**2.1 The inertial navigation**

The inertial navigation can measure the acceleration of prober and use the integral computations to estimate its transient flight speed and spatial position. During that process, no energy will be radiated from the inertial navigation device, and no exterior auxiliary information is needed. The inertial navigation adopts the devices of the accelerometer [21] and the gyroscope [22] to realize the state estimation. The accelerometer [23] is a device, which can measure the acceleration of the carrier. In general, it can be classified into the linear accelerometer and the angular accelerometer. In the practical application, the linear accelerometer is commonly used because of its high precision and excellent stability. Many accelerometers have been designed, such as the piezoelectric accelerometer, the piezoresistive accelerometer, or the capacitive accelerometer. **Table 1** shows a kind of classification of the linear accelerometer. The gyroscope is a device, which can measure the rotation rate. **Table 2** illustrates some gyroscope products. They are the mechanical rotor gyroscope, the electrostatic suspended gyroscope, the vibratory gyroscope [24], the laser gyroscope, and the fiber optic gyroscope [25].

The inertial navigation is the most mature and popular method in the navigation research field. Comparing with other navigation techniques, the inertial navigation at least has three advantages. First, it is independent to the environment.

**Figure 2.** *The popular autonomous navigation methods.*


#### **Table 1.**

*A kind of classification of the linear accelerometer.*


#### **Table 2.**

*A kind of classification of the gyroscope.*

It can realize the all-weather and the all-time working modes in any places. Second, it can provide the position, the speed, the course, and the attitude information of carrier accurately. And its data updating ratio is also high. Third, it has the good performances in the anti-interference and the low system noise. Clearly, the inertial navigation also has some shortcomings. For example, according to its navigation principle, its navigation error will be accumulated. Another problem is that the inertial navigation also cannot give out the time information. Recently, the Micro Electro Mechanical Systems (MEMS) technology [26] has met its great development opportunity. The MEMS technology can realize the optoelectronics product

**17**

*Autonomous Navigation for Mars Exploration DOI: http://dx.doi.org/10.5772/intechopen.92093*

**2.2 The celestial navigation**

methods of the celestial navigation.

the celestial navigation.

**2.3 The visual navigation**

manufacturing in a microscopic degree. It has been used to improve the product performance of the vibratory gyroscope, the laser gyroscope, and the fiber optic gyroscope in recent years. In future, the miniaturization, the high precision, and the high reliability processes will be developed in the inertial navigation system.

The celestial navigation uses the space object, such as the sun, the moon, or the other stellar [27] as a reference to guide the flight direction and the flight attitude of the prober. Clearly, the star sensor [28] should be employed in this method. As a kind of optical measurement device, besides the visible light camera, the infrared camera, the ultraviolet camera, the X-ray camera, the γ-ray camera, and so on can all be used. Many methods have been designed for the celestial navigation, that is, the angle measurement-based navigation [29], the distance measurement-based navigation [30], and the speed measurement-based navigation [31]. The angle measurement-based navigation uses the angles among the sun, the other planets, the planet satellite, the asteroid, or the comet to carry out the autonomous navigation. The distance measurement-based navigation mainly employs the detection result of the arrival time difference between the X-ray pulsar and the standard pulse of the solar system center to estimate the navigation information and the time offset. In addition, the speed measurement-based navigation utilizes the optical Doppler effect [32] to implement the navigation. **Table 3** presents the popular

The celestial navigation at least has three advantages. First, as a kind of optic measurement device, most of the celestial navigation systems are immune to the traditional electromagnetic interference problem [33]. Also, their working reliabilities are comparable high. Second, its navigation accuracy is good. Because the spatial distance between the celestial body and the prober is really large, the navigation precision can be very high if the star sensor performance and the corresponding data processing algorithm are proper. Third, most of the celestial navigation devices can work all-time long as long as the corresponding celestial bodies are visible. The celestial navigation also has some shortcomings. The biggest problem is that some devices cannot be used in the complex light environment. For example, the strong environment light or the cosmic rays will affect the application effect of these optic devices seriously. Another drawback is that some celestial navigation devices cannot give out the sequential output because of the target star occlusion problem. Comparing with the inertial navigation technique, the celestial navigation is still immature, and most techniques do not get the test of the practical flight mission. In future, the new modeling technique of the orbit function [34], the new measurement theory of the star, and the new estimation method of the navigation information can all be researched extensively to improve the application effect of

The visual navigation uses the imaging sensors to accomplish the navigation task. In this chapter, the visual navigation means to use the visual sensors and the corresponding algorithms to the autonomous robot vehicle or the unmanned aerial vehicle for the navigation purpose. In many cases, the visual navigation is used as the direction guidance or the obstacle avoidance device. Without loss of generality, the imaging sensors in the visual navigation include the visible light camera, the infrared or the near-infrared camera, the multispectral camera, the laser imaging camera [35], and even the ghost imaging (i.e., the quantum imaging) camera [36].

manufacturing in a microscopic degree. It has been used to improve the product performance of the vibratory gyroscope, the laser gyroscope, and the fiber optic gyroscope in recent years. In future, the miniaturization, the high precision, and the high reliability processes will be developed in the inertial navigation system.
