CN117075163A - Encoding processing method, device and computer storage medium - Google Patents

Abstract

The application discloses a method, a device and a computer storage medium for coding processing, which comprises the following steps: broadcasting a first multi-signal message including a pseudo-range observation, a carrier observation and a carrier-to-noise ratio to a receiver at a first time; broadcasting a second multi-signal message including the carrier observations to the receiver at a second time instant; the first multi-signal message and the second multi-signal message may be used to determine pseudorange observations and carrier-to-noise ratios at a second time instant; the second multi-signal message has a length less than the first multi-signal message. According to the embodiment of the disclosure, the second multi-signal message is broadcast at the second moment, the pseudo-range observation value and the carrier-to-noise ratio at the second moment can be determined according to the first multi-signal message and the second multi-signal message, and under the condition that the real-time differential positioning (RTK) performance of a user is ensured, the flow consumption of RTK application is reduced.

Description

Encoding processing method, device and computer storage medium

Technical Field

The present application relates to, but is not limited to, satellite positioning technology, and relates to a method, apparatus and computer storage medium for implementing an encoding process.

Background

Currently, there are five widely used global satellite navigation positioning systems (GNSS), which are the Global Positioning System (GPS) in the united states, the GLONASS (GLONASS) in russia, the beidou satellite navigation system (BDS) in china, the Galileo satellite navigation system (Galileo) in the european union, and the quasi-zenith satellite system (QZSS) in japan, respectively; the satellite navigation positioning system has high precision and covers the whole world, and is widely applied to the fields of navigation, survey and mapping, fine agriculture, intelligent robots, unmanned aerial vehicles and the like. The main factors affecting the satellite positioning accuracy are satellite orbit errors, clock error and atmospheric propagation errors. The satellite orbit error and the clock error calculated through the broadcast ephemeris in real time are generally in the order of meters, for example, the accuracy of the broadcast ephemeris of the GPS is 1-2 meters, and the accuracy of the GLONASS broadcast ephemeris is several meters. The atmospheric propagation errors mainly comprise an ionosphere error and a troposphere error, the ionosphere error can reach tens of meters for low elevation satellites in noon, the ionosphere error can be eliminated through a double-frequency observation value by a double-frequency receiver, the troposphere delay can reach 10 meters for low elevation satellites, and 90% of the troposphere error can be eliminated through a troposphere model. Under the condition of no correction, the high-performance dual-frequency receiver can achieve the meter-level positioning precision.

For applications requiring centimeter-level positioning accuracy, such as survey and mapping, fine agriculture, intelligent robots, unmanned and unmanned aerial vehicles, real-time differential positioning (RTK) is mainly adopted for error processing. RTKs can be categorized into single-site RTKs and network RTKs; the single station RTK builds a receiver at a known point as a reference station to provide differential data to the receiver (mobile station) to be located. The network RTK technique establishes a plurality of reference stations within a local or wide area range, and using the plurality of reference station data, the server can calculate differential data based on the user location (mobile station). The mobile station can completely eliminate satellite clock error and most satellite orbit and atmospheric propagation errors by utilizing differential data, and the positioning accuracy can reach 1 cm. The international maritime committee 104 issued a standard protocol RTCM STANDARD, RTCM protocol for short, for solving the problem of compatibility of differential data between different brands of receivers, the latest version of RTCM being RTCM3.3 (RTCM STANDARD 10403.3,2020).

The RTCM protocol solves the problem of differential data interoperability between receivers of different brands and is widely cited in RTK application; in particular, the newly added multisignal message (MSM, multiple Signal Message) in the latest version of RTCM3.3 can encode multisystem multifrequency point observations tracked by the receiver; the MSM introduces a satellite, signal and observation value mask mechanism, and only encodes the observation values tracked by the receiver, so that not only can all the observation data tracked by the satellite to the same frequency point be encoded, but also the observation data with different satellite tracking frequency points can be encoded; compared with the prior dual-frequency coding mechanism, the method can code more available signals, and does not waste coding resources for signals which are not tracked; the satellite observation values are divided into coarse observation values and fine observation values, the plurality of observation values (tens of kilometers) of one satellite only have a difference of tens of meters, the coarse observation values shared by the plurality of observation values are extracted to be uniformly encoded, and each observation value is only encoded relative to the difference value part of the coarse observation value, so that the encoding length can be reduced. The MSM encodes various signals of all the current satellite navigation systems in a universal format, and can efficiently encode all the signals no matter which signal is tracked by a receiver, single-system or multi-system, single-frequency or multi-frequency; the MSM code can be adapted to different types of receivers and can adjust the code length according to satellites and signals tracked by the receivers; the MSM has expansibility, and can support more navigation satellites possibly transmitted in the future and more navigation signals possibly appearing; thus, MSM is the most widely used differential data format in RTK applications.

According to different application requirements, RTCM designs seven MSMs of MSM1-MSM 7. Each MSM message comprises a message header, satellite data and signal data; the message header contains data such as a message number, a base station ID, epoch time, satellite mask, signal mask, and the like. Is the information shared by all satellite corrections of a satellite system. The message header field definitions of MSM1-MSM7 are the same, and table 1 describes the field contents and field lengths contained in the MSM message header. The satellite data part of the MSM comprises information shared by all tracking signals of a satellite, such as a rough pseudo-range, a Doppler observed value and the like; the signal data part of the MSM contains the accurate pseudo-range observation value, carrier observation value, doppler, carrier-to-noise ratio and other information of some signals of a satellite. The satellite data part and the signal data part of the MSM1-MSM7 are different in coding information, and a user can select a proper coding type according to an application scene; table 2 is a table of information composition of MSM1-MSM7, as shown in Table 2, the encoded content of MSM1-MSM7 and the length of each satellite data portion and the respective signal data portion; MSM is used to encode observations of the receiver, which may be used for differential global satellite navigation system (DGNSS)/RTK applications, or for storing observations as post-processing; wherein MSM1 is mainly used for DGNSS application; MSM2 has only carrier observations, typically used in static applications, no pseudorange observations to initialize carrier ambiguity, which can be initialized by static long-time data. MSM3 has a pseudorange observation and a carrier observation, but lacks the observation carrier-to-noise ratio information, which is significant to weighting the observations, so MSM3, while reducing the amount of data compared to MSM4, is not common in RTK applications. The MSM5 and MSM7 are mainly used for storing all observed value information compatible with RINEX format, including Doppler observed value, for post-processing, and also can be used for transmitting physical base station data in network RTK application to a server for resolving, and for network RTK resolving to generate virtual base station correction. MSM4 and MSM6 contain pseudo-range observation value, carrier-to-noise ratio information, these are just all information of the base station that RTK calculates required, are the most commonly used base station data coding type in the RTK application, MSM4 can satisfy most RTK demands, for deformation monitoring etc. to the quasi-static application that requires higher precision, can adopt the higher MSM6 of resolution ratio to broadcast base station data.

Fields	Field length
		Message number	12
Base station ID	12
		Epoch time	30
Message synchronization code	1
		Base station data age	3
Reserved field	7
		Clock error synchronous sign	2
External clock sign	2
		Carrier smoothing pseudo-range sign	1
Carrier smoothed pseudorange time interval	3
		SatelliteMasking mask	64
Signal mask	32
		Observation value mask	X(X<＝64)
Sum up	169+X

TABLE 1

TABLE 2

For applications requiring long-time high-precision positioning every day, such as mowers, high-precision vehicle navigation, intelligent agriculture and the like, besides purchasing network RTK account numbers, annual communication cost is also of special concern to users; for a full system full frequency point tracking station, the average number of tracked satellites is about 50, and the observed value is close to 200. Even if only the dual-frequency observation value is transmitted, the MSM4 broadcasting is adopted, and the traffic approaching 10 kilobits (Kbits) is also needed; if the broadcasting of the full-frequency point observation value or the broadcasting of the MSM6 with higher resolution is adopted, more flow is required to be consumed; according to the base station data of one epoch broadcasted every second and calculated with high-precision positioning time required for 5 hours each day, 180Mbits of flow is required each day; in many applications, the customer purchases traffic at a cost that even exceeds the cost of purchasing a network RTK account.

The newly added MSM of RTCM3.3 is the most widely used RTK differential data coding mode at present; MSM4 and MSM6 broadcast frequencies are typically 1Hz, which are two of the most widely used RTK differential data broadcast messages. For certain applications requiring long time high precision positioning, such as high precision vehicle positioning, mowing robots, intelligent agricultural machinery in fine agricultural applications, unmanned aerial vehicles, etc., most intelligent devices request differential data for more than 5 hours per day. Consumes more than 100 megabits (Mbits) of traffic per day; how to save traffic consumption in RTK applications is a matter of concern for a wide range of users. The simplest method for reducing the traffic is to reduce the broadcasting frequency of the base station data, for example, the traffic can be directly reduced by about 50% from 1 second of a group of base station data to 2 seconds of a group of base station data, but reducing the broadcasting frequency of the base station data can reduce the RTK performance of the user; in RTK solution, the time interval between the base station and the mobile station observations is about long, and the weaker the error correlation in the two station observations is, the larger the positioning error is. The stronger the error correlation is when the base station and mobile station observations are the same, so RTK base station data is commonly broadcast on a 1 second set of frequencies.

In summary, how to reduce the traffic consumption of network RTK applications while guaranteeing the performance of the user RTK becomes a problem to be solved.

Disclosure of Invention

The following is a summary of the subject matter of the detailed description of the application. This summary is not intended to limit the scope of the claims.

The embodiment of the disclosure provides a method, a device and a computer storage medium for encoding processing, which can reduce the flow consumption of network RTK application.

The embodiment of the disclosure provides a method for encoding processing, which comprises the following steps:

broadcasting a first multi-signal message including a pseudo-range observation, a carrier observation and a carrier-to-noise ratio to a receiver at a first time;

broadcasting a second multi-signal message including the carrier observations to the receiver at a second time instant;

wherein the first multi-signal message and the second multi-signal message are usable to determine a pseudorange observation and a carrier-to-noise ratio at a second time instant; the second multi-signal message has a length less than the first multi-signal message.

In another aspect, embodiments of the present disclosure further provide a computer storage medium having a computer program stored therein, which when executed by a processor, implements the method of encoding processing described above.

In yet another aspect, an embodiment of the present disclosure further provides a method of encoding processing, including:

receiving a first multi-signal message broadcast at a first moment and a second multi-signal message broadcast at a second moment;

according to the first multi-signal message and the second multi-signal message, a pseudo-range observation value and a carrier-to-noise ratio at a second moment are determined;

wherein the first multi-signal message comprises a message of a pseudo-range observation value, a carrier observation value and a carrier-to-noise ratio; the second multi-signal message comprises a message of a carrier observation; the second multi-signal message has a length less than the first multi-signal message.

In still another aspect, an embodiment of the present disclosure further provides an apparatus for encoding processing, including: a receiving unit and a determining unit; wherein,

the receiving unit is configured to: receiving a first multi-signal message broadcast at a first moment and a second multi-signal message broadcast at a second moment;

the determination unit is configured to: according to the first multi-signal message and the second multi-signal message, a pseudo-range observation value and a carrier-to-noise ratio at a second moment are determined;

wherein the first multi-signal message comprises a message of a pseudo-range observation value, a carrier observation value and a carrier-to-noise ratio; the second multi-signal message includes a message of a carrier observation.

According to the embodiment of the disclosure, the second multi-signal message is broadcast at the second moment, the pseudo-range observation value and the carrier-to-noise ratio at the second moment can be determined according to the first multi-signal message and the second multi-signal message, and under the condition that the real-time differential positioning (RTK) performance of a user is ensured, the flow consumption of RTK application is reduced.

Additional features and advantages of the application will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the application. Other advantages of the application may be realized and attained by the structure particularly pointed out in the written description and drawings.

Drawings

The accompanying drawings are included to provide an understanding of the principles of the application, and are incorporated in and constitute a part of this specification, illustrate embodiments of the application and together with the description serve to explain, without limitation, the principles of the application.

FIG. 1 is a flow chart of a method of encoding processing according to an embodiment of the present disclosure;

fig. 2 is a flow chart of a method of another encoding process according to an embodiment of the present disclosure.

Detailed Description

The present application has been described in terms of several embodiments, but the description is illustrative and not restrictive, and it will be apparent to those of ordinary skill in the art that many more embodiments and implementations are possible within the scope of the described embodiments. Although many possible combinations of features are shown in the drawings and discussed in the detailed description, many other combinations of the disclosed features are possible. Any feature or element of any embodiment may be used in combination with or in place of any other feature or element of any other embodiment unless specifically limited.

The present application includes and contemplates combinations of features and elements known to those of ordinary skill in the art. The disclosed embodiments, features and elements of the present application may also be combined with any conventional features or elements to form a unique inventive arrangement as defined by the claims. Any feature or element of any embodiment may also be combined with features or elements from other inventive arrangements to form another unique inventive arrangement as defined in the claims. It is therefore to be understood that any of the features shown and/or discussed in the present application may be implemented alone or in any suitable combination. Accordingly, the embodiments are not to be restricted except in light of the attached claims and their equivalents. Further, various modifications and changes may be made within the scope of the appended claims.

Furthermore, in describing representative embodiments, the specification may have presented the method and/or process as a particular sequence of steps. However, to the extent that the method or process does not rely on the particular order of steps set forth herein, the method or process should not be limited to the particular sequence of steps described. Other sequences of steps are possible as will be appreciated by those of ordinary skill in the art. Accordingly, the particular order of the steps set forth in the specification should not be construed as limitations on the claims. Furthermore, the claims directed to the method and/or process should not be limited to the performance of their steps in the order written, and one skilled in the art can readily appreciate that the sequences may be varied and still remain within the spirit and scope of the embodiments of the present application.

Fig. 1 is a flowchart of a method of encoding processing according to an embodiment of the present disclosure, as shown in fig. 1, including:

step 101, a first multi-signal message containing a pseudo-range observation value, a carrier observation value and a carrier-to-noise ratio is broadcast to a receiver at a first moment;

step 102, broadcasting a second multi-signal message containing the carrier observation value to the receiver at a second moment;

wherein the first multi-signal message and the second multi-signal message are usable to determine a pseudorange observation and a carrier-to-noise ratio at the second time; the second multi-signal message has a length less than the first multi-signal message.

According to the embodiment of the disclosure, the second multi-signal message is broadcast at the second moment, the pseudo-range observation value and the carrier-to-noise ratio at the second moment can be determined according to the first multi-signal message and the second multi-signal message, and under the condition that the real-time differential positioning (RTK) performance of a user is ensured, the flow consumption of RTK application is reduced.

In one illustrative example, the disclosed embodiments may perform the broadcasting of the first and second multi-signal messages described above by a predetermined server or receiver.

In one illustrative example, the first time in an embodiment of the present disclosure may include:

a time of a preset period duration other than the preset time;

the preset time comprises the following steps: the time of the RTK account first connecting to the server, the time of the base station switching, the time of the new observation value of the base station and the time of the cycle slip of the carrier observation value of the base station.

In an exemplary embodiment, the preset period duration may be determined according to a variation of a carrier-to-noise ratio, for example, in a preset duration, when a variation of a carrier-to-noise ratio at a start of the preset duration and a carrier-to-noise ratio at an end of the preset duration is smaller than a preset variation threshold, the preset duration is set as the preset period duration; in one illustrative example, the preset period duration of embodiments of the present disclosure may be less than 100 seconds, for example, the preset period duration may be any value from 10 seconds to 100 seconds ago; the preset period duration of the embodiments of the present disclosure may be 10 seconds.

In an illustrative example, the first time in an embodiment of the disclosure may further include one or any combination of the following:

the moment when the RTK account is connected with the server for the first time;

the moment when the base station handover occurs;

the moment when the base station newly adds a new observation value;

the time when the carrier observation of the base station takes a cycle slip.

The first multi-signal message is broadcast with reference to the related art at the time when the RTK account connects to the server for the first time, the time when the base station is switched, the time when the new observation value is added to the base station, and the time when the cycle slip occurs in the carrier observation value of the base station.

In one illustrative example, the second time in the embodiments of the present disclosure includes: the first time intervals are preset for the time of unit duration.

In an exemplary embodiment, the preset unit time length in the embodiment of the present disclosure may be set according to the application positioning accuracy; in an illustrative example, the preset unit duration of an embodiment of the present disclosure may be 1 second, i.e., between two first moments, the second multi-signal message is broadcast at a frequency of every second.

In one illustrative example, a first multi-signal message in an embodiment of the present disclosure includes: multiple Signal Message (MSM) 4 or MSM6.

It should be noted that, in the embodiment of the present disclosure, the first multi-signal message may include a stored MSM determined based on a protocol in the related art, or may be another multi-signal message extended based on the existing protocol.

In one illustrative example, the second multi-signal message in an embodiment of the present disclosure includes MSM2.

It should be noted that, in the embodiment of the present disclosure, the second multi-signal message may be other MSMs, as long as the second multi-signal message includes a carrier observed value, and the traffic consumption of broadcasting the second multi-signal message is less than that of the first multi-signal message.

The embodiment of the disclosure also provides a server, including: a memory and a processor, the memory storing a computer program; wherein the processor is configured to execute the computer program in the memory;

the computer program, when executed by a processor, implements the method of encoding process described above.

Fig. 2 is a flowchart of a method of another encoding process according to an embodiment of the present disclosure, as shown in fig. 2, including:

step 201, receiving a first multi-signal message broadcast at a first moment and a second multi-signal message broadcast at a second moment;

step 202, according to the first multi-signal message and the second multi-signal message, determining a pseudo-range observation value and a carrier-to-noise ratio at a second moment;

wherein the first multi-signal message comprises a message of a pseudo-range observation value, a carrier observation value and a carrier-to-noise ratio; the second multi-signal message comprises a message of a carrier observation; the second multi-signal message has a length less than the first multi-signal message.

According to the embodiment of the disclosure, the pseudo-range observation value and the carrier-to-noise ratio at the second moment can be determined according to the first multi-signal message and the second multi-signal message, and the flow consumption of RTK application is reduced under the condition that the real-time differential positioning (RTK) performance of a user is ensured.

In one illustrative example, the processes of steps 201-202 described above may be performed by a receiver, which may include a receiving end device for survey mapping, fine agriculture, intelligent robotics, drones, and drones.

In one illustrative example, embodiments of the present disclosure determine pseudorange observations at a second time instant comprising:

for each second moment, determining the carrier variation and ionospheric variation between epochs corresponding to the second moment according to the carrier observed values of the first moment and the second moment before, wherein the first moment before is the first moment closest to the second moment before the second moment;

calculating a pseudo-range observation value at the second moment according to the pseudo-range observation value at the first moment in the past, the carrier variation and the ionosphere variation among the determined epochs;

wherein the carrier observations and the pseudorange observations at a preceding first time instant are included in a first multi-signal message at the first time instant.

It should be noted that, the embodiments of the present disclosure perform the above-mentioned processing of calculating the carrier variation, the ionospheric variation and the pseudo-range observation value based on the correlation principle, which is not described herein.

The embodiment of the disclosure also provides a device for encoding processing, which comprises: a receiving unit and a determining unit; wherein,

the receiving unit is configured to: receiving a first multi-signal message broadcast at a first moment and a second multi-signal message broadcast at a second moment;

the determination unit is configured to: according to the first multi-signal message and the second multi-signal message, a pseudo-range observation value and a carrier-to-noise ratio at a second moment are determined;

wherein the first multi-signal message comprises a message of a pseudo-range observation value, a carrier observation value and a carrier-to-noise ratio; the second multi-signal message comprises a message of a carrier observation; the second multi-signal message has a length less than the first multi-signal message.

In an exemplary example, the determining unit in the embodiment of the present disclosure is configured to:

for each second moment, determining the carrier variation and ionospheric variation between epochs corresponding to the second moment according to the carrier observed values of the first moment and the second moment before, wherein the first moment before is the first moment closest to the second moment before the second moment;

calculating a pseudo-range observation value at the second moment according to the pseudo-range observation value at the first moment in the past, the carrier variation and the ionosphere variation among the determined epochs;

wherein the carrier observations and the pseudorange observations at a preceding first time instant are included in a first multi-signal message at the first time instant.

According to the embodiment of the disclosure, the pseudo-range observation value and the carrier-to-noise ratio at the second moment can be determined according to the first multi-signal message and the second multi-signal message, and the flow consumption of RTK application is reduced under the condition that the real-time differential positioning (RTK) performance of a user is ensured.

The embodiment of the disclosure also provides a method for encoding processing, which comprises the following steps:

step 301, a server broadcasts a first multi-signal message containing a pseudo-range observation value, a carrier observation value and a carrier-to-noise ratio to a receiver at a first moment, and broadcasts a second multi-signal message containing the carrier observation value at a second moment;

step 302, the receiver determines a pseudo-range observation value and a carrier-to-noise ratio at a second time according to the first multi-signal message and the second multi-signal message, wherein the length of the second multi-signal message is smaller than that of the first multi-signal message.

The following briefly describes embodiments of the present disclosure by way of application examples, which are merely set forth embodiments of the present disclosure and are not intended to limit the scope of the embodiments of the present disclosure.

RTCM3.3 in order to adapt to different applications, formulated 7 kinds of MSM news of different coding length, in order to let the application of different precision requirements adopt different MSMs to broadcast the base station data, in order to save the flow. For example, in DGNSS application, only the pseudo-range observation value of the base station is needed, and the minimum length MSM1 can be used for broadcasting the base station data. Because of the positioning accuracy and performance requirements, RTK applications typically employ either MSM4 or MSM6 to broadcast base station data, typically at a set of 1 second. Some users use lower frequencies to broadcast base station data, e.g., a group of two seconds, in order to reduce communication traffic, which can reduce RTK positioning accuracy. MSM2 only encodes the carrier observation value of the base station, although the carrier observation value has very high precision, because of the integer ambiguity, for dynamic application, the carrier ambiguity also needs pseudo-range observation value to initialize, and then fix the ambiguity through ambiguity search, realize high-precision RTK positioning; therefore, MSM2 is rarely adopted in RTK applications, and is mainly used in static long-time applications; MSM2 may encode complete carrier observations and if a base station pseudorange observation has been received, the carrier observations in MSM2 may be utilized to generate the base station pseudorange observations based on relationships between the pseudorange carriers.

When a user (a receiver of the user) is connected with the RTK server and requests base station data, the server broadcasts a group of MSM4 (or MSM 6) containing pseudo-range observation values, carrier observation values and carrier-to-noise ratio observation data; and broadcasts a group of MSM4 (or MSM 6) at each next entire 10s (10 seconds of preset period duration in the embodiment of the present disclosure); but at the full second but not full 10 second instant (preset unit duration set to 1 second in the embodiments of the present disclosure) between MSM4 (or MSM 6) messages, MSM2 is substituted for MSM4 (or MSM 6); and decoding complete base station observation value information comprising pseudo-range observation values, carrier-to-noise ratios and the like through the MSM4 (or the MSM 6), and storing the latest pseudo-range observation values, carrier observation values and carrier-to-noise ratios of a group of base stations decoded through the MSM4 (or the MSM 6) in a memory. When receiving MSM2, the method can decode complete carrier observation value, calculate the difference between current MSM2 carrier observation value and the latest MSM4 (or MSM 6) decoded carrier observation value, obtain carrier variation, compensate ionosphere variation, obtain pseudo-range variation between two epochs, and recover (obtain) current pseudo-range observation value. The tracking station is generally in an environment with good observation conditions, the antenna quality is good, the carrier-to-noise ratio change is small in a short time (< 10 s), and the carrier-to-noise ratio in the MSM4 can be directly used for replacing the carrier-to-noise ratio; the method for recovering the current pseudo-range observed value through the MSM4 pseudo-range observed value, the carrier observed value and the current MSM2 carrier observed value in the first few seconds is as follows:

the base station pseudorange observations and carrier observations at observation time m (first time in the disclosed embodiments) may be represented as:

the base station pseudorange observations and carrier observations at observation times n (n > m) (second time in the disclosed embodiments) may be expressed as:

in formulas (1) - (4):

k is a frequency point identifier, and k can be 1, 2, 3, 4, 5 and the like;

pseudo-range observation value of satellite i frequency point k at time m,/->Is the pseudo-range observation value of the i frequency point k of the satellite at the moment n;

is the carrier observation value of the satellite i frequency point k at the moment m,/, and>is the carrier observation value of the i frequency point k of the satellite at the moment n;

is the geometrical distance between the tracking station at time m and satellite i +.>Is the geometrical distance between the tracking station and satellite i at time n;

c represents the speed of light in vacuum;

dT _m,r is the receiver clock difference, dT, contained in the observation of time m _n,r Is the receiver clock difference contained in the observation of time n;

is the tropospheric error contained in the observation of instant m,/->The troposphere error contained in the observed value of the moment n;

ionospheric error contained in the observation of time m,/->Ionospheric error contained in the observation of time n;

square of frequency for the first frequency bin (bin one), +.>The square of the frequency of the kth frequency point (frequency point k);

λ _k is the carrier wavelength of frequency point k;

is the integer ambiguity contained in the time m carrier observations, +.>The integer ambiguity included in the time n carrier observation;

is the time m pseudo-range observation noise, +.>Is the time n pseudo-range observation noise;

is the time m carrier observation noise, +.>Is the time n carrier observation noise.

And obtaining a single difference observation equation of the satellite i frequency point k by solving the difference between the observation values at the time n and the time m:

equations (5) - (6), neglecting observed noise can yield:

if no cycle slip occurs in the carrier observation value of the satellite i frequency point k between the observation time m and the observation time n, thenThe method can obtain:

from the observation equation (8), if no cycle slip occurs between the observation time m and the observation time n, the pseudo-range observation value of the observation time n can be obtained by the pseudo-range observation value of the observation time m, the carrier variation and the ionosphere variation between the observation time m and the observation time n. The ionospheric change quantity between the observation time m and the observation time n can be calculated by ionospheric parameters and a Klobuchar model. Therefore, if MSM4 (or MSM 6) including the pseudo-range observation value, the carrier observation value, and the carrier-to-noise ratio is transmitted (broadcast) at the observation time m and MSM2 having only the carrier observation value is transmitted at the observation time n, the pseudo-range observation value at the observation time n can be calculated by the observation equation (8); when a cycle slip occurs, a group of MSM4 (or MSM 6) containing pseudo-range observation values and carrier observation values is sent at the moment; when a new observation value is added in the observation value of the base station, a group of MSM4 (or MSM 6) containing the pseudo-range observation value and the carrier observation value is sent at the moment; when the base station is switched, a group of MSM4 (or MSM 6) containing pseudo-range observation values and carrier observation values is sent at the moment; at other times of non-full 10 seconds, a smaller amount of MSM2 may be sent.

Table 3 shows four transmission scheme observation value encoding section lengths, and in the case where the statistical base station transmits 150 observation values (the types and lengths of the observation values are different according to the MSM to be transmitted), in a 10-second time interval, MSM4 is transmitted every second, or MSM6 is transmitted every second, and MSM4 (or MSM 6) is transmitted every 10 seconds, and MSM2 is transmitted every 10 seconds, each scheme encoding the required encoding length of the observation value section.

Transmission method	Encoding the length (bit) of 150 observations	New transmission mechanism saving scale
			10 MSM4 group	150*48*10＝72000
Group 1 MSM4+9 MSM2	150*48*1+150*27*9＝43650	39.4％
			Group 10 MSM6	150*65*10＝97500
Group 1 MSM6+9 MSM2	150*65*1+150*27*9＝46200	52.6％

TABLE 3 Table 3

As can be seen from Table 3, the use of MSM4 plus MSM2 mixed transmission of base station data can save about 39% in the coded observation value part compared with the use of MSM4 alone for transmitting base station data; the MSM6 and MSM2 are adopted for mixed transmission of the base station data, so that the base station data can be saved by about 52% in the part of the coded observation value compared with the base station data which is simply transmitted by adopting MSM 6; thus, the two MSM message sending base station observations are mixed, and the communication traffic can be greatly saved.

The embodiment of the disclosure adopts a mode of mixed transmission of two MSM messages with different lengths, and reduces the overall RTCM data flow compared with a mode of simply adopting one MSM message transmission; a method for alternately transmitting the observation values of the base stations through two RTCM MSMs with different lengths; and calculating and obtaining the pseudo-range observation value of the other epoch by using the carrier variation between the two epochs and the pseudo-range observation value of one epoch.

In an illustrative example, processing of an MSM message by embodiments of the present disclosure may include:

when a user connects with a server through an account for the first time, the server sends an MSM4 (or MSM 6) message containing a pseudo-range observation value, a carrier observation value and a carrier-to-noise ratio to the user;

at the full 10 second time, the server sends a set of MSM4 (or MSM 6) to the user;

when a base station handover occurs, the server sends a set of MSM4 (or MSM 6) to the user;

when the base station adds a new observation, the server sends a set of MSM4 (or MSM 6) to the user;

when the cycle slip occurs to the base station carrier observation value, the server sends a group of MSM4 (or MSM 6) to the user;

at other moments, the server sends MSM2 only containing carrier observations, the user can calculate pseudo-range observations at the current moment through carrier variation and ionosphere variation, and the carrier-to-noise ratio can directly adopt the carrier-to-noise ratio in MSM4 (or MSM 6).

Those of ordinary skill in the art will appreciate that all or some of the steps, systems, functional modules/units in the apparatus, and methods disclosed above may be implemented as software, firmware, hardware, and suitable combinations thereof. In a hardware implementation, the division between the functional modules/units mentioned in the above description does not necessarily correspond to the division of physical components; for example, one physical component may have multiple functions, or one function or step may be performed cooperatively by several physical components. Some or all of the components may be implemented as software executed by a processor, such as a digital signal processor or microprocessor, or as hardware, or as an integrated circuit, such as an application specific integrated circuit. Such software may be distributed on computer readable media, which may include computer storage media (or non-transitory media) and communication media (or transitory media). The term computer storage media includes both volatile and nonvolatile, removable and non-removable media implemented in any method or technology for storage of information such as computer readable instructions, data structures, program modules or other data, as known to those skilled in the art. Computer storage media includes, but is not limited to, RAM, ROM, EEPROM, flash memory or other memory technology, CD-ROM, digital Versatile Disks (DVD) or other optical disk storage, magnetic cassettes, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other medium which can be used to store the desired information and which can be accessed by a computer. Furthermore, as is well known to those of ordinary skill in the art, communication media typically embodies computer readable instructions, data structures, program modules or other data in a modulated data signal such as a carrier wave or other transport mechanism and includes any information delivery media.

Claims (10)

1. A method of encoding processing, comprising:

broadcasting a first multi-signal message including a pseudo-range observation, a carrier observation and a carrier-to-noise ratio to a receiver at a first time;

broadcasting a second multi-signal message including the carrier observations to the receiver at a second time instant;

wherein the first multi-signal message and the second multi-signal message are usable to determine a pseudorange observation and a carrier-to-noise ratio at a second time instant; the second multi-signal message has a length less than the first multi-signal message.

2. The method of claim 1, wherein the first time instance comprises:

a time of a preset period duration other than the preset time;

wherein, the preset time includes: the real-time differential positioning RTK account number is connected with a server for the first time, the base station switching occurs, the new observation value of the base station is added, and the carrier observation value of the base station is cycle-hopped.

3. The method of claim 2, wherein the first time instance further comprises one or any combination of:

the moment when the RTK account is connected with the server for the first time;

the moment when the base station handover occurs;

the moment when the base station newly adds a new observation value;

the time when the carrier observation of the base station takes a cycle slip.

4. A method according to claim 2 or 3, wherein the second time instant comprises: and the first time intervals are preset for the time of unit duration.

5. A method according to any one of claims 1 to 3, wherein the first multi-signal message comprises: multi-signal message MSM4 or MSM6.

6. A method according to any one of claims 1 to 3, wherein the second multi-signal message comprises MSM2.

7. A method of encoding processing, comprising:

receiving a first multi-signal message broadcast at a first moment and a second multi-signal message broadcast at a second moment;

according to the first multi-signal message and the second multi-signal message, a pseudo-range observation value and a carrier-to-noise ratio at a second moment are determined;

wherein the first multi-signal message comprises a message of a pseudo-range observation value, a carrier observation value and a carrier-to-noise ratio; the second multi-signal message comprises a message of a carrier observation; the second multi-signal message has a length less than the first multi-signal message.

8. The method of claim 7, wherein said determining pseudorange observations at a second time instant comprises:

for each second moment, determining the carrier variation and ionospheric variation between epochs corresponding to the second moment according to the carrier observed values of the first moment and the second moment before, wherein the first moment before is the first moment closest to the second moment before the second moment;

calculating a pseudo-range observation value at the second moment according to the pseudo-range observation value at the first moment, the carrier variation and the ionosphere variation among the determined epochs;

wherein said carrier observations and said pseudorange observations at said preceding first time instant are contained in said first multi-signal message at that first time instant.

9. A computer storage medium, comprising: a memory and a processor, the memory storing a computer program; wherein,

the processor is configured to execute the computer program in the memory;

the computer program, when executed by the processor, implements a method of encoding a process as claimed in any one of claims 1 to 6.

10. An apparatus of encoding processing, comprising: a receiving unit and a determining unit; wherein,

the receiving unit is configured to: receiving a first multi-signal message broadcast at a first moment and a second multi-signal message broadcast at a second moment;

the determination unit is configured to: according to the first multi-signal message and the second multi-signal message, a pseudo-range observation value and a carrier-to-noise ratio at a second moment are determined;

wherein the first multi-signal message comprises a message of a pseudo-range observation value, a carrier observation value and a carrier-to-noise ratio; the second multi-signal message comprises a message of a carrier observation; the second multi-signal message has a length less than the first multi-signal message.