Method and electronic device for obtaining location information

An electronic device for obtaining location information, comprising:

• a processor;
• and
• a memory, having instructions stored thereon and executable by the processor;
• wherein, when the instructions stored on the memory are executed by the processor, the processor is caused to:
• obtain available measurement of a target node and multi-hop nodes in multiple consecutive time slices up to a current time slice, the measurement comprising measured location information of the target node and the multi-hop nodes and measured relative distance information among the target node and the multi-hop nodes;
• predict unavailable measurement caused by multi-hop transmission delay to obtain prediction information of location information and relative distance information;
• obtain location information of the target node and the multi-hop nodes in the multiple consecutive time slices based on state variables of the target node and the multi-hop nodes in the current time slice and the mobility constraints to obtain trajectory information, wherein the state variables at least comprise location, velocity and acceleration;
• initially estimate state information of the target node and the multi-hop nodes in the current time slice based on available measurement to obtain initial state estimation in the current time slice;
• and
• obtain state estimation of the target node and the multi-hop nodes in the current time slice by jointly processing the available measurement and the prediction information of the location information and the relative distance information, based on the trajectory constraints and the initial state estimation in the current time slice, the state estimation comprising the location estimation of the target node in the current time slice;
• wherein the processor is further caused to:
• establish a location measurement model of reference nodes represented by:
• {tilde over (x)}nt=xnt+bnt;
• establish a range measurement model between all nodes represented by:
• rnjt=h(xnt,xjt)+μnjt=∥xnt−xjt∥+μnjt
• where, n and j represents nodes in ξm including the target node and the multi-hop nodes, xnt represents the real location of a node n∈ξm in a time slice of t, {tilde over (x)}nt represents location measurement of a reference node obtained by the GNSS receiver, bnt represents a measurement noise of the location information meeting a Gaussian distribution with mean value of 0 and a covariance matrix of Unt, rnjt represents a measurement value of relative distance between the node n and the node j, h(xnt,xjt)=∥xnt−xjt∥ represents a real distance, and μnjt represents a measurement noise of the relative distance meeting a Gaussian distribution with mean value of 0 and a variance of (σnjt)2;
• in a case that each node n in ξm moves along a straight line with a constant acceleration, obtain the location information of node n in a time slice of t ∈ based on the location information of node n in the current time slice of k and mobility state of node n in the current time slice of k, where the location information of node n in the time slice of t∈ is represented by:
• xnt=xnk+vnkΔTt+½ank(ΔTt)2,n∈ξm,t∈,
• where, ={τ, τ+1, . . . m k}, τ=k−K+1, ΔT represents the length of each time slice, ΔTt=(t−k)ΔT, vnk represents the speed of node n in the current time slice of k, ank represents the acceleration of node n in the current time slice of k.

A non-transitory computer readable storage medium, having instructions stored thereon, wherein when the instructions are executed by a processor, a method for obtaining location information is performed, the method comprising:

• obtaining available measurement of a target node and multi-hop nodes in multiple consecutive time slices up to a current time slice, the measurement information comprising measured location information of the target node and the multi-hop nodes and measured relative distance information between the target node and the multi-hop nodes;
• predicting unavailable measurement caused by multi-hop transmission delay to obtain prediction information of location information and relative distance information;
• obtaining location information of the target node and the multi-hop nodes in the multiple consecutive time slices based on state variables of the target node and the multi-hop nodes in the current time slice and the mobility constraints to obtain trajectory information, wherein the state variables at least comprise location, velocity and acceleration;
• initially estimating state information of the target node and the multi-hop nodes in the current time slice based on available measurement to obtain initial state estimation in the current time slice;
• and
• obtaining state estimation of the target node and the multi-hop nodes in the current time slice by jointly processing the available measurement and the prediction information of the location information and the relative distance information, based on the trajectory constraints and the initial state estimation in the current time slice, the state estimation comprising the location estimation of the target node;
• wherein the method further comprises:
• establishing a location measurement model of reference nodes represented by:
• {tilde over (x)}nt=xnt+bnt;
• establishing a relative distance measurement model between all nodes represented by:
• rnjt=h(xnt,xjt)+μnjt=∥xnt−xjt∥+μnjt
• where, n and j represents nodes in ξm including the target node and the multi-hop nodes, xnt represents the real location of a node n∈ξm in a time slice of t, {tilde over (x)}nt represents location measurement of a reference node obtained by the GNSS receiver, bnt represents a measurement noise of the location information meeting a Gaussian distribution with mean value of 0 and a covariance matrix of Unt, rnjt represents a measurement value of relative distance between the node n and the node j, h(xnt,xjt)=∥xnt−xjt∥ represents a real distance, and μnjt represents a measurement noise of the relative distance meeting a Gaussian distribution with mean value of 0 and a variance of (σnjt)2;
• and
• in a case that each node in ξm moves along a straight line with a constant acceleration, obtaining the location information of the node n in a time slice of t∈ based on the location information and mobility state of node n in the current time slice of k, where the location information of node n in the time slice of t∈ is represented by:
• xnt=xnk+vnkΔTt+½ank(ΔTt)2,n∈ξm,t∈,
• where, ={τ, τ+1, . . . , k}, τ=k−K+1, ΔT represents the length of each time slice, ΔTt=(t−k)ΔT, vnk represents the speed of node n in the current time slice of k, ank represents the acceleration of node n in the current time slice of k.