwarded to the location manager module 252.

[0019] Upon receiving the packet, the location manager module 252 stored gas measurements in the packet and tries to determine if the portable gas detector 256 location. In order to determine that the portable gas detector position 256, the location manager module 252 passes the result to the signal parameter measurement location engine 268.

[0020] location engine 268 based on signal measurements estimate the gas detector 256 positions. If the RSSI signal is based on the measurement result of the estimation it is based on the assumption that the signal is proportional to the distance of the decays. Amplitude amplitude and the gas detector signal 256 measured by the transmitted knowledge, the engine can be calculated from the position of the gas detector to the position of the anchor 256 in the transceiver 276, 278 and each of the anchor position of each enhanced transceiver 900, 902 distance. By knowing the position of the anchor from 256 type transceiver 900, 902 and the anchor position transceivers 276, 278 of each of the distance of the portable gas detector to enhance the position of the engine 268 is determined by the position of the anchor from enhanced transceiver 900, 902 and location of the anchor transceivers 276, 278 to each of the gas detector 256 crossing distance (intersect1n), to triangulate the position of the gas detector 256.

[0021] If the signal measurement is based on transit time, use a similar process. In this case, the location engine 268 in the signal 276, 278 crossing position anchor type transceiver 900, 902 and the anchor position of the transceiver each time to determine the distance from the gas detector 256 based on the enhancement, and in the same manner as triangulation.

[0022] Enhanced anchor location transceiver 900, 902 at least some of the gas may also include a detector 906, 908. Because some of the enhanced position anchor transceiver 900, 902 includes a gas concentration detector, the enhanced position anchor transceiver 900, 902 may also periodically measure the local gas concentration and the measured gas concentration is reported to the local location manager module 252.

[0023] In this regard, the gas detector has enhanced the position of the anchor transceiver 900, 902 may be in a manner similar to a portable gas detector 256 to operate. In the case of the enhanced anchoring location transceiver 900, 902 is not included in the gas detector, in addition to their transmission does not include a measurement gas outside the enhanced anchoring location transceiver 900, 902 will be similar to portable gas detection 256 approach to the operation. In either case, and in order to transmit the location information to a location manager module 252, the enhanced anchoring location transceiver 900, 902 each (e.g., enhanced anchoring position 900) will first transmit the probe request.

[0024] In a similar manner, any other received enhanced position anchor (e.g., anchor 902 enhanced position) and the position of the probe request 276, 278 through the anchor means comprises a transmitting unit transmitting an identifier 276,278,902 probe response to respond. This enhanced the position of the anchor 902 receives the probe response signal parameters and measuring the position of the anchor from the transceiver 276, 278 and enhanced the position of the anchor transceiver 902 in each of the probe response. This enhanced position to anchor the transceiver 900 and 256 of the gas detector the same manner as the gas transfer measurement results.

[0025] In this regard, the enhanced position of the anchor bolt 276, 278 902 to select a location as an access point to the location of the data packets to block management module 252. Next, the enhanced anchoring position receiver 902 to prepare the gas measurement packet, the data packet includes gas measurement gas concentration measurement and receiver positions 276, 278 and the anchor position of the anchor enhanced receiver 902 in each of the measuring signal parameters. This enhanced the position of the anchor 900 and then 276, 278 to the gas measurement packet to the location manager module 252 through the selected access point.

[0026] Location Manager module 252 receives the gas measurement data packets from enhanced receiver 900 and the anchor position of the gas measurement results are stored in the database. Location Manager module 252 will also be enhanced in response to the position of each anchor receiver 902 and receiver 276, 278 anchor position measurement signal parameters (and System Identifier) ​​is sent to the location engine 268.

[0027] When receiving the measurement signal parameters, the position location engine 268 calculates the estimated position of the anchor enhanced transceiver 900. The location engine 268 then enhanced position location estimation anchor transceiver 900 and known position of the position anchor enhanced transceiver 900 are compared to obtain a measurement or position error value.

[0028] can monitor the location of measurement error or value in a period of time, gradually or rapidly worsening position detecting accuracy. Once deterioration exceeds a certain threshold limit, a human operator can notify the system and / or can be recorded events.

[0029] This gas measurement and reporting process may be performed by an enhanced position anchor transceiver 900, 902 each. In doing so, the position of the engine 268 to obtain error values ​​for position measurements enhanced position anchor transceiver 900, 902 of each. By the location manager to change the accuracy of detection may also include a human operator to detect an area of ​​a deterioration of the error, and inform the deterioration taking place in a region.

[0030] position error measurement can be used to correct the correction factor portable gas detector 256 of the estimated position. For example, if the portable gas detector 256 should provide has enhanced the position of the anchor transceiver same (such as enhanced position anchor transceiver 900) of the signal parameter measurement position anchor transceiver value (for example, the position of the anchor transceiver 276) of signal parameter measurements, the location engine 268 may be a correction factor to impose the gas detector 256 is placed in the estimated location gas detector from the position of the anchor transceiver 276 and from the enhanced position anchor transceiver 900 at the same distance (including adjust the position error measurement results). Moreover, taking into account the position error of several adjacent reinforcing anchor type transceiver location, the location estimation engine may adjust its position for portable gas detector means. Enhanced closest possible position error of the estimate of the anchor to provide the greatest impact. Based on the measured parameters is smaller or larger, a correction factor may be applied to other.

[0031] can also position error and the position error threshold limit value for comparison. In this case, if the position error exceeds the threshold limit, the possibility that the system can warn the user of the system 250 of 250 failed. Such failure may be due to the construction of metal structures such as environmental changes caused in the region, or due to the enhanced anchor position signal transceiver 900, 902 or worsening position anchor transceivers 276, 278 caused by one or more .

[0032] also can give location manager module 252 provides a display 910, the display 910 depicts a map of the region 904 912. Included on the map may be a portable gas detector 256, an enhanced position anchor transceiver 900, 902 and the anchor position transceiver specified positions 276, 278 each.

[0033] In the display 910 of the portable gas detector location around 914 256 shows a bounding box 916, which indicates that the portable gas detector position error estimate 256. For example, if the location-enhanced position anchor transceiver 900, 902 closest to a gas error detector transceiver 256 indicating the estimated position error of 10 feet, you can around the portable gas detector 256 is shown with at least border rim 10 of 916 feet in length. Since the error vector I and comprising components X component, it is also possible that the amount of the corresponding X and y have the bounding rectangle 916, the length of the side of the bounding rectangle at least. However, the bounding box 916 may measure the size of the error inaccurate results. This is because there may be considered and may suggest other sources of error of the frame 916 bigger one. Further, instead of a rectangle, the error can be indicated as an area surrounding the estimated location, in which the shape and size of the area may be proportional to the error vector.

[0034] To illustrate the production and use of the present invention has been described in a manner specific embodiments environmental monitoring system. It should be understood that other variants and modifications of the invention as well as its implementation of various aspects of the skilled artisan will be apparent, and the invention is not limited to the specific embodiments described herein. Thus, it is contemplated that the present invention and fall within the coverage of any and all modifications, variations or equivalents within the herein disclosed and claimed in the basic underlying principles of the true spirit and scope.