[en] Hall sensors of magnetic field resistant to hard ionizing irradiation are developed in order to be operated under radiation conditions of the open space and in charged particle accelerators. Radiation resistance of the sensors is determined first of all by the properties of semiconductor materials of sensitive elements. We use for them microcrystals and thin layers of III-V semiconductors. Applying complex doping by rare-earth elements and isovalent impurities in certain proportion, we have obtained magnetic field sensors resistant to irradiation by fast neutrons and gamma quanta. Tests of their radiation resistance were carried out at IBR-2 in Joint Institute for Nuclear Research (Dubna). When exposing to neutrons with E=0.1 - 13 MeV and intensity of 10¹⁰ n.cm^-2.s^-1 , main parameter of the sensors - their sensitivity to magnetic field - changes no more than by 0.1% up to the fluences of 10¹⁴ n.cm^-2 . The sensitivity change under gamma irradiation at ⁶⁰Co system does not exceed the measurement error of 0.03%. Further improvement of radiation resistance of sensor materials is expected by means of combination of metallurgical methods of complex doping with the technology of radiation modification, which includes an interchanging of the nuclear doping and fast neutron irradiation with thermoprocessing cycles. It will allow improving radiation resistance of semiconductor materials and sensors by one order under high integral irradiation doses. A new approach is developed as well which allows providing high-stable measurement of magnetic field with high accuracy under destabilizing environmental conditions, in their number hard radiation conditions. Special magnetometric system is to be developed which main element is the functionally integrated magnetometric transducer consisting of semiconductor Hall microgenerator and copper microcoil, which forms actuating field around the microgenerator. Application of such magnetometric system with radiation resistant magnetic field sensors will provide magnetic field measurements with an accuracy of 0.1% under hard radiation conditions. (author)