BS ISO 18197 pdf free download
BS ISO 18197-2015 pdf free download.Space systems一Space based services requirements for centimetre class positioning.
This typical system is configured mainly by the fllowing components:
a) GNSS;
b) augmentation satellites;
c) augmentation satellites control stations;
d) ground reference points;
e) positioning augmentation centres;
f) user terminals.
Each component is explained below.
5.2 Classification of augmentation satellites
An augmentation satellite broadcasts augmentation data, uplinked from the positioning augmentation centres for users over wide area. Augmentation satellites are classified into the following:
a) geostationary earth orbit satellite (GEO);
b) inclined geosynchronous satellite orbit (IGSO);
c) medium or low earth orbit satellite (MEO/LEO).
The overview and features of various augmentation satellites is shown in Table 1.
5.3 Positioning augmentation centres
The augmentation centres make augmentation data using the observation data at the ground reference points. The system sustainability is taken into account when making augmentation data. Some remarks are described below about the functions and conditions, message structure, and user operational support service.
5.3.1 Functions and conditions of the positioning augmentation centres
The functions and conditions of the positioning augmentation centres arc as follows.
a) Augmentation data generation
The augmentation centres make augmentation data using the observation data at the ground reference points.
b) Monitoring of operation and measures
The augmentation centres monitor the system operational conditions by analysing data received from augmentation satellites and reference points so as to detect ionosphere disturbance or others. Based on the result, this International Standard should assess the influence on ranging signal or communication link and takes proper measures to recover the situation.
c) Detection of satellite signal anomaly
The augmentation centres calculate the predicted error using observation data at the ground reference points. The signal analysis is provided to specify the malfunction satellite.
5.3.2 Message structure
Figure 2 shows the example of message structure of augmentation data broadcast from the augmentation satellite.
5.3.3 User operational support service
The system should provide useful information for user terminals as follows.
a) Estimation of positioning error.
b) Condition of ionosphere, such as disturbance of ionosphere.
c) Condition of troposphere, such as anomaly of water vapour as caused by local rainfall, resulting in the positioning error due to tropospheric delay mismatch.
5.4 Operation
Some remarks on the operation of positioning augmentation system are as follows.
5.4.1 Simultaneous operation
The centimetre class augmentation data can also be used as the meter class augmentation data at the same time. Therefore, this system enhances the operational variation.
5.4.2 VarIous fields of application
A variety of industrial fields required for centimetre class positioning is illustrated in Annex G.
6 Requirements for positioning augmentation system
6.1 Requirements for augmentation satellites
Requirements for augmentation satellites of various orbits are described below.
a) Orbit constellation
b) Numbers of satellites
c) Antenna coverage
This means a part on the earth where the transmission signal from the augmentation satellite can be reached.
d) Transmission signal characteristics
Over the targeted area, under the condition of the minimum elevation angle of the augmentation satellite, this International Standard establishes the requirements for orbit constellation (satellite number/orbit plane/phase difference between orbit planes).BS ISO 18197 pdf download.
