CN101568120A - GPRS blind area compensation method - Google Patents

Abstract

The invention relates to a GPRS blind area compensation method which is realized through the following steps: points are not recorded if GPS position does not change or changes little in buffering, so that more sampling points can be recorded in a limited space; and the algorithm of sieving GPS data is carried out as follows: normally a sampling point is recorded every ten seconds; the second point is not recorded if the distance between two sampling points is less than 100 meters; and the second point is recorded if the time interval is greater than 30 seconds although the distance between two sampling points is less than 100 meters. The invention has the advantages that a large amount of buffer spaces can be greatly saved, especially in the stopping of a vehicle or slow speed of the vehicle; the playback of blind area trajectory is smoother; the GPRS blind area can be effectively monitored; and vehicle mileage statistical error is greatly reduced.

Description

The method of GPRS blind area compensation

Technical field

The present invention relates to a kind of method of GPRS blind area compensation.

Background technology

China Mobile's operator has been set up huge communication mobile network base station throughout the country at present, and most local, GPRS basically can both be working properly.But this technical standard is the wireless communication networks when being based upon relative " static state ", for quick car-mounted terminal, because relative dynamic and mobile GPRS communications become very unstable, often cause communication disruption, especially vehicle ' is in remote mountain village, the communication disruption probability increases greatly, GPRS communicate by letter undesired zone we be referred to as the GPRS blind area.

Traditional monitoring positioning equipment generally is left intact for the GPRS blind area, that is to say that vehicle ' can't monitor at the driving trace of GPRS blind area, bring following problem will for like this GPS locating and monitoring business:

Can't playback at GPRS blind area driving trace;

Vehicle can't be monitored at the blind area transport condition;

Vehicle mileage statistical error increases greatly.

GPRS metadata cache technology is undertaken by following form in the prior art:

GPRS network is being subjected to the influence of extraneous factor, the phenomenon that can occur breaking, and the GPS locator data can't be sent during broken string, so must preserve gps data.If the hardware system resource abundance of equipment has jumbo memory, preserving data so is not a very difficult thing.But in the design of big multisystem, memory span is very limited, for example in existing equipment, the capacity that is used for the GPRS metadata cache has only 24KB, if a gps data point takies the 12B space, calculate by storing point 10 seconds, also can only preserve the data of 24*1024/12*10=20480 second=5.7 hour, in general do not satisfy actual needs.So optimized Algorithm how is problems that the technical staff will solve in order to the data of storage longer time.

Summary of the invention

The technical issues that need to address of the present invention have provided a kind of method of GPRS blind area compensation, are intended to solve the above problems.

In order to solve the problems of the technologies described above, the present invention realizes by following steps:

In buffer memory, if the GPS position does not change or changes very for a short time, do not write down these points, make limited space can write down more sampled point; The algorithm of screening gps data is:

Normal record is to write down a sampled point per 10 seconds;

If the distance between two sampled points does not write down the 2nd point less than 100 meters;

Though if the distance between two sampled points less than 100 meters, the time interval surpassed for 30 seconds, write down the 2nd point.

Compared with prior art, the invention has the beneficial effects as follows: can save spatial cache in a large number, especially when stationary vehicle or the speed of a motor vehicle are very slow; Make that the blind area trace playback is more level and smooth; Can effectively monitor the GPRS blind area; Vehicle mileage statistical error significantly reduces.

Embodiment

Below in conjunction with embodiment the present invention is described in further detail:

The form of buffer memory gps data is in the prior art:

Normal gps data contains 12B, and longitude, latitude respectively account for 4B, and speed, angle respectively account for 2B.

And the present invention adopts a GPS point as datum mark, writes down the method for the relative value of follow-up GPS point and datum mark, from after make that subsequent point only needs to store with 6B, have only original half.By adopting such storage mode, the 24KB spatial cache just can write down the data more than 10 hours.

GPS date and time data in last table are in other place storage.

The present invention realizes by following steps:

In buffer memory, if the GPS position does not change or changes very for a short time, do not write down these points, make limited space can write down more sampled point; The algorithm of screening gps data is:

Normal record is to write down a sampled point per 10 seconds;

If the distance between two sampled points does not write down the 2nd point less than 100 meters;

When vehicle ' arrived the GPRS blind area, car-mounted terminal had lost with GPS locating and monitoring operation system and has communicated by letter; System start-up GPRS blind area compensation mechanism, to collect traveling-position, direction and state information is saved in the buffer memory, in case communication recovery, onboard system is reissued the data in the buffer memory in the GPS locating and monitoring operation system, is used to row and flatness thereby assurance vehicle monitoring track connects.

Claims (1)

1. the method for a GPRS blind area compensation, realize by following steps:

In buffer memory, if the GPS position does not change or changes very for a short time, do not write down these points, make limited space can write down more sampled point; The algorithm of screening gps data is:

Normal record is to write down a sampled point per 10 seconds;

If the distance between two sampled points does not write down the 2nd point less than 100 meters;

Though if the distance between two sampled points less than 100 meters, the time interval surpassed for 30 seconds, write down the 2nd point.