CN107422301A - A kind of big region high-precision locating method of alternative conventional wireless electricity navigation system - Google Patents

Abstract

The invention discloses a large area high-precision positioning method that can replace the traditional radio navigation system, which includes the following steps: Step 1: Based on the principle that each base station covers about 300 kilometers (radius), select a high point in the area to establish a base station, Determine the geographic location of the base station; Step 2: Use atomic clocks, optical fiber synchronization, time comparison or RTK technology for clock synchronization between base stations; Step 3: Determine the radio navigation signal system, including the selection of carrier frequency and the determination of modulation methods, each base station Transmit positioning signal; Step 4: The receiving terminal performs positioning calculation according to the radio navigation signal transmitted by the base station, and the positioning terminal measurement method is a method combining pseudo-random code pseudo-range measurement and carrier phase pseudo-range measurement. The method of the present invention intends to replace compass, VOR, DME, TACAN, LORAN-C, WAAS and other systems, and the required base stations can be established at the original sites (including airports) of these system base stations, or newly built. It can coexist with GPS and meet the high-precision positioning needs of most navigation users in a large area.

Description

A large-area high-precision positioning method that can replace traditional radio navigation systems

technical field

The invention relates to the field of radio positioning. On the basis of analyzing the performance, advantages and disadvantages of traditional radio navigation systems, a new large-area high-precision radio positioning method that can replace most radio navigation systems is proposed.

Background technique

With the development of radio navigation technology to this day, a relatively complete theoretical system and a very wide range of application fields have been formed. Existing radio navigation systems mainly include compass, Volt (VOR), range finder (DME), Tacan (TACAN), Roland (LORAN-C), satellite navigation system and its augmentation system, etc.

In 2001, the United States Federal Radio Navigation Program believed that with the completion and use of GPS and its augmentation system, other radio navigation services will gradually decrease due to the reduction in demand. The plan predicts that the navigation services provided by the existing traditional radio navigation systems VOR, DME, TACAN and ILS for a precision approach will begin to decrease in 2010. However, during the navigation service provided by GPS and its wide area augmentation system WAAS, some weaknesses of the satellite navigation system were exposed, such as ionospheric scintillation (storm) and radio interference, etc. These weaknesses had a significant impact on the service performance of satellite navigation.

Since the above-mentioned weaknesses of the satellite navigation system have not been overcome, in the 2008 US federal radio navigation plan, satellite navigation service was no longer used as the only means of aviation navigation, and the traditional radio navigation service plan was adjusted, among which DME and TACAN plan In service for a long time, while the Type 1 precision approach ILS will begin to decrease after 2015.

Due to the change of the concept of navigation performance constraints, the US Federal Radio Navigation Plan in 2014 was further adjusted. In 2020, VOR will reduce the number of stations to maintain the most basic working network, and DME will be further expanded to support RNAV. In addition, WAAS will be switched from GPSL2 to GPSL5, thereby increasing the availability of LPV services. At the same time, the FAA will continue to carry out research on the provision of Class II and Class III precision approach services by the Local Area Augmentation System (LAAS).

Although the radio navigation system will continue to provide services, there are inherent defects or problems in the application. The technical characteristics of the traditional radio navigation system are analyzed as follows:

1. Compass direction finding system

The radio compass system uses the zero amplitude point of the figure-eight directional antenna to automatically track the base station for direction finding. It is a single-station direction-finding and multi-station positioning layout. The base station transmits power from hundreds of watts to thousands of watts. The signal frequency is 100-1800kHz, and the coverage range is 250-350km. The direction finding accuracy is 2°, so at 100Km, the position deviation reaches 3489.95m; at 10Km, the position deviation reaches 348.99m. Unlimited capacity, weak anti-interference ability.

It is characterized by high-power transmission, low direction finding accuracy, and lower positioning accuracy.

2. Vol (VOR)

The Vohr system uses the antenna rotation to establish the corresponding relationship between the signal phase and the azimuth, and realizes the measurement of the aircraft azimuth by measuring the phase. Use single-station layout to measure azimuth and multi-station layout for positioning. The route VOR power is 100-200w, and the terminal VOR is 50w. It is an automatic tracking measurement method. The working frequency is 108-117.95MHz. The en route VOR coverage is 200nmile, and the terminal VOR is 25nmile. Ordinary VOR accuracy is 2°-3°, and Doppler VOR accuracy is less than 1° (at 100Km, the position deviation reaches 174.52m; at 10Km, the position deviation reaches 17.45m). Unlimited capacity, strong anti-interference performance of ordinary Volt, strong Doppler Volt.

The characteristic is that the accuracy is average, slightly better than the compass system, and the anti-interference performance is strong.

3. Distance Meter (DME)

The response distance measurement system measures the distance between the aircraft and the ground station by measuring the round-trip propagation time of the signal (pulse) from the aircraft to the ground station, and adopts the method of single-station layout distance measurement and multi-station layout positioning. The power of the terminal station is 100w, and the power of the route station is 1Kw. The ranging method of inquiry-response is adopted. Inquiry frequency 1025-1150MHz, response frequency 962-1213MHz. The coverage area of the route DME station is greater than 200nmile, the terminal DME station is greater than 60nmile, and the precision DME (landing station) is greater than 22nmile. The accuracy of ordinary DME is less than 370m, and the accuracy of standard 1 and standard 2 is less than 30m and 12m respectively. Capacity is limited, up to around 100 aircraft. General anti-interference ability.

It is characterized by high power, low update rate, general accuracy, and limited capacity.

4. TACAN

The Tacan is a composite radionavigation system consisting of a DME and a modified VOR that improves the resolution of azimuths by adding measurements of smaller periods of phase change. The layout method is single station layout, DME ranging, VOR direction finding, and joint polar coordinate positioning. The power of the mobile station is greater than 500w, and the power of the fixed station is 3000w. The direction finding is automatic tracking, and the ranging uses the query-response method. The operating frequency is 963-1213MHz. The coverage range of the fixed station is 350-370Km, and that of the mobile station is 185km. There is a 90°±30° cone-shaped signal dead zone in the headspace. The actual accuracy of direction finding is 0.5° (at 100Km, the position deviation reaches 872.65m; at 10Km, the position deviation reaches 87.27m), and the ranging accuracy can reach 0.1km. The azimuth measurement capacity is unlimited, and the distance measurement capacity is 110 frames. The anti-interference ability of DME is average, and VOR is strong.

It is characterized by high-power transmission, complex system and high measurement accuracy.

5. Roland (LORAN-C)

Loran-C is a composite radio navigation system, which realizes the precise measurement of the distance difference by measuring the phase of the pulse carrier while performing the pulse ranging difference. The layout method is to form a chain of positioning stations with multiple adjacent launch stations, and also includes the monitoring station in the work area and the control center of the station chain. Power is 165-1800KW, positioning rate: 10-20 times/min. The working frequency is 100KHz, and the coverage range is 600-1500 nautical miles. The near area positioning accuracy is 460m (0.25n mile), the far area is 1.2nmile, and the relative positioning accuracy is 18-90m. Unlimited capacity, strong anti-interference ability.

It is characterized by ultra-high power transmission, low positioning accuracy, low update rate, and wide coverage.

6. Satellite Navigation System

The satellite navigation system realizes positioning through multi-satellite pseudo-code correlation peak ranging or carrier phase ranging. Multiple satellites form a navigation constellation covering the whole world; the ground measurement and control station guarantees the operation of the constellation. The transmit power of GPS is 478.63w, and the update rate can reach 50Hz. The working frequency is L1: 1575.42MHz; L2: 1227.60MHz; L5: 1176.45MHz. Coverage is global and partial space. Positioning accuracy P code: 10m (50%); C/A code: 20m (50%); carrier phase positioning accuracy: cm level (but difference is required, and there is ambiguity in the whole circle). Unlimited capacity.

It is characterized by complex system, global coverage, high precision (higher after differential), weak anti-interference ability, and cannot be used indoors.

7. WAAS

The Wide Area Augmentation System (WAAS) is a GPS satellite-based augmentation system. Use multiple ground monitoring stations in a large area to monitor and evaluate GPS signals, improve navigation positioning accuracy and availability through differential, and reduce navigation risks through integrity monitoring.

It is characterized by high accuracy and integrity, but it needs to rely on satellite navigation systems and GEO satellites to work.

From the above analysis, it can be seen that the current radio navigation system has its deficiencies or defects, and the main common problems include:

(1) Low positioning accuracy (compass, VOR, DME, TACAN, LORAN-C);

(2) Weak anti-interference ability (GPS, WAAS);

(3) And the transmission power is large, the coverage area is small, the system is complicated, the capacity is limited, and it is not suitable for indoors.

Contents of the invention

The purpose of the present invention is to solve the above problems, and propose a large-area high-precision positioning method that can replace traditional radio navigation systems. The positioning method of the present invention has the characteristics of independence, large area and high precision, and can completely replace compass, VOR, DME , TACAN, LORAN-C systems can coexist with GPS, but the accuracy and anti-interference ability are superior to GPS. It can also be applied to indoor and outdoor continuous positioning in the background of no electricity, and a corresponding large-area indoor and outdoor continuous radio positioning system can be built on this basis.

A large-area high-precision positioning method that can replace traditional radio navigation systems, including the following steps:

Step 1: Based on the principle that each base station covers about 300 kilometers (radius), select a high point in the area to establish a base station, and determine the geographical location of the base station;

Step 2: Clock synchronization between base stations using atomic clock, optical fiber synchronization, time comparison or RTK technology;

Step 3: Determine the radio navigation signal system, including the selection of the carrier frequency and the determination of the modulation mode, and each base station transmits the positioning signal;

Step 4: The receiving terminal performs positioning calculation according to the radio navigation signal transmitted by the base station, and the positioning terminal measurement method is a combination of pseudo-random code pseudo-range measurement and carrier phase pseudo-range measurement.

The advantages of the present invention are:

The method of the present invention intends to replace compass, VOR, DME, TACAN, LORAN-C, WAAS and other systems, and the required base stations can be established at the original sites (including airports) of these system base stations, or newly built. It can coexist with GPS and meet the high-precision positioning needs of most navigation users in a large area. If this goal is achieved, the obvious advantages are as follows:

(1) Release a large amount of frequency resources.

Select one of the 20MHz-200MHz frequency bands as the carrier frequency band of the radio navigation signal (the width is within 5MHz). According to the analysis of positioning accuracy, the alternative systems of the present invention include compass, DME, VOR, TACAN, LORAN-C, WAAS, and the releasable frequency bands are 100-1800kHz, 108-117.95MHz, 1025-1150MHz, 962-1213MHz, etc. The present invention only occupies a frequency range less than 5MHz, and the frequency resources of other frequency bands can be released for other services.

(2) Simplify a large number of radio navigation equipment to 2-3 units, and land-based stations can be greatly reduced.

Because the navigation system can replace compass, VOR, DME, TACAN, LORAN-C, WAAS and other systems, and coexist with GPS, the radio navigation equipment can be simplified to 2-3 sets. Due to the wide coverage of the single system of the present invention, the number of land-based stations can also be greatly reduced.

(3) Without any enhancement technology, there is no integer ambiguity, and a single system can achieve an accuracy of about 1m.

The present invention does not use the enhanced technology similar to WAAS, but only uses pseudo-code rough measurement to determine the ambiguity of the whole cycle, and then carries out precise measurement by carrier phase distance measurement. The combination of the two achieves high-precision distance measurement, and a single system can achieve an accuracy of about 1 meter.

(4) Strong anti-interference ability, avoiding GPS vulnerability.

The present invention compares with GPS: GPS transmitting power is 478.63w, after the propagation of more than 20,000 kilometers, causes the received signal to be very weak (-166dbm), has been obliterated by noise; After hundreds of kilometers to thousands of kilometers of propagation, the received signal is stronger and less susceptible to interference. Therefore, the invention has strong anti-jamming ability and does not have the fragility of GPS.

(5) Wide coverage and high receiving sensitivity.

The invention adopts pseudo-random code spread spectrum communication, and has high spread spectrum gain due to the good autocorrelation characteristic of the signal, so that the system can receive weak signals with high sensitivity. Therefore, the signal propagation distance can be very far, up to several thousand kilometers, and the coverage area is very wide.

(6) Taking into account the positioning of large indoor and outdoor areas.

The present invention comprehensively considers the propagation performance of electromagnetic waves in the outdoor space and indoor building walls, the transmission performance of electromagnetic waves at the interface, the positioning accuracy requirements and the difficulty of hardware implementation, etc., and selects low-frequency carrier waves, which can spread in a large range on the earth's surface, and can penetrate through buildings. Therefore, continuous positioning in large areas indoors and outdoors can be realized.

(7) Avoid the high complexity of the GPS system, and do not have most of the positioning errors of GPS (such as star clock, ephemeris, ionosphere, troposphere).

The high complexity of the GPS system is self-evident, but the present invention only needs 4 base stations to achieve a large-scale and high-precision target, and the complexity is greatly reduced. Since the GPS system operates in space, the ground monitoring part cannot make absolutely accurate measurements of the orbit and clock drift of the satellite, and there will be errors in the star clock and ephemeris; the transmission to the ground receiver will pass through the atmosphere, and there will be errors in the ionosphere and troposphere. However, the base station of this system is on the ground, which avoids the above-mentioned errors, so the accuracy is further improved.

in conclusion:

Through the above analysis, it can be seen that the present invention has the characteristics of simple system, wide coverage, high precision and strong anti-interference ability.

Description of drawings

Fig. 1 Schematic diagram of the radiolocation method for large-area positioning;

Fig. 2 is a schematic diagram of the implementation steps of large-area radio positioning;

Figure 3 Signal generation and emission block diagram;

Figure 4 CPM modulator block diagram;

Fig. 5 signal receiving block diagram;

Fig. 6 CPM demodulator block diagram;

Figure 7 is a schematic diagram of base station layout and coverage capabilities;

Fig. 8 Comparison of power spectrum between CPM modulation and BPSK, BOC modulation;

Figure 9 is a schematic diagram of the resolution of the carrier phase integer ambiguity and the realization of high-precision ranging.

detailed description

The present invention will be further described in detail with reference to the accompanying drawings and embodiments. Carry out large-area, indoor and outdoor continuous high-precision radio positioning, as shown in Figure 1, and the implementation process is shown in Figure 2, including 4 steps:

Step 1: According to the coverage of the base station, select a high point in the area to build a station, and determine the precise geographical location of the base station.

According to the size of the service area and the environmental characteristics, the base station layout is planned based on the principle that each base station covers about 300 kilometers (radius). Users in the service area receive signals from at least four different base stations at the same time, and the straight-line distance between the base stations is hundreds of kilometers to thousands of kilometers. In order to ensure the positioning accuracy, the positioning network composed of each base station should make the DOP value of the service area as small as possible; after the base station is erected, it is necessary to know the exact geographical location of the base station, and its geographical coordinates can be obtained through pre-calibration or GNSS differential technology;

Step 2: Clock synchronization between base stations is realized by using precise atomic clocks, or using time comparison technology or differential technology of satellite navigation.

The ground base station is mainly composed of two parts: the clock synchronization part and the signal generation and transmission part. An atomic clock is used to provide a reference frequency to ensure its accuracy and stability. Optical fiber synchronization, time comparison technology or satellite navigation differential positioning technology can also be used to synchronize the clocks of the signal sources between the base stations.

Step 3: Each base station transmits a positioning signal. Determine the radio navigation signal system suitable for large-area, indoor and outdoor continuous positioning, including the selection of carrier frequency and the determination of modulation mode.

1) Signal transmission process

The radio positioning signal mainly includes the ranging code signal, the navigation message and the carrier signal. The baseband signal is subjected to direct sequence spread spectrum modulation by the ranging code signal (also known as the spread spectrum code) and the navigation message, and then modulated to all Select the carrier. The base stations therefore transmit on the same carrier frequency in the form of CDMA (Code Division Multiple Access). The signal transmission block diagram is shown in Figure 3.

2) Determination of frequency

Select one of the 20MHz-200MHz frequency bands as the carrier frequency band of the radio navigation signal (the bandwidth is within 5MHz). The selection of this frequency range is based on comprehensive consideration of the propagation performance of electromagnetic waves in large outdoor spaces and indoor building walls, the transmission performance of electromagnetic waves at the interface, the requirements for positioning accuracy, and the difficulty of hardware implementation. The attenuation formula of the signal in obstacles on the earth's surface and in building walls is Where ε"=ε, ε'=σ/ω, μ is the magnetic permeability, ε is the dielectric constant of the wall, σ is the electrical conductivity, and ω is the angular frequency. It can be seen that the signal in this frequency range is compared with 500MHz The attenuation of signals in the -20GHz range will be greatly reduced no matter on the earth's surface or inside building walls, so its indoor and outdoor coverage will increase significantly.

3) Modulation method

The radio signal of the present invention adopts the CPM (Continuous Phase Modulation) modulation mode, and the available bandwidth, the attenuation degree of the signal sidelobe and the like are comprehensively considered in selecting the modulation mode. Compared with the modulation spectrum of satellite navigation BPSK and BOC signals, the CPM signal has higher power concentration, faster sidelobe attenuation, and less interference to out-of-band, so that while obtaining a higher signal-to-noise ratio, the adjacent frequency band The signal interference is also small, and can effectively save frequency resources.

The waveform expression of the CPM modulation signal is

In the formula, ε is the signal symbol energy, T is the symbol interval width, f _c is the carrier frequency, φ ₀ is the initial phase, Represents the time-varying phase function of the modulated signal information.

The block diagram of the modulator that realizes this expression is shown in Figure 4. The modulation process is as follows:

(1) carry out serial-to-parallel conversion (convert to quaternary code element I _k ) of system information;

(2) Then, according to the formula Calculate the phase value;

(3) take cosine (cos) and sine (sin) to phase value again, obtain two-way quadrature low-frequency components;

(4) Finally, quadrature modulation is performed on the two low-pass components and multiplied by the amplitude The CPM radio frequency signal S(t) is obtained.

Step 4: The receiving terminal performs positioning calculation according to the radio navigation signal transmitted by the base station, and the positioning method of the positioning terminal is a combination of pseudo-random code pseudo-range measurement and carrier phase pseudo-range measurement.

1) Signal receiving process

The receiving antenna receives the radio frequency signal, and after down-conversion filtering, A/D sampling is converted into a digital intermediate frequency signal, and the code pseudo-range and carrier pseudo-range information are captured, tracked and calculated, and then the position information is calculated. The signal receiving block diagram is shown in Figure 5.

2) The schematic diagram of the CPM demodulator is shown in Figure 6, and the demodulation steps of the demodulator are:

(1) First, the intermediate frequency signal r(t) is band-pass filtered by the band-pass filter BPF to filter out-of-band noise;

(2) Then, carry out difference frequency respectively to the signal through filtering with two-way orthogonal carrier frequency, pass through low-pass filter LPF again, just obtain the low-pass signal component of two-way orthogonality;

(3) Carry out "additional increment calculation" to the two-way orthogonal low-pass signal components to obtain the increment;

(4) Viterbi decoding is carried out to the increment, and the output is the information symbol;

(5) Finally, perform serial-to-parallel conversion on the information symbols to obtain the required information bit stream.

3) Positioning data calculation

First of all, the use of pseudo-random code ranging, in addition to obtaining the spreading gain, the rough distance measurement can provide support for the resolution of the carrier phase ambiguity, such as the condition of the chip length of 150 meters (pseudo-code rate 2MHz) It can achieve a ranging accuracy of 1.5 to 3 meters (0.01 to 0.02 yards). Secondly, carry out accurate measurement with carrier phase ranging. For example, when the carrier wavelength is 6 meters (carrier frequency is 50MHz), the accuracy of carrier phase ranging will be better than 0.2m (about 3% of the wavelength), so that there is no whole The high-precision pseudo-range measurement of the surrounding ambiguity (or the small and easy-to-solve whole-circumference ambiguity) can obtain high-precision positioning data.

Among them, Figures 7, 8 and 9 are illustrations of some technical means involved in the present invention.

1. As shown in Figure 7:

The frequency band signal selected by the present invention propagates on the surface of the earth, and its attenuation will be greatly reduced, so the coverage area will be greatly increased. Set up signal transmitting base stations at high points on the ground, under the condition that users in the service area can receive at least four positioning and navigation signals from different base stations at the same time, the straight-line distance between base stations can reach hundreds of kilometers to thousands of kilometers .

2. As shown in Figure 8:

The radio navigation signal modulation mode designed by the present invention is CPM modulation, and Fig. 8 is a comparison diagram of MSK signal (a kind of CPM signal) and BPSK signal, BOC signal power spectrum. It can be seen from the figure that compared with BPSK signal and BOC signal, the energy of MSK signal (CPM signal) is more concentrated at the center frequency, and the side lobe attenuation is faster, so it is more suitable for low carrier frequency, narrow available bandwidth, 20MHz- A frequency band in the 200MHz range.

3. As shown in Figure 9:

Taking the pseudo-code rate of 2MHz (the chip length is 150 meters) and the carrier wavelength of 6m (the carrier frequency is 50MHz) as an example, the ranging accuracy is described. Firstly, the code phase pseudo-range measurement is performed, which can achieve a rough measurement accuracy of 1.5m, and solve the ambiguity of the whole cycle when the carrier phase is precisely measured; then, through the carrier phase measurement, a pseudo-range fine measurement of about 0.2m can be realized. Finally, a positioning accuracy of 1m is achieved.

summary

The present invention transmits the radio navigation signal with strong penetrating power and wide coverage designed by the present invention through multiple high-point base stations on the ground in a large area. Each base station is arranged according to a better GDOP according to the target area, and the geographical coordinates of the base stations are known in advance. Or for precise calibration, the time synchronization between base stations is realized by optical fiber synchronization, time comparison technology, differential technology of satellite navigation or precision atomic clock. The indoor and outdoor integrated positioning terminal receives the radio navigation signals radiated by multiple base stations, extracts the navigation message information, and finally calculates the high-precision positioning information of the end user through the pseudo-code rough ranging and phase fine ranging of the radio signals. Specific technological innovations include:

(1) Using low frequency carrier

The system uses a low-frequency carrier wave around 100MHz, and the signal propagates on the surface of the earth, and the propagation distance is farther than that of high-frequency signals; the penetration ability of signals in this frequency range to building walls and floors is greatly increased, so its indoor and outdoor coverage will be greatly improved rise.

(2) Ground station

According to the coverage area of the base station (about 300 kilometers), the system adopts the method of deploying stations at high points on the ground in the area. The precise location of the ground base station is known, the clock is an atomic clock, and the time reference is accurate. The ionospheric and tropospheric errors in the satellite's ephemeris clock and atmospheric propagation are avoided.

(3) Use reasonable transmit power

The present invention selects a reasonable transmit power, which can be tens of watts, hundreds of watts or even stronger, and only passes through hundreds of kilometers to thousands of kilometers of propagation (far less than the propagation distance of satellite navigation signals), and the received signal is strong and anti-interference ability powerful.

(4) Adopt pseudo-random code system

The present invention adopts the pseudo-random code spread spectrum communication system, has high spread spectrum gain due to the good autocorrelation characteristic of the signal, and can receive weak signals with high sensitivity. Therefore, the signal propagation distance is long and the coverage area is wide.

(5) Hybrid ranging method using pseudo-code loaded wave phase

The system adopts pseudo-range coarse ranging to determine the ambiguity of the whole cycle, and then carries out precise measurement by carrier phase ranging. The combination of the two enables high-precision distance measurement.

(6) Using CPM modulation

The radio navigation signal modulation mode designed by the present invention is CPM modulation, the signal energy is more concentrated at the center frequency, and the side lobe decays faster, thus reducing the effective bandwidth of the signal.

Claims (2)

1. A large-area high-precision positioning method that can replace traditional radio navigation systems, comprising the following steps: Step 1: According to the coverage of the base station, select a high point in the area to build a station, and determine the precise geographical location of the base station; According to the size of the service area and the environmental characteristics, the base station layout is planned based on the principle that each base station covers about 300 kilometers (radius). Users in the service area receive signals from at least four different base stations at the same time, and the straight-line distance between the base stations is hundreds of kilometers to thousands of kilometers. In order to ensure the positioning accuracy, the positioning network composed of each base station should make the DOP value of the service area as small as possible; after the base station is erected, it is necessary to know the exact geographical location of the base station, and its geographical coordinates can be obtained through pre-calibration or GNSS differential technology; Step 2: Clock synchronization between base stations is achieved by using precise atomic clocks, or using time comparison technology or satellite navigation differential technology; The ground base station is mainly composed of two parts: the clock synchronization part and the signal generation and transmission part. An atomic clock is used to provide a reference frequency to ensure its accuracy and stability. Optical fiber synchronization, time comparison technology or satellite navigation differential positioning technology can also be used to synchronize the clocks of the signal sources between the base stations. Step 3: Determine the radio navigation signal system, including the selection of the carrier frequency and the determination of the modulation mode, and each base station transmits the positioning signal; (1) Determine the frequency The carrier frequency band of the radio navigation signal is 20MHz-200MHz, and the bandwidth is less than or equal to 5MHz; (2) Modulation method The radio signal of the present invention adopts the CPM (Continuous Phase Modulation) modulation mode, and the available bandwidth, the attenuation degree of the signal sidelobe and the like are comprehensively considered in selecting the modulation mode. Compared with the modulation spectrum of satellite navigation BPSK and BOC signals, the CPM signal has higher power concentration, faster sidelobe attenuation, and less interference to out-of-band, so that while obtaining a higher signal-to-noise ratio, the adjacent frequency band The signal interference is also small, and can effectively save frequency resources. Step 4: The receiving terminal performs positioning calculation according to the radio navigation signal transmitted by the base station, and the positioning terminal measurement method is a combination of pseudo-random code pseudo-range measurement and carrier phase pseudo-range measurement; (1) The demodulation steps of the CPM demodulator are: The intermediate frequency signal is filtered out of the out-of-band noise through a band-pass filter, and then the filtered signal is frequency-differenced by two orthogonal carrier frequencies, and then the information symbols are decoded, and finally the serial-to-parallel conversion is performed to obtain the information bit stream. (2) Calculation of positioning data Firstly, the pseudo-code ranging is used for rough distance measurement; secondly, the carrier phase ranging is used for precise measurement, and finally high-precision positioning data is obtained. 2. The present invention transmits radio navigation signals with strong penetration and wide coverage designed by the present invention through multiple high-point base stations on the ground in a large area. Each base station is laid out according to the better GDOP according to the target area. It is known or accurately calibrated, and the time synchronization between base stations is realized by optical fiber synchronization, time comparison technology, satellite navigation differential technology or precise atomic clock. The indoor and outdoor integrated positioning terminal receives the radio navigation signals radiated by multiple base stations, extracts the navigation message information, and finally calculates the high-precision positioning information of the end user through the pseudo-code rough ranging and phase fine ranging of the radio signals. Specific technological innovations include: (1) Using low frequency carrier The system uses a low-frequency carrier wave around 100MHz, and the signal propagates on the surface of the earth, and the propagation distance is farther than that of high-frequency signals; the penetration ability of signals in this frequency range to building walls and floors is greatly increased, so its indoor and outdoor coverage will be greatly improved rise. (2) Ground station According to the coverage area of the base station (about 300 kilometers), the system adopts the method of deploying stations at high points on the ground in the area. The precise location of the ground base station is known, the clock is an atomic clock, and the time reference is accurate. The ionospheric and tropospheric errors in the satellite's ephemeris clock and atmospheric propagation are avoided. (3) Use reasonable transmit power The present invention selects a reasonable transmit power, which can be tens of watts, hundreds of watts or even stronger, and only passes through hundreds of kilometers to thousands of kilometers of propagation (far less than the propagation distance of satellite navigation signals), and the received signal is strong and anti-interference ability powerful. (4) Adopt pseudo-random code system The present invention adopts the pseudo-random code spread spectrum communication system, has high spread spectrum gain due to the good autocorrelation characteristic of the signal, and can receive weak signals with high sensitivity. Therefore, the signal propagation distance is long and the coverage area is wide. (5) Hybrid ranging method using pseudo-code loading wave phase The system adopts pseudo-range coarse ranging to determine the ambiguity of the whole cycle, and then carries out precise measurement by carrier phase ranging. The combination of the two enables high-precision distance measurement. (6) Using CPM modulation The radio navigation signal modulation mode designed by the present invention is CPM modulation, the signal energy is more concentrated at the center frequency, and the side lobe decays faster, thus reducing the effective bandwidth of the signal.