Osaka, Japan - Panasonic Corporation today announced it has developed high precision, wide field of view millimeter-wave technologies, that are able to separately detect cars, pedestrians and bicycles in less than 0.1 seconds, on the condition that they are separated by 20cm .These technologies will be applied to 79GHz radar [1], and utilized in detection sensors to avoid accidents occurring at intersections, accelerating the adoption of advanced safety support systems.
Millimeter-wave radar is capable of detecting pedestrians and vehicles in night time and bad weather conditions. Panasonic's new technologies have improved the detection accuracy of the radar, so that it can separately detect cars, bicycles and pedestrians that are separated by a distance of 20cm at a speed of less than 0.1 seconds. These technologies also allow the operation of multiple millimeter radars, enables for a wider field-of-view (FOV) system. These features offer greater flexibility for installation at intersections.
- Multi-dimensional electrical scanning technology that is capable of rapid location sensing and maintains a high degree of sensitivity for pedestrian detection by the suppression of noise due to reflections from metallic vehicles.
- The orthogonal complementary coded modulation technology has superior separation capabilities without interference, realizing both a high resolution and wide FOV simultaneously, even for a multiple radar configuration operating at the same frequency,.
A radar sensor in the millimeter-wave band can detect moving objects. However, in order to achieve higher location accuracy while maintaining the FOV, a higher dynamic range was necessary. In addition, it had not been possible to a cover a wide FOV that would enable the monitoring of a complete intersection.
Panasonic has developed the new radar technology as the part of "Research and Development Project for Expansion of Radio Spectrum Resources" supported by the Ministry of Internal Affairs and Communications of Japan. The company will demonstrate the technology at the ITS World Congress 2013 (October 15 to 18 at Tokyo Big Sight in Japan), using test equipment with an experimental radio license.
On the new radar technology, Panasonic holds 27 patents in Japan and 14 patents overseas including pending applications.
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Coded pulse modulation technology using complementary codes [3] has been applied to 79GHz radar which can utilize the wide frequency band over 1 GHz. Therefore, a physical property of millimeter-waves can be exploited to gain larger Doppler frequency shifts than in the case of using the microwave band. Specifically, by the use of wide band in the 79GHz band, it has achieved a 20cm resolution that is 2.5 times better performance than the previous millimeter-wave radar models, and at the same time it has realized 1km/h resolution in velocity calculated by the Doppler frequency sifts. Moreover, the electrical scanning technology which independently measures range, angle, and velocity with high resolution that has been developed, in addition to reflected power sensing technology with a high dynamic range that suppresses a level of reflected noise from car body to less than -40dB. This high resolution scanning in 4-dimensional domains can be adopted for millimeter wave radar, so that it can provide more stable separation detection for pedestrians and bicycles nearby cars and other vehicles.
Code modulation radar method using complementary codes, which is a kind of pair codes, has an essential characteristic that completely cancels range side lobes [4] which are the factors of increasing the noise level due to strong reflected waves. On the other hand, when multiple radars are simultaneously operated, the strong reflected waves from car bodies or others cause mutual interference between radars at the direction of which each antenna beam is closed in angular domain. At this time, through coded multiplexed beamforming technology such as orthogonal coding [5] superposed on the sequence of the complementary codes, succeeding in suppressing the mutual interference between pulse radars to less than -40dB. As a result, multiple millimeter wave radars are capable of simultaneous operation with sectoring in angular domain that has achieved both an FOV of more than 120 degrees and a data cycle less than 0.1 seconds.
Notes:
- [1] 79GHz radar
- In Japan, based on the definition of the specified low-power radio stations designated in Article 6, Paragraph 4, Item 2 of the Regulations for Enforcement of the Radio Law, ARIB STD-T111: "79GHz BAND HIGH-RESOLUTION RADAR" had been published.
- [2] Typical intersection
- This is a model case of the intersection which has the shape of that 20m width roads cross at right angles, for example 6-lane roads are crossed.
- [3] Complementary codes
- These are a kind of digital bit sequence commonly employed in wireless LAN communication, and this shows good auto-correlation characteristics. These codes have a characteristic that the number of same bit pairs is the same as the number of different bit pairs in comparison between the two complementary code sequences.
- [4] Range side lobe
- This is a characteristic of the side lobe which is provided as autocorrelation characteristic including both main and side lobes in the range domain. In case of frequency modulation, such as chirp pulsed method or others, its characteristics commonly designed by using a window function in time domain, but these methods cannot completely cancel the range side lobe.
- [5] Orthogonal coding
- This is a kind of coding scheme commonly employed in 3rd generation cellular phone system. It can be realized by using the code sequence with superior characteristics of mutual correlation which affects the interference suppression performance between coded radio signals.
Application image using millimeter-wave radar
Verification of newly developed millimeter-wave radar technology
About Panasonic
Panasonic Corporation is a worldwide leader in the development and engineering of electronic technologies and solutions for customers in residential, non-residential, mobility and personal applications. Since its founding in 1918, the company has expanded globally and now operates over 500 consolidated companies worldwide, recording consolidated net sales of 7.30 trillion yen for the year ended March 31, 2013. Committed to pursuing new value through innovation across divisional lines, the company strives to create a better life and a better world for its customers. For more information about Panasonic, please visit the company's website at http://panasonic.net/.
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