CN-121978622-A - RSS positioning method based on directional gain correction

CN121978622ACN 121978622 ACN121978622 ACN 121978622ACN-121978622-A

Abstract

The invention relates to an RSS positioning method based on directional gain correction, which is used for performing target positioning under the condition of neglecting antenna directional gain and is easy to generate systematic errors in a three-dimensional space. The invention designs an RSS positioning method based on directional gain correction, which comprises the steps of firstly introducing an antenna directional gain term into a classical logarithmic path loss model to describe the relation between signal strength and space direction more accurately, solving an optimization problem by using an iterative algorithm, optimizing local fixed parameters through directional gain in each iteration, and converting an original non-convex positioning problem into a solvable convex SDP problem. Simulation experiment results show that the positioning accuracy of the invention can approach the lower boundary of the Keramelteon, and still keeps higher robustness under the serious shadow fading condition.

Inventors

XU WEIQI
JIN MING
CHEN CHENG

Assignees

宁波大学

Dates

Publication Date: 20260505
Application Date: 20251128

Claims (8)

1. An RSS positioning method based on directional gain correction, characterized in that the method comprises the following steps: S1, introducing a receiving and transmitting antenna directivity gain parameter into a classical logarithmic path loss model, and constructing an improved RSS measurement model containing directivity gain; S2, a wireless sensor network is arranged in a three-dimensional space, the wireless sensor network comprises a target node with unknown positions and M receiving nodes with known positions, RSS observation values between the target node and each receiving node are obtained according to the improved RSS measurement model, corresponding pitch angle parameters are calculated by combining with a space geometric relationship, and directional gains of each receiving node are obtained according to the pitch angle parameters; S3, averaging the positions of all the receiving nodes to obtain an initial target position estimated value; S4, taking the initial target position estimation value as a current target position estimation value, and carrying out target position estimation in an iterative mode based on the RSS observation value and the directional gain of each receiving node until convergence conditions are met, wherein the target position estimation is specifically carried out in the iterative mode: S4.1, based on the current target position estimation value, carrying out local fixed parameter optimization on the directional gain of each receiving node to obtain optimized directional gain, and correcting the RSS observation value to obtain a corrected RSS observation value; s4.2, constructing a positioning optimization problem according to the corrected RSS observation value, and constructing an equivalent convex constraint problem by adopting a discarding rank one constraint and a Schur complement mode according to the positioning optimization problem; s4.3, solving the convex constraint problem to obtain a target position estimation result of the current iteration round; S4.4, judging whether a target position estimation result of the current iteration round meets a convergence condition, if so, outputting the result as a final three-dimensional space coordinate of a target node, and if not, taking the target position estimation result of the current iteration round obtained in the step S4.3 as a current target position estimation value, and returning to the step S4.1 to continuously execute the next iteration round.
2. The RSS positioning method based on directional gain correction according to claim 1, wherein in step S1, the improved RSS measurement model including directional gain is specifically expressed as: ; Wherein, the Indicating the distance between the receiving end and the receiving end The average received power at which the received power is to be averaged, Expressed in reference distance The received power at which the power is to be received, Which represents the path loss index (pathloss) and, , Representing the log-normal shadow fading, Indicating the gain parameter of the receiver-direction, Indicating the directional gain parameter of the transmitting antenna, , The angle between the vertical direction and the connection between the transmitter and the receiver, i.e. the pitch angle, is indicated.
3. The RSS positioning method based on directional gain correction according to claim 2, wherein in step S2, the RSS observations between the target node and each receiving node are specifically expressed as: ; Wherein, the Indicating the directional gain of the i-th receiving node, ; Representing log normal shadow fading.
4. The RSS positioning method based on directional gain correction as set forth in claim 3, wherein said receiving node and said receiving and transmitting antennas corresponding to said target node are vertical dipole antennas and are vertically placed, said pitch angle parameter The concrete steps are as follows: ; Wherein, the Representing the euclidean distance between the target node and the i-th receiving node, Representing a horizontal distance between the target node and the ith receiving node; , Representing a target node location; , Indicating the location of the i-th receiving node, 。
5. The RSS positioning method based on directional gain correction as set forth in claim 4, wherein in step S4.1, said specific process of performing local fixed parameter optimization on directional gain of each receiving node is to set the target position estimation value at the kth iteration as Based on the target position estimation value The pitch angle of the ith receiving node in the k+1th iteration is calculated as follows: based on pitch angle at the (k+1) th iteration The optimized directivity gain is obtained, which is specifically expressed as: 。
6. The RSS positioning method based on directional gain correction according to claim 5, wherein the corrected RSS observations are specifically expressed as: ; Wherein, the The reference power value after the directivity gain is stripped is shown.
7. The RSS positioning method based on directional gain correction according to claim 6, wherein the specific procedure of step S4.2 is as follows: reference power value after stripping directivity gain And modified RSS observations The physical distance relation of the ith receiving node in the k+1 iteration is obtained, and the physical distance relation is specifically expressed as follows: ; Wherein, the , Representing distance measurements in the present run; According to the physical distance relation, constructing a positioning optimization problem, which is specifically expressed as follows: ; Wherein, the , Representing the physical distance relationship vector in the k +1 round of iteration, , Representing a vector of distance measurement values, , Representing a weight matrix, which is the inverse of the noise covariance, ; Definition of the definition , The method comprises the following steps of: ; From the following components Satisfy the following requirements And (3) with The equivalent optimization problem of the positioning optimization problem is obtained, and the equivalent optimization problem is specifically expressed as follows: ; wherein i, j represents the index of the receiving node, and the value range is Matrix of (a) Diagonal elements of (a) Square of corresponding distance Off-diagonal element The cross item representing node i and node j corresponds to ; Performing semi-definite relaxation treatment on the equivalent optimization problem, discarding rank one constraint, and using Schur complement to represent the semi-definite constraint to obtain an equivalent convex constraint problem: ; Wherein, the Representing a three-dimensional identity matrix; solving the equivalent convex constraint problem to obtain a target position estimate for the (k+1) th iteration as 。
8. The RSS positioning method based on directional gain correction according to claim 7, wherein in step S4.4, the convergence condition is specifically: ; Wherein, the Indicating the set convergence threshold.

Description

RSS positioning method based on directional gain correction Technical Field The invention relates to the technical field of wireless positioning and signal processing, in particular to a method for positioning received signal strength (RECEIVED SIGNAL STRENGTH, RSS) based on directional gain correction. Background In recent years, with rapid development of wireless sensor networks (Wireless Sensor Networks, WSNs), internet of things (Internet of Things, ioT), and smart space (SMART SPACE), application demands of Location-Based Services (LBS) in fields of indoor and outdoor navigation, asset tracking, smart logistics, emergency rescue, and the like are increasing. Although the conventional satellite positioning system (such as GPS and beidou) can provide a high-precision position estimation in an outdoor environment, in a complex indoor environment, satellite signals are significantly attenuated due to the influence of wall, obstruction and multipath effects, so that indoor positioning requirements are difficult to meet. Therefore, how to realize high-precision and low-cost wireless positioning in a complex environment without satellite signal coverage becomes a current research hot spot. Among the wireless positioning methods, the positioning method based on the received signal strength (RECEIVED SIGNAL STRENGTH, RSS) is widely used because of low hardware requirements, simple implementation and controllable cost. The RSS positioning method utilizes a logarithmic distance path loss model to estimate the distance between a receiving end and a transmitting end through measuring the power of signals received by equipment, and combines a geometric constraint relation to realize target position calculation. Compared with Time of Arrival (TOA) and Time difference of Arrival (TDOA) methods requiring high Time synchronization accuracy, or Angle of Arrival (AOA) methods requiring complex antenna array structures, the RSS positioning method has significant advantages in terms of system complexity, energy consumption and deployment flexibility, and is particularly suitable for resource-constrained terminal devices and existing Wi-Fi infrastructure environments. However, conventional RSS positioning methods generally assume that the propagation of the wireless signal is isotropic, i.e. the gains of the transmitting antenna and the receiving antenna are the same in all directions. This assumption is often not true in practical applications. Because the antenna has inherent directional gain characteristics, the radiation power of the antenna is unevenly distributed in space, so that the received signal strengths in different directions at the same distance have obvious differences. In addition, factors such as pitch angle, polarization mode, installation posture and environmental reflection of the antenna can also influence the signal intensity, so that systematic errors are introduced in a three-dimensional positioning scene, and the positioning result deviates from the real position. This effect of error accumulation is particularly pronounced in complex building environments where high-level distributions are significant or multiple floors are considered. Therefore, how to effectively overcome positioning errors caused by signal multipath, shielding and antenna directivity in a complex indoor environment and improve the accuracy and stability of positioning based on RSS has become a key technical problem to be solved in the current wireless positioning and signal processing field. Disclosure of Invention The invention aims to solve the technical problem of providing an RSS positioning method based on directional gain correction, which can carry out gain correction on an RSS measured value by establishing a directional gain model of a transmitting end and a receiving end, thereby effectively eliminating systematic errors caused by antenna directivity and improving the accuracy and the robustness of target positioning in a complex three-dimensional space. The technical scheme adopted by the invention is that the RSS positioning method based on directional gain correction comprises the following steps: S1, introducing a receiving and transmitting antenna directivity gain parameter into a classical logarithmic path loss model, and constructing an improved RSS measurement model containing directivity gain; S2, a wireless sensor network is arranged in a three-dimensional space, the wireless sensor network comprises a target node with unknown positions and M receiving nodes with known positions, RSS observation values between the target node and each receiving node are obtained according to the improved RSS measurement model, corresponding pitch angle parameters are calculated by combining with a space geometric relationship, and directional gains of each receiving node are obtained according to the pitch angle parameters; S3, averaging the positions of all the receiving nodes to obtain an initial target position estimated v