The present invention relates to the field of inertial angular sensors such as a vibrating gyro or a gyro, particularly microelectromechanical or MEMS sensors (Micro Electro-Mechanical System). CONTEXT Vibrating inertial angular sensors MEMS are generally classified into two families according to the nature of the resonator. A resonator is a physical structure having a mechanical resonance at a frequency called resonance frequency. In the first family, the resonator is a deformable body, generally of revolution (ring, cylinder, hemisphere, disk). In the second family, the resonator consists of one or more non-deformable masses connected to a support by elastic elements. The present invention particularly relates to a resonator belonging to the second group, and thus the form of a mass / spring system. An inertial angular sensor generally comprises actuators arranged to make the resonator vibrate at a given resonance frequency, and detectors resonator deformations. The actuators and strain detectors are generally mounted between the resonator and the substrate. An angular sensor inertial MEMS type can measure an angular velocity (rate gyro mode) or an angular position (gyro mode). To obtain a high-performance inertial sensor, it is important that the characteristics of the resonator be isotropic, that is to say they are the same regardless of the orientation of the vibration of the resonator. In other words, there is no measurement error depending on the angular position of the vibration. If we take the example of a gyroscope in which the resonator has two eigenmodes whose directions of vibration are 90 degrees, when a rotation is applied to the resonator of the support, the relative movement of the vibration relative to the resonator is exactly the opposite of this rotation. To improve the accuracy of such a gyroscope, the stiffness and damping characteristics of the resonator be isotropic, ie uniform in all directions. For conventional achievements of MEMS sensors, processing the details of the resonators are not sufficient to achieve the required isotropy of stiffness. For example, for a resonator having a frequency of about 10kHz, the anisotropy rate achieved can reach ± ​​1% or ± 100Hz, while the functional requirement for the realization of a vibrating gyroscope requires accurate anisotropy much less than ± Wz. An objective is to provide a correction solution of the frequency anisotropy of a suspended resonator mass to obtain an efficient vibratory gyroscope. A suspended mass resonator is a known type of resonator in MEMS. It comprises at least a mass / spring system having two orthogonal modes whose own vibration frequencies are close, for measuring the rotations axis perpendicular to the mass plane of vibration. The suspended mass has three degrees of freedom including two translations and one rotation. French patent application FR 2983574 proposes a solution for balancing a vibrating inertial angular sensor such as a vibrating gyroscope making more stable damping anisotropy of the resonator. The resonator described comprises two concentric annular masses of square shapes. Balancing based on the correction of dynamic unbalance resulting from the movement of the overall center of gravity of the masses in the vibration frequency. The correction is obtained thanks to a particular mechanical structure of the inertial angular sensor and an individual adjustment of electrostatic stiffness springs. The used electrostatic springs have action directions perpendicular to the sides of the masses which does not allow compensation of the frequency anisotropy in all directions. RESUME The present invention provides a solution to make the isotropic stiffness resonator in all directions, and by a substantially electrically adjustable and non-mechanical, making this advantageously applicable solution to the inertial angular sensors may have mechanical structures and varying forms. The present invention relates to a resonator configured to be integrated with an inertial angular sensor, said resonator comprising at least a mass suspended by mechanical springs and having a number N of pairs Pj (2 2, the · ¾ .¾. The sensor 2, said masses with identical natural frequencies. A vibration mode used corresponds to displacements in opposition of the two masses. This vibration may be at any orientation. for each of the 3.1 and 3.2 masses, a topology electrostatic springs 50 as described by the pattern of FIG.6 10.2 was used. In the exemplary embodiment of FIG.7, there are four pairs of electrostatic springs 50 for each suspended mass 3.1 and 3.2. According to a preferred embodiment, 3.1 and 3.2 masses are substantially square annular shapes. However, this is not an obligation for domestic mass 3.1 that can be square and full. In FIG.8, there is shown another embodiment of an inertial angular sensor 2 wherein the topology electrostatic springs 50 used is described by the pattern 10.1 of FIG.5. Furthermore, it is possible, according to another possible embodiment, to employ a topology springs defined by a different pattern for each mass 3.1 and 3.2, for example the pattern 10.1 for the mass 3.1 and the pattern 10.2 for the mass 3.2 or vice versa. In the embodiment of the sensor 2 of FIG.7, the resonator 1 comprises two masses systems / springs, the first system comprising the mass 3.1 and 5 associated mechanical springs, and the second system comprising 3.2 mass and mechanical springs 5 associates. Electrostatic springs 50 can advantageously have a structure in the form of electrodes combs whose teeth are inserted between each other. The combs 50 electrostatic springs have a mode of operation with variable air gap. The present invention also provides a method of correcting the stiffness of the resonator 1 integrated in an angular inertial sensor as described above, and comprising the steps of: - measurement of the resonator vibration frequency for different directions of vibration, by means of deformation sensors 12 placed between the blocks of electrostatic springs 50, as shown in FIG.7 and FIG.8. determining, from these measurements, the magnitude of the anisotropy and orientation, ie the lack of stiffness kappa Ÿ the resonator, calculating voltages to be applied on certain springs to compensate for the sine and cosine components of the fault stiffness of the resonator, - if the vibration frequency of the resonator anisotropy is greater than a predetermined value, preferably of 1 Hz, the previous steps are repeated. The above procedure allows making isotropic stiffness by an electric adjustment and not a mechanical adjusting a resonator 1 to be integrated in an angular inertial sensor 2 as a mass system / springs. CLAIMS 1. inertial angular sensor (2) comprising a support (4), characterized in that it comprises a resonator (1), said resonator (1) comprising at least two masses (3) suspended by mechanical springs (5), a number N of pairs Ρ <(2≤ I