A seamless indoor and outdoor positioning method and system based on pseudo-satellite technology

Abstract

The present invention discloses a method and system for seamless indoor and outdoor positioning based on pseudo-satellite technology. By changing the pseudo-satellite transmitting end into a transceiver system, external satellite signals can be received while positioning indoors, so that indoor positioning and outdoor positioning are combined. The system also adds a reference transmitting end to assist in calculating the outdoor position by obtaining the distance and angle with the indoor target. The present invention can realize flexible indoor and outdoor positioning switching. Since the pseudo-satellite message is highly similar to the satellite in the sky, it does not affect the normal capture of the receiver. Whether the positioning target is indoors or outdoors, the signal can be received normally. Therefore, there is no need to design a special receiver and switch the indoor and outdoor modes. The system technology is simple to implement, and the algorithm is easy to implement and has strong controllability.

Description

Technical Field

[0001] The present invention relates to the field of indoor positioning technology, and in particular to a method and system for seamless indoor and outdoor positioning based on pseudo-satellite technology. Background Art

[0002] For satellite positioning systems, as long as the receiver can capture more than 4 GPS satellite signals at any position, positioning can be completed. However, due to the characteristics of satellite signals, it is difficult for the signals to completely penetrate obstacles. Therefore, in some closed environments, such as underground parking lots, tunnels, shopping malls and other indoor scenes, the GPS receiving antenna is blocked and can only capture weak signals, or even cannot track more than 4 satellites, which has a huge impact on the stability and accuracy of positioning. For this reason, indoor positioning technology is a hot topic in current research and development, and most of the indoor positioning systems currently under development or put into use are independent of satellite navigation systems, such as ultra-wideband technology, RFID, Bluetooth technology, and Wifi positioning. However, due to the great differences between the technologies used and the GPS system, indoor positioning often exists independently of satellite positioning. The problem brought about by this is that when the user switches between indoor and outdoor scenes during an activity, the positioning method cannot be switched immediately to cope with the new scene. This will bring many problems in applications that require continuous positioning. For example, if there is a need to monitor target vehicles in multiple tunnels in real time, or to locate vehicles entering underground parking lots in real time, it is difficult to ensure the stability and accuracy of positioning in indoor environments if only the GPS positioning system is relied upon. If other systems are used for separate positioning in indoor environments, it is difficult to ensure the continuity and convenience of positioning. Summary of the invention

[0003] The present invention aims to solve the problem that the existing indoor positioning method cannot achieve seamless indoor and outdoor positioning, and provides a method and system for seamless indoor and outdoor positioning based on pseudo-satellite technology.

[0004] To solve the above problems, the present invention is achieved through the following technical solutions:

[0005] The invention discloses an indoor and outdoor seamless positioning system based on pseudo-satellite technology, which is composed of a pseudo-satellite receiving end, i.e. a user to be positioned, a reference transmitting end, at least three pseudo-satellite simulation transceivers, and a main control end; wherein each pseudo-satellite simulation transceiver is composed of a satellite signal receiver and a satellite signal simulator; the pseudo-satellite simulation transceiver and the reference transmitting end are respectively arranged at different positions indoors, and the three-dimensional position coordinates of the pseudo-satellite simulation transceiver and the reference transmitting end are known; the input end of the satellite signal receiver of the pseudo-satellite simulation transceiver is connected to a satellite in the sky, the output end of the satellite signal receiver of the pseudo-satellite simulation transceiver is connected to the input end of the main control end, the output end of the main control end is connected to the input end of the satellite signal simulator of the pseudo-satellite simulation transceiver, and the output end of the satellite signal simulator of the pseudo-satellite simulation transceiver is connected to the input end of the pseudo-satellite receiving end; the output end of the reference transmitting end is also connected to the input end of the pseudo-satellite receiving end; and the output end of the pseudo-satellite receiving end is connected to the input end of the main control end.

[0006] In the above system, the satellite signal receiver of the pseudo-satellite simulation transceiver is placed outdoors, and the satellite signal simulator is placed indoors.

[0007] The indoor and outdoor seamless positioning system implements a pseudo-satellite technology-based indoor and outdoor seamless positioning method, which is characterized by comprising the following steps:

[0008] Step 1: The satellite signal receiver of each pseudo-satellite simulation transceiver receives the satellite signal of the satellite in the sky, captures and tracks the satellite signal, and transmits the carrier-to-noise ratio obtained by the capture and tracking back to the main control end;

[0009] Step 2: The main control end allocates a captured satellite in the sky to the satellite signal simulator of each pseudolite simulation transceiver based on the carrier-to-noise ratio transmitted by the satellite signal receiver of each pseudolite simulation transceiver;

[0010] Step 3, the satellite signal simulator of each pseudo-satellite simulation transceiver demodulates the satellite signal of the assigned satellite in the sky according to the assigned satellite in the sky, and calculates the pseudo-range and horizontal angle between the pseudo-satellite simulation transceiver and the assigned satellite in the sky; the calculated pseudo-range and horizontal angle between the pseudo-satellite simulation transceiver and the assigned satellite in the sky are added on the basis of the copied original ephemeris, and the pseudo-satellite signal is generated after modulation and transmitted;

[0011] Step 4: The reference transmitter directly simulates the satellite signal of the given backup satellite in the sky, generates a pseudo-satellite signal and transmits it;

[0012] Step 5: The pseudolite receiving end simultaneously receives the pseudolite signals transmitted by the satellite signal simulators of all pseudolite simulation transceivers and the reference transmitting end, captures, tracks and demodulates the observation data of the pseudolite simulation transceivers and the reference transmitting end, and sends the observation data to the main control end;

[0013] Step 6: The main control end calculates the real position of the pseudo-satellite receiving end using the observation data sent by the pseudo-satellite receiving end, that is:

[0014] Step 6.1, the main control end uses the observation data sent by each pseudo-satellite receiving end and the reference transmitting end to calculate the pseudo-range between the pseudo-satellite receiving end and each pseudo-satellite simulated transceiver, as well as the pseudo-range between the pseudo-satellite receiving end and the reference transmitting end, and simultaneously obtains the pseudo-range and horizontal angle between the pseudo-satellite simulated transceiver and the assigned satellite in the sky;

[0015] Step 6.2: For each pseudolite simulated transceiver, calculate the angle between the line connecting the pseudolite receiving end and the pseudolite simulated transceiver and the line connecting the pseudolite simulated transceiver and the reference transmitting end, that is:

[0016]

[0017] Step 6.3, respectively calculate the pseudo-ranges between the pseudo-satellite receiving end and the satellites in the sky assigned to each pseudo-satellite simulation transceiver, that is:

[0018]

[0019] Step 6.4, using a positioning algorithm to calculate the real position of the pseudolite receiving end according to the pseudoranges of the satellites in the sky allocated to the pseudolite receiving end and each pseudolite simulation transceiver, and the three-dimensional position coordinates of each pseudolite simulation transceiver;

[0020] In the formula, β j is the angle between the line connecting the pseudo-satellite receiving terminal and the pseudo-satellite simulation transceiver terminal j and the line connecting the pseudo-satellite simulation transceiver terminal j and the reference transmitting terminal; d j is the distance from the reference transmitter to the pseudo-satellite simulated transceiver j, which is calculated from the three-dimensional position coordinates of the reference transmitter and the pseudo-satellite simulated transceiver j; ρ0 is the pseudo-range between the pseudo-satellite receiving end and the reference transmitter; ρ j is the pseudorange between the pseudo-satellite receiving end and the pseudo-satellite simulation transceiver j; ρ′ i is the pseudorange of satellite i in the sky allocated to the pseudosatellite receiving end and the pseudosatellite simulation transceiver end j; ρ i is the pseudo-range between pseudo-satellite simulation transceiver j and the assigned satellite i in the sky; j is the horizontal angle of pseudo-satellite simulation transceiver j; j = 1, 2, ..., N, N is the number of pseudo-satellite simulation transceivers.

[0021] The allocation process of step 2 above is as follows:

[0022] Step 2.1, the master control end simultaneously obtains the carrier-to-noise ratio of each captured satellite in the sky from N pseudo-satellite simulation transceivers, selects N pre-assigned satellites in the sky based on the average carrier-to-noise ratio and the captured ratio, and numbers the pre-assigned satellites in order of their satellite numbers as 1, 2, ..., N, and initializes the number of satellites to be assigned WD = 1;

[0023] Step 2.2, let the number of the currently pre-allocated satellite in the sky be x=WD;

[0024] Step 2.3: The pseudo-satellite simulation transceiver corresponding to the current maximum carrier-to-noise ratio of the currently pre-assigned satellite x is used as the pre-assigned end C of the currently pre-assigned satellite x. x , and the difference between the current maximum carrier-to-noise ratio of the currently pre-assigned satellite x and the current second largest carrier-to-noise ratio is used as the current correlation value K of the currently pre-assigned satellite x x ;

[0025] Step 2.4: Determine whether WD is equal to 1: If so, set WD=WD+1 and go to step 2.2; otherwise, go to step 2.5;

[0026] Step 2.5: Determine the pre-allocated end C of the currently pre-allocated satellite x x Whether it overlaps with the pre-allocated end of all satellites in the sky that have pre-allocated ends:

[0027] If none of them are repeated, further determine whether WD is equal to N:

[0028] If yes, the allocation process ends, and the satellite signal simulator of each pseudo-satellite simulation transceiver is allocated to a captured satellite in the sky;

[0029] Otherwise, set WD=WD+1 and return to step 2.2;

[0030] If repeated, further compare the current correlation value K of the currently pre-assigned satellite x in the sky x The current correlation value K of the repeated pre-assigned satellite y in the sky y , where y ≠ x:

[0031] If K x >K y , first delete the current maximum carrier-to-noise ratio of the repeated pre-assigned satellite y, and use the current second largest carrier-to-noise ratio of the repeated pre-assigned satellite y as the current maximum carrier-to-noise ratio of the repeated pre-assigned satellite y, then set the number of the current pre-assigned satellite x=y, and return to step 2.3;

[0032] If K x≤K y , then first delete the current maximum carrier-to-noise ratio of the currently pre-assigned satellite x, and use the current second largest carrier-to-noise ratio of the currently pre-assigned satellite x as the current maximum carrier-to-noise ratio of the currently pre-assigned satellite x, and return to step 2.3;

[0033] The above N is the number of pseudo-satellite simulation transceivers.

[0034] In the above step 2.1, the average carrier-to-noise ratio of each satellite in the sky is equal to the sum of the carrier-to-noise ratios obtained by all satellite signal receivers of the pseudo-satellite simulation transceiver ends that have captured the satellite in the sky divided by the number of satellite signal receivers of the pseudo-satellite simulation transceiver ends that have captured the satellite in the sky.

[0035] In the above step 2.1, the capture ratio of each satellite in the sky is equal to the sum of the number of satellite signal receivers of pseudolite simulation transceivers that capture the satellite in the sky divided by the number of satellite signal receivers of all pseudolite simulation transceivers.

[0036] In the above step 2.1, the pre-assigned satellites are selected by sorting based on the captured ratio as a main factor and the average carrier-to-noise ratio as a supplement.

[0037] In the above step 5, the observation data sent by the pseudo-satellite receiving end to the main control end include: the pseudo-range and horizontal angle between the satellite in the sky and the corresponding pseudo-satellite simulation transceiver; the pseudo-code phase and carrier phase between the pseudo-satellite simulation transceiver and the pseudo-satellite receiving end; the pseudo-code phase and carrier phase between the reference transmitting end and the pseudo-satellite receiving end; the reception time of the pseudo-satellite receiving end to the pseudo-satellite signal; and the coordinate parameters of the satellite in the sky.

[0038] Compared with the prior art, the present invention improves the structure of the pseudo-satellite system. By changing the pseudo-satellite transmitting end into a transceiver system, the external satellite signal can be received while positioning indoors, so that indoor positioning and outdoor positioning are combined. The system also adds a reference transmitting end, which assists in calculating the outdoor position by obtaining the distance and angle with the indoor target. The present invention can realize flexible indoor and outdoor positioning switching. Since the pseudo-satellite message is highly similar to the satellite in the sky, it does not affect the normal capture of the receiver. Whether the positioning target is indoors or outdoors, the signal can be received normally. Therefore, there is no need to design a special receiver and switch the indoor and outdoor modes. The system technology is simple to implement, and the algorithm is easy to implement and has strong controllability. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 Schematic diagram of a seamless indoor and outdoor positioning system based on pseudo-satellite technology.

[0040] Figure 2 The schematic diagram is a principle block diagram of a seamless indoor and outdoor positioning method based on pseudo-satellite technology.

[0041] Figure 3 For seamless positioning schematics. DETAILED DESCRIPTION

[0042] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with specific examples.

[0043] A seamless indoor and outdoor positioning system based on pseudo-satellite technology, such as Figure 1 As shown, it is composed of a pseudo-satellite receiving end (i.e., the user to be positioned), at least three pseudo-satellite simulation transceivers, a reference transmitting end, and a master control end. In order to locate the user, it is necessary to arrange at least three pseudo-satellite simulation transceivers in different positions. When a positioning method based on arrival time (ToA), received signal strength (RSS), and arrival angle (AoA) is adopted, three pseudo-satellite simulation transceivers can be adopted. When a positioning method based on arrival time difference (TDoA) is adopted, four pseudo-satellite simulation transceivers need to be adopted. In this embodiment, the system is equipped with four pseudo-satellite simulation transceivers. Each pseudo-satellite simulation transceiver includes a satellite signal receiver connected to a satellite signal simulator, wherein the satellite signal receiver is placed outdoors and is responsible for satellite signal reception, and the satellite signal simulator is placed indoors and is responsible for signal transmission. The pseudo-satellite simulation transceiver and the reference transmitting end are placed at different positions, and the three-dimensional coordinates of the position are known. The input end of the satellite signal receiver of the pseudo-satellite simulation transceiver is connected to the satellite in the sky, the output end of the satellite signal receiver of the pseudo-satellite simulation transceiver is connected to the input end of the main control end, the output end of the main control end is connected to the input end of the satellite signal simulator of the pseudo-satellite simulation transceiver, and the output end of the satellite signal simulator of the pseudo-satellite simulation transceiver is connected to the input end of the pseudo-satellite receiving end; the output end of the reference transmitting end is also connected to the input end of the pseudo-satellite receiving end; the output end of the pseudo-satellite receiving end is connected to the input end of the main control end.

[0044] The system implements a seamless indoor and outdoor positioning method based on pseudo-satellite technology, such as Figure 2 As shown, the specific process is as follows:

[0045] Step 1: The satellite signal receiver of each pseudo-satellite simulation transceiver receives the satellite signal of the satellite in the sky, captures and tracks the satellite signal, and transmits the carrier-to-noise ratio obtained by the capture and tracking back to the main control end.

[0046] Step 2: The master control end allocates a satellite number to the satellite signal simulator of each pseudolite simulation transceiver based on the carrier-to-noise ratio transmitted by the satellite signal receiver of each pseudolite simulation transceiver.

[0047] Since the satellite signal receiver of each pseudo-satellite simulation transceiver usually captures multiple satellites, and the satellite signal simulator of each pseudo-satellite simulation transceiver will only simulate one satellite at a time for signal transmission, the satellite signal simulator of each satellite simulation transceiver needs to select a suitable satellite number from the signal captured by the satellite signal receiver of the pseudo-satellite simulation transceiver for simulation and reproduction, so it is also necessary to allocate the transmitting satellite number of each transmitter through the main control end. The allocation requirement is that the carrier-to-noise ratio of the allocated satellite is as large as possible to ensure signal stability in harsh environments. The allocation steps are as follows:

[0048] Step 2.1, the master control end simultaneously obtains the carrier-to-noise ratio of each captured satellite in the sky from N pseudo-satellite simulation transceivers, selects N pre-assigned satellites in the sky based on the average carrier-to-noise ratio and the captured ratio, and numbers the pre-assigned satellites in order of their satellite numbers as 1, 2, ..., N, and initializes the number of satellites to be assigned WD = 1;

[0049] The average carrier-to-noise ratio of each satellite is equal to the sum of the carrier-to-noise ratios obtained by the satellite signal receivers of all pseudo-satellite simulation transceivers that have captured the satellite divided by the number of satellite signal receivers of the pseudo-satellite simulation transceivers that have captured the satellite. The capture ratio of each satellite is equal to the number of satellite signal receivers of the pseudo-satellite simulation transceivers that have captured the satellite divided by the number of satellite signal receivers of all pseudo-satellite simulation transceivers. In the preferred embodiment of the present invention, the pre-allocated satellites are selected by sorting based on the capture ratio as the main factor and the average carrier-to-noise ratio as the auxiliary factor, that is, first select from the satellites with the largest capture ratio. When the number of satellites with the largest capture ratio is greater than the number of pseudo-satellite simulation transceivers, select satellites with a larger average carrier-to-noise ratio from these satellites with the largest capture ratio. When the number of satellites with the largest capture ratio is less than the number of pseudo-satellite simulation transceivers, select from satellites with a capture ratio greater than this.

[0050] Step 2.2, let the number of the currently pre-allocated satellite in the sky be x=WD;

[0051] Step 2.3: The pseudo-satellite simulation transceiver corresponding to the current maximum carrier-to-noise ratio of the currently pre-assigned satellite x is used as the pre-assigned end C of the currently pre-assigned satellite x. x , and the difference between the current maximum carrier-to-noise ratio of the currently pre-assigned satellite x and the current second largest carrier-to-noise ratio is used as the current correlation value K of the currently pre-assigned satellite x x ;

[0052] Step 2.4: Determine whether WD is equal to 1: If so, set WD=WD+1 and go to step 2.2; otherwise, go to step 2.5;

[0053] Step 2.5: Determine the pre-allocated end C of the currently pre-allocated satellite x x Whether it overlaps with the pre-allocated end of all satellites in the sky that have pre-allocated ends:

[0054] If none of them are repeated, further determine whether WD is equal to N:

[0055] If yes, the allocation process ends, and the satellite signal simulator of each pseudo-satellite simulation transceiver is allocated to a captured satellite in the sky;

[0056] Otherwise, set WD=WD+1 and return to step 2.2;

[0057] If repeated, further compare the current correlation value K of the currently pre-assigned satellite x in the sky x The current correlation value K of the repeated pre-assigned satellite y in the sky y , where y ≠ x:

[0058] If K x >K y , first delete the current maximum carrier-to-noise ratio of the repeated pre-assigned satellite y, and use the current second largest carrier-to-noise ratio of the repeated pre-assigned satellite y as the current maximum carrier-to-noise ratio of the repeated pre-assigned satellite y, then set the number of the current pre-assigned satellite x=y, and return to step 2.3;

[0059] If K x ≤K y , then first delete the current maximum carrier-to-noise ratio of the currently pre-assigned satellite x, and use the current second largest carrier-to-noise ratio of the currently pre-assigned satellite x as the current maximum carrier-to-noise ratio of the currently pre-assigned satellite x, and return to step 2.3;

[0060] The above N is the number of pseudo-satellite simulation transceivers.

[0061] Due to the small difference in the carrier-to-noise ratio of several receivers tracking a satellite at the same time and in close positions, but the carrier-to-noise ratio of the same receiver tracking several different satellites may be very different. Therefore, through the method described above, according to this property, the calculation is carried out from a single satellite as the entry point to obtain the K value to consider whether the difference in the carrier-to-noise ratio of the same satellite at different pseudo-satellite simulation transceivers can be ignored, and the inter-satellite maximum value comparison is repeatedly performed to obtain a more appropriate allocation scheme. The reason for the immediate allocation after capture and tracking is to enable the pseudo-satellite simulation transceiver to accurately demodulate the target satellite, saving unnecessary waste of resources and computing time.

[0062] Step 3: After receiving the satellite number of each group, the pseudo-satellite simulation transceiver only demodulates the satellite signal, copies the data code structure, and calculates the pseudo-range and horizontal angle (i.e., elevation angle) of the pseudo-satellite simulation transceiver; adds the obtained pseudo-range and horizontal angle values ​​to the copied original ephemeris, generates a pseudo-code of the corresponding satellite number, obtains the pseudo-satellite signal after BPSK modulation, and transmits it.

[0063] The generation of pseudo-satellite signals is classified and processed by the satellite number assigned by the pseudo-satellite simulation transceiver. For a single pseudo-satellite simulation transceiver, firstly, according to the corresponding satellite number, only the data code of the satellite is demodulated, and the elevation angle α can be calculated according to the parameters given by the ephemeris. i and the pseudorange ρ i , and then write these two parameters into the telegram. At the same time, the transmitting module of the pseudo-satellite simulation transceiver will generate the C / A code of the corresponding satellite, copy the modified telegram, and modulate it into a pseudo-satellite signal for indoor transmission.

[0064] Step 4: Place a reference transmitter at a known location to generate simulated satellite signals, but do not interact with other modules. It is mainly used to measure the indoor horizontal angle. In signal modulation, a backup satellite number must be selected to prevent conflict with the actual captured satellite signal.

[0065] The reference transmitter uses the backup satellite number for modulation, and needs to produce the C / A code of the backup satellite. It is not necessary to write the telegram information because the position coordinates of the reference transmitter are known, the transmission angle can be calculated through the coordinates, and the room is stationary relative to the ground. The orbital eccentricity, orbital inclination change rate, mean angular velocity, ascending node right ascension change rate, orbit perigee angular distance, perturbation force correction parameters and other values ​​in the telegram can be made always equal to zero, which does not affect the reception of the receiver.

[0066] Step 5: The pseudo-satellite receiving end simultaneously receives the pseudo-satellite signals from the four pseudo-satellite simulation transceivers and the reference transmitting end, captures, tracks and demodulates the observation data of each transmitting position (pseudo-satellite simulation transceiver or reference transmitting end), and then sends the observation data to the main control end.

[0067] The pseudo-satellite receiver completes the capture and tracking of indoor signals. Its specific structure is similar to that of a conventional satellite receiver, but it needs to expand the search range during capture so that the backup satellite number can be captured. At the same time, since satellite signals in the sky can also be received indoors, this may interfere with the reception results. Outdoor signals are generally weak, and even if they are captured, the correlation peak is not high. The transmission power of indoor signals is relatively stable, and the signal strength is much greater than that of outdoor signals. Therefore, the capture end needs to be processed at the software level: (1) Increase the capture threshold value; (2) Expand the range of the pseudo-code search sequence in the three-dimensional search, and use parallel frequency search to increase the capture speed; (3) Limit the capture channel, and stop capturing when only 5 satellites are captured and one of them is a backup satellite. After the pseudo-satellite receiving end completes tracking and demodulation, it interacts with the main control end and further processes the observation data at the main control end. The required observation data transmitted to the main control end include: (1) the pseudo-range and horizontal angle between the satellite in the sky and the corresponding pseudo-satellite simulation transceiver; (2) the pseudo-code phase and carrier phase between the pseudo-satellite simulation transceiver and the pseudo-satellite receiving end; (3) the pseudo-code phase and carrier phase between the reference transmitter and the pseudo-satellite receiving end; (4) the reception time of the pseudo-satellite receiving end to the pseudo-satellite signal; and (5) the coordinate parameters of the satellite in the sky.

[0068] Step 6: The main control end calculates the real position of the pseudolite receiving end using the observation data sent by the pseudolite receiving end.

[0069] According to the pseudo-satellite system structure designed by the present invention, the original pseudo-range and horizontal angle are first obtained by demodulating the satellite ephemeris message through the pseudo-satellite simulation transceiver. The position coordinates of the pseudo-satellite simulation transceiver and the reference transmitting end are fixed and known. The pseudo-range measurement value of each endpoint (pseudo-satellite receiving end and reference transmitting end) from the pseudo-satellite receiving end can be calculated. The angle is calculated with the assistance of the pseudo-range of the reference transmitting end, and the real distance of the indoor position can be calculated by the cosine theorem.

[0070] Step 6.1: At the beginning of the system operation, take the reference transmitter as the origin, establish the three-dimensional position coordinates of four pseudo-satellite simulation transceivers and one reference transmitter, and use these three-dimensional position coordinates (x i ,y i ,z i ) are written to the master end together.

[0071] Step 6.2: The master end calculates the pseudorange ρ between the pseudo-satellite receiving end and the pseudo-satellite simulation transceiver end by using the pseudo-code phase or carrier phase in the observed data. j , and the pseudorange ρ0 between the pseudo-satellite receiver and the reference transmitter.

[0072] The pseudorange ρ0 between the pseudosatellite receiving end and the reference transmitting end and the pseudorange ρ between the pseudosatellite receiving end and the pseudosatellite simulation transmitting and receiving endj The calculation process is similar to that of . j Take this as an example to illustrate:

[0073] Considering that the carrier phase needs to consider the integer ambiguity problem, the pseudo code phase CP i It is easier to implement but the accuracy will be affected to a certain extent. The expression of pseudorange is as follows:

[0074]

[0075] Where c is the speed of light, t u (t) = t + δt u (t) represents the receiving time, t γ Indicates other delay interference, represents the transmission time of the corresponding transceiver, t is the pseudo-satellite time when the signal is received, and τ is the actual propagation time of the signal, where t u Contains the receiver clock error δt u (t), Includes the transmitting clock error Therefore, under normal circumstances, t is affected by the clock error and has a different value from τ. However, the pseudo-satellite system is different from the GPS satellite in that it is always in motion. The pseudo-satellite system can eliminate the pseudo-satellite's transmission clock error by broadcasting correction parameters, and the receiver clock error can be eliminated by initializing TDOA processing. Therefore, the two clock errors are equivalent to known quantities, and there is no need to consider the atmospheric propagation delay and ionospheric propagation delay in indoor environments. Therefore, t γ =0.

[0076] In actual processing, t u can be read directly from the receiver clock, but It is necessary to calculate through the pseudo code phase. Assuming that the clock error has been eliminated, we have:

[0077]

[0078] Among them, TOW is the time in week, w is the word representing the navigation message data code, b is the bit number, time is in seconds, and a pseudo code period is 1ms, which is 0.001s, and a message length is 20ms, which is 0.02s. 1023 means that there are a total of 1023 code bits in a pseudo code period. The wavelength of a pseudo code can reach 293m. Therefore, there is basically no need to consider the number of whole cycles indoors, and the pseudo code phase indirectly reflects the pseudo range.

[0079] Step 6.3: Calculate the pseudo-range ρ′ between the pseudo-satellite receiver and the satellite in the sky i .

[0080] Taking a satellite in the sky and a pseudo-satellite simulating a transceiver as an example, the principle diagram of seamless positioning is as follows: Figure 3 As shown. In the figure, point A is the satellite in the sky; point B is the pseudo-satellite simulation transceiver; point C is the pseudo-satellite receiving end; point D is the reference transmitting end. Special note, here we can completely ignore the distance between the transmitting antenna and the receiving antenna of the pseudo-satellite simulation transceiver by placing them in the correct position, reducing the calculation complexity of the system. Generally, the receiving antenna is located on the surface of the outdoor roof, and the transmitting antenna is located on the surface of the ceiling of the top floor indoors. The actual distance is within 2 to 3 meters. As long as the positions of the two antennas are vertically on the same straight line, then the distance of 20200km from the receiving antenna to the satellite in the sky can be ignored.

[0081] Through the previous steps, the master control end assigns the satellite in the sky at point A to the pseudo-satellite simulation transceiver at point B. In this process, the pseudo-satellite simulation transceiver will demodulate the signal and calculate the pseudo-range ρ of AB i Angle α with the horizontal j (Calculated in step 3). The pseudo-range BC between the pseudo-satellite simulation transceiver and the pseudo-satellite receiving end is ρ j , can be obtained by the above equations (1) and (2); similarly, the pseudo-range DC between the reference transmitter and the pseudo-satellite receiver is ρ0. Since the three-dimensional position coordinates of points D and B are known, the distance d between BD is j In this way, the angle β between the line BC connecting the pseudo-satellite receiving end and the pseudo-satellite simulated transceiver and the line BD connecting the pseudo-satellite simulated transceiver and the reference transmitting end can be calculated. j :

[0082]

[0083] Here β j The reason why it is necessary to use a reference transmitter to measure instead of directly calculating the coordinates obtained by the pseudo-satellite receiving end at point C is that the coordinates obtained at this time are coarse coordinates calculated through the pseudo-code phase. As a positioning result, the error is acceptable at the decimeter level, but in calculating the angle, the decimeter-level error will bring about a large deviation, so it is necessary to set up a reference transmitter to correct the angle.

[0084] Let θ j =α j +β j ,Depend on Figure 3 , we can calculate the pseudo-range ρ′ between the pseudo-satellite receiver C and the satellite in the sky at point A i :

[0085]

[0086] The other three satellites use the same method to calculate pseudoranges, thus obtaining four different distance values; in the process of modulating the pseudosatellite signal, the constellation coordinates of the corresponding satellite are copied and written into the pseudosatellite's ephemeris, so the receiver can solve the satellite coordinates as a known quantity.

[0087] Step 6.4: According to the pseudo-ranges of the satellites in the sky allocated to the pseudo-satellite receiving end and each pseudo-satellite simulation transceiver, and the three-dimensional position coordinates of each pseudo-satellite simulation transceiver, the real position of the pseudo-satellite receiving end is calculated using a traditional positioning solution algorithm (such as the TDOA algorithm).

[0088] The pseudo-ranges between the pseudo-satellite receiving end and each pseudo-satellite simulated transceiver are known, and the three-dimensional position coordinates of each pseudo-satellite simulated transceiver are known. The existing positioning solution algorithm can be used to solve the three-dimensional position coordinates (X, Y, Z) of the located point, i.e., the pseudo-satellite receiving end.

[0089] Taking the positioning algorithm TDOA as an example, the expression can be listed as follows:

[0090]

[0091] in ε i is the environmental noise error. The arrival time difference algorithm can just offset the receiving end clock error δt u The influence of (t), the environmental noise error can be suppressed by the anti-multipath algorithm, and the obtained target coordinates will have a positioning accuracy of decimeter level.

[0092] The present invention arranges a satellite-like signal transmitting source indoors to form a pseudo-satellite network, adds a satellite signal receiver on the basis of a pseudo-satellite system satellite signal simulator to receive satellite signals in real time, and arranges a reference transmitting end at a known point indoors to calculate the height of the target point, combines several groups of received data to calculate the real indoor position, and can quickly respond when the indoor and outdoor scenes are switched, without affecting the real-time positioning solution, which can ensure the accuracy of indoor positioning and the continuity of positioning. The system, such as capture tracking, pseudo-satellite signal modulation, etc., belongs to mature technologies, so it is not elaborated too much.

[0093] It should be noted that although the embodiments of the present invention described above are illustrative, they are not intended to limit the present invention, and therefore the present invention is not limited to the above specific embodiments. Without departing from the principles of the present invention, any other embodiments obtained by those skilled in the art under the guidance of the present invention are deemed to be within the protection of the present invention.

Claims

1. A method for seamless indoor and outdoor positioning based on pseudo-satellite technology implemented by an indoor and outdoor seamless positioning system, wherein the indoor and outdoor seamless positioning system is composed of a pseudo-satellite receiving end, i.e., a user to be positioned, a reference transmitting end, at least three pseudo-satellite simulation transceivers, and a main control end; wherein each pseudo-satellite simulation transceiver is composed of a satellite signal receiver and a satellite signal simulator; the pseudo-satellite simulation transceiver and the reference transmitting end are respectively arranged at different positions indoors, and the three-dimensional position coordinates of the pseudo-satellite simulation transceiver and the reference transmitting end are known; the input end of the satellite signal receiver of the pseudo-satellite simulation transceiver is connected to a satellite in the sky, the output end of the satellite signal receiver of the pseudo-satellite simulation transceiver is connected to the input end of the main control end, the output end of the main control end is connected to the input end of the satellite signal simulator of the pseudo-satellite simulation transceiver, and the output end of the satellite signal simulator of the pseudo-satellite simulation transceiver is connected to the input end of the pseudo-satellite receiving end; the output end of the reference transmitting end is also connected to the input end of the pseudo-satellite receiving end; the output end of the pseudo-satellite receiving end is connected to the input end of the main control end; and the characteristic is that The steps include: Step 1: The satellite signal receiver of each pseudo-satellite simulation transceiver receives the satellite signal of the satellite in the sky, captures and tracks the satellite signal, and transmits the carrier-to-noise ratio obtained by the capture and tracking back to the main control end; Step 2: The main control end allocates a captured satellite in the sky to the satellite signal simulator of each pseudolite simulation transceiver based on the carrier-to-noise ratio transmitted by the satellite signal receiver of each pseudolite simulation transceiver; Step 3, the satellite signal simulator of each pseudo-satellite simulation transceiver demodulates the satellite signal of the assigned satellite in the sky according to the assigned satellite in the sky, and calculates the pseudo-range and horizontal angle between the pseudo-satellite simulation transceiver and the assigned satellite in the sky; the calculated pseudo-range and horizontal angle between the pseudo-satellite simulation transceiver and the assigned satellite in the sky are added on the basis of the copied original ephemeris, and the pseudo-satellite signal is generated after modulation and transmitted; Step 4: The reference transmitter directly simulates the satellite signal of the given backup satellite in the sky, generates a pseudo-satellite signal and transmits it; Step 5: The pseudolite receiving end simultaneously receives the pseudolite signals transmitted by the satellite signal simulators of all pseudolite simulation transceivers and the reference transmitting end, captures, tracks and demodulates the observation data of the pseudolite simulation transceivers and the reference transmitting end, and sends the observation data to the main control end; Step 6: The main control end calculates the real position of the pseudo-satellite receiving end using the observation data sent by the pseudo-satellite receiving end, that is: Step 6.1, the main control end uses the observation data sent by each pseudo-satellite receiving end and the reference transmitting end to calculate the pseudo-range between the pseudo-satellite receiving end and each pseudo-satellite simulated transceiver, as well as the pseudo-range between the pseudo-satellite receiving end and the reference transmitting end, and simultaneously obtains the pseudo-range and horizontal angle between the pseudo-satellite simulated transceiver and the assigned satellite in the sky; Step 6.2: For each pseudolite simulated transceiver, calculate the angle between the line connecting the pseudolite receiving end and the pseudolite simulated transceiver and the line connecting the pseudolite simulated transceiver and the reference transmitting end, that is: Step 6.3, respectively calculate the pseudo-ranges between the pseudo-satellite receiving end and the satellites in the sky assigned to each pseudo-satellite simulation transceiver, that is: Step 6.4, using a positioning algorithm to calculate the real position of the pseudolite receiving end according to the pseudoranges of the satellites in the sky allocated to the pseudolite receiving end and each pseudolite simulation transceiver, and the three-dimensional position coordinates of each pseudolite simulation transceiver; In the formula, β j is the angle between the line connecting the pseudo-satellite receiving terminal and the pseudo-satellite simulation transceiver terminal j and the line connecting the pseudo-satellite simulation transceiver terminal j and the reference transmitting terminal; d j is the distance from the reference transmitter to the pseudo-satellite simulated transceiver j, which is calculated from the three-dimensional position coordinates of the reference transmitter and the pseudo-satellite simulated transceiver j; ρ0 is the pseudo-range between the pseudo-satellite receiving end and the reference transmitter; ρ j is the pseudorange between the pseudo-satellite receiving end and the pseudo-satellite simulation transceiver j; ρ i ′ is the pseudorange of satellite i in the sky allocated by the pseudosatellite receiving end and the pseudosatellite simulation transceiver end j; ρ i is the pseudo-range between pseudo-satellite simulation transceiver j and the assigned satellite i in the sky; j is the horizontal angle of pseudo-satellite simulation transceiver j; j = 1, 2, ..., N, N is the number of pseudo-satellite simulation transceivers.

2. The method for seamless indoor and outdoor positioning based on pseudo-satellite technology according to claim 1, characterized in that: The allocation process of step 2 is as follows: Step 2.1, the master control end simultaneously obtains the carrier-to-noise ratio of each captured satellite in the sky from N pseudo-satellite simulation transceivers, selects N pre-assigned satellites in the sky based on the average carrier-to-noise ratio and the captured ratio, and numbers the pre-assigned satellites in order of their satellite numbers as 1, 2, ..., N, and initializes the number of satellites to be assigned WD = 1; Step 2.2, let the number of the currently pre-assigned satellite in the sky be x=WD; Step 2.3: The pseudo-satellite simulation transceiver corresponding to the current maximum carrier-to-noise ratio of the current pre-assigned satellite x is used as the pre-assigned end C of the current pre-assigned satellite x. x , and the difference between the current maximum carrier-to-noise ratio of the currently pre-assigned satellite x and the current second largest carrier-to-noise ratio is used as the current correlation value K of the currently pre-assigned satellite x x ; Step 2.4: Determine whether WD is equal to 1: If so, set WD=WD+1 and go to step 2.2; otherwise, go to step 2.5; Step 2.5: Determine the pre-allocated end C of the currently pre-allocated satellite x x Whether it overlaps with the pre-allocated end of all satellites in the sky that have pre-allocated ends: If none of them are repeated, further determine whether WD is equal to N: If yes, the allocation process ends, and the satellite signal simulator of each pseudo-satellite simulation transceiver is allocated to a captured satellite in the sky; Otherwise, set WD=WD+1 and return to step 2.2; If repeated, further compare the current correlation value K of the currently pre-assigned satellite x in the sky x The current correlation value K of the repeated pre-assigned satellite y in the sky y , where y ≠ x: If K x >K y , first delete the current maximum carrier-to-noise ratio of the repeated pre-assigned satellite y, and use the current second largest carrier-to-noise ratio of the repeated pre-assigned satellite y as the current maximum carrier-to-noise ratio of the repeated pre-assigned satellite y, then set the number of the current pre-assigned satellite x=y, and return to step 2.3; If K x ≤K y , then first delete the current maximum carrier-to-noise ratio of the currently pre-assigned satellite x, and use the current second largest carrier-to-noise ratio of the currently pre-assigned satellite x as the current maximum carrier-to-noise ratio of the currently pre-assigned satellite x, and return to step 2.3; The above N is the number of pseudo-satellite simulation transceivers.

3. The method for seamless indoor and outdoor positioning based on pseudo-satellite technology according to claim 2, characterized in that: In step 2.1, the average carrier-to-noise ratio of each satellite in the sky is equal to the sum of the carrier-to-noise ratios obtained by all satellite signal receivers of the pseudo-satellite simulation transceiver ends that have captured the satellite in the sky divided by the number of satellite signal receivers of the pseudo-satellite simulation transceiver ends that have captured the satellite in the sky.

4. The method for seamless indoor and outdoor positioning based on pseudo-satellite technology according to claim 2, characterized in that: In step 2.1, the capture ratio of each satellite in the sky is equal to the sum of the number of satellite signal receivers of pseudolite simulation transceivers that capture the satellite in the sky divided by the number of satellite signal receivers of all pseudolite simulation transceivers.

5. The method for seamless indoor and outdoor positioning based on pseudo-satellite technology according to claim 2, characterized in that: In step 2.1, the pre-assigned satellites are selected by sorting based on the captured ratio as the main factor and the average carrier-to-noise ratio as the auxiliary factor.

6. The method for seamless indoor and outdoor positioning based on pseudo-satellite technology according to claim 1, characterized in that: In step 5, the observation data sent by the pseudo-satellite receiving end to the main control end include: the pseudo-range and horizontal angle between the satellite in the sky and the corresponding pseudo-satellite simulation transceiver; the pseudo-code phase and carrier phase between the pseudo-satellite simulation transceiver and the pseudo-satellite receiving end; the pseudo-code phase and carrier phase between the reference transmitter and the pseudo-satellite receiving end; the reception time of the pseudo-satellite receiving end to the pseudo-satellite signal; and the coordinate parameters of the satellite in the sky.

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