CN106900056A - Omni-directional radio frequency alignment system and method based on multiple antennas - Google Patents

Abstract

The invention provides a kind of omni-directional radio frequency alignment system and method based on multiple antennas, including：Positioning node (10), anchor node (11) and signal processing module；The anchor node (11) receives the radiofrequency signal that the positioning node (10) sends, and generates multigroup original radio frequency positioning result；The signal processing module is analyzed after processing the positional information for obtaining positioning node (10) to multigroup original radio frequency positioning result of anchor node (11), and the positional information is final radio frequency positioning result.The present invention can carry out high-precision positioning to positioning node based on angle, and positioning precision does not change with the change of target range.In position fixing process, even if exist to block between positioning node and anchor node can be also accurately positioned.The rf receiver unit used in the present invention possesses the characteristic of the non-omnidirectional of high accuracy, by the way of the combination of multiple rf receiver units and carries out data fusion, and can reach carries out omnidirectional's high accuracy positioning to target.

Description

Omni-directional radio frequency positioning system and method based on multiple antennas

technical field

The invention relates to the field of sensing measurement and mobile positioning technology, in particular to an omnidirectional radio frequency positioning system and method based on multiple antennas.

Background technique

In recent years, a variety of systems and algorithms for local and indoor localization have emerged. At present, the commonly used local positioning methods include positioning methods based on Received Signal Strength (RSS), positioning methods based on Angle of Arrival (Arrival of Angle, AoA), positioning methods based on Time Of Arrival (TOA) and A positioning method based on time difference of arrival (Time Differential Of Arrive, TDOA). The advantage of the positioning method based on received signal strength lies in the low cost of hardware, because most buildings are equipped with wireless local area network (Wireless Local Area Network, WLAN) and multiple AP (Access Point, AP) access points, however This method has low positioning accuracy (about a few meters), is not robust in complex environments, and requires a lot of time to manually calibrate the environment.

Utilization of TDOA/TOA based ultrasonic positioning has a long history. Compared with positioning based on signal strength, ultrasonic positioning based on TOA has better accuracy (about 10 cm), but it also has defects such as short measurement range, poor directionality, and instability in complex environments. Similarly, ultrasonic positioning does not have the ability of omnidirectional positioning in space.

The methods based on TOA, TDOA, and RSSI all need to arrange the different positions of multiple anchor nodes in space in advance, and then locate the target node through trilateration, multilateral measurement, fingerprint matching, etc.; The distance must be large enough to obtain the desired accuracy. Therefore, anchor nodes are generally installed on buildings and require infrastructure support.

The AoA-based method generally uses multiple receiving antenna arrays at fixed positions to detect the phase difference of the signal, so as to determine the angular position of the target. Generally, the distance between antenna arrays is very small (less than half the wavelength of the carrier). The AoA anchor node has the characteristics of small size and can be loaded on a small mobile device to complete the relative positioning between the mobile device and the target node.

Ultra-Wide Band (UWB) technology has the characteristics of long working distance (up to hundreds of meters) and high-precision ranging (up to 10cm). At the same time, UWB is a radio frequency signal that can penetrate obstacles to achieve beyond-the-horizon positioning.

In order to improve the positioning accuracy of the target, more and more radio frequency tags are used, that is, the method of using signal feature matching. However, this radio frequency tag positioning technology relies on expensive professional equipment, which is not conducive to popularization.

retrieved

Application number: 201010206570.8, titled "Radio Frequency Tag Positioning System for Implementing a Radio Frequency Tag Positioning Method", the radio frequency positioning system includes a radio frequency tag, at least one reader and a backend server. The radio frequency tag periodically sends a plurality of tag signals with different original signal strengths, and the original signal strength of each tag signal determines a receiving boundary relative to the radio frequency tag. The reader is used to read the tag signal, and the tag signal that can be received by the reader is a receivable signal. The backend server determines the possible position range of the radio frequency tag relative to the reader according to the receiving boundary corresponding to the receivable signal.

The above technical solution cannot realize omnidirectional positioning, and the positioning accuracy is affected by the target distance.

Application number: 200810148801.7, titled "Radio Frequency Positioning System and Method", which is used to locate radio frequency devices on a plane, and can provide more diverse and accurate positioning functions. The radio frequency positioning system utilizes the property that a radio frequency device will generate a response signal when receiving a radio frequency signal to perform positioning. The radio frequency positioning system includes an antenna group, a switching unit, a radio frequency module and a micro control unit. An antenna group includes a plurality of antennas of different sizes. The switching unit is coupled to the antenna group. The radio frequency module is coupled to the switch unit for generating the radio frequency signal. The micro control unit is coupled to the switching unit and the radio frequency module, and is used to control the switching unit to select one of the antennas of the antenna group, and control the radio frequency module to generate the radio frequency signal, and to estimate whether the response signal can be received when the antenna is used. The distance between the radio frequency device and the radio frequency positioning system.

The above-mentioned technical solution requires complex control technology, the implementation system is complicated, and the positioning accuracy is not high.

Contents of the invention

In view of the defects in the prior art, the object of the present invention is to provide an omnidirectional radio frequency positioning system and method based on multiple antennas.

The multi-antenna-based omnidirectional radio frequency positioning system provided according to the present invention includes: a positioning node, an anchor node, and a signal processing module; the anchor node receives the radio frequency signal sent by the positioning node, and generates multiple sets of original radio frequency positioning results; The signal processing module analyzes and processes multiple sets of original radio frequency positioning results of the anchor node to obtain position information of the positioning node, and the position information is the final radio frequency positioning result.

Preferably, the anchor node includes N groups of radio frequency receiving units, each group of radio frequency receiving units is provided with at least one radio frequency receiving antenna, and the radio frequency receiving antenna is electrically connected to the radio frequency IC, where N is a natural number greater than or equal to 2.

Preferably, each group of radio frequency receiving units in the N groups of radio frequency receiving units has a different position and/or orientation to realize omnidirectional positioning of the positioning node, and each group of radio frequency receiving units will generate a radio frequency signal according to the radio frequency signal sent by the positioning node Raw radio frequency positioning results.

Preferably, the signal processing module includes an AoA algorithm module, a data filtering module and a weighted fusion module;

The AoA algorithm module is used to calculate the angle of arrival between the positioning node and each group of radio frequency receiving units in the anchor node, and the angle of arrival is the original radio frequency positioning result;

The data filtering module is used to perform filtering processing on multiple sets of original radio frequency positioning results according to the radio frequency diagnosis information when the N groups of radio frequency receiving units in the anchor node receive the radio frequency signals sent by the positioning node;

The weighted fusion module is used to calculate the weight of each group of radio frequency receiving units according to the radio frequency diagnosis information of the N groups of radio frequency receiving units in the anchor node when they receive the radio frequency signals sent by the positioning node, and calculate the weight of the N original radio frequency receiving units according to the weights. The radio frequency positioning results are weighted and fused, and the fusion result is the final radio frequency positioning result.

Preferably, the radio frequency diagnostic information includes: RSSI, TOF.

Preferably, the radio frequency signal transmitted by the positioning node adopts UWB technology.

Preferably, each group of radio frequency receiving units includes two radio frequency receiving antennas, and the radio frequency diagnostic information further includes: the signal strength difference between the two receiving antennas of the radio frequency receiving unit; the difference between FPRSSI and RSSI of the radio frequency receiving unit.

Preferably, if the filtering strategy of the data filtering module meets any of the following conditions, then filter out:

Condition 1: If the signal strength difference between two receiving antennas of a certain group of radio frequency receiving units exceeds a given threshold, the AoA data of this group of radio frequency receiving units is considered invalid, and the AoA data is filtered out;

Condition 2: If the difference between FPRSSI and RSSI of a certain group of radio frequency receiving units exceeds a given threshold, the AoA data of this group of radio frequency receiving units is considered invalid, and the AoA data is filtered out.

Preferably, the determination strategy of the weight of the weighted fusion module satisfies the following principles:

1) For any two groups of radio frequency receiving units, the weight of the AoA result of the group with the larger RSSI is greater, and when the RSSI difference between the two groups of radio frequency receiving units exceeds a given threshold, the weight of the AoA result of the radio frequency receiving unit with the smaller RSSI is 0;

2) For any two groups of RF receiving units, the smaller the TOF, the greater the weight of the AoA result;

3) For any two groups of radio frequency receiving units, the weight of the AoA result of the radio frequency receiving unit with the smaller signal strength difference between the receiving antennas is greater;

4) For any two groups of radio frequency receiving units, the weight of the AoA result of the group of radio frequency receiving units with the smaller difference between FPRSSI and RSSI is greater;

The filtering strategy of the data filtering module also includes: performing median filtering on each group of radio frequency receiving units, that is: sorting the AoA data of the first n times of the receiving unit, taking the median value as the AoA result after this filtering, and n is positive integer.

The multi-antenna-based omnidirectional radio frequency positioning method according to the present invention is characterized in that the above-mentioned multi-antenna-based omnidirectional radio frequency positioning system is used for positioning.

Compared with the prior art, the present invention has the following beneficial effects:

1. The present invention can perform high-precision positioning on positioning nodes, and the angle-based positioning accuracy does not change with the change of the target distance.

2. In the positioning process of the present invention, accurate positioning can be performed even if there is an occlusion between the positioning node and the anchor node.

3. The radio frequency receiving unit used in the present invention has high-precision non-omnidirectional characteristics, and the method of combining multiple radio frequency receiving units and performing data fusion can achieve omnidirectional and high-precision positioning of the target.

Description of drawings

Other characteristics, objects and advantages of the present invention will become more apparent by reading the detailed description of non-limiting embodiments made with reference to the following drawings:

Fig. 1 is the structural representation of the multi-antenna-based omnidirectional radio frequency positioning system provided by the present invention;

Figure 2 is a schematic diagram of AoA;

FIG. 3 is a schematic diagram of AoA based on a dual antenna array;

Fig. 4 is a schematic diagram of fusion positioning of two groups of radio frequency receiving units;

In the picture:

10 - positioning node;

11-anchor node;

12-RF receiving unit;

13-RF receiving antenna;

14- The orientation of the radio frequency receiving antenna;

201-transmitting node;

202 - receiving antenna array;

301-signal transmitting node;

302 - the first receiving antenna;

303 - the second receiving antenna;

401-the first position of the positioning node;

402-anchor node location;

403-the first radio frequency receiving unit;

404-the second radio frequency receiving unit;

405-absorbing material;

406 —Locate the second position of the node.

detailed description

The present invention will be described in detail below in conjunction with specific embodiments. The following examples will help those skilled in the art to further understand the present invention, but do not limit the present invention in any form. It should be noted that those skilled in the art can make several changes and improvements without departing from the concept of the present invention. These all belong to the protection scope of the present invention.

According to the multi-antenna-based omnidirectional radio frequency positioning system provided by the present invention, it includes: a positioning node 10, an anchor node 11 and a signal processing module; the anchor node 11 receives the radio frequency signal sent by the positioning node 10, and generates multiple sets of original Radio frequency positioning results: the signal processing module analyzes and processes multiple sets of original radio frequency positioning results of the anchor node 11 to obtain position information of the positioning node 10, and the position information is the final radio frequency positioning results.

The anchor node 11 includes N groups of radio frequency receiving units, each group of radio frequency receiving units is provided with at least one radio frequency receiving antenna, and the radio frequency receiving antenna is electrically connected to a radio frequency IC (Integrated Circuit) (connected directly or through a switch to RF IC), where N is a natural number greater than or equal to 2.

Each group of radio frequency receiving units in the N groups of radio frequency receiving units has a different position and/or orientation to realize omnidirectional positioning of the positioning node 10, and each group of radio frequency receiving units will generate an original radio frequency signal according to the radio frequency signal sent by the positioning node 10. Radio frequency positioning results. Among them, the original radio frequency positioning results can only reach the designed positioning accuracy level when the positioning node is located within the working area of the current radio frequency receiving unit, and the positioning accuracy in other areas is relatively poor or there is no positioning result. The working area of a single group of radio frequency receiving units is not omnidirectional, and does not have the ability of omnidirectional high-precision positioning.

The signal processing module calculates the weight of each group of radio frequency receiving units according to the radio frequency diagnosis information of the N groups of radio frequency receiving units in the anchor node 11 when receiving the radio frequency signal sent by the positioning node 10, and calculates the weight of the N original radio frequency according to the weight The positioning results are weighted and fused, and the fused result is the final radio frequency positioning result.

The radio frequency diagnostic information includes: RSSI (Received Signal Strength Indication, received signal strength), TOF (Time Of Flight, time of flight) and the like.

The original radio frequency positioning result includes: the angle of arrival of radio frequency signals received by each group of radio frequency receiving units, that is, the angle of the positioning node 10 relative to the anchor node 11 .

The radio frequency adopted by the positioning node 10 is UWB (Ultra-Wide Band, UWB, ultra-wideband technology).

Preferably, each group of radio frequency receiving units of the multi-antenna-based omnidirectional radio frequency positioning system includes two radio frequency receiving antennas, and the radio frequency diagnostic information also includes: the signal strength difference of the two receiving antennas of the radio frequency receiving unit, FPRSSI (First Path Received Signal Strength Indication, the shortest path received signal strength) and the difference between RSSI.

The technical solutions in the present invention will be described in more detail below in conjunction with the accompanying drawings.

Since AoA is a signal parameter containing the position information of the positioning node 10, the angle between the receiving antenna array and the transmitting node can be calculated by using the phase difference of the signal arriving at the antenna array of a certain receiving unit in the anchor node, as shown in Figure 2 201 represents the transmitting node, 202 represents the receiving antenna array, d in the figure represents the distance between the transmitting node and the receiving antenna array, and the angle α is AoA.

Furthermore, each group of antenna arrays in the present invention includes two antennas, as shown in FIG. 3 . The signal arrival phase delay between adjacent antennas can be calculated by the following formula:

In the formula, τ is the time delay, l is the distance between adjacent antennas, α is AoA, and c is the speed of light.

Therefore, if the arrival phase difference between the antenna arrays is measured, a set of AoA results can be obtained:

In FIG. 3 , 301 represents a signal transmitting node, 302 represents a first receiving antenna, 303 represents a second receiving antenna, and l in the figure represents a distance between the first receiving antenna and the second receiving antenna.

As shown in Figure 4, 401 represents the first position of the positioning node, 406 represents the second position of the positioning node, 402 represents the position of the anchor node, 403 represents the first radio frequency receiving unit, 404 represents the second radio frequency receiving unit, 405 Indicates the absorbing material. Wherein, the absorbing material 405 is placed between the first radio frequency receiving unit 403 and the second radio frequency receiving unit 404, and the radio frequency receiving unit has high AoA positioning accuracy only within the 180 degree working range of its orientation. When the positioning node 10 is located at the first position 401 of the positioning node, the first radio frequency receiving unit 403 is towards the positioning node 10, its AoA result is accurate, and the AoA result of the second radio frequency receiving unit 404 is inaccurate; when the positioning node 10 When located at the second position 406 of the positioning node, the second radio frequency receiving unit 404 faces the positioning node 10, and its AoA result is accurate, but the AoA result of the first radio frequency receiving unit 403 is inaccurate. If the positioning node 10 sends out a radio frequency signal at the first position 401 of the positioning node, the radio frequency signal will first pass through the first radio frequency receiving unit 403 and be attenuated by the absorbing material 405 before reaching the second radio frequency receiving unit 404 . Therefore, the TOF and RSSI of the first RF receiving unit 403 and the second RF receiving unit 404 can be compared, and it is found that the TOF of the first RF receiving unit 403 is smaller and the RSSI is stronger, so the confidence/weight of the AoA result is higher.

Specifically, the data received by the receiving unit needs to undergo data filtering. When the signal is critically blocked by an obstacle during transmission (on the radio frequency propagation path, only one of the two antennas of a given group of radio frequency receiving units is blocked), the signal strength between the two receiving antennas will decrease If there is a difference, the AoA result calculated at this time is extremely inaccurate and needs to be filtered out;

Specifically, the data received by the receiving unit needs to undergo data filtering. When the signal is seriously blocked during transmission to the antenna, the FP_RSSI will be smaller than the RSS, and the more serious the blocking, the larger the difference, and the less reliable the AoA data will be. Therefore, in the measurement process, the reliability of the signal can be judged by judging the difference in strength between the two signals. When the difference exceeds a certain threshold, the data needs to be filtered out.

Specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art may make various changes or modifications within the scope of the claims, which do not affect the essence of the present invention. In the case of no conflict, the embodiments of the present application and the features in the embodiments can be combined with each other arbitrarily.

Claims (10)

1. a kind of omni-directional radio frequency alignment system based on multiple antennas, it is characterised in that including：Positioning node (10), anchor node And signal processing module (11)；The anchor node (11) receives the radiofrequency signal that the positioning node (10) sends, and generates Multigroup original radio frequency positioning result；The signal processing module is divided multigroup original radio frequency positioning result of anchor node (11) The positional information of positioning node (10) is obtained after analysis treatment, the positional information is final radio frequency positioning result.

2. the omni-directional radio frequency alignment system based on multiple antennas according to claim 1, it is characterised in that the anchor node (11) including N group rf receiver units, at least one radio frequency reception antenna, the radio frequency are provided with every group of rf receiver unit Reception antenna is electrically connected with RFCO2 laser, and wherein N is the natural number more than or equal to 2.

3. the omni-directional radio frequency alignment system based on multiple antennas according to claim 2, it is characterised in that the N groups radio frequency Every group of rf receiver unit in receiving unit has different position and/or directions, realizes the omnidirectional to positioning node (10) Positioning, one original radio frequency positioning knot of radiofrequency signal generation that every group of rf receiver unit can send according to positioning node (10) Really.

4. the omni-directional radio frequency alignment system based on multiple antennas according to claim 2, it is characterised in that the signal transacting Module includes AoA algoritic modules, data filtering module and Weighted Fusion module；

The AoA algoritic modules, for calculate respectively in positioning node (10) and anchor node (11) every group of rf receiver unit it Between angle of arrival, the angle of arrival is original radio frequency positioning result；

The data filtering module, positioning node (10) is being received for the N groups rf receiver unit in anchor node (11) Radio frequency diagnostic message during the radiofrequency signal for sending, and treatment is filtered to multigroup original radio frequency positioning result；

The Weighted Fusion module, positioning node (10) is being received for the N groups rf receiver unit in anchor node (11) Radio frequency diagnostic message during the radiofrequency signal for sending calculates every group of weight of rf receiver unit, and according to the weight to N Individual original radio frequency positioning result is weighted fusion, and the result of fusion is final radio frequency positioning result.

5. the omni-directional radio frequency alignment system based on multiple antennas according to claim 4, it is characterised in that the radio frequency diagnosis Information includes：RSSI、TOF.

6. the omni-directional radio frequency alignment system based on multiple antennas according to claim 1, it is characterised in that positioning node (10) Transmitting radiofrequency signal uses UWB technology.

7. the omni-directional radio frequency alignment system based on multiple antennas according to claim 2, it is characterised in that every group of radio frequency reception Include two radio frequency reception antennas in unit, the radio frequency diagnostic message also includes：Two reception days of rf receiver unit Difference in signal strength between line；The difference of the FPRSSI and RSSI of rf receiver unit.

8. the omni-directional radio frequency alignment system based on multiple antennas according to claim 4, it is characterised in that the data filtering If the filtering strategies of module meet following either condition, filter：

Condition one：Difference in signal strength between certain group two reception antenna of rf receiver unit exceedes certain given threshold value, then it is assumed that This group of AoA data invalid of rf receiver unit, filters the AoA data；

Condition two：The difference of certain group rf receiver unit FPRSSI and RSSI has exceeded given threshold value, then it is assumed that this group of radio frequency connects The AoA data invalids of unit are received, the AoA data are filtered.

9. the omni-directional radio frequency alignment system based on multiple antennas according to claim 4, it is characterised in that the Weighted Fusion The determination strategy of the weights of module meets following principle：

1) for wantonly two groups of rf receiver units, one group of RSSI bigger AoA result weight is bigger, when two groups of rf receiver units When RSSI differences exceed given threshold value, the AoA results weight of RSSI small rf receiver unit is 0；

2) for wantonly two groups of rf receiver units, TOF is smaller, then AoA results weight is bigger；

3) for wantonly two groups of rf receiver units, the AoA of the smaller radio frequency receiving unit of difference in signal strength between reception antenna As a result weight is bigger；

4) for wantonly two groups of rf receiver units, the AoA results of that group of smaller rf receiver unit of FPRSSI and RSSI differences Weight is bigger；

The data filtering module filtered strategy also includes：Medium filtering is carried out to every group of rf receiver unit, i.e.,：To the reception N AoA data are ranked up before unit, take median as this filtered AoA result, and n is positive integer.

10. a kind of omni-directional radio frequency localization method based on multiple antennas, it is characterised in that using described in claim 1 based on many The omni-directional radio frequency alignment system of antenna is positioned.