The grades of four aerospace and defense stocks are better this week, according to the Portfolio Grader database. Every one of these stocks has an “A” (“strong buy”) or “B” overall (“buy”) rating.

DigitalGlobe, Inc. (DGI) ups its rating to a B (“buy”) this week after earning a C (“hold”) in the week before. DigitalGlobe provides commercial earth imagery products and information services worldwide. In Portfolio Grader’s specific subcategory of Sales Growth, DGI also gets an A. For more information, get Portfolio Grader’s complete analysis of DGI stock.

This week, TASER International, Inc. (TASR) is showing good progress as the company’s rating jumps from a B (“buy”) last week to an A (“strong buy”). Taser International develops, assembles, and markets less-lethal weapons for use in the law enforcement, private security, and personal defense markets. For more information, get Portfolio Grader’s complete analysis of TASR stock.

CAE Inc. (CAE) is seeing ratings go up from a C last week to a B this week. CAE is engaged in the design, development and production of simulation tools and equipment for commercial airlines, business aircraft operators, aircraft manufacturers and military organizations. Shares of the stock have been changing hands at an unusually rapid pace, twice the rate of the week prior. For more information, get Portfolio Grader’s complete analysis of CAE stock.

AeroVironment, Inc. (AVAV) boosts its rating from a C to a B this week. AeroVironment designs, tests, and manufactures diversified technological products, including small, unmanned, remote-control military aircraft and rapid battery-charging stations. For more information, get Portfolio Grader’s complete analysis of AVAV stock.

Louis Navellier’s proprietary Portfolio Grader stock ranking system assesses roughly 5,000 companies every week based on a number of fundamental and quantitative measures. Stocks are given a letter grade based on their results — with A being “strong buy,” and F being “strong sell.” Explore the tool here.