BS ISO 18197:2015 pdf download – Space systems — Space based services requirements for centimetre class positioning.
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).
b) Geometrical allocation — Regular allocation The ground reference points shall be selected so that they are located regularly or in grid type. — Irregular allocation The density of ground reference points varies according to the necessity of the respective regions. c) Objectives of ground reference points — Determination of satellite clock error — Determination of satellite orbit error — Determination of ionospheric delay — Determination of tropospheric delay — Determination of signal biases — Determination of integer biases d) Case of distinction between primary and secondary reference points Augmentation data shall be defined for the primary reference points. But, in some cases, the augmentation data can be made by use of not only primary reference point data, but secondary reference point data. — Reason for the necessity of secondary reference points e) Case of improper allocation The method for application of augmentation data shall be clarified in the following cases. — Case of positioning over ocean The case should be remarked where no ground reference points are found in the neighbourhood of the user terminal. — Case of height difference influence It should be remarked that augmentation data like tropospheric delay depends on the height above sea level. f) Location of reference points The highly accurate location of all the reference points for augmentation data generation shall be clarified beforehand. The ground reference networks in Japan, Germany, France, Europe, United States, China, Latin America, and the whole world can be referred in Reference [9] to Reference [16], respectively.